Soil Biota

Impact of Pesticides on Soil Biota

Soil biota can be affected directly or indirectly, through pesticide use and conventional farming technologies that promote the use of pesticides.

A study by LeBlanc et. al. in 2007 found that the rhizospheres (soil and microorganisms around the roots of a plant or tree) of Bacillus thuringiensis (Bt)-modified trees meant to alleviate insect damage had clear alterations when compared to the rhizospheres of non-Bt modified trees.
In 2013, a study by Anjum et. al. found that silver nanoparticles, a novel nanomaterial that the EPA recently agreed to regulate, has a profound effect on soil microorganisms, leading to a collapse in metabolic abilities and diversity in soils with low organic matter. Similar effects were found in soil with high organic matter, but to a lesser extent.
Earthworms are excellent indicators of soil health, and provide vitally important ecosystem services by aerating the soil, cycling nutrients, and increasing microbial activity:
Mycorrhizae fungi within soil are relied on by most plants for nutrients and moisture:

[See More Scientific Studies Below]

Economic Cost

The microbes in soil are essential to ecosystem functioning because they break down organic matter and enable chemical elements to be reused. They are also nitrogen fixers, which is necessary for plants and the ecosystem as a whole. Earthworms are an intrinsic part of soil biota, providing support for important ecosystem functioning. Their burrows, sometimes deep into the soil, create pores for moisture and oxygen to travel and their waste becomes part of soil structure. They also break down dead organic matter and incorporate new organic matter into soil systems.

When pesticides reduce species diversity within the soil, it impacts the ecosystem as a whole. The European Academies' Science Advisory Council (EASAC) estimates soil organisms and their role in agricultural productivity to be worth $25 billion a year, globally.

Litigation & Lawsuits

In early 2015, EPA finally agreed to regulate novel nanomaterial pesticides as a result of a lawsuit filed by Center for Food Safety (CFS) and joined by Beyond Pesticides in December. In 2008, a coalition of more than 13 organizations filed a legal petition requesting, among other things, that EPA recognize the risks associated with a growing class of nano-silver consumer products and regulate them as new pesticides. After EPA had failed to respond to the petition for six years, in December 2014 some of the petitioner groups sued the agency to force it to respond. That lawsuit succeeded in March 2015, with EPA issuing a response.

Quick Links

Groups Petition EPA to Stop Sale of Nanosilver Products (May 2008)
Lawsuit Challenges EPA’s Failure to Regulate Nanomaterial Pesticides (Dec. 2014)
Legal Petition Text
EPA’s Response

What Can You Do?

Learn about the Hazards and Alternatives to using lawn pesticides.
Go Organic – Visit our Eating with a Conscience page to learn why eating organic foods is the right choice.
Visit our Tools for Change page to learn how to organize your community against pesticide use.
Sign up for Beyond Pesticides’ Action Alerts to stay up-to-date on the latest petitions and news.
Scientific Studies:
- Current-use pesticides in vegetation, topsoil and water reveal contaminated landscapes of the Upper Rhine Valley, Germany
  Non-target areas in agricultural landscapes serve as invaluable refuges for organisms and safeguard biodiversity. This research aimed to examine the landscape-scale distribution of Current Use Pesticides (CUPs) in the Upper Rhine Valley in Germany, a region characterised by intensive agriculture in the valley and bordered by forested lower mountain regions. We sampled vegetation, topsoil, and surface water at 78 non-target, off-field sites during the pesticide application season in 2022. The sites were located in six 30 km long transects to cover both the valley and mountain regions. Samples were analysed for 93 CUPs. In total, 63 different CUPs (29 fungicides, 19 herbicides and 15 insecticides) were detected in all samples (n = 186). CUPs were recorded in 97% of all vegetation and 97% of all topsoil samples (76 of 78 samples each). In total, 140 unique mixtures with ≥2 components were recorded. A prediction map using additional site parameters suggests a widespread presence of CUPs extending multiple hundred meters beyond CUP application areas. Landscape-scale mixture contamination is not addressed in environmental risk assessment for the regulation of pesticides. The study design could serve as a benchmark for evaluating landscape-scale pesticide contamination after implementation of pesticide reduction efforts in agricultural policies and practice.
  [Mauser, K.M., Wolfram, J., Spaak, J.W. et al. Current-use pesticides in vegetation, topsoil and water reveal contaminated landscapes of the Upper Rhine Valley, Germany. Commun Earth Environ 6, 166 (2025). https://doi.org/10.1038/s43247-025-02118-2]
- Effects of Microplastics on Bioavailability, Persistence and Toxicity of Plant Pesticides: An Agricultural Perspective
  Microplastic–pesticide interactions influence pesticide performance, soil health, and environmental safety. This review aims to comprehensively present the effects of microplastic–pesticide interactions on pesticide bioavailability, persistence, and toxicity, along with their agricultural implications on pest control. It reviews more than 90 related articles from established scholarly databases. Most studies indicate that pesticide bioavailability decreases in the presence of microplastics due to adsorption, which is frequently influenced by the hydrophobicity (log Kow) of the pesticides and the surface area and type of microplastics. Higher log Kow results in higher adsorption and lower bioavailability. Aged microplastics have higher surface areas for adsorption, thus reducing pesticide bioavailability. This decreases the effectiveness of systematic and contact pesticides. Lower bioavailability leads to less adsorption of the former by plants to control pest infestation and less contact of the latter with pests in the soil to kill them directly. Higher pesticide adsorption also increases the persistence of pesticides, as indicated by their extended degradation half-lives. However, some studies demonstrate that biodegradable microplastics, especially the aged ones, have less effect on pesticide persistence because they release pesticides for degradation when they break down. Few studies on how microplastics alter pesticide toxicity on target organisms are available, but the available ones point to potentially higher toxicity on crops and beneficial soil organisms. Overall, the review highlights a significant negative effect of microplastics on pesticide bioavailability. This may prompt the application of more pesticides to achieve the desired level of crop protection, which bears cost and environmental consequences.
  [Tang, K. (2025) Effects of Microplastics on Bioavailability, Persistence and Toxicity of Plant Pesticides: An Agricultural Perspective, Agriculture. Available at: https://www.mdpi.com/2077-0472/15/4/356.]
- Increasing pesticide diversity impairs soil microbial functions
  Pesticide application is essential for stabilizing agricultural production. However, the effects of increasing pesticide diversity on soil microbial functions remain unclear, particularly under varying nitrogen (N) fertilizer management practices. In this study, we investigated the stochasticity of soil microbes and multitrophic networks through amplicon sequencing, assessed soil community functions related to carbon (C), N, phosphorus (P), and sulfur (S) cycling, and characterized the dominant bacterial life history strategies via metagenomics along a gradient of increasing pesticide diversity under two N addition levels. Our findings show that higher pesticide diversity enriches the abundance of bacterial specialists and opportunists capable of degrading or resisting pesticides, reducing the proportion of bacterial generalists in the absence of N addition. These shifts can complicate multitrophic microbial networks. Under increased pesticide diversity, selective pressure may drive bacteria to streamline their average genome size to conserve energy while enhancing C, N, P, and S metabolic capacities, thus accelerating soil nutrient loss. In comparison, N addition was found to reduce bacterial niche differentiation at higher pesticide diversity, mitigating the impacts of network complexity and functional traits associated with pesticide diversity, ultimately alleviating soil nutrient loss. Our results reveal the contrasting impacts of pesticide diversity on microbial functions under different N input scenarios and emphasize that strategic N fertilizer management can mitigate the ecological effects of pesticide use in agricultural systems.
  [Ni, Bang & Xiao, Lu & Lin, Da & Zhang, Tian-Lun & Zhang, Qi & Liu, Yanjie & Dong, Zhu & Qian, Haifeng & Rillig, Matthias. (2025). Increasing pesticide diversity impairs soil microbial functions. Proceedings of the National Academy of Sciences. 122. 10.1073/pnas.2419917122. ]
- Meta-analysis reveals globally sourced commercial mycorrhizal inoculants fall short
  Several researchers have highlighted the potential of microbial inoculants to advance sustainable agriculture (Elnahal et al., 2022; O'Callaghan et al., 2022). Among microbial inoculants, arbuscular mycorrhizal (AM) fungi have garnered attention for their ability to enhance soil health and plant fitness. AM fungi can increase plant growth through enhanced access to limiting soil resources, improve plant defense against herbivores and pathogens, increase tolerance to drought and salinity stress, and increase carbon sequestration (Reynolds et al., 2006; Bennett et al., 2009; Ji & Bever, 2016). With this promise, the commercial market for AM inoculants is rapidly growing, approaching 995 million USD globally (Mordor Intelligence, 2024). AM inoculants, often referred to as ‘endomycorrhizal’ inoculants on commercial product labels, are easily and widely available in many regions of the world.
  [Koziol, L., McKenna, T.P. and Bever, J.D. (2025), Meta-analysis reveals globally sourced commercial mycorrhizal inoculants fall short. New Phytol. https://doi.org/10.1111/nph.20278]
- Microbial biofertilizers and algae-based biostimulant affect fruit yield characteristics of organic processing tomato
  BACKGROUND
  Microbial biofertilizers and algae-based biostimulants have been recognized for supporting sustainable agriculture. Field experiments were conducted in 2022 and 2023 growing seasons in an organic farm located in Ferrara (Italy) with the aim of evaluating plant growth-promoting microorganisms (PGPMs) and algae-based biostimulants (Biost) in tomato (Solanum lycopersicum L.). The experimental treatments were: (i) two microbial biofertilizers (PGPM_1, PGPM_2) and no inoculated plants (No_PGPM); and (ii) two algae-based biostimulant rates (0.5% (Biost_0.5%), 1.0% (Biost_1.0%)) and no application (No_Biost). PGPMs were applied at transplanting, while biostimulants at 15 and 30 days after transplanting. Treatments were replicated three times according to a split-plot experimental design. Plant characteristics were evaluated at 30 days after transplanting in No_Biost treatments. During tomato cultivation, soil plant analysis development (SPAD), nitrogen difference vegetation index (NDVI), leaf area index (LAI) and photosynthetic photon flux density (PPFD) were monitored. Tomato yield was determined.
  
  RESULTS
  PGPM_2 showed the highest shoot biomass (132.9 g plant−1), plant height (44.7 cm), leaf number (34.0 plant−1) and root biomass (9.22 g plant−1). Intermediate values were observed in PGPM_1, while all parameters were lower in No_PGPM. Both PGPMs achieved higher values of SPAD, NDVI, PPFD and LAI than No_PGPM. Biost_1.0% increased all measured growth parameters followed by Biost_0.5% and No_Biost, respectively. Tomato yield was the highest for PGPM_2–Biost_1.0% (67.2 t ha−1). PGPMs affected fruit size and sugar content, while biostimulants were associated with color and lycopene.
  
  CONCLUSION
  The application of microbial biofertilizers and algae-based biostimulants could be part of environment-friendly practice in organic farming. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
  [Quintarelli, V., Borgatti, D., Baretta, M., Stazi, S.R., Allevato, E., Pancaldi, S., Baldisserotto, C., Mancinelli, R., Tedeschi, P., Radicetti, E. and Ben Hassine, M. (2025), Microbial biofertilizers and algae-based biostimulant affect fruit yield characteristics of organic processing tomato. J Sci Food Agric, 105: 530-539. https://doi.org/10.1002/jsfa.13851]
- Pesticide residue in cucumber-exposed plants, and its associated effects on soil nematode population
  This study investigates pesticide residues in cucumber plants and their impact on soil nematode populations while evaluating the effect of pesticides on cucumber growth and yield. Gas Chromatography Tandem Mass Spectrometry (GC-MS/MS) was used to quantify pesticide residues, comparing the results to the Maximum Residue Limits (MRLs) defined by the Codex Alimentarius. Significant differences in residue levels were found between various pesticides and application rates. Diazinon residues ranged from 0.86 to 2.28 mg/kg, exceeding the MRL of 0.1 mg/kg, indicating soil contamination. Endosulfan had the lowest residues, from 0.44 to 1.75 mg/kg, which were within acceptable limits. Conversely, Malathion and Methoxychlor residues notably surpassed their MRLs, raising potential safety concerns. Further analysis using a linear regression model revealed a negative correlation between pesticide application and soil nematode populations. There was a proportional decrease in nematode populations with increasing pesticide application rate, with Malathion having the most significant impact, followed by Endosulfan, Methoxychlor, and Diazinon. The impact of pesticide application on cucumber plant growth and yield was assessed using one-way ANOVA, which uncovered significant differences across treatment groups. While pesticides are effective for pest control, their application must be carefully managed to avoid phytotoxicity and ensure optimal plant and environmental health, thereby enhancing maximum productivity.
  [Imonikebe, P. et al. (2025) Pesticide residue in cucumber-exposed plants, and its associated effects on soil nematode population, Advances in Modern Agriculture. Available at: https://www.researchgate.net/publication/390847748_Pesticide_residue_in_cucumber-exposed_plants_and_its_associated_effects_on_soil_nematode_population.]
- Regenerative organic agriculture and soil ecosystem service delivery: A literature review
  Regenerative Organic Agriculture (ROAg) can have several beneficial effects on soil health and the delivery of important soil ecosystem services. Yet, the net effect of multiple ROAg practices (i.e. minimum soil disturbance, crop rotation, cover cropping, organic fertilization, etc.) on soil health and ecosystem service delivery has been rarely assessed. The challenge remains to compare how diverse ROAg practices vs. conventional agriculture might influence soil biogeochemical properties using replicated field experiments lasting at least few years.
  We performed a systematic literature review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) approach and selected English written peer-reviewed scientific papers focused on the effects that ROAg might have on soil health and soil ecosystem service delivery. Findings were analysed with a vote-count procedure and data extracted from comparative studies between conventional and regenerative organic agriculture were utilized to calculate an impact score. After screening 271 records, 24 studies met all the inclusion criteria. Among them, 17 research studies experimentally compared ROAg vs. conventional practices and quantitative data extracted from 63 observations were used for the impact assessment.
  Our findings show that ROAg improved soil health and soil ability to deliver multiple ecosystem services. The vote-count including 45 observations from 24 selected studies, shows how ROAg had positive effects on soil ecosystem services in 64% of the total number of observations. The impact assessment analysis, which included quantitative data extracted from 63 experimental observations, also show positive effects on multiple soil ecosystem services and soil biogeochemical parameters. ROAg increased soil organic C (SOC; g kg−1) by 22 %, soil total nitrogen (STN; g kg−1) by 28 %, and soil microbial biomass carbon (MBC; g kg−1) by 133 % compared to conventional agriculture. The highest number of positive ROAg effects were associated with supporting services (e.g. SOM dynamics, soil nutrient and water cycling). A negative ROAg effect was observed on the ‘food and fiber production’ provisioning service, where yields (food quantity) were 24 % lower when compared to conventional agriculture. However, the only data available on potential links between soil management and plant health, shows ROAg positive effects on plant nutrient density (food quality).
  Our review demonstrates that ROAg has significant positive impacts on soil health and ecosystem service delivery and highlights the need for long-term comparative studies across world regions to address knowledge gaps and assess potential economic, social and human health benefits associated with a greater implementation of ROAg practices.
  [Colombi, Greta & Martani, Enrico & Fornara, Dario. (2025). Regenerative organic agriculture and soil ecosystem service delivery: A literature review. Ecosystem Services. 10.1016/j.ecoser.2025.101721. ]
- Soil organic carbon and total nitrogen after 34 years under conventional and organic management practices at the Rodale Institute Farming Systems Trial
  Long-term agricultural experiments are uniquely positioned to capture the spatiotemporal dynamics of farming system effects on soil profile properties, which typically require decades for measurable changes to become apparent. Soil organic carbon (SOC) and total nitrogen (TN) concentrations and stocks were determined at a depth of 0–30 cm in the 34th year of the Rodale Institute Farming Systems Trial (FST), Kutztown, Pennsylvania, USA. Only the organic agriculture (OA) with manure (OA-MNR) system plots had higher SOC concentrations and stocks than the plots of the other systems but only at depths of 0–10 and 10–20 cm, and not on equivalent soil mass (ESM) basis to 30-cm depth. The ESM SOC stocks to 30-cm depth at the tilled plots were 53.3, 56.2, and 61.9 Mg C ha−1 for conventional (CONV), OA-legume (OA-LEG), and OA-MNR systems, respectively. The concentrations and stocks of TN, as well as ESM TN stocks to 30-cm depth at the tilled plots, were higher for both OA systems compared to CONV. However, observations at the recently established reduced tillage (RT) subplots were inconsistent, as at least 10 years may be needed to ensure that differences in tillage treatment effects on SOC can be detected. The results are consistent with many other long-term field experiments that have reported differences in SOC and TN concentrations and stocks only in the topsoil. Overall, the OA-MNR system was advantageous in 2015 in increasing SOC and TN compared to the CONV and OA-LEG systems. Thus, OA practices when combined with composted manure addition can result in increases in the SOC stock in the long term. However, subsequent studies should assess the implications for input of manure sourced from outside the OA-MNR system. Further, soil samples should be taken several times over multiple years to more comprehensively assess management-induced changes in soil properties.
  [Lorenz, K., Omondi, E., Lal, R., Das, S., & Smith, A. (2025). Soil organic carbon and total nitrogen after 34 years under conventional and organic management practices at the Rodale Institute Farming Systems Trial. Soil Science Society of America Journal, 89, e70000. https://doi.org/10.1002/saj2.70000]
- Systematic assessments of ecological and health risks of soil pesticide residues
  Pesticides have represented a crucial tool to ensure the efficient production and development of modern agriculture; however, they inevitably polluted the environment and have posed threats to ecological security and human health. Although agricultural soil pesticide residues have long threatened the environment, a relatively complete system for evaluating their health and ecological risks has not yet been developed. To address this research gap, based on the health and ecological risk values calculated by a detailed detection of 50 pesticides on agricultural lands in Zhejiang Province, China, and supplemented by the analysis of soil microbial community composition, the present study proposed a comprehensive assessment system for pesticide residue risks. We found that 98.62 % of the soil samples contained more than ten pesticide types. Notably, while both carcinogenic and non-carcinogenic threat posed by pesticide residues to soil ecological security and human health was assessed as low, risk values varied significantly across different regions and agricultural practices. With an increase in the ecological risk of pesticide residues, the relative abundance of Firmicutes in the soil decreased significantly, indicating that Firmicutes may be used as an indicator of the ecological risk of pesticides. Taking advantage of differences in ecological risk, we also identified that some special microbial groups are substantially enriched in the face of pesticide pollution stress and can be used as candidate pesticide-degrading bacteria. This study investigated the correlation between pesticide residue risks and soil ecological security and human health, revealed the response characteristics of soil microbial communities under pesticide stress, and identified microbes strongly related to pesticide ecological risks. These findings can provide theoretical support for the future green management of pesticide residues in agricultural lands.
  [Tang, T. et al. (2025) Systematic assessments of ecological and health risks of soil pesticide residues, Environmental Pollution. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0269749125007213.]
- The combination of microplastics and glyphosate affects the microbiome of soil inhabitant Enchytraeus crypticus
  Microplastics and pesticides are emerging contaminants that threaten soil ecosystems, yet their combined effects on soil health and soil fauna remain poorly understood. In this study, we constructed a microcosm to assess the individual and combined effects of microplastics and glyphosate on soil physicochemical properties, microbial communities, and the gut microbiome of soil invertebrates (Enchytraeus crypticus). Biodegradable polylactic acid (PLA) and conventional polyethylene terephthalate (PET) were introduced at environmentally relevant concentrations. Our results revealed that PLA had a stronger disruptive effect on soil microbial communities than PET, altering microbial diversity and functional composition. Glyphosate, in contrast, primarily influenced the gut microbiome of E. crypticus, reducing microbial diversity and inducing oxidative stress. Combined exposure to microplastics and glyphosate significantly intensified oxidative stress but did not amplify microbial dysbiosis beyond the effects of microplastics alone. Compare to PET, PLA combined with glyphosate had the most pronounced effects on both soil and gut microbiomes, suggesting that biodegradable microplastics may pose greater ecological risks than conventional microplastics when used alongside pesticides. These findings underscore the need for a reassessment of biodegradable plastic use in agriculture and highlight the complex interactions between microplastics and pesticides in shaping soil ecosystem health.
  [Yang, Huihui & Zheng, Guogang & Qin, Guoyan & Zhang, Qi & Zhang, Ziyao & Chen, Bingfeng & Lei, Chaotang & Liu, Meng & Cui, Rui & Sun, Liwei & Xia, Shengjie & Peijnenburg, Willie & Lu 陆涛, Tao & Tang, Tao & Qian, Haifeng. (2025). The combination of microplastics and glyphosate affects the microbiome of soil inhabitant Enchytraeus crypticus. Journal of hazardous materials. 489. 137676. 10.1016/j.jhazmat.2025.137676. ]
- Warming exacerbates the effects of pesticides on the soil collembolan gut microbiome and antibiotic resistome
  In the context of global climate warming, studies have yet to fully clarify how pollutants affect the gut microbiome and antibiotic resistance genes (ARGs) in nontarget soil fauna. This study investigates the interactive effects of pesticide exposure (imidacloprid) and elevated temperature on the gut bacterial community and ARGs in the model soil collembolan Folsomia candida. Our results demonstrate warming exacerbates the toxicity of imidacloprid in collembolans. While exposure to both warming and pesticide significantly altered the gut microbial composition of F. candida, impairing microbial metabolic diversity and potential host defense mechanisms, it also increased collembolan mortality. This combined exposure significantly enhanced the abundance and diversity of ARGs in the collembolan gut. A notable correlation between ARGs and mobile genetic elements (MGEs) underscores the potential risk of ARG transmission. Co-occurrence network analysis identified 52 bacterial genera as potential ARG hosts. Additionally, pure-culture exposure experiments with the isolated bacterium Serratia liquefaciens revealed the adaptability of ARG hosts to pesticide and warming stress plays an important role in driving the observed increase in ARGs. In conclusion, this study highlights the synergistic effects of climate warming and pesticide contamination on nontarget soil organisms, emphasizing the potential long-term risks to soil ecosystem health and stability.
  [Wang, Y. N., Cai, T. G., Li, Y., Dai, W. C., Lin, D., Zheng, J. T., Wang, Y. F., & Zhu, D. (2025). Warming exacerbates the effects of pesticides on the soil collembolan gut microbiome and antibiotic resistome. Journal of hazardous materials, 492, 138294. Advance online publication. https://doi.org/10.1016/j.jhazmat.2025.138294]
- Adsorption behavior of triazine pesticides on polystyrene microplastics aging with different processes in natural environment
  The presence of microplastics in the ecological environment, serving as carriers for other organic pollutants, has garnered widespread attention. These microplastics exposed in the environment may undergo various aging processes. However, there is still a lack of information regarding how these aged microplastics impact the environmental behavior and ecological toxicity of pollutants. In this study, we modified polystyrene microplastics by simulating the aging behavior that may occur under environmental exposure, and then explored the adsorption behavior and adsorption mechanism of microplastics before and after aging for typical triazine herbicides. It was shown that all aging treatments of polystyrene increased the adsorption of herbicides, the composite aged microplastics had the strongest adsorption capacity and the fastest adsorption rate, and of the three herbicides, metribuzin was adsorbed the most by microplastics. The interactions between microplastics and herbicides involved mechanisms such as hydrophobic interactions, surface adsorption, the effect of π-π interactions, and the formation of hydrogen bonds. Further studies confirmed that microplastics adsorbed with herbicides cause greater biotoxicity to E. coli. These findings elucidate the interactions between microplastics before and after aging and triazine herbicides. Acting as carriers, they alter the environmental behavior and ecological toxicity of organic pollutants, providing theoretical support for assessing the ecological risk of microplastics in water environments.
  [Zihang, Zeng & Jia, Bingni & Liu, Xiaofeng & Chen, Lixiang & Peng, Zhang & Qing, Taiping & Feng, Bo. (2024). Adsorption behavior of triazine pesticides on polystyrene microplastics aging with different processes in natural environment. Environmental Pollution. 356. 124319. 10.1016/j.envpol.2024.124319. ]
- Adsorption of neonicotinoid insecticides by mulch film-derived microplastics and their combined toxicity
  Mulch films allow for efficient crop production, yet their low recovery after use causes severe microplastics (MPs) pollution in agricultural soils. MPs in agricultural environments undergo complex ageing processes, which can alter their interactions with coexisting neonicotinoids and result in unpredictable ecological risks. Here, polyethylene (PE) and polybutylene adipate terephthalate (PBAT), typical mulch films, were chosen for the preparation of PE-MPs and PBAT-MPs. The adsorption of two common neonicotinoids, imidacloprid and dinotefuran, by the two MPs and their joint toxicity were examined. We found that the specific surface area of PBAT-MPs (7.59 m2 g−1) is greater than that of PE-MPs (2.83 m2 g−1), which results in a greater adsorption capacity for neonicotinoids. Additionally, ageing increased the adsorption capacity of MPs for neonicotinoids by 37.50–40.68 % for PBAT-MPs and 44.23–72.34 % for PE-MPs. This enhancement is attributed to the introduction of additional oxygen-containing functional groups on the MPs' surfaces, which can form hydrogen bonds with the amino groups in imidacloprid and dinotefuran. Furthermore, compared to single MPs and neonicotinoids, stronger inhibition in the growth of Escherichia coli and the germination of lettuce seeds was observed when they coexisted. This study highlights the importance of assessing the interactions between MPs and neonicotinoids and their joint toxicity, thereby improving our understanding of the potential risks of MPs towards the agricultural ecosystems.
  [Zhang, Q., Xu, P., Yan, N., Ren, Y., Liang, X., & Guo, X. (2024). Adsorption of neonicotinoid insecticides by mulch film-derived microplastics and their combined toxicity. The Science of the total environment, 955, 177238. https://doi.org/10.1016/j.scitotenv.2024.177238]
- An assessment of twenty-three mycorrhizal inoculants reveals limited viability of AM fungi, pathogen contamination, and negative microbial effect on crop growth for commercial products
  Ensuring sustainable agriculture is crucial amidst global challenges, demanding effective methods to enhance soil health and nutrient cycling. Microbial inoculants, particularly arbuscular mycorrhizal (AM) fungi, offer promising solutions. However, concerns persist regarding the efficacy and quality control of commercial products. Past work assessing commercial inoculants have not controlled for fertilizers added to individual products when assessing product effects under typical use.
  This study examines twenty-three mycorrhizal inoculants using conventions of organic production to shed light on differences between laboratory grown fungi, commercial products, and field soil. Employing a comprehensive approach, inoculants were assessed through spore enumeration, root infection potential, and crop growth response.
  The results uncover significant shortcomings in many commercial products compared to laboratory grown fungi. Key findings include discrepancies of up to 100 % in reported propagule counts versus spore concentrations, insufficient root colonization by commercial inoculants, and contamination by fungal plant pathogens, particularly Olpidium, in products. Moreover, while laboratory grown fungi exhibited superior symbiotic relationships with host plants due to increased colonization abilities and crop benefit, commercial inoculants often failed to deliver significant growth benefits when fertilizers are controlled for.
  These findings highlight the urgent need for improved standards and practices within the commercial inoculant industry.
  [Liz Koziol, Terra Lubin, James D. Bever, An assessment of twenty-three mycorrhizal inoculants reveals limited viability of AM fungi, pathogen contamination, and negative microbial effect on crop growth for commercial products, Applied Soil Ecology, Volume 202, 2024, 105559, ISSN 0929-1393, https://doi.org/10.1016/j.apsoil.2024.105559.]
- Analyzing soil enzymes to assess soil quality parameters in long-term copper accumulation through a machine learning approach
  Soil contamination by agrochemicals is a big concern for soil health and ecosystem functioning. This is especially true for non-degradable substances like heavy metals (HM) that, because of their long-term use, are reaching significant values today due to soil accumulation. Among agrochemicals, copper (Cu) has been important in fighting fungal diseases on perennial crops for centuries.
  Laboratory experiments can be useful to understand the highest potential toxic effect of Cu but need to reflect what happens with long-term application in a dynamic and living agroecosystem. This study uses multivariate data analysis and machine learning to investigate long-term Cu accumulation on soil quality parameters, especially soil extracellular enzymatic activities. We collected soil samples from 21 apple orchards in South Tyrol, Italy. The orchards had different concentrations of Cu. We took 315 samples in total and analyzed them for various soil properties. We also measured the concentrations of elements in apple leaves and the activities of soil extracellular enzymes. We depicted the effect of Cu on several enzymatic activities, shedding light on the effect of Cu on the soil microbial communities functionality. Our results show that Cu concentrations in the study area affect only phosphatase activity, showing effects above 60 mg kg−1 of available Cu. Protease activity was positively correlated with Cu, while soil organic matter and management mainly influenced the carbon (C) cycle enzymes. Phosphatase decrease could be of concern for the potential disruption of the Phosphorus (P) cycle in the soil and plays a role in plant nutrition, as seen by P concentration in apple trees' leaves.
  We demonstrated how machine learning can help interpret complex and multivariate environmental data and overcome some downsides of traditional statistical models.
  [Genova, Giulio & Borruso, Luigimaria & Signorini, Marco & Mitterer, M. & Niedrist, G. & Cesco, Stefano & Felderer, B. & Cavani, Luciano & Mimmo, Tanja. (2024). Analyzing soil enzymes to assess soil quality parameters in long-term copper accumulation through a machine learning approach. Applied Soil Ecology. 195. 105261. 10.1016/j.apsoil.2023.105261. ]
- Antibiotics and Pesticides Enhancing the Transfer of Resistomes among Soil-Bayberry-Fruit Fly Food Chain in the Orchard Ecosystem
  While substantial amounts of antibiotics and pesticides are applied to maintain orchard yields, their influence on the dissemination and risk of antibiotic resisitome in the orchard food chain remains poorly understood. In this study, we characterized the bacterial and fungal communities and differentiated both antibiotic resistance genes (ARGs) and virulence factor genes (VFGs) in the soil, Chinese bayberry (matured and fallen), and fruit fly gut, collected from five geographic locations. Our results showed that fruit fly guts and soils exhibit a higher abundance of ARGs and VFGs compared with bayberry fruits. We identified 112 shared ARGs and 75 shared VFGs, with aminoglycoside and adherence factor genes being among the most abundant. The co-occurrence network revealed some shared microbes, such as Bacillus and Candida, as potential hosts of ARGs, highlighting the vector risks for both above- and below-ground parts of the orchard food chain. Notably, the elevated levels of antibiotics and pesticide residues in orchard soils increase ARGs, mobile genetic elements (MGEs), and VFGs in the soil-bayberry-fruit fly food chain. Our study highlighted that agricultural management, including the overuse of antibiotics and pesticides, could be the key factor in accumulating resistomes in the orchard food chain.
  [Yi, G., Jin, M. K., Cai, T. G., Xu, R., Gou, X. W., Yang, N., Feng, Y. L., Zhang, S. W., Qi, X. J., Zhu, Y. G., Zhu, D., & Li, H. (2024). Antibiotics and Pesticides Enhancing the Transfer of Resistomes among Soil-Bayberry-Fruit Fly Food Chain in the Orchard Ecosystem. Environmental science & technology, 58(41), 18167–18176. https://doi.org/10.1021/acs.est.4c05829]
- Assessing pesticide residue occurrence and risks in the environment across Europe and Argentina
  The widespread and extensive use of pesticides in European crop production to reduce losses from weeds, diseases, and insects may have serious consequences on the ecosystem and human health. This study aimed to identify 20 active substances of high health risk, based on their detection frequency within and across the environmental matrices (soil, crop, water, and sediment) and to identify their associated hazardous effects. A sampling campaign was conducted across 10 case study sites in Europe and 1 in Argentina and included conventional and organic farming systems. In 31% of cases, the detected substances were found at a higher concentration in the soil than in the corresponding crops, 93% of the compounds were fungicides, and the remainder were insecticides. 43% of the substances, 57% of which were insecticides, were detected only in soil. There was a clear relationship between soils and crops in terms of contamination, but not between water and sediment. Portuguese soil (wine grapes) had the highest number of substances (12) with average concentrations (AC) varying between 1 and 162 μg/kg, followed by French (11 substances in wine grapes) (1≤AC≤64 μg/kg) and Spanish soils (9 substances in vegetables) (3≤AC≤59 μg/kg). The crops corresponding to these soils contained a relatively high number of detected substances and several in high average concentrations (AC). The risk quotient was consistently higher for conventional farms than for organic farms. For the soils from conventional farms, 5 active substances (chlorpyrifos, glyphosate, boscalid, difenoconazole, lambda-cyhalothrin, and one metabolite: AMPA) were considered high risk. For water samples, 2 substances (dieldrin and terbuthylazine) found were high risk, and for sediment, there were 3 substances (metalaxyl-M, spiroxamine, and lambda-cyhalothrin). There were 6 substances detected in crops that are suspected to cause human health effects. Uncontaminated soil is a prerequisite for the adoption of sustainable alternatives to pesticides. Efforts are needed to elucidate the unknown effects of mixtures, including biocides and banned compounds in addition to the substances used in agriculture.
  [Alaoui, A., Christ, F., Abrantes, N., Silva, V., González, N., Gai, L., Harkes, P., Navarro, I., Torre, A., Martínez, M. Á., Norgaard, T., Vested, A., Schlünssen, V., Aparicio, V. C., Campos, I., Pasković, I., Pasković, M. P., Glavan, M., Ritsema, C., & Geissen, V. (2024). Assessing pesticide residue occurrence and risks in the environment across Europe and Argentina. Environmental pollution (Barking, Essex : 1987), 363(Pt 1), 125056. https://doi.org/10.1016/j.envpol.2024.125056]
- Biofertilizer use in the United States: definition, regulation, and prospects
  The increasing demand for sustainable food production has driven a surge in the use and commercialization of biological inputs, including biofertilizers. In this context, biofertilizers offer potential benefits for nutrient use efficiency, crop yield and sustainability. However, inconsistent definition of the term “biofertilizer” and regulations, particularly in the USA, hinder market growth and consumer confidence. While the European Union, and countries like Brazil, India, and China have made progress in this area, the USA market, projected to exceed $1 billion by 2029, lacks clear guidelines for biofertilizer production and sale. The USA market is dominated by Rhizobium genus, Mycorrhizae fungi, and Azospirillum species and based products targeting various crops. Although there is a growing and promising market for the use of biofertilizers, there are still many challenges to overcome, and to fully realize the potential of biofertilizers, future research should focus on modes of action, specific claims, and robust regulations that must be established.
  [Santos, F., Melkani, S., Oliveira-Paiva, C. et al. Biofertilizer use in the United States: definition, regulation, and prospects. Appl Microbiol Biotechnol 108, 511 (2024). https://doi.org/10.1007/s00253-024-13347-4]
- Biological Interactions Mediate Soil Functions by Altering Rare Microbial Communities
  Soil microbes, the main driving force of terrestrial biogeochemical cycles, facilitate soil organic matter turnover. However, the influence of the soil fauna on microbial communities remains poorly understood. We investigated soil microbiota dynamics by introducing competition and predation among fauna into two soil ecosystems with different fertilization histories. The interactions significantly affected rare microbial communities including bacteria and fungi. Predation enhanced the abundance of C/N cycle-related genes. Rare microbial communities are important drivers of soil functional gene enrichment. Key rare microbial taxa, including SM1A02, Gammaproteobacteria, and HSB_OF53-F07, were identified. Metabolomics analysis suggested that increased functional gene abundance may be due to specific microbial metabolic activity mediated by soil fauna interactions. Predation had a stronger effect on rare microbes, functional genes, and microbial metabolism compared to competition. Long-term organic fertilizer application increased the soil resistance to animal interactions. These findings provide a comprehensive understanding of microbial community dynamics under soil biological interactions, emphasizing the roles of competition and predation among soil fauna in terrestrial ecosystems.
  [Wang, Y. F., Xu, J. Y., Liu, Z. L., Cui, H. L., Chen, P., Cai, T. G., Li, G., Ding, L. J., Qiao, M., Zhu, Y. G., & Zhu, D. (2024). Biological Interactions Mediate Soil Functions by Altering Rare Microbial Communities. Environmental science & technology, 58(13), 5866–5877. https://doi.org/10.1021/acs.est.4c00375]
- Bumblebee (Bombus impatiens) queens prefer pesticide-contaminated soils when selecting underground hibernation sites
  New evidence points to substantial impacts of exposure to pesticide residues in soil for a range of bee taxa that have close regular contact with this substrate. Among others, the risk of exposure is high for bumblebee (Bombus spp.) queens hibernating in agricultural soils. An important question is whether bumblebee queens can detect and avoid pesticide-contaminated soils, or whether they might be attracted to such agrochemical residues. To address this question, we performed a multiple-choice preference experiment in which newly emerged bumblebee (Bombus impatiens) queens were given access to arrays of 36 crates of soil treated with different pesticides in large mesh-covered enclosures. Five of the most commonly encountered pesticides in agricultural soils (boscalid, chlorantraniliprole, clothianidin, cyantraniliprole, difenoconazole) were selected for testing at two contamination levels (lower or higher), based on field-realistic exposure estimates. Bumblebee queens consistently avoided hibernating in pesticide-free soil at both contamination levels, while showing no avoidance for any pesticide-treated soil types. At the lower contamination level, queens selected the pesticide-free soil 1.3 to 2.4-fold less frequently on average than any of the spiked soils, while none of the queens from the higher contamination group selected pesticide-free soil. This apparent preference for pesticide-contaminated soils increases the likelihood of exposure to and potential hazard from pesticide residues in soil for bumblebee queens during hibernation, a critical and highly vulnerable period of their annual life cycle.
  [Rondeau, S. and Raine, N. (2024) Bumblebee (Bombus impatiens) queens prefer pesticide-contaminated soils when selecting underground hibernation sites, The Science of the Total Environment. Available at: https://pubmed.ncbi.nlm.nih.gov/39332727/. ]
- Chlorpyrifos degradation and its impacts on phosphorus bioavailability in microplastic-contaminated soil
  Pesticide residues and microplastics (MPs) in agricultural soils are two major concerns for soil health and food safety. The degradation of chlorpyrifos (CPF), an organophosphorus pesticide, releases phosphates. This process may be affected by the presence of MPs in the soil. The combination of CPF and MPs presence in the soil may thus produce interaction effects that alter the soil phosphorus (P) balance. This study explores the degradation pathways of CPF (6 mg kg−1, 12 mg kg−1 of CPF addition) in soils with different levels of polylactic acid MPs (PLA-MPs) (0.0 %, 0.1 %, 0.5 %, 1.0 % w/w), and analyzes soil P fractions and phosphatase enzyme activities to investigate soil P bioavailability under different treatments. Results show that the degradation of CPF fits to a first-order decay model, with half-lives (DT50) ranging from 11.0 to 14.8 d depending on PLA-MPs treatment. The concentration of its metabolite 3, 5, 6-trichloropyridine 2-phenol (TCP) reached a peak of 0.93–1.67 mg kg−1 within 7–14 days. Similarly, the degradation of CPF led to a significant transient increase in P bioavailability within 3–7 days (p < 0.05), with a peak range of 22.55–26.01 mg kg−1 for Olsen-P content and a peak range of 4.63–6.76 % for the proportions of available P fractions (H2O-P+NaHCO3-P+NaOH-P), before returning to prior levels (Olsen-P: 11.28–19.52 mg kg−1; available soil P fractions: 4.15–5.61 %). CPF degradation (6 mg kg−1) was significantly inhibited in soil with 1.0 % PLA-MPs addition. The effects of MPs and CPF on soil P fractions occur at different time frames, implying that their modes of action and interactions with soil microbes differ.
  [Ding, L., Wang, Y., Ju, H., Tang, D. W. S., Xue, S., Geissen, V., & Yang, X. (2024). Chlorpyrifos degradation and its impacts on phosphorus bioavailability in microplastic-contaminated soil. Ecotoxicology and environmental safety, 277, 116378. https://doi.org/10.1016/j.ecoenv.2024.116378]
- Co-exposure to boscalid and amoxicillin inhibited the degradation of boscalid and aggravated the threat to the earthworm
  The extensive application of pesticides and antibiotics in agricultural production makes it possible for them to coexist in farmland, and the interaction of the two pollutants can lead to changes in environmental behavior and toxicity, creating uncertainty risks to soil and soil organisms. In this study, we explored the environmental behavior and the effects of earthworms under co-exposure to amoxicillin and boscalid and further explored the accumulation and toxic effects on earthworms. The results showed that amoxicillin increased the adsorption of boscalid in soil and inhibited its degradation. In addition, we noticed that the co-exposure of amoxicillin and boscalid caused intestinal barrier damage, which increased the bioaccumulation of earthworms for boscalid and led to more severe oxidative stress and metabolic disorders in earthworms. In summary, our findings indicate that amoxicillin can increase the ecological risk of boscalid in the environment and imply that the encounter between antibiotics and pesticides in the environment can amplify the toxic effects of pesticides, which provides new insights into the ecological risks of antibiotics.
  [Han, S., Sun, W., Sun, X., Yue, Y., Miao, J., Dang, X., Diao, J., Teng, M., & Zhu, W. (2024). Co-exposure to boscalid and amoxicillin inhibited the degradation of boscalid and aggravated the threat to the earthworm. Pesticide biochemistry and physiology, 203, 106022. https://doi.org/10.1016/j.pestbp.2024.106022]
- Combined effects of polyethylene microplastics and carbendazim on Eisenia fetida: A comprehensive ecotoxicological study
  Microplastic (MP) pollution is becoming an emerging environmental concern across aquatic and terrestrial ecosystems. Plastic mulching and the use of pesticides in agriculture can lead to microplastics and agrochemicals in soil, which can result in unintended exposure to non-target organisms. The combined toxicity of multiple stressors represents a significant paradigm shift within the field of ecotoxicology, and its exploration within terrestrial ecosystems involving microplastics is still relatively limited. The present study investigated the combined effects of polyethylene MP (PE-MP) and the agrochemical carbendazim (CBZ) on the earthworm Eisenia fetida at different biological levels of organization. While E. fetida survival and reproduction did not exhibit significant effects following PE-MP treatment, there was a reduction in cocoon and hatchling numbers. Notably, prolonged exposure revealed delayed toxicity, leading to substantial growth impairment. Exposure to CBZ led to significant alterations in the endpoints mentioned above. While there was a decrease in cocoon and hatchling numbers, the combined treatment did not yield significant effects on earthworm reproduction except at higher concentrations. However, lower concentrations of PE-MP alongside CBZ induced a noteworthy decline in biomass content, signifying a form of potentiation interaction. In addition, concurrent exposure led to synergistic effects, from oxidative stress to modifications in vital organs such as the body wall, intestines, and reproductive structures (spermathecae, seminal vesicles, and ovarian follicles). The comparison of multiple endpoints revealed that seminal vesicles and ovarian follicles were the primary targets during the combined exposure. The research findings suggest that there are variable and complex responses to microplastic toxicity in terrestrial ecosystems, especially when combined with other chemical stressors like agrochemicals. Despite these difficulties, the study implies that microplastics can alter earthworms' responses to agrochemical exposure, posing potential ecotoxicological risks to soil fauna.
  [Gautam, K., Dwivedi, S., Verma, R., Vamadevan, B., Patnaik, S., & Anbumani, S. (2024). Combined effects of polyethylene microplastics and carbendazim on Eisenia fetida: A comprehensive ecotoxicological study. Environmental pollution (Barking, Essex : 1987), 348, 123854. https://doi.org/10.1016/j.envpol.2024.123854]
- Different effects of polyethylene microplastics on bioaccumulation of three fungicides in maize (Zea mays L.)
  Despite the ubiquity of microplastics (MPs) and pesticides in agricultural soils, the effects of MPs on the behavior and bioavailability of pesticides in soil–plant systems remain largely unknown. This study comparatively investigated the adsorption and dissipation of three commonly used fungicides (metalaxyl, azoxystrobin and tebuconazole) in soil as well as their accumulation and distribution in maize Zea mays L. with and without the amendment of polyethylene MPs (PE-MPs). The results showed that the adsorption of the fungicides to both MPs and soil was strongly dependent on their octanol/water partition coefficients (logKow). The addition of 5% PE-MPs significantly increased the adsorption of the hydrophobic fungicides azoxystrobin and tebuconazole to soil due to their greater adsorption affinity to PE-MPs than to soil, while the effect was negligible in the case of the hydrophilic fungicide metalaxyl. The enhanced adsorption of azoxystrobin and tebuconazole to soil with the amendment of PE-MPs decreased their bioavailable fractions in soil, especially the concentration in in situ pore water, resulting in prolonged persistence in soil and reduced accumulation in maize plants. PE-MPs caused a greater reduction in the dissipation and bioaccumulation of tebuconazole than azoxystrobin, presumably because PE-MPs were more effective in promoting the adsorption of tebuconazole (with a higher logKow) in soil. Comparatively, PE-MPs had little effect on the dissipation and bioaccumulation of metalaxyl since its bioavailability was almost unaffected. Our work provides effective information for the risk assessment of co-contamination of MPs and pesticides.
  [Qiu, S., Shen, H., Song, J. et al. Different effects of polyethylene microplastics on bioaccumulation of three fungicides in maize (Zea mays L.). Crop Health 2, 7 (2024). https://doi.org/10.1007/s44297-024-00028-x]
- Direct evidence on the impact of organic amendments on carbon stabilization in soil microaggregates
  Direct evidence-based approaches are vital in understanding the involvement of abiotic/biotic factors and evaluating the newly proposed theories on soil carbon (C) stabilization. Microaggregates (150–250 µm) collected from a corn system (>22 years; Kansas, USA), which had been under no-till with different nitrogen (N) treatments were analyzed (N treatments: manure/compost, urea, zero fertilizer). We studied C stabilization in free soil microaggregates (with preserved aggregate architecture), directly using scanning transmission X-ray microscopy coupled with near edge X-ray absorption fine structure (STXM-NEXAFS) spectroscopy. Submicron scale findings were complemented with bulk chemical analysis. The STXM-NEXAFS analysis revealed soil organic carbon (SOC) preservation inside nano- and micro-pores and organo–mineral association, various degrees of humification, and high molecular diversity. The presence of microbial-derived C was found in manure-/compost-added microaggregates highlighting the contribution of organic amendments in facilitating microbial diversity. The incidence of aragonite-like minerals suggested the biologically/chemically active nature of microaggregate cores. Bulk analysis of free microaggregates showed a higher concentration of SOC (6.5%), ammonium oxalate extractable Fe/Al/Si), and higher aliphaticity of humic acid in manure-/compost-added soils compared to inorganic fertilizer (3% SOC) and control (2.7% SOC) treatments. The co-existence of elements (calcium [Ca]/C, iron [Fe]/N, Fe/C, aluminum [Al]/C, and silicon [Si]/C) was partially supported by bulk chemical analysis that indicated a strong association between ammonium oxalate extractable Fe/Al/Si and SOC (R2 = 0.63—0.77). Overall, our study provided direct/indirect evidence for the complex and interactive involvement of chemical, mineralogical, and biological mechanisms that may have been stimulated by the long-term addition of compost/manure in stabilizing SOC.
  [Pitumpe Arachchige, P.S. et al. (2024) Direct evidence on the impact of organic amendments on carbon stabilization in soil microaggregates, Soil Science Society of America. Available at: https://acsess.onlinelibrary.wiley.com/doi/10.1002/saj2.20701. ]
- Drivers and barriers to adoption of regenerative agriculture: cases studies on lessons learned from organic
  Regenerative agriculture has emerged as a potentially outcome-based paradigm centring on soil health, biodiversity and other environmental and social parameters. Early days of organic agriculture also focused on philosophy first and evolved into a process-based regulatory paradigm whose adoption remains small relative to conventional production. Five case studies of professional growers, representing a total of 100,000 acres of production, were collected to identify reasons for choosing to grow or stop growing organic, challenges faced and attitudes around regenerative agriculture. Growers identified issues of complex and unpredictable regulation, labour, inability to predict market trends and secure needed premiums, cost and effectiveness of natural fertilizers and lack of effectiveness in pest control. These growers adopted similar practices (e.g., integrated pest management) for environmental benefits across conventional and organic acres, and viewed consumer demand and potential profitability rather than environmental benefits as the main drivers for practising organic. Growers expressed interest in outcome-based regenerative agriculture. To be viable, a programme requires criteria on measurement and certification, regionally tailored flexibility and clear financial incentives. Growers doubt such a programme would replace organic but see opportunities for new marketing programmes, particularly in carbon sequestration and water management. Challenges identified by growers warrant further study.
  [Lemke, S. et al. (2024) Drivers and barriers to adoption of regenerative agriculture: cases studies on lessons learned from organic, International Journal of Agricultural Sustainability. Available at: https://www.tandfonline.com/doi/full/10.1080/14735903.2024.2324216. ]
- Effect of Mineral Fertilizers and Pesticides Application on Bacterial Community and Antibiotic-Resistance Genes Distribution in Agricultural Soils
  Soils are a hotspot for the emergence and spread of antibiotic resistance. The effects of agrochemical treatments on the bacterial community of agricultural soils and the content of antibiotic-resistance genes (ARGs) were studied. Treatments included the following: control, mineral fertilizers (NPKs), pesticides, and the combined treatment of soils under soya (Glycine max), sunflower (Helianthus annuus L.), and wheat (Triticum aestivum). Bacterial community taxonomic composition was studied using 16S rRNA gene sequencing. The content of 10 ARGs and 3 integron genes (intI1, intI2, intI3) was determined using quantitative real-time PCR. The results showed that the treatments had little effect on the taxonomic composition and diversity of the soil bacterial community. The most significant factors determining differences in the microbial community were sampling time and soil physico-chemical parameters. A significant role of the bacterial community in ARG distribution in soils was demonstrated. Representatives of the Pseudomonas, Bacillus, Sphingomonas, Arthrobacter genera, and the Nocardioidaceae and Micrococcaceae families were likely ARG hosts. The presence of integron genes of all three classes was detected, the most numerous being intI3. This work provides important information on the role of agricultural soils in ARG transfer, and the findings may be useful for sustainable and safe agricultural development.
  [Khmelevtsova, L. et al. (2024) Effect of mineral fertilizers and pesticides application on bacterial community and antibiotic-resistance genes distribution in agricultural soils, Agronomy. Available at: https://www.mdpi.com/2073-4395/14/5/1021]
- Effect of organic farming on root microbiota, seed production and pathogen resistance in winter wheat fields
  Societal Impact Statement
  Agricultural intensification is a major driver of biodiversity decline in agrosystems. For instance, it has been shown that conventional farming leads to a decline in soil microbial diversity and triggers a strong selection process, altering the functioning of the whole ecosystem. The present study shows that organic farming increases diversity and affects composition of crop plant microbiota, mostly as a response to field management and soil characteristics. Furthermore, crop plant microbiota influences crop production and resistance to pathogens. Therefore, agricultural practices affect plant performance through microorganism-mediated changes, which may be important pillars of future sustainable crop production.
  
  Summary
  Agricultural intensification threatens biodiversity, but the effects of intensification on microorganisms are still overlooked despite their role in ecosystem functioning. Microorganisms associated with plants provide many services that affect plant growth and health. Organic farming is expected to strongly affect species composition, richness, and their interactions. We analyzed the effect of the farming system on endophytic microbial assemblages associated with winter wheat plants and plant performance in the field.
  We collected environmental data through farmer interviews, soil analyses, and plant inventories and analyzed root microbiota at vegetative and flowering stages.
  Organic farming increased fungal and bacterial diversity associated to wheat plants and affected species composition in most phyla. This effect was mostly due to soil characteristics and field management and a little to plant diversity in the field. Microbial responses were more pronounced at the late developmental stage, likely as a result of accumulative effect of management actions during plant development. Seed production and resistance to pathogens were related to specific phyla that are important for seed production and/or wheat resistance to septoriose.
  This work advances our understanding of how agricultural practices affect plant performance through microorganism-mediated changes and supports the use of microorganisms as pillars of sustainable crop production.
  [Ricono, C. et al. (2024) Effect of organic farming on root microbiota, seed production and pathogen resistance in winter wheat fields, Plants, People, Planet. Available at: https://nph.onlinelibrary.wiley.com/doi/10.1002/ppp3.10602.]
- Effects of microplastics on 3,5-dichloroaniline adsorption, degradation, bioaccumulation and phytotoxicity in soil-chive systems
  Microplastics (MPs) and pesticides are two pollutants of concern in agricultural soils. 3,5-dichloroaniline (3,5-DCA), a highly toxic metabolite of dicarboximide fungicides, commonly co-exists with MPs and poses a risk to the environment and food safety. Batch adsorption and soil incubation experiments were employed to investigate the effects of polyethylene (PE) and polylactic acid (PLA) MPs on the environmental behavior of 3,5-DCA in soil. Chive (Allium ascalonicum) was used as the experimental plant, a pot experiment was conducted to examine the effects of individual or combined exposure to MPs and 3,5-DCA on plant 3,5-DCA bioaccumulation, growth characteristics, and phytotoxicity. The results showed that PE- and PLA-MPs increased the adsorption capacity of soil to 3,5-DCA and prolonged the degradation half-life of 3,5-DCA by 6.24 and 16.07 d, respectively. Two MPs partially alleviated the negative effects of 3,5-DCA on the root length and fresh weight of chives, while PE-MPs had a positive and dose-dependent impact on the contents of photosynthetic pigment in chive leaves. Co-exposure to 3,5-DCA and MPs increased residues of 3,5-DCA in soil and chive roots but had no significant effect on 3,5-DCA residues in chive stems or leaves. Moreover, 3,5-DCA residues in PLA-MP soil were consistently higher than those in PE-MP soil. Conclusively, MPs altered the 3,5-DCA adsorption and degradation behavior in soil, as well as its bioaccumulation in chives. Co-exposure to MPs and 3,5-DCA had dose-dependent and MP-specific effects on chive plant development and phytotoxicity.
  [Yang, J., Li, J., Guo, Z. et al. Effects of microplastics on 3,5-dichloroaniline adsorption, degradation, bioaccumulation and phytotoxicity in soil-chive systems. Environ Geochem Health 46, 519 (2024). https://doi.org/10.1007/s10653-024-02305-8]
- Effects of microplastics on the environmental behaviors of the herbicide atrazine in soil: Dissipation, adsorption, and bioconcentration
  As an emerging contaminant in soil, the impact of microplastics (MPs) on the environmental behavior of other organic pollutants remains uncertain, potentially threatening the sustainability of agricultural production. In this study, the impact of two kinds of MPs on the environmental behaviors of herbicide atrazine in soil-plant system was investigated. The results showed that MPs significantly reduced the half-life 17.69 ∼ 21.86 days of atrazine in the soil, compared to the control group. Meanwhile, the introduction of MPs substantially increased atrazine adsorption. Additionally, MPs substantially enriched the diversity and functionality of soil microbiome, and the soil metabolic activity was stimulated. Regarding the crop growth, the accumulation of atrazine in maize were significantly decreased by approximately 48.4–78.5 % after exposure to MPs. In conclusion, this study reveals the impact of MPs on atrazine's environmental behaviors in soil and highlights their less effect on maize growth, providing valuable insights for managing MPs contamination in sustainable agriculture.
  [Guo, J., Du, Y., Yang, L., Luo, Y., Zhong, G., Zhao, H. M., & Liu, J. (2024). Effects of microplastics on the environmental behaviors of the herbicide atrazine in soil: Dissipation, adsorption, and bioconcentration. Journal of hazardous materials, 465, 133085. https://doi.org/10.1016/j.jhazmat.2023.133085]
- Effects of sustainable agricultural practices on soil microbial diversity, composition, and functions
  Soil microorganisms can provide multiple benefits to agroecosystems, which are assumed to be promoted by sustainable agricultural practices. However, the mechanisms that explain this relationship have not been clearly elucidated. Although studies have reported that sustainable agricultural practices promote microbial biomass, the broader implications for soil microbial composition and functions remain uncertain. Accordingly, we searched field experiments worldwide contrasting soil microbial communities under conventional and sustainable agricultural practices. We analysed 924 results of relative abundance of bacteria or fungi (using 16 S and ITS rRNA amplicon sequencing, respectively) at the Family taxonomic level obtained from 46 articles. We found higher soil bacterial richness and higher abundance of copiotrophic bacteria under sustainable agricultural practices. Organic fertilisation promoted the abundance of bacteria involved in C and N cycling, while conservation tillage decreased those involved in the decomposition of plant residue. While sustainable agricultural practices had a minor effect on the overall fungal structure, they led to increases in symbiotic fungi abundance (e.g., Geoglossaceae). Additionally, we observed a slight increase in arbuscular mycorrhizal fungi and a slight reduction in pathogenic fungi associated with plant disease (e.g., Botryosphaeriaceae). Higher soil microbial taxonomic diversity did not lead to increased soil multifunctionality; however, it could safeguard resilience for soil functions via the diversity insurance effect. This study establishes that sustainable agricultural practices can significantly influence microbial communities, leading to compositional and structural changes, as well as promoting relevant functions for agroecosystems. Altogether, these results highlight the importance of integrating concepts of community ecology into agricultural management practices for reaching sustainable agricultural systems.
  [Mondaca, P. et al. (2024) ‘Effects of sustainable agricultural practices on soil microbial diversity, composition, and functions’, Agriculture, Ecosystems & Environment, 370, p. 109053. doi:10.1016/j.agee.2024.109053.]
- Exploring negative emission potential of biochar to achieve carbon neutrality goal in China
  Limiting global warming to within 1.5 °C might require large-scale deployment of premature negative emission technologies with potentially adverse effects on the key sustainable development goals. Biochar has been proposed as an established technology for carbon sequestration with co-benefits in terms of soil quality and crop yield. However, the considerable uncertainties that exist in the potential, cost, and deployment strategies of biochar systems at national level prevent its deployment in China. Here, we conduct a spatially explicit analysis to investigate the negative emission potential, economics, and priority deployment sites of biochar derived from multiple feedstocks in China. Results show that biochar has negative emission potential of up to 0.92 billion tons of CO2 per year with an average net cost of US$90 per ton of CO2 in a sustainable manner, which could satisfy the negative emission demands in most mitigation scenarios compatible with China’s target of carbon neutrality by 2060.
  [Deng, X. et al. (2024) Exploring negative emission potential of biochar to achieve carbon neutrality goal in China, Nature Communications. Available at: https://www.nature.com/articles/s41467-024-45314-y. ]
- Harnessing soil carbon sequestration to address climate change challenges in agriculture
  Elevating levels of atmospheric carbon dioxide (CO2), primarily driven by the burning of fossil fuels, combustion of organic matter, and unsustainable land practices, have amplified global concerns regarding climate change. The industrial revolution has propelled the rise in CO2 emissions, leading to anticipated increases in concentrations and alterations in CO2 sequestration within agricultural soils. Land use alterations, encompassing deforestation, biomass burning, changes in agricultural conditions, drainage of natural wetlands, and incorrect soil management practices, have further amplified these emissions. Moreover, the reduction of soil organic carbon (SOC), an outcome of soil degradation and mismanagement, has intensified atmospheric CO2 levels. However, by implementing state-of-the-art land application and contemporary management systems in agriculture, there's potential to slow the rate of CO2 emissions. The restoration of depleted SOC is possible through various strategies, such as converting marginal lands into restorative uses, promoting reduced or zero-tillage practices combined with cover or residue crops, and implementing nutrient cycling via composting, manure application, and other sustainable soil and water management techniques. Long-term soil carbon sequestration is increasingly being viewed as a comprehensive strategy to combat climate change. By rejuvenating depleted soils, enhancing biomass production, purifying surface and groundwater, and offsetting CO2 emissions from fossil fuels, soil carbon sequestration can serve as a holistic and effective approach for mitigating current climatic changes. Adoption of these innovative techniques is crucial in managing the challenges imposed by recent environmental changes, positioning soil carbon sequestration as a promising solution. This review aims to explore the potential methods of mitigating climate change through the implementation of soil carbon sequestration strategies.
  [Nazir, M.J. et al. (2024) Harnessing soil carbon sequestration to address climate change challenges in agriculture, Soil and Tillage Research. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0167198723003264. ]
- Herbicides and pesticides synergistically interact at low concentrations in complex mixtures
  Assessing a complex mixture of pesticides at the impacted sites has been challenging for risk assessors for 50 years. The default assumption is that at low concentrations, pesticides interact additively with one another; thus, the risk posed by each component of a complex mixture could be simply added up. The EPA interaction-based hazard index (HIInteraction) modifies this assumption using a binary weight-of-evidence (BINWOE). However, data gaps often preclude HIInteraction use at most sites. This study evaluated these assumptions using the BINWOE to estimate the hazard index (HI) of select pesticide mixtures. The lack of in vivo binary interaction data led us to use a cell line, SH-SY5Y, to obtain the data necessary for the BINWOE approach. In the risk assessment, we considered the most active exposure scenario inhaling a mixture of volatile pesticides from contaminated soil and groundwater. The potential interactions between pesticides in 15 binary mixtures were investigated using the MTT assay in SH-SY5Y cells. Our findings showed that 60% of the binary mixtures elicited synergism (in at least one concentration), 27% displayed antagonism, and 13% showed additive effects in SH-SY5Y cells. Combining human safety data with in vitro interaction data indicated that adults and toddlers were at the highest risk when considering industrial and commercial land use, respectively, compared to other subpopulations. Incorporating interaction data into the risk assessment either increased the risk by up to 20% or decreased the risk by 2%, depending on the mixture. Our results demonstrate the predominant synergistic interactions, even at low concentrations, altered risk characterization at the complex operating site. Most concerning, organochlorine pesticides with the same mechanism of action did not follow dose additivity when evaluated by SH-SY5Y cell lines. Based on our observations, we caution that current HI methods based on additivity assumptions may underestimate the risk of organochlorine mixtures.
  [Alehashem, M. et al. (2024) Herbicides and pesticides synergistically interact at low concentrations in complex mixtures, Chemosphere. Available at: https://www.sciencedirect.com/science/article/pii/S0045653524003242?via%3Dihub. ]
- Impact of repeated fumigant applications on soil properties, crop yield, and microbial communities in a plastic-mulched tomato production system
  Pre-plant soil fumigation is widely applied to control nematodes, soil-borne fungal pathogens, and weeds in vegetable crops. However, most of the research evaluating the effect of fumigants on crop yield and soil microbial communities has been done on single compounds despite growers mainly applying fumigant combinations. We studied the effect of different fumigant combinations (chloropicrin, 1,3-dichloropropene, and metam potassium) on soil properties, crop yield, and the soil bacterial and fungal microbiome for two consecutive years in a plastic-mulched tomato production system in Florida (United States). While combinations of fumigants did not improve plant productivity more than the individual application of these products, application of fumigants with >60 % chloropicrin did significantly increase yield. Fumigant combinations had no significant effect on bacterial diversity, but fumigants with >35 % chloropicrin reduced soil fungal diversity and induced temporary changes in the soil bacterial and fungal community composition. These changes included short-term increases in the relative abundance of Firmicutes and Ascomycota, as well as decreases in other bacterial and fungal taxa. Repeated fumigation reduced network complexity and the relative abundance of several predicted bacterial functions and fungal guilds, particularly after fumigation and at end of harvest (3-months post fumigation). A structural equation model (SEM) showed fumigants not only directly impact crop yield, but they can also indirectly determine variations in plant productivity through effects on the soil microbiome. Overall, this study increases our understanding of the environmental and agricultural impacts of fumigants in a plastic-mulched tomato production system.
  [Castellano-Hinojosa, A. et al. (2024) Impact of repeated fumigant applications on soil properties, crop yield, and microbial communities in a plastic-mulched tomato production system, Science of The Total Environment. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0048969724007988. ]
- Increased Transmission of Antibiotic Resistance Occurs in a Soil Food Chain under Pesticide Stress
  The rising spread of antibiotic resistance is a global concern, but the pathways of dissemination within soil ecosystems remain poorly understood. Here, we quantified the occurrence of antibiotic resistance genes (ARGs) in gut microbiomes of soil collembolans (Folsomia candida) under pesticide stress (zinc thiazole, ZT) and analyzed the trophic transfer of ARGs to the microbiomes of predatory mites (Hypoaspis aculeifer), natural predators of collembolans. High throughput quantitative PCR was used to quantify ARGs, whereas gut microbiomes of collembolans and mites were characterized using 16S rRNA gene amplicon sequencing, and potential pathogens were identified. Our results revealed that ZT exposure significantly elevated the abundance of ARGs (e.g., AAC(6’)-Ir) in soil collembolan microbiomes. With the increase of ARGs in prey collembolan microbiomes, an increase of ARGs in predatory mite microbiomes was observed through trophic transfer. Mobile genetic elements (MGEs) significantly contribute to the transmission of ARGs within this food chain. Additionally, co-occurrence analysis indicated a strong association between gut resistomes and pathogens, such as Brevundimonas diminuta, in the collembolans and predatory mites. Overall, our study provides evidence for the dissemination of ARGs through the collembolan-predatory mite food chain following pesticide exposure, which is important for understanding the broader dynamics of antibiotic resistance spreading in soil ecosystems.
  [Liu, Z. et al. (2024) Increased Transmission of Antibiotic Resistance Occurs in a Soil Food Chain under Pesticide Stress, Environmental Science & Technology. Available at: https://pubs.acs.org/doi/epdf/10.1021/acs.est.4c07822. ]
- Influence of Pesticides Contamination on Microbial Population of Selected Farmlands
  Pesticides play a pivotal role in agriculture by combating various pests and increasing crop yields. However, extensive use of pesticides can result in unintended consequences, including potential impact on soil microbes. This study was aimed at investigating the influence of pesticides contamination on microbial population of farmlands in Otuoke, Nigeria. Soil samples were collected from four pesticide treated farmlands designated Bakery 1, Bakery 2, Dorcas, and PGS. A farmland without pesticide treatment served as Control. Microbial population, physiochemical parameters and pesticide residue of samples were investigated using standard techniques. Results revealed significant differences in microbial populations between pesticide-contaminated soils and control. The highest bacterium isolated and occurrence (%) in each location was; Streptomyces coelicolor 42(45.7%), Proteus vulgaris 179(59.9%), Streptomyces scabies 41(38.7%), Streptococcus pyrogenes 101(44.7%), and Pseudomonas aeruginosa 69(40.6%) for Bakery 1, Bakery 2, Dorcas, PGS, and control respectively. Highest fungus isolated and occurrence (%) was; Rhodotorula glutini 51(82.3%), 31(77.5%), and 43(81.1%) for Bakery 1, Bakery 2, and Dorcas respectively; and Candida tropicalis 25(80.6%) and Lichtheimia hyalospora 4(28.6%) for PGS and Control respectively. Pesticide analysis showed that Paraquat dichloride, Endosulfan, Diazinon, and N-(phosphonomethyl) glycine were present in the soil samples with about 75% residue. Site-specific pesticide concentrations varied in soil samples, with Bakery 1 having the highest concentrations Endosulfan and Diazinon, bakery 2 had highest concentration of N-(phosphonomethyl) glycine, and PGS had the highest concentration of Paraquat. Physiochemical characteristics showed that temperature ranged from 28.70 – 26.70°C, electrical conductivity 508 – 365µS/cm, moisture content 7.50 – 3.10%, pH 6.90 -3.90, and organic matter 4.70 – 3.00%. Decreasing order of cation exchange capacity (CEC) in farmlands was PGS > Bakery 2 > Bakery 1 > Dorcas > Control. There was no significant difference (p > 0.05) in each parameter between locations.
  [Uneze, D.P., Kugbenu, G.J. and Obire, O. (2024) Influence of pesticides contamination on microbial population of selected farmlands, British Journal of Environmental Sciences. Available at: https://eajournals.org/bjes/vol12-issue-5-2024/influence-of-pesticides-contamination-on-microbial-population-of-selected-farmlands/. ]
- Interaction between imidacloprid residues in maize rhizospheric soil and soil nematode community
  Although imidacloprid has been shown to present potential risks to non-target invertebrates and vertebrates, researches exploring this risk from the perspective of the underground ecosystem remains incomplete. In this study, we determined that the presence of imidacloprid significantly reduced the abundance and diversity of soil nematodes in maize rhizospheric soil. Furthermore, imidacloprid also exerted negative effects on the body length, reproduction, locomotion, lipid accumulation, lipofuscin accumulation, and acetylcholinesterase activity in the model organism Caenorhabditis elegans. These toxic phenotypes are correlated with the upregulation of fat-2, fat-6, hsp-16.41, and hsp-16.2, along with the downregulation of ace-1, ace-2, and ace-3. In response to these toxic effects of imidacloprid, nematodes also developed corresponding adaptive mechanisms. UPLC-MS/MS analysis revealed that nematodes could convert imidacloprid to imidacloprid-guanidine and imidacloprid-urea to reduce the toxicity of imidacloprid. Moreover, C. elegans and Meloidogyne incognita exhibited repellent behavior towards imidacloprid-treated area, even the concentration of imidacloprid is only 0.4 μg/mL. This study revealed the interaction between imidacloprid and nematodes, providing a basis for understanding the potential risks of non-target soil nematodes after application of imidacloprid in sustainable agriculture and the resistance mechanism of nematodes to nematocidal pesticide.
  [Zhang, J. et al. (2024) Interaction between imidacloprid residues in maize rhizospheric soil and soil nematode community, Pesticide Biochemistry and Physiology. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0048357524004528.]
- Interactions of traditional and biodegradable microplastics with neonicotinoid pesticides
  Neonicotinoid pesticides (NNPs) and microplastics (MPs) are two emerging contaminants in agricultural environment. However, the interaction between MPs (especially biodegradable plastics) and NNPs is currently unclear. Therefore, taking thiacloprid (THI) as an example of NNPs, this study explores the adsorption-desorption process and mechanism of NNPs on MPs (traditional and biodegradable plastics), and analyzed the main factors affecting the adsorption (pH, salinity and dissolved organic matter). In addition, by using diffusive gradients in thin-films device, this study assessed the impact of MPs on the bioavailability of NNPs in soil. The results showed that the maximum adsorption capacity of polyamide 6 (96.49 μg g-1) for THI was greater than that of poly (butylene adipate co-terephthalate) (88.78 μg g-1). Aging increased the adsorption amount of THI (5.53 %-15.8 %) due to the higher specific surface area and reduced contact angle of MPs, but the adsorption mechanism remained unchanged. The desorption amount of THI from MPs in simulated intestinal fluid is 1.30-1.36 times. The MPs in soil alter the distribution of THI in the soil, increasing the bioavailability of THI while inhibiting its degradation. The results highlighted the significance of examining the combined pollution caused by MPs and NNPs.
  [Wang, K. et al. (2024) Interactions of traditional and biodegradable microplastics with neonicotinoid pesticides, The Science of The Total Environment. Available at: https://pubmed.ncbi.nlm.nih.gov/38972406/. ]
- Investigating protistan predators and bacteria within soil microbiomes in agricultural ecosystems under organic and chemical fertilizer applications
  Organic farming can enhance biodiversity and soil health and is a sustainable alternative to conventional farming. Yet, soil protists especially protistan predators, have received inadequate attention, and their contributions to the sustainability of organic farming remained underexplored. In this study, we examined soil microbial communities from 379 samples, including both organic and chemically fertilized soils from China. Our findings revealed higher bacterial diversity and increases in plant-beneficial bacteria in organically farmed soils. Notably, organic farming systems facilitated dynamic predator-prey interactions, which may be disrupted by the application of chemical fertilizers. Additionally, organic farming enriched protistan predators, enhancing the relative abundance of functional PGPR, thus improving soil health. We further conducted a case study highlighting the critical role of organic matter in sustaining protistan predator populations and their interactions with bacteria. We propose the crucial contributions of organic inputs for supporting protistan predators and the interplay of predator-prey, ultimately enhancing soil functions and promoting agricultural sustainability.
  [Liu, C. et al. (2024) Investigating protistan predators and bacteria within soil microbiomes in agricultural ecosystems under organic and chemical fertilizer applications, Biology and Fertility of Soils . Available at: https://link.springer.com/article/10.1007/s00374-024-01845-6. ]
- Modeling pesticides and ecotoxicological risk assessment in an intermittent river using SWAT
  The present work aimed to predict the fate of two pesticides, copper (Cu) and glyphosate in a Mediterranean basin with an intermittent river and to assess the ecotoxicological risk related to their presence in water bodies coupling field measurements of streamflow and pesticide concentrations, and an eco-hydrological model. The Soil and Water Assessment Tool (SWAT) model was calibrated and, subsequently used to assess predicted environmental concentrations of pesticides in surface waters. The ecotoxicological risk related to the presence of Cu and glyphosate in surface water was assessed at the reach scale by using the Toxicity to Exposure Ratio approach (TER). Measurements of glyphosate concentrations (< 0.5 μg l−1) exceeded the maximum European threshold of environmental quality standards for pesticides (EQS) of 0.1 μg l−1. High concentrations of glyphosate were predicted in the wet season and in September, when glyphosate is mostly used in vineyards and olive grove productions. Acute risk (TER < 100) associated with the presence of glyphosate was detected for several reaches. High concentrations of Cu (< 6.5 μg l−1), mainly used as a fungicide in vineyards, were predicted in several river reaches. The results of the ecotoxicological risk assessment revealed that November and January were the critical months during which most of the river reaches showed a chronic risk associated with the presence of Cu.
  [Centanni, M. et al. (2024) Modeling pesticides and ecotoxicological risk assessment in an intermittent river using Swat, Scientific Reports. Available at: https://www.nature.com/articles/s41598-024-56991-6#Sec14. ]
- Organic farming promotes the abundance of fungi keystone taxa in bacteria-fungi interkingdom networks
  Soil bacteria-fungi interactions are essential in the biogeochemical cycles of several nutrients, making these microbes major players in agroecosystems. While the impact of the farming system on microbial community composition has been extensively reported in the literature, whether sustainable farming approaches can promote associations between bacteria and fungi is still unclear. To study this, we employed 16S, ITS, and 18S DNA sequencing to uncover how microbial interactions were affected by conventional and organic farming systems on maize crops. The Bray–Curtis index revealed that bacterial, fungal, and arbuscular mycorrhizal fungi communities were significantly different between the two farming systems. Several taxa known to thrive in healthy soils, such as Nitrosophaerales, Orbiliales, and Glomus were more abundant in the organic farming system. Constrained ordination revealed that the organic farming system microbial community was significantly correlated with the β-glucosidase activity, whereas the conventional farming system microbial community significantly correlated with soil pH. Both conventional and organic co-occurrence interkingdom networks exhibited a parallel node count, however, the former had a higher number of edges, thus being denser than the latter. Despite the similar amount of fungal nodes in the co-occurrence networks, the organic farming system co-occurrence network exhibited more than 3-fold the proportion of fungal taxa as keystone nodes than the conventional co-occurrence network. The genera Bionectria, Cercophora, Geastrum, Penicillium, Preussia, Metarhizium, Myceliophthora, and Rhizophlyctis were among the fungal keystone nodes of the organic farming system network. Altogether, our results uncover that beyond differences in microbial community composition between the two farming systems, fungal keystone nodes are far more relevant in the organic farming system, thus suggesting that bacteria-fungi interactions are more frequent in organic farming systems, promoting a more functional microbial community.
  [Matteoli, F.P. et al. (2024) ‘Organic farming promotes the abundance of fungi keystone taxa in bacteria-fungi interkingdom networks’, World Journal of Microbiology and Biotechnology, 40(4). doi:10.1007/s11274-024-03926-y.]
- Organic food has lower environmental impacts per area unit and similar climate impacts per mass unit compared to conventional
  In recent years, interest in studying the climate and environmental impact of organic food has grown. Here, we compared the environmental impacts of organic and conventional food using data from 100 life cycle assessment studies. Most studies focused on climate impacts, with fewer addressing biodiversity loss and ecotoxicity. Findings revealed no significant differences in global warming, eutrophication potential, and energy use per mass unit. However, organic food showed lower global warming, eutrophication potential, and energy use per area unit, with higher land use. Additionally, organic farming showed lower potential for biodiversity loss and ecotoxicity. Challenges in life cycle assessment include evaluating biodiversity, toxicity, soil quality, and carbon changes. The choice of functional units influences results, highlighting the importance of considering multiple units in assessing organic food’s environmental footprint. This study emphasizes the necessity for comprehensive assessments at both product and diet levels to support informed decisions.
  [Hashemi, F. et al. (2024) Organic food has lower environmental impacts per area unit and similar climate impacts per mass unit compared to conventional, Communications Earth & Environment. Available at: https://www.nature.com/articles/s43247-024-01415-6. ]
- Pesticide residues in ornamental plants marketed as bee friendly: Levels in flowers, leaves, roots and soil
  Ornamental plants rich in pollen and nectar are often marketed as “pollinator-friendly” by flower retailers. However, even though the plants are attractive from a foraging perspective, i.e pollen and nectar rich, bees and other pollinating insects could be at risk from exposure of pesticide residues on the plants or from pesticide used during production. Pesticides used in ornamental plant production could lead to environmental emissions both during cultivation, at retailer displays and when planted in gardens by the consumers. This study aims to investigate what pesticides that are used in the production of perennial ornamental plants sold in Sweden and if the residues could pose a risk for wild pollinators. We analyze an array of 536 pesticides in whole flowers, leaves, roots and soil of 54 individual (46 had flowers) perennial plants specifically marketed as “bee friendly”. In addition, seeds from 65 seed bags were analyzed for the same pesticides. Our result show for the first time the distribution of pesticide residues between flowers, leaves, roots and soils of ornamental plants. We also show that all ornamental plants analyzed contained at least one pesticide, and that some samples contained up to 19 different substances.
  [Tove Porseryd, Kristina Volkova Hellström, Patrik Dinnétz, Pesticide residues in ornamental plants marketed as bee friendly: Levels in flowers, leaves, roots and soil, Environmental Pollution, Volume 345, 2024, 123466, ISSN 0269-7491, https://doi.org/10.1016/j.envpol.2024.123466.]
- Relationship between farming practices, soil macrofauna and litter decomposition in organic versus conventional banana agroecosystems
  Many agricultural practices used in conventional farming can have negative impacts on soil biodiversity and decomposition process. Conversion to organic farming could reduce the effect of these disturbances, but in situ consequences of these effects are still poorly investigated. In order to better support the ecological transition towards an organic agriculture in tropical agroecosystems, it is important to better understand the links between agricultural practices, soil macrofauna and the decomposition process. To reach this goal, we conducted a field experiment in banana agroecosystems in Martinique (Lesser Antilles). We selected six organic and six conventional banana fields located in two bioclimatic zones. In order to measure the microbial and macrofaunal contribution to decomposition, 264 litterbags, with either a small or large mesh size, were positioned and left in the field for three months. Glyphosate-contaminated and glyphosate-free banana leaf litters were tested. Biotic and abiotic field characteristics were measured. Our results confirmed the overall beneficial effect of converting to organic agriculture on the decomposition process (+24 %) for bananas leaf litter. Macrofaunal decomposition was increased more (55 %) than microbial decomposition (20 %), indicating that organic farming removes a constraint of conventional farming especially affecting macrofauna. Glyphosate contamination of the litter did not have a significant effect on overall litter decomposition. By using structural equations, we were able to link farming practices to macrofauna diversity and to decomposition process, through a cascading chain of effects. We found that organic farming enhanced macrofaunal contribution to decomposition by enhancing both macro-arthropod and earthworm richness by providing a diversity of microhabitats with dense and species-rich plant cover. Our results suggested a weak effect of the direct toxicity by glyphosate-contaminated litter ingestion, but an indirect effect of herbicides by destroying the soil weed cover providing resources and microhabitats for soil macrofauna. Soil weed cover thus appears to be an important element of the agroecosystem ensuring the sustainability of ecosystem processes.
  [Jaouhari, M., Damour, G. and Coulis, M. (2024) Relationship between farming practices, soil macrofauna and litter decomposition in organic versus conventional banana agroecosystems, Applied Soil Ecology. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0929139324004281. ]
- Size-dependent responses of colony-founding bumblebee (Bombus impatiens) queens to exposure to pesticide residues in soil during hibernation
  Bumblebees and other key pollinators are experiencing global declines, a phenomenon driven by multiple environmental stressors, including pesticide exposure. While bumblebee queens spend most of their life hibernating underground, no study to date has examined how exposure to pesticide-contaminated soils might affect bumblebee queens during this solitary phase of their lifecycle. We exposed Bombus impatiens queens (n = 303) to soil treated with field-realistic concentrations of two diamide insecticides (chlorantraniliprole and cyantraniliprole) and two fungicides (boscalid and difenoconazole), alone or combined, during a 30-week hibernation period. We found that exposure to boscalid residues in soil doubled the likelihood of queens surviving through the colony initiation period (after successful hibernation) and laying eggs. Our data also revealed complex interactions between pesticide exposure and queen body mass on aspects of colony founding. Among others, exposure to cyantraniliprole led to lethal and sublethal post-hibernation effects that were dependent on queen size, with larger queens showing higher mortality rates, delayed emergence of their first brood, and producing smaller workers. Our results show that effects of pesticide exposure depend on intrinsic traits of bumblebee queen physiology and challenge our understanding of how bees respond to pesticides under environmentally realistic exposure scenarios.
  [Rondeau, S. and Raine, N. (2024) Size-dependent responses of colony-founding bumblebee (Bombus impatiens) queens to exposure to pesticide residues in soil during hibernation, The Science of the Total Environment. Available at: https://pubmed.ncbi.nlm.nih.gov/39029756/. ]
- Soil chemical fumigation alters soil phosphorus cycling: effects and potential mechanisms
  Soil chemical fumigation is an effective and popular method to increase agricultural productivity. However, the broad-spectrum bioactivity of fumigants causes harm to soil beneficial microorganisms involved in the soil phosphorous cycle, such as soil phosphorus solubilizing microorganisms (PSMs). We review the effects of soil chemical fumigation on soil phosphorus cycling, and the potential underlying mechanisms that ultimately lead to altered phosphorus availability for crops. These complex processes involve the highly diverse PSM community and a plethora of soil phosphorus forms. We discuss phosphatizing amendments aimed at counteracting the possible negative effects of fumigation on phosphorus availability, phosphorus use efficiency, and crop yields. We also emphasize distinguishing between the effects on soil phosphorus cycling caused by the chemical fumigants, and those caused by the fumigation process (e.g. plastic mulching). These are typically conflated in the literature; distinguishing them is critical for identifying appropriate amendments to remediate possible post-fumigation soil phosphorus deficiencies.
  [Wang, Y. and Tang, D.W.S. (2024) Soil chemical fumigation alters soil phosphorus cycling: effects and potential mechanisms, Frontiers in Plant Science. Available at: https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1289270/full. ]
- The Role of Biodiversity in Agricultural Resilience: Protecting Ecosystem Services for Sustainable Food Production
  Biodiversity plays a fundamental role in enhancing agricultural resilience and sustaining food production by supporting critical ecosystem services. A diverse array of species within agroecosystems, from crops and livestock to soil organisms and pollinators, contributes to the stability, productivity, and adaptability of farming systems. This biodiversity-driven resilience is essential for mitigating the impacts of climate change, pests, diseases, and resource scarcity, which pose significant threats to global food security. Agricultural systems rich in biodiversity benefit from improved soil fertility, enhanced pollination, natural pest control, and water regulation, all of which reduce dependence on external inputs such as chemical fertilizers and pesticides. Moreover, maintaining genetic diversity within crops and livestock strengthens resilience against environmental stressors and promotes long-term sustainability. However, modern intensive agricultural practices, including monocropping and the overuse of agrochemicals, have resulted in significant biodiversity loss, compromising ecosystem health. This article explores the role of biodiversity in agricultural resilience, examines the threats posed by conventional farming practices, and discusses strategies for integrating biodiversity into agricultural systems to protect ecosystem services. By fostering biodiversity, farmers and policymakers can enhance the sustainability and resilience of agricultural landscapes, contributing to global food security in a changing climate.
  [Christianah, D. and Folarin, I. (2024) The Role of Biodiversity in Agricultural Resilience: Protecting Ecosystem Services for Sustainable Food Production, International Journal of Research Publication and Reviews. Available at: https://www.researchgate.net/publication/384848907_The_Role_of_Biodiversity_in_Agricultural_Resilience_Pr]
- A holistic review on trend, occurrence, factors affecting pesticide concentration, and ecological risk assessment
  Demographic outbursts and increased food demands invoke excessive use of pesticides in the agricultural field for increasing productivity which leads to the relentless decline of riverine health and its tributaries. These tributaries are connected to a plethora of point and non-point sources that transport pollutants including pesticides into the Ganga river's mainstream. Simultaneous climate change and lack of rainfall significantly increase pesticide concentration in the soil and water matrix of the river basin. This paper is intended to review the paradigm shift of pesticide pollution in the last few decades in the river Ganga and its tributaries. Along with this, a comprehensive review suggests the ecological risk assessment method which facilitates policy development, sustainable riverine ecosystem management, and decision-making. Before 2011, the total mixture of Hexachlorocyclohexane was found at 0.004-0.026 ng/mL in Hooghly, but now, the concentration has increased up to 0.465-4.132 ng/mL. Aftermath of critical review, we observed maximum residual commodities and pesticide contamination reported in Uttar Pradesh > West Bengal > Bihar > Uttara Khand possibly because of agricultural load, increasing settlement, and incompetency of sewage treatment plant in the reclamation of pesticide contamination.
  [Singh, R.P., Mahajan, M., Gandhi, K., Gupta, P.K., Singh, A., Singh, P., Singh, R.K. and Kidwai, M.K., 2023. Environmental Monitoring and Assessment, 195(4), p.451.]
- A review on arsenic in the environment: contamination, mobility, sources, and exposure
  Arsenic is one of the regulated hazard materials in the environment and a persistent pollutant creating environmental, agricultural and health issues and posing a serious risk to humans. In the present review, sources and mobility of As in various compartments of the environment (air, water, soil and sediment) around the World are comprehensively investigated, along with measures of health hazards. Multiple atomic spectrometric approaches have been applied for total and speciation analysis of As chemical species. The LoD values are basically under 1 μg L−1, which is sufficient for the analysis of As or its chemical species in environmental samples. Both natural and anthropogenic sources contributed to As in air, while fine particulate matter tends to have higher concentrations of arsenic and results in high concentrations of As up to a maximum of 1660 ng m−3 in urban areas. Sources for As in natural waters (as dissolved or in particulate form) can be attributed to natural deposits, agricultural and industrial effluents, for which the maximum concentration of 2000 μg L−1 was found in groundwater. Sources for As in soil can be the initial contents, fossil fuel burning products, industrial effluents, pesticides, and so on, with a maximum reported concentration up to 4600 mg kg−1. Sources for As in sediments can be attributed to their reservoirs, with a maximum reported concentration up to 2500 mg kg−1. It is notable that some reported concentrations of As in the environment are several times higher than permissible limits. However, many aspects of arsenic environmental chemistry including contamination of the environment, quantification, mobility, removal and health hazards are still unclear.
  [Patel, K.S. et al. (2023) A review on arsenic in the environment: Contamination, mobility, sources, and exposure, RSC advances. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10020839/. ]
- An insight into the sorption kinetics of boscalid onto soils: Effect of general soil properties
  Boscalid is a carboxamide fungicide widely used for crop protection, however owing to its high persistence, it is detected in high concentrations in various environments. Since the fate of such xenobiotics is strongly influenced by its interaction with soil components a better understanding of its adsorption onto soils of varying properties could allow the adjustment of its application in a given agro-ecological region to limit the consequent environmental burden. The present investigation was carried out to examine the kinetics of boscalid adsorption onto ten Indian soils of varying physico-chemical properties. Kinetic data of boscalid for all soils under investigation fitted well to both pseudo-first-order and pseudo-second-order kinetic models. However, based on the standard error of estimate (S.E.est.) values pseudo-first-order model was better for all soil samples, except one soil which had the lowest readily oxidizable organic carbon. Adsorption of boscalid by soils appeared to be controlled by the diffusion-chemisorption process while for soils especially rich in readily oxidizable organic carbon or clay + silt content the intra-particle diffusion process seemed to be more important. Stepwise regression of kinetic parameters on soil properties revealed that the inclusion of a set of some soil properties could help better prediction of adsorbed amounts of boscalid and kinetic constants. These findings may help assess the fate and possible transport of boscalid fungicide in different soils.
  [Bhatt, D., Srivastava, A., & Srivastava, P. C. (2023). An insight into the sorption kinetics of boscalid onto soils: Effect of general soil properties. Chemosphere, 325, 138274. https://doi.org/10.1016/j.chemosphere.2023.138274]
- Bioaccumulation and toxicity of terbuthylazine in earthworms (Eisenia fetida)
  Terbuthylazine is an effective and widely used s-triazine herbicide. However, limited data exists on its toxicity and bioaccumulation in earthworms (Eisenia fetida). In this study, we investigated the bioaccumulation, antioxidant enzyme activity, detoxification enzyme activity, and DNA damage in earthworms when exposed to terbuthylazine. The results indicated that terbuthylazine in soil had low bioaccumulation in earthworms and the biota-soil accumulation factors of terbuthylazine declined with an increasing soil terbuthylazine concentration. In the enzyme activity assays, the superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST) activities showed upward trends when compared with the control. The carboxylesterase (CarE) activity increased on day 21. The 8-hydroxy-2-deoxyguanosine (8-OHdG) content, a DNA damage bioindicator, was higher than that of the control on day 21. Combined with the integrated biological response index version 2 analysis, these results can provide a comprehensive evaluation of the toxicological effects that terbuthylazine has on earthworms and soil ecosystems.
  [Li, S., Yuan, Y., Wang, X., Cai, L., Wang, J., Zhao, Y., Jiang, L., & Yang, X. (2023). Bioaccumulation and toxicity of terbuthylazine in earthworms (Eisenia fetida). Environmental toxicology and pharmacology, 97, 104016. https://doi.org/10.1016/j.etap.2022.104016]
- Biopesticides as a promising alternative to synthetic pesticides: A case for microbial pesticides, phytopesticides, and nanobiopesticides
  Over the years, synthetic pesticides like herbicides, algicides, miticides, bactericides, fumigants, termiticides, repellents, insecticides, molluscicides, nematicides, and pheromones have been used to improve crop yield. When pesticides are used, the over-application and excess discharge into water bodies during rainfall often lead to death of fish and other aquatic life. Even when the fishes still live, their consumption by humans may lead to the biomagnification of chemicals in the body system and can cause deadly diseases, such as cancer, kidney diseases, diabetes, liver dysfunction, eczema, neurological destruction, cardiovascular diseases, and so on. Equally, synthetic pesticides harm the soil texture, soil microbes, animals, and plants. The dangers associated with the use of synthetic pesticides have necessitated the need for alternative use of organic pesticides (biopesticides), which are cheaper, environment friendly, and sustainable. Biopesticides can be sourced from microbes (e.g., metabolites), plants (e.g., from their exudates, essential oil, and extracts from bark, root, and leaves), and nanoparticles of biological origin (e.g., silver and gold nanoparticles). Unlike synthetic pesticides, microbial pesticides are specific in action, can be easily sourced without the need for expensive chemicals, and are environmentally sustainable without residual effects. Phytopesticides have myriad of phytochemical compounds that make them exhibit various mechanisms of action, likewise, they are not associated with the release of greenhouse gases and are of lesser risks to human health compared to the available synthetic pesticides. Nanobiopesticides have higher pesticidal activity, targeted or controlled release with top-notch biocompatibility and biodegradability. In this review, we examined the different types of pesticides, the merits, and demerits of synthetic pesticides and biopesticides, but more importantly, we x-rayed appropriate and sustainable approaches to improve the acceptability and commercial usage of microbial pesticides, phytopesticides, and nanobiopesticides for plant nutrition, crop protection/yield, animal/human health promotion, and their possible incorporation into the integrated pest management system.
  [Ayilara, M.S. et al. (2023) Biopesticides as a promising alternative to synthetic pesticides: A case for microbial pesticides, phytopesticides, and nanobiopesticides, Frontiers in Microbiology. Available at: https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1040901/full. ]
- Combined ecotoxicological effects of different-sized polyethylene microplastics and imidacloprid on the earthworms (Eisenia fetida)
  Microplastics (MPs) and pesticides frequently coexist in farmland soil; however, there are relatively few studies on the ecological risk assessment of soil animals attributed to the combined pollution caused by MPs and pesticides. Moreover, the influence of particle size on the combined toxic effects of MPs and pesticides remains poorly understood. In this study, different-sized polyethylene MPs (PE MPs; 10 μm, 500 μm, and 2 mm) were combined with a series of imidacloprid concentrations (IMI; 0.10, 0.50 and 1.00 mg/kg), and earthworms (Eisenia fetida) were exposed to these MP and IMI combinations for 28 d to explore the combined toxic effects and mechanisms. The results showed, compared with IMI or PE MPs exposure alone, the combined exposure of IMI and PE MPs did not substantially increase the acute toxicity of earthworms but significantly inhibited weight increase and induced more serious epidermal damage to earthworms with a size effect; among these 10 μm PE MPs combined with IMI exhibited the strongest toxic effects. In addition, the combined exposure decreased antioxidant enzymes activity and caused oxidative damage in earthworms. Transcriptome results demonstrated most of the treatment combinations affected the ferroptosis pathway, which was further verified by the increase in the total iron content, reactive oxygen species, and malondialdehyde content in earthworms. Combined with the analysis of key signalling pathways, the above results revealed that the combined exposure to IMI and PE MPs showed stronger toxicity to earthworms than exposure to either IMI or MPs alone, which was mediated by the superimposed effect of ferroptosis and oxidative damage. Moreover, the effect was size-dependent, with 10 μm PE MPs combined with IMI exhibiting the strongest toxic effects. This study aimed to provide data to support the ecological risk assessment of soil animals caused by the combined pollution of MPs and coexisting pesticides.
  [Fu, H., Zhu, L., Mao, L., Zhang, L., Zhang, Y., Chang, Y., Liu, X., & Jiang, H. (2023). Combined ecotoxicological effects of different-sized polyethylene microplastics and imidacloprid on the earthworms (Eisenia fetida). The Science of the total environment, 870, 161795. https://doi.org/10.1016/j.scitotenv.2023.161795]
- Directly Fluorinated Containers as a Source of Perfluoroalkyl Carboxylic Acids
  Direct fluorination of plastics is performed to impart chemical resistance via exposure of polyethylene to fluorine gas to produce a fluorine-modified surface layer. Leaching experiments were performed on a directly fluorinated container under various conditions and with different matrices, including foodstuffs. The average sum of per- and polyfluoroalkyl substances (PFAS) concentrations measured from extraction of a fluorinated container was 63.75 ± 13.2 ng/g plastic. Seven-day leaching experiments of fluorinated containers with water, methanol, and acetone produced sums of PFAS concentrations that ranged from 0.99 to 66.92 ng/g plastic. Leaching experiments with food matrices produced sums of PFAS concentrations ranging from 2.66 to 7.19 ng/g plastic. A subset of samples subjected to leaching at elevated temperatures generated sums of PFAS concentrations up to 830% higher. In all experiments, short-chain perfluoroalkyl carboxylic acids (PFCAs) were detected in the highest frequencies and concentrations with analyte concentration decreasing as chain length increased. An estimate for PFAS released into food ranged from 0.77 to 2.68 ng/kg body weight per week, showing ingestion of food stored in these containers could be a significant source of exposure. Based on the large number of applications where directly fluorinated containers find use, the observation of PFAS migration suggests use regulations are warranted, and future studies should explore their fate when disposed or recycled.
  [Whitehead, H.D. and Peaslee, G.F., 2023. Environmental Science & Technology Letters, 10(4), pp.350-355.]
- Driving factors on accumulation of cadmium, lead, copper, zinc in agricultural soil and products of the North China Plain
  The accumulation of heavy metals in agricultural soils concerns food security. By using the Geographical Detector, this study investigated the influence of six types of factors (eleven factors) on the accumulation of Cd, Pb, Cu, Zn in agricultural soil and products of the North China Plain and confirmed the dominant factor. The results showed that heavy metals had accumulated in regional agricultural soils and the accumulation of Cd was severe. The accumulation of heavy metals was significantly influenced by policy factors (the management and reduction in usage of fertilizers and pesticides), fertilization factors (application of organic and chemical fertilizers), pesticide factors (application of herbicide and insecticide) and atmospheric deposition factors (heavy metal concentration in atmospheric deposition). The policy factor dominated the other three types of factors. Atmospheric deposition and the excess application of fertilizers and pesticides directly lead to the accumulation of heavy metals. Due to the high concentrations of heavy metals and abundant application amounts, organic fertilizers have contributed high levels of heavy metals to agricultural soils. This study suggests that formulated fertilization and action plans for pesticide reduction could effectively decrease the accumulation of heavy metals in agricultural soils and products in the study area.
  [Liu, Z., Bai, Y., Gao, J. and Li, J., 2023. Scientific Reports, 13(1), p.7429.]
- Farmer perspectives on carbon markets incentivizing agricultural soil carbon sequestration
  Climate change mitigation efforts to achieve net-zero emissions require not only decreasing current greenhouse gas emissions, but also the deployment of negative emissions technologies. Soil organic carbon sequestration in agricultural lands is one such negative emissions strategy, currently being incentivized predominantly through voluntary carbon offset markets. Through semi-structured interviews, we assess both conventional and organic farmer perspectives on soil carbon offset programs that have been created in the United States since 2017. The perspectives of farmers both participating and not participating in agricultural soil carbon markets were similar and consistent. Farmers in both groups expressed concerns about the convoluted, burdensome and unpredictable nature of receiving offset credits and emphasized that they were implementing practices for their own business interests and sustainability concerns, not the financial incentive of the generation of carbon credits. Based on our research, carbon offset credit payments for agricultural soil carbon sequestration are largely reaching farmers who were already implementing these beneficial practices or were already strongly interested in implementing these practices, and the payments for the offset credits are seen as a ‘gravy on top’, suggesting that these offset markets face strong challenges of ensuring true additionality essential to effective climate mitigation.
  [Barbato, C.T. and Strong, A.L. (2023) Farmer perspectives on carbon markets incentivizing agricultural soil carbon sequestration, Climate Action. Available at: https://www.nature.com/articles/s44168-023-00055-4. ]
- Harnessing of plant growth-promoting rhizobacteria and arbuscular mycorrhizal fungi in agroecosystem sustainability
  Background
  Soil microorganisms including rhizobacteria and fungi play a key role in soil health, biodiversity and productivity of natural and managed ecosystems. Plant growth-promoting rhizobacteria (PGPR) associated with plant roots enhance the uptake of nutrient and improve productivity. Similarly, mycorrhizal fungi particularly, arbuscular mycorrhizal fungi (AMF), form a mutualistic association with plants and enhance nutrients uptake and consequently promote plant growth and productivity.
  
  Methods
  Here we show how harnessing beneficial soil microorganisms like PGPR and AMF with their positive effect on plant development can contribute to the green and clean economic growth strategy.
  
  Results
  Through a review of the state-of -art knowledge in this area we demonstrate that this approach can improve uptake of nutrients, enhance plant growth, yield and tolerance to biotic and abiotic stress. We argue that this approach can reduce the need for agrochemicals that destabilizes the ecological system.
  
  Conclusions
  This review provides a state-of-the-art synthesis of the knowledge generated so far and insight into the multifunctional strategies employed by AMF and PGPR toward ensuring sustainable agriculture.
  [Fasusi, O.A., Babalola, O.O. & Adejumo, T.O. Harnessing of plant growth-promoting rhizobacteria and arbuscular mycorrhizal fungi in agroecosystem sustainability. CABI Agric Biosci 4, 26 (2023). https://doi.org/10.1186/s43170-023-00168-0]
- Intensive vegetable production under plastic mulch: A field study on soil plastic and pesticide residues and their effects on the soil microbiome
  Intensive agriculture relies on external inputs to reach high productivity and profitability. Plastic mulch, mainly in the form of Low-Density Polyethylene (LDPE), is widely used in agriculture to decrease evaporation, increase soil temperature and prevent weeds. The incomplete removal of LDPE mulch after use causes plastic contamination in agricultural soils. In conventional agriculture, the use of pesticides also leaves residues accumulating in soils. Thus, the objective of this study was to measure plastic and pesticide residues in agricultural soils and their effects on the soil microbiome. For this, we sampled soil (0–10 cm and 10–30 cm) from 18 parcels from 6 vegetable farms in SE Spain. The farms were under either organic or conventional management, where plastic mulch had been used for >25 years. We measured the macro- and micro-light density plastic debris contents, the pesticide residue levels, and a range of physiochemical properties. We also carried out DNA sequencing on the soil fungal and bacterial communities. Plastic debris (>100 μm) was found in all samples with an average number of 2 × 103 particles kg−1 and area of 60 cm2 kg−1. We found 4–10 different pesticide residues in all conventional soils, for an average of 140 μg kg−1. Overall, pesticide content was ∼100 times lower in organic farms. The soil microbiomes were farm-specific and related to different soil physicochemical parameters and contaminants. Regarding contaminants, bacterial communities responded to the total pesticide residues, the fungicide Azoxystrobin and the insecticide Chlorantraniliprole as well as the plastic area. The fungicide Boscalid was the only contaminant to influence the fungal community. The wide spread of plastic and pesticide residues in agricultural soil and their effects on soil microbial communities may impact crop production and other environmental services. More studies are required to evaluate the total costs of intensive agriculture.
  [Beriot, N., Zornoza, R., Lwanga, E. H., Zomer, P., van Schothorst, B., Ozbolat, O., Lloret, E., Ortega, R., Miralles, I., Harkes, P., van Steenbrugge, J., & Geissen, V. (2023). Intensive vegetable production under plastic mulch: A field study on soil plastic and pesticide residues and their effects on the soil microbiome. The Science of the total environment, 900, 165179. https://doi.org/10.1016/j.scitotenv.2023.165179]
- Interactions of Microplastics with Pesticides in Soils and Their Ecotoxicological Implications
  Abstract
  
  In the middle of the 20th century, the production of plastics exploded worldwide because of their low cost and the versatility of their applications. However, since plastic debris is highly resistant to environmental degradation, a growing presence of plastics in all the ecosystems has been confirmed. Among them, plastic particles < 5 mm, also known as microplastics (MPs), are of special concern because they are dispersed in aerial, terrestrial and aquatic environments, being the soil the main environmental sink of these contaminants. Due to their large specific surface area and hydrophobicity, MPs are considered good adsorbents for other environmental organic pollutants also present in terrestrial ecosystems, such as pharmaceuticals, personal-care products or pesticides with which they can interact and thus modify their environmental fate. In this review article, we examine the recent literature (from 2017 to 2022) to get a better understanding of the environmental fate of pesticides in soil (adsorption, mobility and/or degradation) when they are simultaneously present with MPs and the ecological risks on living organisms of the interactions between MPs and pesticides in soil. More studies are needed to fully understand the toxicological impact of the copresence in soil of pesticides and MPs.
  
  [Peña, A., Rodríguez-Liébana, J.A. and Delgado-Moreno, L. (2023) ‘Interactions of microplastics with pesticides in soils and their ecotoxicological implications’, Agronomy, 13(3), p. 701. doi:10.3390/agronomy13030701. ]
- Metabolic Consequences of the Water We Drink: A Study Based on Field Evidence and Animal Model Experimentation
  The effect of the chronic consumption of water contaminated with residual concentrations of DDT's metabolites (DDD-dichlorodiphenyldichloroethane and DDE-dichlorodiphenyldichloroethylene) found in the environment were evaluated on the biometric, hematological and antioxidant system parameters of the hepatic, muscular, renal and nervous tissues of Wistar rats. The results showed that the studied concentrations (0.002 mg.L-1 of DDD plus 0.005 mg.L-1 of DDE) could not cause significant changes in the hematological parameters. However, the tissues showed significant alteration in the activity of the antioxidant system represented by the increase in the activity of the enzymes gluthathione S-transferases in the liver, superoxide dismutase in the kidney, gluthathione peroxidase in the brain, and several changes in enzymatic activity in muscle (SOD, GPx and LPO). The enzymes alanine aminotransaminase (ALT) and aspartate aminotransaminase (AST) were also evaluated for the amino acids' metabolism in the liver, with ALT showing a significant increase in the exposed animals. In the integrative analysis of biomarkers (Permanova and PCOA), the studied concentrations showed possible metabolic changes and damage to cellular structures evidenced by increased oxidative stress and body weight gain among the treated animals. This study highlights the need for further studies on the impact of banned pesticides still present in soils that may induce adverse effects in organisms that may prevail in future generations and the environment.
  [Wolfart, J.C., Theodoro, J.L., Silva, F.C., de Oliveira, C.M.R., Ferreira, N.G. and Bittencourt Guimarães, A.T., 2023. Toxics, 11(4), p.315.]
- Persistence of triclopyr, dicamba, and picloram in the environment following aerial spraying for control of dense pine invasion
  Aerial application of an herbicide mixture of triclopyr, dicamba, picloram, and aminopyralid is used to control dense infestations of exotic conifers, notably lodgepole pine (Pinus contorta Douglas ex Loudon), in New Zealand. The rates of herbicide applied to control these tree weeds has the potential for off-target impacts through persistence in the forest floor, soil, and water. Persistence of three of these herbicides was investigated in cast needles, forest floor (litter, fermented humic layer [LFH]), and soil following their operational aerial application (triclopyr: 18 kg ai ha−1; dicamba: 5 kg ai ha−1; picloram: 2 kg ai ha−1) at three sites across New Zealand (KF, MD, GE) with dense invasions of P. contorta. Water was collected from a local stream at two sites (KF, MD) in the days/months after spraying. Active ingredients detected across all sites in cast needles, LFH, and mineral soil generally reflected their application rates, with total amounts comprising 81% triclopyr, 14% dicamba, and 5% picloram. Most of the active ingredients were detected in the LFH (59%), a heavy lignin-rich layer of dead needles overlaying the soil. All three herbicides persisted in this layer, at all sites, for up to 2 yr (at study termination). Only triclopyr was detected in mineral soil, where it declined to below detection levels (0.2 mg kg−1) within 1 yr. All three herbicides were detected in stream water on the day of spray application at KF, and during a rainfall event 1 mo later. However, amounts did not exceed New Zealand environmental and drinking water standards, an outcome attributed to a 30-m no-spray buffer zone used at this site. At MD, herbicides were detectable in water up to 4 mo after spraying, with amounts exceeding New Zealand drinking water standards on one occasion, 1 mo after spray application. No spray buffer zones were used at the MD site.
  [Rolando, C.A. et al. (2023) Persistence of Triclopyr, dicamba, and Picloram in the environment following aerial spraying for control of dense pine invasion, Invasive Plant Science and Management. Available at: https://www.cambridge.org/core/journals/invasive-plant-science-and-management/article/persistence-of-triclopyr-dicamba-and-picloram-in-the-environment-following-aerial-spraying-for-control-of-dense-pine-invasion/EC888894C5B7A927AD5E5A3E0C06CD8D. ]
- Pesticide bioaccumulation in radish produced from soil contaminated with microplastics
  The aging of microplastics (MPs) in soils may affect crop bioaccumulation of coexisting contaminants. We examined the bioaccumulation of pesticides (chlorpyrifos (CPF), difenoconazole (DIF) and their mixture) in radish (Raphanus sativus) planted in soils contaminated with MPs (low-density polyethylene or biodegradable MPs). The experiment was conducted with different contamination scenarios taking into account the use of aged MPs and pesticide mixtures. Radish root biomass was negatively affected in the scenarios with aged MPs. CPF bioaccumulation in radishes appears to be enhanced by the presence of MPs, especially aged MPs, and the pesticide mixture. The results show that food safety risks associated with the bioaccumulation of individual pesticides and their mixtures are increased in soils polluted by MPs, particularly MP after aging.
  [Ju, Hui & Yang, Xiaomei & Tang, Darrell & Osman, Rima & Geissen, Violette. (2023). Pesticide bioaccumulation in radish produced from soil contaminated with microplastics. Science of The Total Environment. 910. 168395. 10.1016/j.scitotenv.2023.168395. ]
- Pesticide interference and additional effects on plant microbiomes
  Pesticides are essential to modern human production activities, particularly those increasing global food production and quality; however, corresponding pesticide contamination is becoming more prominent. Plant microbiomes, containing different assemblages of microbial communities in the rhizosphere, endosphere, and phyllosphere, in addition to the mycorrhizal microbiome, substantially impact plant health and productivity. Therefore, the relationships among pesticides, plant microbiomes, and plant communities are important to evaluate the ecological safety of pesticides. To date, the majority of research efforts aimed at understanding the effects of pesticides on microbial communities have focused on single niche microbiomes. However, a comprehensive review of the effects of pesticides on microbial communities and co-occurrence patterns in different ecological niches is still lacking. This review fills this gap by providing an overview of the effects of pesticides on plant microbial communities across ecological niches. Specifically, we discuss the potential feedback and risks associated with these effects on plant health. Through a thorough examination of the available literature, we provide a comprehensive perspective of the impacts of pesticides on plant microbiomes, which may facilitate the development of effective strategies to mitigate these effects.
  [Yu, Zhitao & Lu, Tao & Qian, Haifeng. (2023). Pesticide interference and additional effects on plant microbiomes. The Science of the total environment. 888. 164149. 10.1016/j.scitotenv.2023.164149. ]
- Plastic contamination in agricultural soils: a review
  Researchers are focused on the global issue of plastic contamination in agricultural soils because of the known effects of plastics on the soil ecosystem. Previous reviews did not pay attention to plastic sources, standardized extraction methods, soil characterization, and the abundance of plastics in agricultural soils. This study aims to review up-to-the-minute knowledge about plastic contamination studies, suggest the best method for microplastic studies, and propose future research areas. The research about plastic contamination in agricultural soils published from January 2018 to March 2022 was reviewed for this review article. Studies focusing on microplastics in soils other than agricultural soils were not considered in the present review. The data were acquired from several databases, namely Web of Science and Google Scholar. The keywords used to search these databases were "microplastics AND agricultural soils" and "macroplastics AND agricultural soils". Other literature sources were obtained from the reference lists of downloaded articles, and other pieces of literature that directly dealt with macroplastic and microplastic contamination in agricultural soils were obtained from relevant journals and books. Overall, 120 sources of literature, including 102 original research articles, 13 review articles, and five books, were selected, reviewed, and synthesized. As expected, agricultural soils, including arable lands, paddy lands, uplands, irrigation, and greenhouse soils, receive plastic contaminants. The contaminants of different sizes and forms are distributed spatially and temporally in the surface, subsurface, and profiles of the agricultural soils. Unlike previous studies that reported many studies on sewage sludge, the significant sources of plastic contamination in the agricultural soils included mulching, sludge and compost placement, and greenhouses abandonment. The distribution of plastic contamination studies in the agricultural lands is Asia: 60%; Europe: 29%; Africa: 4%; North America: 4%; Latin America: 3%; and Australia: 0%. After careful analysis of the methods used for the plastics contamination studies, the study concluded that floatations with low-density solutions such as distilled water and NaCl are efficient in separating light-density microplastics. In contrast, ZnCl and NaI are incredibly efficient in separating the heavy-density microplastics. Moreover, this review provides insight for future research in the field.
  [Sa’adu, I. and Farsang, A. (2023) Plastic contamination in agricultural soils: A Review, Environmental Sciences Europe. Available at: https://enveurope.springeropen.com/articles/10.1186/s12302-023-00720-9. ]
- Residues and Bioavailability of Neonicotinoid Pesticide in Shaanxi Agricultural Soil
  Shaanxi is an important agricultural province in China. The rapid development of agriculture has led to an increase in the use of pesticides, which has resulted in a serious pesticide pollution problem. In addition, assessing the total residue concentrations would overestimate the actual hazard of neonicotinoid pesticides, so it is essential to study the bioavailability of neonicotinoid pesticides. In the study, 115 soil samples collected from different areas from northern, central, and southern Shaanxi were used to determine the residues of four neonicotinoid pesticides: imidacloprid, acetamiprid, clothianidin, and thiamethoxam. An analytical method applied to assess the bioavailability of neonicotinoid pesticides was established, the bioavailability of different types of neonicotinoid pesticides and related factors affecting their bioavailability were determined, and the changes in the bioavailability of neonicotinoid pesticides in actual and simulated soils were explored. The results showed that the detection rates and residue levels of neonicotinoid pesticides varied in different regions of Shaanxi. By studying the bioavailability of neonicotinoid pesticides, it was found that the bioavailability of the four neonicotinoid pesticides was always: thiamethoxam > acetamiprid > imidacloprid > clothianidin, which may be related to their structural properties. Soil pH is positively related to the size of the bioavailability of neonicotinoid pesticides, while soil organic matter content and soil aging time are negatively related to the size of the bioavailability of neonicotinoid pesticides.
  [Hua, L., Zhao, D., Wang, H. et al. Residues and Bioavailability of Neonicotinoid Pesticide in Shaanxi Agricultural Soil. Water Air Soil Pollut 234, 129 (2023). https://doi.org/10.1007/s11270-023-06159-1]
- Time to Treat the Climate and Nature Crisis as One Indivisible Global Health Emergency
  Over 200 health journals call on the United Nations, political leaders, and health professionals to recognize that climate change and biodiversity loss are one indivisible crisis and must be tackled together to preserve health and avoid catastrophe. This overall environmental crisis is now so severe as to be a global health emergency.
  
  The world is currently responding to the climate crisis and the nature crisis as if they were separate challenges. This is a dangerous mistake. The 28th Conference of the Parties (COP) on climate change is about to be held in Dubai while the 16th COP on biodiversity is due to be held in Turkey in 2024. The research communities that provide the evidence for the 2 COPs are unfortunately largely separate, but they were brought together for a workshop in 2020 when they concluded that “Only by considering climate and biodiversity as parts of the same complex problem…can solutions be developed that avoid maladaptation and maximize the beneficial outcomes.”
  
  As the health world has recognized with the development of the concept of planetary health, the natural world is made up of one overall interdependent system. Damage to one subsystem can create feedback that damages another—for example, drought, wildfires, floods, and the other effects of rising global temperatures destroy plant life and lead to soil erosion and so inhibit carbon storage, which means more global warming. Climate change is set to overtake deforestation and other land-use change as the primary driver of nature loss.
  
  Nature has a remarkable power to restore. For example, deforested land can revert to forest through natural regeneration, and marine phytoplankton, which act as natural carbon stores, turn over 1 billion tons of photosynthesizing biomass every 8 days. Indigenous land and sea management has a particularly important role to play in regeneration and continuing care.
  
  Restoring one subsystem can help another—for example, replenishing soil could help remove greenhouse gases from the atmosphere on a vast scale. But actions that may benefit one subsystem can harm another—for example, planting forests with one type of tree can remove carbon dioxide from the air but can damage the biodiversity that is fundamental to healthy ecosystems.
  [Abbasi K, Ali P, Barbour V, et al. Time to Treat the Climate and Nature Crisis as One Indivisible Global Health Emergency. JAMA. 2023;330(20):1958–1960. doi:10.1001/jama.2023.20840]
- Advances and future prospects of pyrethroids: Toxicity and microbial degradation
  Pyrethroids are a class of insecticides structurally similar to that of natural pyrethrins. The application of pyrethrins in agriculture and pest control lead to many kinds of environmental pollution affecting human health and loss of soil microbial population that affect soil fertility and health. Natural pyrethrins have been used since ancient times as insect repellers, and their synthetic versions especially type 2 pyrethroids could be highly toxic to humans. PBO (Piperonyl butoxide) is known to enhance the toxicity of prallethrin in humans due to the resistance in its metabolic degradation. Pyrethroids are also known to cause plasma biochemical profile changes in humans and they also lead to the production of high levels of reactive oxygen species. Further they are also known to increase SGPT activity in humans. Due to the toxicity of pyrethrins in water bodies, soils, and food products, there is an urgent need to develop sustainable approaches to reduce their levels in the respective fields, which are eco-friendly, economically viable, and socially acceptable for on-site remediation. Keeping this in view, an attempt has been made to analyse the advances and prospects in using pyrethrins and possible technologies to control their harmful effects. The pyrethroid types, composition and biochemistry of necessary pyrethroid insecticides have been discussed in detail, in the research paper, along with their effect on insects and humans. It also covers the impact of pyrethroids on different plants and soil microbial flora. The second part deals with the microbial degradation of the pyrethroids through different modes, i.e., bioaugmentation and biostimulation. Many microbes such as Acremonium, Aspergillus, Microsphaeropsis, Westerdykella, Pseudomonas, Staphylococcus have been used in the individual form for the degradation of pyrethroids, while some of them such as Bacillus are even used in the form of consortia.
  [Singh, S. et al. (2022) Advances and future prospects of pyrethroids: Toxicity and microbial degradation, Science of The Total Environment. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0048969722016540. ]
- Deciphering the diversity, composition, function, and network complexity of the soil microbial community after repeated exposure to a fungicide boscalid
  Boscalid is a novel, highly effective carboximide fungicide that has been substantially and irrationally applied in greenhouses. However, little is known about the residual characteristics of boscalid and its ecological effects in long-term polluted greenhouse soils. Therefore, actual boscalid pollution status in greenhouse soils was simulated by repeatedly introducing boscalid into the soil under laboratory conditions. The degradation characteristics of boscalid, and its effects on the diversity, composition, function, and co-occurrence patterns of the soil microbial community were systematically investigated. Boscalid degraded slowly, with its degradation half-lives ranging from 31.5 days to 180.1 days in the soil. Boscalid degradation was further delayed by repeated treatment and increasing its initial concentration. Boscalid significantly decreased soil microbial diversity, particularly at the recommended dosage. Amplicon sequencing analysis showed that boscalid altered the soil microbial community and further stimulated the phylum Proteobacteria and four potential boscalid-degrading bacterial genera, Sphingomonas, Starkeya, Citrobacter, and Castellaniella. Although the network analysis revealed that boscalid significantly reduced the microbial network complexity, it enhanced the vital roles of Proteobacteria by increasing its proportion and strengthening the relationships among the internal bacteria in the network. The soil microbial function in the boscalid treatment were simulated at the recommended dosage and two-fold recommended dosage but showed an inhibition-recovery-stimulation trend at the five-fold recommended dosage with an increase in treatment frequency. Moreover, the expression of nitrogen cycling functional genes, nifH, AOA amoA, AOB amoA, nirK, and nirS in all boscalid treatments displayed an inhibition-recovery-stimulation trend during the entire experimental period, and the effects were more pronounced at the five-fold recommended dosage. In conclusion, repeated boscalid treatments delayed degradation, reduced soil microbial diversity and network complexity, disturbed soil microbial community, and interfered with soil microbial function.
  [Han, L., Xu, M., Kong, X., Liu, X., Wang, Q., Chen, G., Xu, K., & Nie, J. (2022). Deciphering the diversity, composition, function, and network complexity of the soil microbial community after repeated exposure to a fungicide boscalid. Environmental pollution (Barking, Essex : 1987), 312, 120060. https://doi.org/10.1016/j.envpol.2022.120060]
- Effects of Commercial Arbuscular Mycorrhizal Inoculants on Plant Productivity and Intra-Radical Colonization in Native Grassland: Unintentional De-Coupling of a Symbiosis?
  There has been a surge in industries built on the production of arbuscular mycorrhizal (AM) fungal-based inoculants in the past few decades. This is not surprising, given the positive effects of AM fungi on plant growth and nutritional status. However, there is growing concern regarding the quality and efficacy of commercial inoculants. To assess the potential benefits and negative consequences of commercial AM fungal inoculants in grasslands, we conducted a controlled growth chamber study assessing the productivity and AM fungal root colonization of nine grassland plant species grown in grassland soil with or without one of six commercial AM fungal products. Our research showed no evidence of benefit; commercial inoculants never increased native plant biomass, although several inoculants decreased the growth of native species and increased the growth of invasive plant species. In addition, two commercial products contained excessive levels of phosphorus or nitrogen and consistently reduced AM fungal root colonization, indicating an unintentional de-coupling of the symbiosis. As there is little knowledge of the ecological consequences of inoculation with commercial AM fungal products, it is critical for restoration practitioners, scientists, and native plant growers to assess the presence of local AM fungal communities before investing in unnecessary, or possibly detrimental, AM fungal products.
  [Duell, E. B., Cobb, A. B., & Wilson, G. W. T. (2022). Effects of Commercial Arbuscular Mycorrhizal Inoculants on Plant Productivity and Intra-Radical Colonization in Native Grassland: Unintentional De-Coupling of a Symbiosis? Plants, 11(17), 2276. https://doi.org/10.3390/plants11172276]
- Effects of microplastics on soil microbiome: The impacts of polymer type, shape, and concentration
  Increasing research has recognized that the ubiquitous presence of microplastics in terrestrial environments is undeniable, which potentially alters the soil ecosystem properties and processes. The fact that microplastics with diverse characteristics enter into the soil may induce distinct effects on soil ecosystems. Our knowledge of the impacts of microplastics with different polymers, shapes, and concentrations on soil bacterial communities is still limited. To address this, we examined the effects of spherical microplastics (150 μm) with different polymers (i.e., polyethylene (PE), polystyrene (PS), and polypropylene (PP)) and four shapes of PP microplastics (i.e., fiber, film, foam, and particle) at a constant concentration (1%, w/w) on the soil bacterial community in an agricultural soil over 60 days. Treatments with different concentrations (0.01–20%, w/w) of PP microplastic particles (150 μm) were also included. The bacterial communities in PE and PP treatments showed a similar pattern but separated from those in PS-treated soils, indicating the polymer backbone structure is an important factor modulating the soil bacterial responses. Fiber, foam, and film microplastics significantly affected the soil bacterial composition as compared to the particle. The community dissimilarity of soil bacteria was significantly (R2 = 0.592, p < 0.001) correlated with the changes of microplastic concentration. The random forest model identified that certain bacteria belonging to Patescibacteria were closely linked to microplastic contamination. Additionally, analysis of the predicted function further showed that microplastics with different characteristics caused distinct effects on microbial community function. Our findings suggested that the idiosyncrasies of microplastics should not be neglected when studying their effects on terrestrial ecosystems.
  [Sun, Y., Duan, C., Cao, N., Li, X., Li, X., Chen, Y., Huang, Y., & Wang, J. (2022). Effects of microplastics on soil microbiome: The impacts of polymer type, shape, and concentration. The Science of the total environment, 806(Pt 2), 150516. https://doi.org/10.1016/j.scitotenv.2021.150516]
- Modulation of chlorpyrifos toxicity to soil arthropods by simultaneous exposure to polyester microfibers or tire particle microplastics
  Synthetic fibers released from sewage sludge and tire particles released from traffic are among the most common types of microplastics in soil. In soil, microplastics may interact with chemicals, such as plant protection products used in agriculture. Most studies on the interactions of microplastics and chemicals focused on aquatic environments and only few addressed soil arthropods. To increase the understanding of the combined effects of microplastics and chemicals on soil arthropods, we studied the effects of polyester fibers and tire particles on the toxicity of the insecticide chlorpyrifos. Springtails (Folsomia candida) and woodlice (Porcellio scaber) were exposed in Lufa 2.2 soil to a range of chlorpyrifos concentrations (0.0088–0.8 and 0.2–3.9 mg kg−1 dry soil, respectively) without or with 0.05 % w/w (“low”) or 0.5 % w/w (“high”) of microplastics. Tire particles reduced the lethality of chlorpyrifos to springtails (LC50 = 0.13–0.14 mg kg−1 dry soil) and isopods (LC50 = 1.6 mg kg−1 dry soil) by a factor of 2- > 2.5 and the chlorpyrifos-induced inhibition of acetylcholinesterase (AChE) activity and changes in electron transfer system (ETS) activity in P. scaber by a factor of 2–4. Polyester fibers reduced the chlorpyrifos-induced inhibition of AChE activity by a factor of 2 and increased (ETS) activity in P. scaber by a factor of >3. The fibers did not affect the toxicity of chlorpyrifos to the survival of P. scaber or the survival and reproduction of F. candida. These results indicate that the bioavailability of chlorpyrifos may be decreased by microplastics, especially by tire particles. This study shows the importance of applying a mixture toxicity approach for understanding the threats of microplastics to soil, but also suggests that the organism and the endpoints chosen are crucial for the interpretation of the effects of combined exposures to microplastics and chemicals.
  [Selonen, Salla & Jemec Kokalj, Anita & Benguedouar, Hiba & Alavian, Somayye & Dolar, Andraž & Drobne, Damjana & Gestel, Cornelis. (2022). Modulation of chlorpyrifos toxicity to soil arthropods by simultaneous exposure to polyester microfibers or tire particle microplastics. Applied Soil Ecology. 104657. 10.1016/j.apsoil.2022.104657. ]
- Outside the Safe Operating Space of a New Planetary Boundary for Per- and Polyfluoroalkyl Substances (PFAS)
  It is hypothesized that environmental contamination by per- and polyfluoroalkyl substances (PFAS) defines a separate planetary boundary and that this boundary has been exceeded. This hypothesis is tested by comparing the levels of four selected perfluoroalkyl acids (PFAAs) (i.e., perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), and perfluorononanoic acid (PFNA)) in various global environmental media (i.e., rainwater, soils, and surface waters) with recently proposed guideline levels. On the basis of the four PFAAs considered, it is concluded that (1) levels of PFOA and PFOS in rainwater often greatly exceed US Environmental Protection Agency (EPA) Lifetime Drinking Water Health Advisory levels and the sum of the aforementioned four PFAAs (Σ4 PFAS) in rainwater is often above Danish drinking water limit values also based on Σ4 PFAS; (2) levels of PFOS in rainwater are often above Environmental Quality Standard for Inland European Union Surface Water; and (3) atmospheric deposition also leads to global soils being ubiquitously contaminated and to be often above proposed Dutch guideline values. It is, therefore, concluded that the global spread of these four PFAAs in the atmosphere has led to the planetary boundary for chemical pollution being exceeded. Levels of PFAAs in atmospheric deposition are especially poorly reversible because of the high persistence of PFAAs and their ability to continuously cycle in the hydrosphere, including on sea spray aerosols emitted from the oceans. Because of the poor reversibility of environmental exposure to PFAS and their associated effects, it is vitally important that PFAS uses and emissions are rapidly restricted.
  [Cousins, I.T., Johansson, J.H., Salter, M.E., Sha, B. and Scheringer, M. Environmental Science & Technology.]
- Pesticide effects on nitrogen cycle related microbial functions and community composition
  The extensive application of pesticides in agriculture raises concerns about their potential negative impact on soil microorganisms, being the key drivers of nutrient cycling. Most studies have investigated the effect of a single pesticide on a nutrient cycling in single soil type. We, for the first time, investigated the effect of 20 commercial pesticides with different mode of actions, applied at their recommended dose and five times their recommended dose, on nitrogen (N) microbial cycling in three different agricultural soils from southern Australian. Functional effects were determined by measuring soil enzymatic activities of β-1,4-N-acetyliglucosaminidase (NAG) and l-leucine aminopeptidase (LAP), potential nitrification (PN), and the abundance of functional genes involved in N cycling (amoA and nifH). Effects on nitrifiers diversity were determined with amplicon sequencing. Overall, the pesticides effect on N microbial cycling was dose-independent and soil specific. The fungicides flutriafol and azoxystrobin, the herbicide chlorsulfuron and the insecticide fipronil induced a significant reduction in PN and β-1,4-N-acetylglucosaminidase activity (P < 0.05) (NAG) in the alkaline loam soil with low organic carbon content i.e. a soil with properties which typically favors pesticide bioavailability and therefore potential toxicity. For the nitrifier community, the greatest pesticide effects were on the most dominant Nitrososphaeraceae (ammonia-oxidizing archaea; AOA) whose abundance increased significantly compared to the less dominant AOA and other nitrifiers. The inhibiting effects were more evident in the soil samples treated with fungicides. By testing multiple pesticides in a single study, our findings provide crucial information that can be used for pesticide hazard assessment.
  [Sim, J. X. F., Doolette, C. L., Vasileiadis, S., Drigo, B., Wyrsch, E. R., Djordjevic, S. P., Donner, E., Karpouzas, D. G., & Lombi, E. (2022). Pesticide effects on nitrogen cycle related microbial functions and community composition. The Science of the total environment, 807(Pt 1), 150734. https://doi.org/10.1016/j.scitotenv.2021.150734]
- PFAS Molecules: A Major Concern for the Human Health and the Environment
  Per- and polyfluoroalkyl substances (PFAS) are a group of over 4700 heterogeneous compounds with amphipathic properties and exceptional stability to chemical and thermal degradation. The unique properties of PFAS compounds has been exploited for almost 60 years and has largely contributed to their wide applicability over a vast range of industrial, professional and non-professional uses. However, increasing evidence indicate that these compounds represent also a serious concern for both wildlife and human health as a result of their ubiquitous distribution, their extreme persistence and their bioaccumulative potential. In light of the adverse effects that have been already documented in biota and human populations or that might occur in absence of prompt interventions, the competent authorities in matter of health and environment protection, the industries as well as scientists are cooperating to identify the most appropriate regulatory measures, substitution plans and remediation technologies to mitigate PFAS impacts. In this review, starting from PFAS chemistry, uses and environmental fate, we summarize the current knowledge on PFAS occurrence in different environmental media and their effects on living organisms, with a particular emphasis on humans. Also, we describe present and provisional legislative measures in the European Union framework strategy to regulate PFAS manufacture, import and use as well as some of the most promising treatment technologies designed to remediate PFAS contamination in different environmental compartments.
  [Panieri, E. et al. (2022) Pfas molecules: A major concern for the human health and the environment, Toxics. Available at: https://www.mdpi.com/2305-6304/10/2/44. ]
- Quantifying exposure of bumblebee (Bombus spp.) queens to pesticide residues when hibernating in agricultural soils
  Exposure to pesticides is a major threat to bumblebee (Bombus spp.) health. In temperate regions, queens of many bumblebee species hibernate underground for several months, putting them at potentially high risk of exposure to soil contaminants. The extent to which bumblebees are exposed to residues in agricultural soils during hibernation is currently unknown, which limits our understanding of the full pesticide exposome for bumblebees throughout their lifecycle. To generate field exposure estimates for overwintering bumblebee queens to pesticide residues, we sampled soils from areas corresponding to suitable likely hibernation sites at six apple orchards and 13 diversified farms throughout Southern Ontario (Canada) in fall 2019-2020. Detectable levels of pesticides were found in 65 of 66 soil samples analysed for multi-pesticide residues (UPLC-MS/MS). A total of 53 active ingredients (AIs) were detected in soils, including 27 fungicides, 13 insecticides, and 13 herbicides. Overall, the frequency of detection, residue levels (median = 37.82 vs. 2.20 ng/g), and number of pesticides per sample (mean = 12 vs. 4 AIs) were highest for orchard soils compared to soils from diversified farms. Ninety-one percent of samples contained multiple residues (up to 29 different AIs per sample), including mixtures of insecticides and fungicides that might lead to synergistic effects. Our results suggest that when hibernating in agricultural areas, bumblebee queens are very likely to be exposed to a wide range of pesticide residues in soil, including potentially harmful levels of insecticides (e.g., cyantraniliprole up to 148.82 ng/g). Our study indicates the importance of empirically testing the potential effects of pesticide residues in soils for hibernating bumblebee queens, using field exposure data such as those generated here. The differences in potential exposure that we detected between cropping systems can also be used to better inform regulations that govern the use of agricultural pesticides, notably in apple orchards.
  [Rondeau, S. et al. (2022) Quantifying exposure of bumblebee (Bombus spp.) queens to pesticide residues when hibernating in agricultural soils, Environmental Pollution. Available at: https://pubmed.ncbi.nlm.nih.gov/35809712/. ]
- Response of microbial antibiotic resistance to pesticides: An emerging health threat
  The spread of microbial antibiotic resistance has seriously threatened public health globally. Non-antibiotic stressors have significantly contributed to the evolution of bacterial antibiotic resistance. Although numerous studies have been conducted on the potential risk of pesticide pollution for bacterial antibiotic resistance, a systematic review of these concerns is still lacking. In the present study, we elaborate the mechanism underlying the effects of pesticides on bacterial antibiotic resistance acquisition as well as the propagation of antimicrobial resistance. Pesticide stress enhanced the acquisition of antibiotic resistance in bacteria via various mechanisms, including the activation of efflux pumps, inhibition of outer membrane pores for resistance to antibiotics, and gene mutation induction. Horizontal gene transfer is a major mechanism whereby pesticides influence the transmission of antibiotic resistance genes (ARGs) in bacteria. Pesticides promoted the conjugation transfer of ARGs by increasing cell membrane permeability and increased the proportion of bacterial mobile gene elements, which facilitate the spread of ARGs. This review can improve our understanding regarding the pesticide-induced generation and spread of ARGs and antibiotic resistant bacteria. Moreover, it can be applied to reduce the ecological risks of ARGs in the future.
  [Qiu, D. et al. (2022) Response of microbial antibiotic resistance to pesticides: An emerging health threat, Science of The Total Environment. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0048969722051567. ]
- Soil protists: An untapped microbial resource of agriculture and environmental importance
  Protists are essential components of soil biodiversity and ecosystem functioning. They play a vital role in the microbial food web as consumers of bacteria, fungi, and other small eukaryotes and are also involved in maintaining soil fertility and plant productivity. Protists also contribute to regulating and shaping the bacterial community in terrestrial ecosystems via specific prey spectra. They play a role in plant growth promotion and plant health improvement, mostly via nutrient cycling, grazing, and the activation of bacterial genes required for plant growth and phytopathogen suppression. Thus, protists may prove to be a useful inoculant as biofertilizer and biocontrol agent. They can also be applied as model organisms as bioindicators of soil health. Despite their usefulness and essentiality, they are often forgotten and under-researched components of the soil microbiome, as most of our research focuses on bacteria and fungi. In this review, we provide an overview of the role of protists in plant productivity and plant health management and in shifts in soil bacterial community composition, as well as their roles as bioindicator. We also discuss the perspectives of knowledge gaps and future prospects to further improve soil biology. More research in soil protistology will provide insights into sustainable agriculture and environmental health alongside the study of bacteria and fungi.
  [Chandarana, K. and Amaresan, N. (2022) Soil protists: An untapped microbial resource of agriculture and environmental importance, Pedosphere. Available at: https://www.sciencedirect.com/science/article/abs/pii/S1002016021600668. ]
- Studies on the abilities of uptake and translocation from root to shoot of pesticides in soil
  The uptake experiments with pesticides were performed to clarify differences among plant species, and the influence of growth stages and conditions on the uptake and translocation ability of pesticides. There were 2–10-fold differences among plant species in the root and shoot concentrations of each pesticide, and shoot concentrations of pesticides in Brassica rapa L. var. perviridis were relatively high. In addition, the changes in shoot concentrations with growth stage of B. rapa were affected by root system development. The influence of temperature on uptake and translocation ability differed for each pesticide, while uptake and translocation ability were high for short day lengths. This indicated that plant uptake and translocation of pesticides were affected by root system development and growth conditions such as temperature and day length, not only the relationships to the chemical’s properties and behavior of organic chemicals in the soil.
  [Namiki, S. (2022) Studies on the abilities of uptake and translocation from root to shoot of pesticides in soil, Journal of Pesticide Science. Available at: https://www.jstage.jst.go.jp/article/jpestics/47/3/47_J22-01/_article. ]
- Targeted analysis and Total Oxidizable Precursor assay of several insecticides for PFAS
  Targeted analysis for 24 Per- and Polyfluoroalkyl Substances (PFAS) was conducted on 10 insecticide formulations used on a United States Department of Agriculture crop research field. Perfluorooctane sulfonic acid (PFOS) was found in 6 of the 10 formulations with concentrations ranging from 3.92 to 19.2 mg/kg. Further analysis of soil and plant samples collected at the site found several additional PFAS, with PFOS being the most prominent. Suspect screening was then conducted on the formulations and provided several suspected PFAS in addition to the 24 targeted analyzed PFAS in 7 of the 10 samples, one of which showed no PFAS during targeted analysis. PFAS-precursor oxidation was then conducted on the two insecticide formulations with the greatest lists of suspected PFAS as validation of potential unknown PFAS in the formulations. This study revealed a previously unknown potential PFAS contamination source for rural and agricultural environments.
  [Lasee, S. et al. (2022) Targeted analysis and Total Oxidizable Precursor assay of several insecticides for PFAS, Journal of Hazardous Materials Letters. Available at: https://www.sciencedirect.com/science/article/pii/S266691102200020X#! ]
- The Fate of Fluopyram in the Soil–Water–Plant Ecosystem: A Review
  This review aims to discuss all likely pathways of the environmental fate of fluopyram to enable a better understanding of the probable ecological risks associated with its agricultural usage. The fluopyram is a broad-spectrum molecule to control various fungal plant pathogens as well as nematodes. It belongs to a new chemical class named ‘pyridinyl ethylbenzamides’. The literature review has shown that the sorption–desorption, degradation and leaching of fluopyram differed among the soil types, and much is still to be studied concerning the fate of fluopyram in different types of the soil environment. Indeed, research suggests that the high persistent behaviour of fluopyram particularly in soil and water/sediment environment can present environmental risks. Hence, with a foreseen widespread and substantial use of fluopyram, it would be indeed crucial to assess the possible environmental risks due to injudicious usage of fluopyram.
  [Rathod, P.H., Shah, P.G., Parmar, K.D. et al. The Fate of Fluopyram in the Soil–Water–Plant Ecosystem: A Review. Reviews Env.Contamination (formerly:Residue Reviews) 260, 1 (2022). https://doi.org/10.1007/s44169-021-00001-7]
- An evaluation of biological soil health indicators in four long-term continuous agroecosystems in Canada
  The soil microbial community (SMC) and soil organic matter (SOM) are inherently related and are sensitive to land-use changes. Microorganisms regulate essential soil functions that are key to SOM dynamics, whereas SOM dynamics define the SMC. To expand our understanding of soil health, we evaluated biological and SOM indicators in long-term (18-yr) continuous silage corn (Zea mays L.), continuous soybean [Glycine max (L.) Merr.], and perennial grass ecosystems in Ontario, Canada. The SMC was evaluated via ester-linked fatty acid methyl ester (EL-FAME) and amplicon sequencing. Soil organic matter was evaluated via a new combined enzyme assay that provides a single biogeochemical cycling value for C, N, P, and S cycling activity (CNPS), as well as loss-on-ignition, permanganate oxidizable C (POXC), and total C and N. Overall, soil health indicators followed the trend of grasses > corn > soybean. Grass systems had up to 8.1 times more arbuscular mycorrhizal fungi, increased fungal/bacteria ratios (via EL-FAME), and higher microbial diversity (via sequencing). The POXC was highly variable within treatments and did not significantly differ between systems. The novel CNPS activity assay, however, was highly sensitive to management (up to 2.2 and 3.2 times higher under grasses than corn and soybean, respectively) and was positively correlated (ρ > .92) to SOM, total C, and total N. Following the “more is better” model, where higher values of the measured parameters indicate a healthier soil, our study showed decreased soil health under monocultures, especially soybean, and highlights the need to implement sustainable agriculture practices that maintain soil health.
  [Pérez‐Guzmán, L., Phillips, L.A., Seuradge, B.J., Agomoh, I., Drury, C.F. and Acosta‐Martínez, V. Agrosystems, Geosciences & Environment, 4(2), p.e20164.]
- Effect of microplastics and arsenic on nutrients and microorganisms in rice rhizosphere soil
  The presence of microplastics and arsenic in soil can endanger crop growth; therefore, their effects on the properties of rhizosphere soil should be evaluated. Large (10–100 µm) and small (0.1–1 µm) polystyrene (PSMP) and polytetrafluorethylene (PTFE) particles were added to soil with different arsenic concentrations (1.4, 24.7, and 86.3 mg kg−1) to investigate the combined effect of microplastics and arsenic pollution on rice rhizosphere soil. After the addition of PSMP and PTFE, pH, arsenic (V) and arsenic (III) in the soil were observed to decrease. The interaction of arsenic with PSMP and PTFE resulted in this phenomenon, leading to a decrease of arsenic bioavailability in the soil. PSMP, PTFE, and arsenic reduced the abundance of Proteobacteria, increased the abundance of Chloroflexi and Acidobacteria, and inhibited soil urease, acid phosphatase, protease, dehydrogenase, and peroxidase activity via affecting the tertiary structure of the enzyme. PSMP, PTFE, and arsenic also reduced the available nitrogen and phosphorus content in the soil. Arsenic increased the soil organic matter content, whereas PSMP and PTFE reduced the organic matter content. Furthermore, microplastics inhibited the effects of arsenic on the microbial and chemical properties of the rhizosphere soil. This study revealed the effects of microplastic and arsenic pollution on rice rhizosphere microorganisms and nutrients, and elucidated the mechanism by which these pollutants retard crop growth in the designed growth medium.
  [Dong, Y., Gao, M., Qiu, W., & Song, Z. (2021). Effect of microplastics and arsenic on nutrients and microorganisms in rice rhizosphere soil. Ecotoxicology and environmental safety, 211, 111899. https://doi.org/10.1016/j.ecoenv.2021.111899]
- Effect of Polyvinyl Chloride Microplastics on Bacterial Community and Nutrient Status in Two Agricultural Soils
  Knowledge of the influence of microplastics on soil microbiome and nutrients is important for understanding the ecological consequences of microplastic pollution in terrestrial ecosystems. In this study, we investigated whether polyvinyl chloride (PVC) microplastic pollution at environmentally relevant concentrations would affect soil bacterial community and available nitrogen/phosphorus content. The results showed that although PVC microplastics at 0.1% and 1% levels did not have a significant effect on overall bacterial community diversity and composition in soil over the course of 35 days, a number of bacterial genera were significantly reduced or enriched by the presence of microplastics. Potentially due to their effect on certain functional groups, microplastics caused a significant change in soil available P content. It is noteworthy that, depending on soil type, pollution level and plasticizer presence, contrasting effects of microplastics may be observed. Further research is definitely warranted to gain a clearer picture of the threats posed by microplastic pollution in soil environments.
  [Yan, Y., Chen, Z., Zhu, F. et al. Effect of Polyvinyl Chloride Microplastics on Bacterial Community and Nutrient Status in Two Agricultural Soils. Bull Environ Contam Toxicol 107, 602–609 (2021). https://doi.org/10.1007/s00128-020-02900-2]
- Effects of plastic mulch film residues on soil-microbe-plant systems under different soil pH conditions
  Plastic mulch film residues (PMFR) accumulated throughout mulching years can result in serious environmental problems, especially in hotter areas with frequent farming (e.g. the tropics). The effects of long-term mulching on the soil-microbe-plant system, however, are largely unknown. As mulching years is positively correlated with PMFR concentrations, we used a controlled pot experiment to investigate the effects of mulching years (20a: The concentration of PMFR is about 2 g kg−1, 60a: About 6 g kg−1) on rice growth, rhizosphere bacterial communities, and soil organic carbon (SOC) under different soil pH conditions. Mulching years reduced rice growth; 20a showed more negative effects than 60a on rice tillers number and biomass. PMFR changed the composition, diversity, and metabolic function of the rhizosphere bacterial communities. The content of SOC decreased as mulching residues increased; total organic carbon (TOC), soil organic matter (SOM), Fn (355), and humification index (HIX) declined by 30.24%, 55.97%, 59.74%, and 70.24%, respectively. Furthermore, significant correlations between bacterial communities and SOC were observed in the soil-microbe-plant system. PMFR showed stronger negative effects on rice growth in acidic soil (pH 4.5); however, in basic soil (pH 8.5), there were stronger variations within the bacterial communities and a more significant decline in SOC than acidic soil (pH 4.5). The results of this study are expected to provide theoretical references for understanding of the effects of PMFR on agroecosystems and preventing and controlling plastic pollution.
  [Liu, Y., Huang, Q., Hu, W., Qin, J., Zheng, Y., Wang, J., Wang, Q., Xu, Y., Guo, G., Hu, S., & Xu, L. (2021). Effects of plastic mulch film residues on soil-microbe-plant systems under different soil pH conditions. Chemosphere, 267, 128901. https://doi.org/10.1016/j.chemosphere.2020.128901]
- Heavy Metals and Pesticides Toxicity in Agricultural Soil and Plants: Ecological Risks and Human Health Implications
  Environmental problems have always received immense attention from scientists. Toxicants pollution is a critical environmental concern that has posed serious threats to human health and agricultural production. Heavy metals and pesticides are top of the list of environmental toxicants endangering nature. This review focuses on the toxic effect of heavy metals (cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn)) and pesticides (insecticides, herbicides, and fungicides) adversely influencing the agricultural ecosystem (plant and soil) and human health. Furthermore, heavy metals accumulation and pesticide residues in soils and plants have been discussed in detail. In addition, the characteristics of contaminated soil and plant physiological parameters have been reviewed. Moreover, human diseases caused by exposure to heavy metals and pesticides were also reported. The bioaccumulation, mechanism of action, and transmission pathways of both heavy metals and pesticides are emphasized. In addition, the bioavailability in soil and plant uptake of these contaminants has also been considered. Meanwhile, the synergistic and antagonistic interactions between heavy metals and pesticides and their combined toxic effects have been discussed. Previous relevant studies are included to cover all aspects of this review. The information in this review provides deep insights into the understanding of environmental toxicants and their hazardous effects.
  [Alengebawy A, Abdelkhalek ST, Qureshi SR, Wang M-Q. Heavy Metals and Pesticides Toxicity in Agricultural Soil and Plants: Ecological Risks and Human Health Implications. Toxics. 2021; 9(3):42. https://doi.org/10.3390/toxics9030042]
- Microplastics have shape- and polymer-dependent effects on soil aggregation and organic matter loss – an experimental and meta-analytical approach
  Microplastics are a diverse and ubiquitous contaminant, a global change driver with potential to alter ecosystem properties and processes. Microplastic-induced effects in soils are manifold as microplastics differ in a variety of properties among which the shape is of special interest. Our knowledge is limited regarding the impact of various microplastic shapes on soil processes. Therefore, we conducted this two-part research comprising a meta-analysis on published literature and a lab experiment focusing on microplastic shapes- and polymer-induced effects on soil aggregation and organic matter decomposition. We here focus on fibers, films, foams and particles as microplastic shapes.
  
  In the meta-analysis, we found a strong research focus on fibrous and particulate microplastic materials, with films and foams neglected.
  
  Our experiment showed that microplastic shapes are important modulators of responses in soil aggregation and organic matter decomposition. Fibers, irrespective of their chemistry, negatively affected the formation of aggregates. However, for other shapes like foams and particles, the polymer identity is an important factor co-modulating the soil responses.
  
  Further research is needed to generate a data-driven foundation to permit a better mechanistic understanding of the importance and consequences of microplastics added to soils.
  [Lehmann, A., Leifheit, E.F., Gerdawischke, M. et al. Microplastics have shape- and polymer-dependent effects on soil aggregation and organic matter loss – an experimental and meta-analytical approach. Micropl.&Nanopl. 1, 7 (2021). https://doi.org/10.1186/s43591-021-00007-x]
- Persistence of aerially-sprayed naled in coastal sediments
  Aerial sprays of the organophosphate pesticide, naled, were intensified over beach areas during the summer of 2016 to control the locally-acquired Zika outbreak in the continental U.S. Concerns were raised in beach frequented areas about contaminated sediments. The aim of this study was to evaluate the persistence and levels of naled and its byproduct, dichlorvos, in sediments obtained from the affected areas. Laboratory experiments were designed to simulate the effect of various natural conditions on the decomposition of naled in three sediment types (beach sand, marl, and calcinated beach sand). The three sediment samples were also exposed to field aerial sprays. After 30 min of exposure, more dichlorvos was detected in the sediments than naled, with 33 to 43% of the molar concentration initially applied as either naled or dichlorvos. Under dark conditions, trace levels of naled were observed after 24 h on sediments. Higher temperature accelerated the natural decomposition of both naled and dichlorvos in sediments. The half-life of naled ranged from 3 to 5 h at 22.5 °C and ranged from 1 to 3 h at 30 °C. Expedited decomposition of naled was observed under sunlight conditions with a half-life of naled of 20 min. In the field, only dichlorvos was detected in the sediment samples at concentrations between 0.0011 and 0.0028 μmol/g 1 h after aerial sprays. This data can be used towards a risk assessment that evaluates exposures to naled and dichlorvos through beach sands impacted by aerial spray activities.
  [Bamiduro, G. J., Kumar, N., Solo-Gabriele, H. M., & Zahran, E. M. (2021). Persistence of aerially-sprayed naled in coastal sediments. The Science of the total environment, 794, 148701. https://doi.org/10.1016/j.scitotenv.2021.148701]
- Protists as main indicators and determinants of plant performance
  Background
  Microbiomes play vital roles in plant health and performance, and the development of plant beneficial microbiomes can be steered by organic fertilizer inputs. Especially well-studied are fertilizer-induced changes on bacteria and fungi and how changes in these groups alter plant performance. However, impacts on protist communities, including their trophic interactions within the microbiome and consequences on plant performance remain largely unknown. Here, we tracked the entire microbiome, including bacteria, fungi, and protists, over six growing seasons of cucumber under different fertilization regimes (conventional, organic, and Trichoderma bio-organic fertilization) and linked microbial data to plant yield to identify plant growth-promoting microbes.
  
  Results
  Yields were higher in the (bio-)organic fertilization treatments. Soil abiotic conditions were altered by the fertilization regime, with the prominent effects coming from the (bio-)organic fertilization treatments. Those treatments also led to the pronounced shifts in protistan communities, especially microbivorous cercozoan protists. We found positive correlations of these protists with plant yield and the density of potentially plant-beneficial microorganisms. We further explored the mechanistic ramifications of these relationships via greenhouse experiments, showing that cercozoan protists can positively impact plant growth, potentially via interactions with plant-beneficial microorganisms including Trichoderma, the biological agent delivered by the bio-fertilizer.
  
  Conclusions
  We show that protists may play central roles in stimulating plant performance through microbiome interactions. Future agricultural practices might aim to specifically enhance plant beneficial protists or apply those protists as novel, sustainable biofertilizers.
  [Guo, S. et al. (2021) Protists as main indicators and determinants of plant performance, Microbiome. Available at: https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-021-01025-w. ]
- The effects of three different microplastics on enzyme activities and microbial communities in soil
  Soils always receive microplastics (MPs) from plastic mulching, compost, and sewage irrigation, but the effects of MPs on soil environment remain largely unexplored. The objectives of this study were to investigate the effects of three MPs (membranous polyethylene (PE), fibrous polypropylene (PP), and microsphere PP) on enzyme activities and microbial community structure in one loamy and sandy soil. The concentration of microsphere PP (2 mg/g) was one-tenth of those of the other two MPs (20 mg/g). The results showed that the effects of three MPs on urease, dehydrogenase, and alkaline phosphatase activities followed the order: fibrous PP > membranous PE > microsphere PP, membranous PE > microsphere PP > fibrous PP and fibrous PP > microsphere PP > membranous PE, respectively. Results from high-throughput sequencing of 16S rRNA revealed that the membranous PE and fibrous PP raised the alpha diversities of the soil microbiota, whereas the diversity indexes of microbiota on MPs surfaces were significantly lower than those in the amended soils. MPs significantly altered the microbial community structure, especially for the enrichment of Acidobacteria and Bacteroidetes, the depletion of Deinococcus-Thermus and Chloroflexi. Aeromicrobium, Streptomyces, Mycobacterium, Janibacter, Nocardia, Arthrobacter were prone to inhabit on the MPs surfaces.
  [Yi, M., Zhou, S., Zhang, L. and Ding, S. (2021), The effects of three different microplastics on enzyme activities and microbial communities in soil. Water Environ Res, 93: 24-32. https://doi.org/10.1002/wer.1327]
- Winter cover crops shape early-season predator communities and trophic interactions
  Despite the dynamic nature of annual cropping systems, few studies have investigated how the structure of predator communities and their interactions with prey corresponds with crop seasonality. Adding winter habitat, such as cover crops, improves soil health and likely contributes seasonal habitat availability for arthropod communities. Stable habitat may lead to functionally diverse predatory communities and their associated ecosystem services, such as biological control. Here, we estimated predatory community functional changes based on foraging traits determined by molecular gut–content analysis (MGCA) in response to winter cover crops (rye and crimson clover) in a cotton agroecosystem. Predators were collected from replicated 1-ha experimental field plots during each major stage of crop development in 2017 and 2018, and MGCA was used to estimate predator roles and responses to cover crop treatments. Cotton planted into a rye cover crop residue promoted unique predator communities in the early and mid-season as compared to no-cover fields. Correspondingly, we observed dissimilar prey consumption among cover crop treatments. Winter cover crops led to an increase in consumption of alternative prey and incidental pests by natural enemies on seedling cotton and encouraged high predator diversity that aligns temporally with potential early-season pest outbreaks. Therefore, cover crops commonly employed for soil health and erosion benefits also contribute to pest management by providing habitat and alternative prey resources that boost early-season predatory arthropod communities.
  [Bowers, C., Toews, M.D. and Schmidt, J.M. Ecosphere, 12(7), p.e03635.]
- (Nano)microplastics promote the propagation of antibiotic resistance genes in landfill leachate
  Municipal landfill leachate is a huge reservoir of (nano)microplastics (N/MPs) and antibiotic resistance genes (ARGs). N/MPs have a proven ability to affect the growth of bacteria and composition of bacterial communities, which may further influence the spread of ARGs in the environment. To extrapolate the interactions between these two emerging contaminants, we investigated the variations of the ARG levels in leachate with exposures to different sizes of N/MPs. The results showed that ARGs were enriched in the N/MPs-exposed groups, especially in the 200–500 nm MP group. Notably, the enrichment became more pronounced in the long-term exposure samples than the short-term ones. Together with this process, the total abundance of bacteria, as well as the potential ARG-carrying bacteria, also increased in the N/MP-exposed groups, and the long-term N/MP exposure led more bacteria genera, such as Pseudomonas, Syntrophomonas, and Desulfotomaculum, to become closely associated with ARG variations. Meanwhile, the production of reactive oxygen species (ROS) induced by exposure to the 50–100 nm NPs and the 200–500 nm MPs was observed to increase bacterial membrane permeability, which might result in more bacteria becoming potential receptors of ARGs via the intra-bacterial community transfer of mobile genetic elements. Overall, the current study demonstrated that the presence of N/MPs in leachate promoted the propagation of ARGs due to their impacts on the bacterial community and cellular membrane permeability. These findings have important implications for understanding the environmental risks of the combined pollution of N/MPs and ARGs.
  [Shi, J. et al. (2020) (Nano)microplastics promote the propagation of antibiotic resistance genes in landfill leachate, Environmental Science: Nano. Available at: https://www.researchgate.net/publication/346720300_Nanomicroplastics_promote_the_propagation_of_antibiotic_resistance_genes_in_landfill_leachate. ]
- A review of the pesticide MCPA in the land-water environment and emerging research needs
  Due to its high solubility and poor adsorption to the soil matrix, the post-emergence herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) is susceptible to transport into surface and groundwater bodies, where it can result in compromised water quality and breaches of legislative standards. However, there is still poor understanding of catchment scale dynamics and transport, particularly across heterogeneous hydrogeological settings. While it is known that MCPA degrades under aerobic conditions, negligible breakdown can occur in anaerobic environments, potentially creating a legacy in saturated soils. Fast runoff pathways post application are likely transport routes, but the relative contribution from the mobilization of legacy MCPA from anaerobic zones has yet to be quantified, making the delineation of MCPA sources encountered during monitoring programs challenging. While ecotoxicological effects have been examined, little is known about the interaction of MCPA (and its degradation products) with other pesticides, with nutrients or with colloids, and how this combines with environmental conditions to contribute to multiple stressor effects. We examine the state of MCPA knowledge, using case study examples from Ireland, and consider the implications of its widespread detection in waterbodies and drinking water supplies. Research themes required to ensure the sustainable and safe use of MCPA in an evolving agricultural, social and political landscape are identified here. These include the need to identify mitigation measures and/or alternative treatments, to gain insights into the conditions governing mobilization and attenuation, to map pathways of migration and to identify direct, synergistic and antagonistic ecotoxicological effects.
  [Morton, P. et al. (2020) A review of the pesticide MCPA in the land‐water environment and emerging research needs, WIREs Water. Available at: https://wires.onlinelibrary.wiley.com/doi/full/10.1002/wat2.1402. ]
- Effects of Microplastics on the Adsorption and Bioavailability of Three Strobilurin Fungicides
  Microplastics (MPs) and fungicides have been recognized as two main pollutants in ecological environments, especially in aqueous ecosystems. In this study, the adsorption behavior of three typical strobilurins (azoxystrobin, picoxystrobin, and pyraclostrobin) on polystyrene (PS) and polyethylene (PE) was investigated, and the effects of adsorption on the residual behavior and bioavailability of pyraclostrobin were evaluated. The results showed that MPs had strong adsorption capacity for the three kinds of strobilurins. Under similar conditions, the adsorption capacity was the highest for pyraclostrobin, followed by picoxystrobin and azoxystrobin, which was consistent with their octanol–water partition coefficients. Moreover, the adsorption capacity of PS was slightly higher than that of PE. The pH of aqueous solution had little effect on adsorption capacity, while an increase in ionic strength increased the adsorption capacity of azoxystrobin and picoxystrobin. The Fourier transform infrared spectra of MPs showed that no new chemical groups were formed during the adsorption process. Thus, it is speculated that hydrophobic interactions may be the driving force behind the adsorption of strobilurins on the MPs. Additionally, the adsorption of pyraclostrobin on MPs significantly reduced its residual amount in the aqueous solution, which reduced the adsorption and bioavailability of pyraclostrobin in black bean seedlings. The study provides effective information for environmental safety risk assessments with regard to the combined pollution risks of MPs and strobilurins.
  [Hai, N., Liu, X., Li, Y., Kong, F., Zhang, Y., & Fang, S. (2020). Effects of Microplastics on the Adsorption and Bioavailability of Three Strobilurin Fungicides. ACS omega, 5(47), 30679–30686. https://doi.org/10.1021/acsomega.0c04787]
- Long-term effects of neonicotinoid insecticides on ants
  The widespread prophylactic usage of neonicotinoid insecticides has a clear impact on non-target organisms. However, the possible effects of long-term exposure on soil-dwelling organisms are still poorly understood especially for social insects with long-living queens. Here, we show that effects of chronic exposure to the neonicotinoid thiamethoxam on black garden ant colonies, Lasius niger, become visible before the second overwintering. Queens and workers differed in the residue-ratio of thiamethoxam to its metabolite clothianidin, suggesting that queens may have a superior detoxification system. Even though thiamethoxam did not affect queen mortality, neonicotinoid-exposed colonies showed a reduced number of workers and larvae indicating a trade-off between detoxification and fertility. Since colony size is a key for fitness, our data suggest long-term impacts of neonicotinoids on these organisms. This should be accounted for in future environmental and ecological risk assessments of neonicotinoid applications to prevent irreparable damages to ecosystems.
  [Schläppi, D., Kettler, N., Straub, L., Glauser, G. and Neumann, P., 2020. Communications biology, 3(1), pp.1-9.]
- Microplastic in terrestrial ecosystems
  Concern about microplastics polluting different environmental compartments is mounting. Research has recently begun to embrace terrestrial systems, having initially focused at least a decade earlier on marine and aquatic ecosystems. The early research agenda on microplastics in both aquatic and terrestrial systems was mainly ecotoxicological. It included laboratory tests on individual organisms, often well-established test species, and also targeted selected soil properties and processes. Such research is necessary to establish baseline mechanisms, which is important because microplastics differ from other pollutants. Many of their effects appear to be mediated by physical parameters, such as particle shape and size rather than overt chemically mediated toxicity. Moreover, their effects are mostly sublethal or even nominally positive. Although the study of other global change factors has tended to focus at the level of the ecosystem, research on microplastic is only now on the verge of this wider view.
  [Matthias C. Rillig, Anika Lehmann ,Microplastic in terrestrial ecosystems.Science368,1430-1431(2020).DOI:10.1126/science.abb5979]
- Mobility, Degradation, and Uptake of Indaziflam under Greenhouse Conditions
  The objectives of this study were to evaluate the leaching, degradation, uptake, and mass balance of indaziflam, as well as its potential to produce phytotoxicity effects on young pecan trees. Pecan trees were planted in pots with homogeneous porous media (sandy loam soil), preferential flow channels open to the soil surface, and shallow tillage at the soil surface. Pots were treated with indaziflam at two application rates of 25 and 50 g a.i./ha in 2014 and 2015. Each pecan tree was irrigated with 7 L of water every 2 weeks during the growing season. An irrigation volume of 2 L was used to maximize indaziflam retention time in the soil from Dec. 2015 until the end of the trees’ dormant stage. In 2014, leachate samples were collected after each irrigation for quantifying indaziflam mobility. Soil samples were collected at depths of 0 to 12 and 12 to 24 cm after 45, 90, and 135 days of indaziflam application, and leaf samples were collected at the end of the growing season to quantify mobility and uptake. Indaziflam was detected in leachate samples, and the leaf indaziflam content increased with increasing application rate. Indaziflam and its breakdown products were detected at both sampling depths. Mass recovery and half-life values for indaziflam in the soil ranged from 38% to 68% and 63 to 99 days, respectively. No phytotoxicity effects were observed from increasing application rate and retention time of indaziflam in the soil. Most of the applied indaziflam was retained in the soil at shallow depth.
  [González-Delgado, A.M. and Shukla, M.K. (2020) Mobility, degradation, and uptake of Indaziflam under greenhouse conditions, HortScience. Available at: https://journals.ashs.org/hortsci/view/journals/hortsci/55/8/article-p1216.xml. ]
- Residue and toxicity of cyantraniliprole and its main metabolite J9Z38 in soil-earthworm microcosms
  As part of a new generation of diamide insecticides, cyantraniliprole has broad application prospects. In the present study, a QuEChERS-UPLC-MS/MS method was established to determine the residues of cyantraniliprole and its main metabolite J9Z38 in soil and earthworms. Moreover, the accumulation and toxicity of cyantraniliprole and J9Z38 in earthworms were evaluated. The present results show that the detection method of cyantraniliprole and J9Z38 has high sensitivity and accuracy, which could be used for the accurate quantification of cyantraniliprole and J9Z38 residues in soil and earthworms. Additionally, cyantraniliprole degraded faster than its main metabolite J9Z38 in the artificial soil. Moreover, the bioenrichment efficiency of cyantraniliprole was higher than J9Z38. The toxicity test result showed that cyantraniliprole and J9Z38 could induce oxidative stress effect in earthworms from 5.0 mg/kg, finally resulting in cellular damage. Moreover, the oxidative damage degree induced by cyantraniliprole was higher than J9Z38. Combining the results of residue test and toxicity test, although cyantraniliprole degraded faster than its main metabolite J9Z38 in the artificial soil, its risk to earthworms was higher than J9Z38.
  [Zhang, X., Wang, X., Liu, Y., Fang, K., & Liu, T. (2020). Residue and toxicity of cyantraniliprole and its main metabolite J9Z38 in soil-earthworm microcosms. Chemosphere, 249, 126479. https://doi.org/10.1016/j.chemosphere.2020.126479]
- The impact and toxicity of glyphosate and glyphosate-based herbicides on health and immunity
  Glyphosate, or N-phosphomethyl(glycine), is an organophosphorus compound and a competitive inhibitor of the shikimate pathway that allows aromatic amino acid biosynthesis in plants and microorganisms. Its utilization in broad-spectrum herbicides, such as RoundUp®, has continued to increase since 1974; glyphosate, as well as its primary metabolite aminomethylphosphonic acid, is measured in soils, water, plants, animals and food. In humans, glyphosate is detected in blood and urine, especially in exposed workers, and is excreted within a few days. It has long been regarded as harmless in animals, but growing literature has reported health risks associated with glyphosate and glyphosate-based herbicides. In 2017, the International Agency for Research on Cancer (IARC) classified glyphosate as “probably carcinogenic” in humans. However, other national agencies did not tighten their glyphosate restrictions and even prolonged authorizations of its use. There are also discrepancies between countries’ authorized levels, demonstrating an absence of a clear consensus on glyphosate to date. This review details the effects of glyphosate and glyphosate-based herbicides on fish and mammal health, focusing on the immune system. Increasing evidence shows that glyphosate and glyphosate-based herbicides exhibit cytotoxic and genotoxic effects, increase oxidative stress, disrupt the estrogen pathway, impair some cerebral functions, and allegedly correlate with some cancers. Glyphosate effects on the immune system appear to alter the complement cascade, phagocytic function, and lymphocyte responses, and increase the production of pro-inflammatory cytokines in fish. In mammals, including humans, glyphosate mainly has cytotoxic and genotoxic effects, causes inflammation, and affects lymphocyte functions and the interactions between microorganisms and the immune system. Importantly, even as many outcomes are still being debated, evidence points to a need for more studies to better decipher the risks from glyphosate and better regulation of its global utilization.
  [Peillex, C. and Pelletier, M. (2020) The impact and toxicity of glyphosate and glyphosate-based herbicides on health and immunity, Journal of Immunotoxicology. Available at: https://www.tandfonline.com/doi/full/10.1080/1547691X.2020.1804492.]
- Microplastics Can Change Soil Properties and Affect Plant Performance
  Microplastics can affect biophysical properties of the soil. However, little is known about the cascade of events in fundamental levels of terrestrial ecosystems, i.e., starting with the changes in soil abiotic properties and propagating across the various components of soil–plant interactions, including soil microbial communities and plant traits. We investigated here the effects of six different microplastics (polyester fibers, polyamide beads, and four fragment types: polyethylene, polyester terephthalate, polypropylene, and polystyrene) on a broad suite of proxies for soil health and performance of spring onion (Allium fistulosum). Significant changes were observed in plant biomass, tissue elemental composition, root traits, and soil microbial activities. These plant and soil responses to microplastic exposure were used to propose a causal model for the mechanism of the effects. Impacts were dependent on particle type, i.e., microplastics with a shape similar to other natural soil particles elicited smaller differences from control. Changes in soil structure and water dynamics may explain the observed results in which polyester fibers and polyamide beads triggered the most pronounced impacts on plant traits and function. The findings reported here imply that the pervasive microplastic contamination in soil may have consequences for plant performance and thus for agroecosystems and terrestrial biodiversity.
  [Machado, A. et al. (2019) Microplastics can change soil properties and affect plant performance, Environmental Science & Technology. Available at: https://pubs.acs.org/doi/10.1021/acs.est.9b01339. ]
- Occurrence and Ecological Impacts of Microplastics in Soil Systems: A Review
  Microplastics, as a group of emerging contaminants, are receiving growing attention. During the last decade, their occurrence and toxicity in aquatic ecosystems have been intensively studied and reviewed, but less attention has been paid on soil ecosystems. Given the importance of soil ecosystems and the call for increasing research on soil from scientific communities, it is predicted that relevant studies will boom in the following years. The present review intends to provide a comprehensive overview of current knowledge on microplastic pollution in soil environments. We critically summarize the source, contamination level and fate of microplastics in (industrial and arable) soils. Then, we thoroughly describe what effects have been observed on soil microbes, animals and plants, and analyze what insights we can get from available information. Finally, we identify knowledge gaps that need to be filled and give suggestions for future research.
  [Zhu, F. et al. (2019) Occurrence and ecological impacts of microplastics in soil systems: A Review, Bull Environ Contam Toxicol. Available at: https://pubmed.ncbi.nlm.nih.gov/31069405/. ]
- Pyrethroid exposure alters internal and cuticle surface bacterial communities in Anopheles albimanus
  A deeper understanding of the mechanisms underlying insecticide resistance is needed to mitigate its threat to malaria vector control. Following previously identified associations between mosquito microbiota and insecticide resistance, we demonstrate for the first time, the effects of pyrethroid exposure on the microbiota of F₁ progeny of field-collected Anopheles albimanus. Larval and adult mosquitoes were exposed to the pyrethroids alphacypermethrin (only adults), permethrin, and deltamethrin. While there were no significant differences in bacterial composition between insecticide-resistant and insecticide-susceptible mosquitoes, bacterial composition between insecticide-exposed and non-exposed mosquitoes was significantly different for alphacypermethrin and permethrin exposure. Along with other bacterial taxa not identified to species, Pantoea agglomerans (a known insecticide-degrading bacterial species) and Pseudomonas fragi were more abundant in insecticide-exposed compared to non-exposed adults, demonstrating that insecticide exposure can alter mosquito bacterial communities. We also show for the first time that the cuticle surfaces of both larval and adult An. albimanus harbor more diverse bacterial communities than their internal microbial niches. Together, these findings demonstrate how insecticide pressure could be selecting for certain bacteria within mosquitoes, especially insecticide-metabolizing bacteria, thus potentially contributing to insecticide resistance.
  [Nsa Dada, Juan C Lol, Ana Cristina Benedict, Francisco López, Mili Sheth, Nicole Dzuris, Norma Padilla, Audrey Lenhart, Pyrethroid exposure alters internal and cuticle surface bacterial communities in Anopheles albimanus, The ISME Journal, Volume 13, Issue 10, October 2019, Pages 2447–2464, https://doi.org/10.1038/s41396-019-0445-5]
- Uptake and distribution of fluopyram and tebuconazole residues in tomato and bell pepper plant tissues
  The present study describes the uptake and distribution of fungicides, fluopyram, and tebuconazole in tomato and bell pepper plant tissues from the soil drench application of their combination product fluopyram17.7% + tebuconazole 17.7%. For extraction and cleanup of fluopyram, its metabolite fluopyram benzamide, and tebuconazole samples, the QuEChERS method was used in conjunction with LC-MS/MS. The limit of detection (LOD) and limit of quantification (LOQ) of the method determined were 1.5 μg kg−1 and 0.005 mg kg−1, respectively, and recoveries of all analytes from sample matrices remained within the acceptable range of 70–120%. Rapid uptake of the fungicides by tomato and bell pepper plants was observed from the first day onwards. In the tomato plant, the major part of the fungicides accumulated in the roots, whereas in bell pepper plant, it accumulated both in the roots and in the leaves. Accumulation of fluopyram and tebuconazole residues was lowest in tomato and bell pepper fruits which were much below their respective maximum residue limits (MRLs). The highest residue concentration of fluopyram and tebuconazole in tomato fruits was 0.060 and 0.009 mg kg−1; the corresponding values in bell pepper fruits were 0.080 and 0.013 mg kg−1. In field soil, fluopyram residues were 3.18–3.570 mg kg−1 initially which dissipated at the half-life of 36 days. Tebuconazole concentration was 1.57–1.892 mg kg−1 initially, and it dissipated at the half-life of 44.5–49.5 days. The major metabolite of fluopyram, fluopyram benzamide, was detected in plant tissues as well as in soil, and remained within 12% of the parent compound. The results of the study indicated that fluopyram and tebuconazole are less likely of entry into food chain through intake of tomato and bell pepper fruits if these crops are grown on soil contaminated with these fungicides.
  [Matadha, N.Y. et al. (2019) Uptake and distribution of fluopyram and tebuconazole residues in tomato and bell pepper plant tissues, Environmental Science and Pollution Research. Available at: https://link.springer.com/article/10.1007/s11356-018-04071-4. ]
- Influence of microplastic addition on glyphosate decay and soil microbial activities in Chinese loess soil
  The intensive use of pesticide and plastic mulches has considerably enhanced crop growth and yield. Pesticide residues and plastic debris, however, have caused serious environmental problems. This study investigated the effects of the commonly used herbicide glyphosate and micrometre-sized plastic debris, referred as microplastics, on glyphosate decay and soil microbial activities in Chinese loess soil by a microcosm experiment over 30 days incubation. Results showed that glyphosate decay was gradual and followed a single first-order decay kinetics model. In different treatments (with/without microplastic addition), glyphosate showed similar half-lives (32.8 days). The soil content of aminomethylphosphonic acid (AMPA), the main metabolite of glyphosate, steadily increased without reaching plateau and declining phases throughout the experiment. Soil microbial respiration significantly changed throughout the entirety of the experiment, particularly in the treatments with higher microplastic addition. The dynamics of soil β-glucosidase, urease and phosphatase varied, especially in the treatments with high microplastic addition. Particles that were considerably smaller than the initially added microplastic particles were observed after 30 days incubation. This result thus implied that microplastic would hardly affect glyphosate decay but smaller plastic particles accumulated in soils which potentially threaten soil quality would be further concerned especially in the regions with intensive plastic mulching application.
  [Yang, X., Bento, C. P. M., Chen, H., Zhang, H., Xue, S., Lwanga, E. H., Zomer, P., Ritsema, C. J., & Geissen, V. (2018). Influence of microplastic addition on glyphosate decay and soil microbial activities in Chinese loess soil. Environmental pollution (Barking, Essex : 1987), 242(Pt A), 338–347. https://doi.org/10.1016/j.envpol.2018.07.006]
- Microplastics in soils: Analytical methods, pollution characteristics and ecological risks
  Microplastics are emerging persistent contaminants of increasing concern. Although microplastics have been extensively detected in aquatic environments, their occurrence in soil ecosystems remains largely unexplored. This review focused on recent progress in analytical methods, pollution characteristics and ecological effects of microplastics in soils. In spite of the presence of microplastics in soils, no standardized methods are available for the quantification. Uniform protocols including microplastic extraction and identification are urgently needed to develop. In soil environments, main sources of microplastics include mulching film, sludge, wastewater irrigation and atmospheric deposition. The fate of microplastics is closely related to soil physio-chemistry and biota. Existing evidence shows that microplastics can influence soil biota at different trophic levels, and even threaten human health through food chains. Therefore, further research is needed to fully reveal the fate and ecological risks of microplastics in soils; and necessary action is required to control microplastic pollution in terrestrial ecosystems.
  [He, D. et al. (2018) Microplastics in soils: Analytical methods, pollution characteristics and ecological risks, TrAC Trends in Analytical Chemistry. Available at: https://www.sciencedirect.com/science/article/pii/S0165993618304102?ref=pdf_download&fr=RR-7&rr=87d9ad93cbbf2f24. ]
- Sub-micron level investigation reveals the inaccessibility of stabilized carbon in soil microaggregates
  Direct evidence-based approaches are vital to evaluating newly proposed theories on the persistence of soil organic carbon and establishing the contributions of abiotic and biotic controls. Our primary goal was to directly identify the mechanisms of organic carbon stabilization in native-state, free soil microaggregates without disrupting the aggregate microstructure using scanning transmission x-ray microscopy coupled with near edge x-ray absorption fine structure spectroscopy (STXM-NEXAFS). The influence of soil management practices on microaggregate associated-carbon was also assessed. Free, stable soil microaggregates were collected from a tropical agro-ecosystem in Cruz Alta, Brazil. The long-term experimental plots (>25 years) comparing two tillage systems: no-till and till with a complex crop rotation. Based on simultaneously collected multi-elemental associations and speciation, STXM-NEXAFS successfully provided submicron level information on organo-mineral associations. Simple organic carbon sources were found preserved within microaggregates; some still possessing original morphology, suggesting that their stabilization was not entirely governed by the substrate chemistry. Bulk analysis showed higher and younger organic carbon in microaggregates from no-till systems than tilled systems. These results provide direct submicron level evidence that the surrounding environment is involved in stabilizing organic carbon, thus favoring newly proposed concepts on the persistence of soil organic carbon.
  [Pitumpe Arachchige, P.S. et al. (2018) Sub-micron level investigation reveals the inaccessibility of stabilized carbon in soil microaggregates, Scientific Reports. Available at: https://www.nature.com/articles/s41598-018-34981-9. ]
- Field‐scale examination of neonicotinoid insecticide persistence in soil as a result of seed treatment use in commercial maize (corn) fields in southwestern Ontario
  Neonicotinoid insecticides, especially as seed treatments, have raised concerns about environmental loading and impacts on pollinators, biodiversity, and ecosystems. The authors measured concentrations of neonicotinoid residues in the top 5 cm of soil before planting of maize (corn) in 18 commercial fields with a history of neonicotinoid seed treatment use in southwestern Ontario in 2013 and 2014 using liquid chromatography–tandem mass spectrometry with electrospray ionization. A simple calculator based on first‐order kinetics, incorporating crop rotation, planting date, and seed treatment history from the subject fields, was used to estimate dissipation rate from the seed zone. The estimated half‐life (the time taken for 50% of the insecticide to have dissipated by all mechanisms) based on 8 yr of crop history was 0.64 (range, 0.25–1.59) yr and 0.57 (range, 0.24–2.12) yr for 2013 and 2014, respectively. In fields where neonicotinoid residues were measured in both years, the estimated mean half‐life between 2013 and 2014 was 0.4 (range, 0.27–0.6) yr. If clothianidin and thiamethoxam were used annually as a seed treatment in a typical crop rotation of maize, soybean, and winter wheat over several years, residues would plateau rather than continue to accumulate. Residues of neonicotinoid insecticides after 3 yr to 4 yr of repeated annual use tend to plateau to a mean concentration of less than 6 ng/g in agricultural soils in southwestern Ontario.
  [Arthur Schaafsma, Victor Limay‐Rios, Yingen Xue, Jocelyn Smith, Tracey Baute, Field‐scale examination of neonicotinoid insecticide persistence in soil as a result of seed treatment use in commercial maize (corn) fields in southwestern Ontario, Environmental Toxicology and Chemistry, Volume 35, Issue 2, 1 February 2016, Pages 295–302, https://doi.org/10.1002/etc.3231]
- Healthy soils: a prerequisite for sustainable food security
  Soil health constitutes the foundation for the production of healthy food and thus contributes to local and global food security. Recent findings indicate that there will need to be a 60 % increase in global food production and associated ecosystem services by 2050. However, one-third of global soils are currently facing moderate to severe degradation through soil erosion, nutrient depletion, salinity, sealing and contamination. Evidence-based decisions and soil information are crucial for achieving sustainable soil management at all levels. In 2012, the Food and Agriculture Organization (FAO) of the United Nations established the Global Soil Partnership to highlight effective and concerted actions against soil degradation and to advocate healthy soils for a food secure world.
  [Rojas, R.V. et al. (2016) Healthy soils: A prerequisite for Sustainable Food Security - Environmental Earth Sciences, Soil Physics and Land Management. Available at: https://link.springer.com/article/10.1007/s12665-015-5099-7. ]
- Environmental fate and exposure; neonicotinoids and fipronil
  Systemic insecticides are applied to plants using a wide variety of methods, ranging from foliar sprays to seed treatments and soil drenches. Neonicotinoids and fipronil are among the most widely used pesticides in the world. Their popularity is largely due to their high toxicity to invertebrates, the ease and flexibility with which they can be applied, their long persistence, and their systemic nature, which ensures that they spread to all parts of the target crop. However, these properties also increase the probability of environmental contamination and exposure of nontarget organisms. Environmental contamination occurs via a number of routes including dust generated during drilling of dressed seeds, contamination and accumulation in arable soils and soil water, runoff into waterways, and uptake of pesticides by nontarget plants via their roots or dust deposition on leaves. Persistence in soils, waterways, and nontarget plants is variable but can be prolonged; for example, the half-lives of neonicotinoids in soils can exceed 1,000 days, so they can accumulate when used repeatedly. Similarly, they can persist in woody plants for periods exceeding 1 year. Breakdown results in toxic metabolites, though concentrations of these in the environment are rarely measured. Overall, there is strong evidence that soils, waterways, and plants in agricultural environments and neighboring areas are contaminated with variable levels of neonicotinoids or fipronil mixtures and their metabolites (soil, parts per billion (ppb)-parts per million (ppm) range; water, parts per trillion (ppt)-ppb range; and plants, ppb-ppm range). This provides multiple routes for chronic (and acute in some cases) exposure of nontarget animals. For example, pollinators are exposed through direct contact with dust during drilling; consumption of pollen, nectar, or guttation drops from seed-treated crops, water, and consumption of contaminated pollen and nectar from wild flowers and trees growing near-treated crops. Studies of food stores in honeybee colonies from across the globe demonstrate that colonies are routinely and chronically exposed to neonicotinoids, fipronil, and their metabolites (generally in the 1–100 ppb range), mixed with other pesticides some of which are known to act synergistically with neonicotinoids. Other nontarget organisms, particularly those inhabiting soils, aquatic habitats, or herbivorous insects feeding on noncrop plants in farmland, will also inevitably receive exposure, although data are generally lacking for these groups. We summarize the current state of knowledge regarding the environmental fate of these compounds by outlining what is known about the chemical properties of these compounds, and placing these properties in the context of modern agricultural practices.
  [Bonmatin, JM., Giorio, C., Girolami, V. et al. Environmental fate and exposure; neonicotinoids and fipronil. Environ Sci Pollut Res 22, 35–67 (2015). https://doi.org/10.1007/s11356-014-3332-7]
- Non-target species mortality and the measurement of brodifacoum rodenticide residues after a rat (Rattus rattus) eradication on Palmyra Atoll, tropical Pacific
  The use of rodenticides to control or eradicate invasive rats (Rattus spp.) for conservation purposes has rapidly grown in the past decades, especially on islands. The non-target consequences and the fate of toxicant residue from such rodent eradication operations have not been well explored. In a cooperative effort, we monitored the application of a rodenticide, ‘Brodifacoum 25W: Conservation’, during an attempt to eradicate Rattus rattus from Palmyra Atoll. In 2011, Brodifacoum 25W: Conservation was aerially broadcasted twice over the entire atoll (2.5 km2) at rates of 80 kg/ha and 75 kg/ha and a supplemental hand broadcast application (71.6 kg/ha) occurred three weeks after the second aerial application over a 10 ha area. We documented brodifacoum residues in soil, water, and biota, and documented mortality of non-target organisms. Some bait (14–19% of the target application rate) entered the marine environment to distances 7 m from the shore. After the application commenced, carcasses of 84 animals representing 15 species of birds, fish, reptiles and invertebrates were collected opportunistically as potential non-target mortalities. In addition, fish, reptiles, and invertebrates were systematically collected for residue analysis. Brodifacoum residues were detected in most (84.3%) of the animal samples analyzed. Although detection of residues in samples was anticipated, the extent and concentrations in many parts of the food web were greater than expected. Risk assessments should carefully consider application rates and entire food webs prior to operations using rodenticides.
  [Pitt, William & Berentsen, Are & Shiels, Aaron & Volker, Steven & Eisemann, John & Wegmann, Alexander & Howald, Gregg. (2015). Non-target species mortality and the measurement of brodifacoum rodenticide residues after a rat (Rattus rattus) eradication on Palmyra Atoll, tropical Pacific. Biological Conservation. 185. 10.1016/j.biocon.2015.01.008. ]
- Soil biodiversity and human health
  Soil biodiversity is increasingly recognized as providing benefits to human health because it can suppress disease-causing soil organisms and provide clean air, water and food. Poor land-management practices and environmental change are, however, affecting belowground communities globally, and the resulting declines in soil biodiversity reduce and impair these benefits. Importantly, current research indicates that soil biodiversity can be maintained and partially restored if managed sustainably. Promoting the ecological complexity and robustness of soil biodiversity through improved management practices represents an underutilized resource with the ability to improve human health.
  [Wall, D., Nielsen, U. & Six, J. Soil biodiversity and human health. Nature 528, 69–76 (2015). https://doi.org/10.1038/nature15744]
- An overview of the environmental risks posed by neonicotinoid insecticides
  Neonicotinoids are now the most widely used insecticides in the world. They act systemically, travelling through plant tissues and protecting all parts of the crop, and are widely applied as seed dressings. As neurotoxins with high toxicity to most arthropods, they provide effective pest control and have numerous uses in arable farming and horticulture. However, the prophylactic use of broad-spectrum pesticides goes against the long-established principles of integrated pest management (IPM), leading to environmental concerns. It has recently emerged that neonicotinoids can persist and accumulate in soils. They are water soluble and prone to leaching into waterways. Being systemic, they are found in nectar and pollen of treated crops. Reported levels in soils, waterways, field margin plants and floral resources overlap substantially with concentrations that are sufficient to control pests in crops, and commonly exceed the LC50 (the concentration which kills 50% of individuals) for beneficial organisms. Concentrations in nectar and pollen in crops are sufficient to impact substantially on colony reproduction in bumblebees. Although vertebrates are less susceptible than arthropods, consumption of small numbers of dressed seeds offers a route to direct mortality in birds and mammals. Synthesis and applications. Major knowledge gaps remain, but current use of neonicotinoids is likely to be impacting on a broad range of non-target taxa including pollinators and soil and aquatic invertebrates and hence threatens a range of ecosystem services.
  [Goulson, D. (2013) An overview of the environmental risks posed by neonicotinoid insecticides, Journal of Applied Ecology. Available at: https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2664.12111. ]
- Snails as indicators of pesticide drift, deposit, transfer and effects in the vineyard
  This paper presents a field-study of real pesticide application conditions in a vineyard. The objective was to measure the exposure, the transfer and the effects of pesticides on a non-target soil invertebrate, the land snail Helix aspersa. There was no drift of the herbicides (glyphosate and glufosinate) whereas the fungicides (cymoxanil, folpet, tebuconazole and pyraclostrobin) were detected up to 20 m from the treated area. For folpet and particularly tebuconazole, spray deposits on soil (corresponding to losses for the intended target i.e. the vine leaves) were high (41.1% and 88.8% loss of applied dose, respectively). For herbicides, the target was the soil and losses (percentage of compounds which did not reach the soil) were of 22% for glufosinate and 52% for glyphosate. In the study plot, glyphosate was transferred to and accumulated in snail tissues (4 mg kg−1 dry weight, dw), as was its metabolite AMPA (8 mg kg−1 dw) which could be in relation with the reduced growth observed in snails. No effects on snail survival or growth were found after exposure to the other organic compounds or to copper and sulphur-fungicides, although transfer of tebuconazole, pyraclostrobin and copper occurred. This study brings original field data on the fate of pesticides in a vineyard agro-ecosystem under real conditions of application and shows that transfer and effects of pesticides to a non-target organism occurred.
  [Druart, C. et al. (2011) Snails as indicators of pesticide drift, deposit, transfer and effects in the vineyard, Science of The Total Environment. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0048969711007224?via%3Dihub. ]
- Organic Pollutants in Areas Impacted by Flooding in 2002: A 4-Year Survey
  This paper summarizes a 4-year survey focused on polycyclic aromatic hydrocarbons (PAHs) and halogenated persistent organic pollutants (POPs) in river sediments, soil and crops collected in the locality impacted by catastrophic floods that occurred in the western part of Bohemia in August 2002. In spite of relatively high levels of polychlorinated biphenyls (PCBs) in river sediments, the increase of these POPs in flooded arable soil was not significant. On the other hand, remarkably higher levels of PAHs and dichlorodiphenyl trichloroethane (DDTs) were found as compared to those in reference soil samples. Regardless of this increased soil pollution, no measurable elevated concentrations of POPs occurred in the wheat grown in this area.
  [Pulkrabová, J. et al. (2008) Organic Pollutants in Areas Impacted by Flooding in 2002: A 4-Year Survey, Bulletin of Environmental Contamination and Toxicology. Available at: https://link.springer.com/article/10.1007/s00128-008-9486-6. ]
- Soil health and global sustainability: translating science into practice
  Interest in the quality and health of soil has been stimulated by recent awareness that soil is vital to both production of food and fiber and global ecosystems function. Soil health, or quality, can be broadly defined as the capacity of a living soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and promote plant and animal health. Soil quality and health change over time due to natural events or human impacts. They are enhanced by management and land-use decisions that weigh the multiple functions of soil and are impaired by decisions which focus only on single functions, such as crop productivity. Criteria for indicators of soil quality and health relate mainly to their utility in defining ecosystem processes and in integrating physical, chemical, and biological properties; their sensitivity to management and climatic variations; and their accessibility and utility to agricultural specialists, producers, conservationists, and policy makers. Although soils have an inherent quality as related to their physical, chemical, and biological properties within the constraints set by climate and ecosystems, the ultimate determinant of soil quality and health is the land manager. As such, the assessment of soil quality or health, and direction of change with time, is the primary indicator of sustainable management. Scientists can make a significant contribution to sustainable land management by translating scientific knowledge and information on soil function into practical tools and approaches by which land managers can assess the sustainability of their management practices. The first steps, however, in our communal journey towards sustainable land management must be the identification of our final destination (sustainability goals), the strategies or course by which we will get there, and the indicators (benchmarks) that we are proceeding in the right direction. We too often rush to raise the sails of our ‘technological’ ship to catch the wind, before knowing from where it comes or in properly defining our destination, charting our course, and setting the rudder of our ship. Examples are given of approaches for assessing soil quality and health to define the sustainability of land management practices and to ‘translate our science into practice’.
  [Duran, J. (2002) Soil Health and Global Sustainability: Translating Science Into Practice, Agriculture, Ecosystems & Environment. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0167880901002468. ]
- Soil health and sustainability: managing the biotic component of soil quality
  Soil health is the capacity of soil to function as a vital living system, within ecosystem and land-use boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and promote plant and animal health. Anthropogenic reductions in soil health, and of individual components of soil quality, are a pressing ecological concern. A conference entitled ‘Soil Health: Managing the Biological Component of Soil Quality’ was held was held in the USA in November 1998 to help increase awareness of the importance and utility of soil organisms as indicators of soil quality and determinants of soil health. To evaluate sustainability of agricultural practices, assessment of soil health using various indicators of soil quality is needed. Soil organism and biotic parameters (e.g. abundance, diversity, food web structure, or community stability) meet most of the five criteria for useful indicators of soil quality. Soil organisms respond sensitively to land management practices and climate. They are well correlated with beneficial soil and ecosystem functions including water storage, decomposition and nutrient cycling, detoxification of toxicants, and suppression of noxious and pathogenic organisms. Soil organisms also illustrate the chain of cause and effect that links land management decisions to ultimate productivity and health of plants and animals. Indicators must be comprehensible and useful to land managers, who are the ultimate stewards of soil quality and soil health. Visible organisms such as earthworms, insects, and molds have historically met this criterion. Finally, indicators must be easy and inexpensive to measure, but the need for knowledge of taxonomy complicates the measurement of soil organisms. Several farmer-participatory programs for managing soil quality and health have incorporated abiotic and simple biotic indicators. The challenge for the future is to develop sustainable management systems which are the vanguard of soil health; soil quality indicators are merely a means towards this end.
  [Doran, J.W. and Zeiss, M.R. (2000) Soil Health and Sustainability: Managing the biotic component of Soil Quality, Applied Soil Ecology. Available at: https://digitalcommons.unl.edu/agronomyfacpub/15/.]
- Isoxaben soil biodegradation in pear tree orchard after repeated high dose application
  During the past nine years, each of the plots of a pear tree orchard were treated annually with the same herbicide treatment. The following herbicide treatments were compared, each being made by application of a mixture of two or three herbicides: 1a, no herbicide at all, weeds being hoed (control 1a); 2, diuron + paraquat 3 + 1 kg/ha; 3, simazine + paraquat 2 + 1 kg/ha; 4, isoxaben + diuron + paraquat 0.5 + 1.6 + 1 kg/ha; and 5, isoxaben + simazine + paraquat 0.5 + 1.25 + 1 kg/ha. In March 1996, one year after the final orchard herbicide treatment, isoxaben could not be detected in the soils of any field plots; isoxaben was incorporated at 0.74 mg/kg in the loamy soils sampled separately in each of the field plots, and the soils were incubated in the laboratory. Isoxaben soil half-lives were 92 days in the soils treated previously with herbicide treatments 1a, 2, or 3 and 42 days in the soils treated with herbicide treatments 4 and 5. The repeated isoxaben treatments applied in the past thus enhanced the isoxaben soil biodegradation; diuron, simazine, and paraquat had no influence on this rate enhancement. On the other hand, herbicide treatments 4 and 5 were applied in the orchard in April 1996 on the corresponding plots treated in this manner for the last nine years. Isoxaben + paraquat 0.5 + 1 kg/ha was applied simultaneously on other plots (control 1b) not treated in the past with isoxaben. During the growth season in the orchard, the isoxaben soil half-lives in the control plots 1b was 101 days, and 41 days in the plots where herbicide treatments 4 or 5 were applied.
  [Rouchaud J, Neus O, Bulcke R, Callens D, Dekkers T. Isoxaben soil biodegradation in pear tree orchard after repeated high dose application. Arch Environ Contam Toxicol. 1997 Oct;33(3):247-51. doi: 10.1007/s002449900250. PMID: 9353201.]
- Abiotic and Biotic Degradation of Dithiopyr in Golf Course Greens
  Results of previous research have indicated that only a small fraction of dithiopyr [S,S-dimethyl 2-(difluoromethyl)-4-(2-methylpropyl)-6-(trifluoromethyl)-3,5-pyridinedicarbothioate] is lost in the surface water or by infiltration in soil leachate following application to golf course greens. The purpose of this research was to investigate the abiotic and biotic agents for dithiopyr loss from golf course greens. Growth chamber and laboratory studies were conducted to determine dithiopyr loss in response to volatilization, photodegradation, chemical transformation, and biological degradation in sterile and nonsterile rooting media (RM) and RM leachate collected from established golf course greens maintained in the greenhouse. Following application to RM, dithiopyr was lost primarily by volatilization which increased with increasing treatment period and temperature. The estimated half-life for dithiopyr in RM ranged from 68.8 days (sterile RM, dark, 20 °C) to 39.2 days (nonsterile RM, dark, 35 °C). Dithiopyr degradation in RM leachate was greater under UV radiation than in the dark and was faster than in distilled water under the same conditions indicating the potential for the presence of photosensitizers prompting photodegradation of dithiopyr in the RM leachate. The estimated half-lives for dithiopyr in RM leachate ranged from 515 days (sterile RM leachate, dark, 6.8 pH, 20 °C) to 0.8 days (nonsterile RM leachate, UV light, 6.8 pH, 20 °C). Results indicate a large effect of environmental variables on dithiopyr loss and its persistence in the turfgrass ecosystem.
  [Hong, S. and Smith, A. (1996) Abiotic and Biotic Degradation of Dithiopyr in Golf Course Greens, Journal of Agricultural and Food Chemistry. Available at: https://pubs.acs.org/doi/abs/10.1021/jf950768g. ]

Soil Biota

Scientific Studies:

Abstract