Concerted Evaluation of Pesticides in Soils of Extensive Grassland Sites and Organic and Conventional Vegetable Fields Facilitates the Identification of Major Input Processes

The intensive use of pesticides and their subsequent distribution to the environment and non-target organisms is of increasing concern. So far, little is known about the occurrence of pesticides in soils of untreated areas─such as ecological refuges─as well as the processes contributing to this unwanted pesticide contamination. In this study, we analyzed the presence and abundance of 46 different pesticides in soils from extensively managed grassland sites, as well as organically and conventionally managed vegetable fields (60 fields in total). Pesticides were found in all soils, including the extensive grassland sites, demonstrating a widespread background contamination of soils with pesticides. The results suggest that after conversion from conventional to organic farming, the organic fields reach pesticide levels as low as those of grassland sites not until 20 years later. Furthermore, the different pesticide composition patterns in grassland sites and organically managed fields facilitated differentiation between long-term persistence of residues and diffuse contamination processes, that is, short-scale redistribution (spray drift) and long-scale dispersion (atmospheric deposition), to offsite contamination

Soil microbiome signatures are associated with pesticide residues in arable landscapes

Pesticides are widely applied in agriculture to combat disease, pests, and weeds, leading to long-lasting contamination of agricultural soils with pesticide residues. While classical risk assessment experiments have repeatedly addressed immediate pesticide effects, we employ an ecological approach to investigate how pesticide residues persisting in soils influence the soil microbiome under realistic agricultural conditions. We assessed a wide range of soil characteristics, including the occurrence of 48 widely-used pesticides in 60 fields under conventional, no-tillage and organic management. We then tested which factors best explain soil microbiome traits. Environmental factors, including climate, geography, and soil characteristics, were the soil microbiome's leading drivers. Remarkably, of all management factors, pesticide residues showed the strongest associations with soil microbiome traits, which were even more pronounced than the effects of cropping systems. Pesticide residues were almost exclusively positively associated with the relative abundance of 113 bacterial and 130 fungal taxa, many of them being assigned to taxa of known pesticide degraders. While fungal diversity and abundance were primarily positively associated with pesticide residues, bacterial diversity and abundance of the gene nifH - essential for biological nitrogen fixation - were negatively linked to the concentration of individual pesticide residues. Our results suggest that pesticide residues alter the soil microbiome, with potential long-term implications for the functioning of agricultural soils

Increasing the number of stressors reduces soil ecosystem services worldwide

Increasing the number of environmental stressors could decrease ecosystem functioning in soils. Yet this relationship has never been globally assessed outside laboratory experiments. Here, using two independent global standardized field surveys, and a range of natural and human factors, we test the relationship between the number of environmental stressors exceeding different critical thresholds and the maintenance of multiple ecosystem services across biomes. Our analysis shows that, multiple stressors, from medium levels (>50%), negatively and significantly correlates with impacts on ecosystem services, and that multiple stressors crossing a high-level critical threshold (over 75% of maximum observed levels), reduces soil biodiversity and functioning globally. The number of environmental stressors >75% threshold was consistently seen as an important predictor of multiple ecosystem services, therefore improving prediction of ecosystem functioning. Our findings highlight the need to reduce the dimensionality of the human footprint on ecosystems to conserve biodiversity and function

Soil contamination in nearby natural areas mirrors that in urban greenspaces worldwide

Soil contamination is one of the main threats to ecosystem health and sustainability. Yet little is known about the extent to which soil contaminants differ between urban greenspaces and natural ecosystems. Here we show that urban greenspaces and adjacent natural areas (i.e., natural/semi-natural ecosystems) shared similar levels of multiple soil contaminants (metal(loid)s, pesticides, microplastics, and antibiotic resistance genes) across the globe. We reveal that human influence explained many forms of soil contamination worldwide. Socio-economic factors were integral to explaining the occurrence of soil contaminants worldwide. We further show that increased levels of multiple soil contaminants were linked with changes in microbial traits including genes associated with environmental stress resistance, nutrient cycling, and pathogenesis. Taken together, our work demonstrates that human-driven soil contamination in nearby natural areas mirrors that in urban greenspaces globally, and highlights that soil contaminants have the potential to cause dire consequences for ecosystem sustainability and human wellbeing

Soil microbiome signatures are associated with pesticide residues in arable landscapes

Pesticides are widely applied in agriculture to combat disease, pests, and weeds, leading to long-lasting contamination of agricultural soils with pesticide residues. While classical risk assessment experiments have repeatedly addressed immediate pesticide effects, we employ an ecological approach to investigate how pesticide residues persisting in soils influence the soil microbiome under realistic agricultural conditions. We assessed a wide range of soil characteristics, including the occurrence of 48 widely-used pesticides in 60 fields under conventional, no-tillage and organic management. We then tested which factors best explain soil microbiome traits. Environmental factors, including climate, geography, and soil characteristics, were the soil microbiome’s leading drivers. Remarkably, of all management factors, pesticide residues showed the strongest associations with soil microbiome traits, which were even more pronounced than the effects of cropping systems. Pesticide residues were almost exclusively positively associated with the relative abundance of 113 bacterial and 130 fungal taxa, many of them being assigned to taxa of known pesticide degraders. While fungal diversity and abundance were primarily positively associated with pesticide residues, bacterial diversity and abundance of the gene nifH - essential for biological nitrogen fixation - were negatively linked to the concentration of individual pesticide residues. Our results suggest that pesticide residues alter the soil microbiome, with potential long-term implications for the functioning of agricultural soils

Widespread Occurrence of Pesticides in Organically Managed Agricultural Soils—the Ghost of a Conventional Agricultural Past?

Pesticides are applied in large quantities to agroecosystems worldwide. To date, few studies assessed the occurrence of pesticides in organically managed agricultural soils, and it is unresolved whether these pesticide residues affect soil life. We screened 100 fields under organic and conventional management with an analytical method containing 46 pesticides (16 herbicides, 8 herbicide transformation products, 17 fungicides, seven insecticides). Pesticides were found in all sites, including 40 organic fields. The number of pesticide residues was two times and the concentration nine times higher in conventional compared to organic fields. Pesticide number and concentrations significantly decreased with the duration of organic management. Even after 20 years of organic agriculture, up to 16 different pesticide residues were present. Microbial biomass and specifically the abundance of arbuscular mycorrhizal fungi, a widespread group of beneficial plant symbionts, were significantly negatively linked to the amount of pesticide residues in soil. This indicates that pesticide residues, in addition to abiotic factors such as pH, are a key factor determining microbial soil life in agroecosystems. This comprehensive study demonstrates that pesticides are a hidden reality in agricultural soils, and our results suggest that they have harmful effects on beneficial soil life

Pesticides in Agricultural Soils: Major Findings from Various Monitoring Campaigns in Switzerland

Synthetic pesticides are widely applied in modern agriculture, where they are used against diseases, pests, and weeds to secure crop yield and quality. However, their intensive application has led to widespread contamination of the environment, including soils. Due to their inherent toxicity, they might pose a risk to soil health by causing harm to non-target organisms and disrupting ecosystem services in both agricultural and other exposed soils. Following the Swiss National Action Plan on the reduction of pesticide risks, Agroscope has conducted several soil monitoring studies that are briefly presented here. All of them resort to different multi-residue trace analytical approaches to simultaneously quantify up to about 150 modern pesticides by either accelerated solvent, or Quick, Easy, Cheap, Efficient, Rugged, Safe (QuEChERS) extraction, followed by separation and detection with liquid chromatography-triple quadrupole mass spectrometry. While partly still in progress, our investigations led to the following major findings this far: Multiple pesticides are commonly present in soils, with individual concentrations in agricultural soils often reaching up to a few tens of µg/kg. Pesticide occurrence and concentrations in agricultural soils primarily depend on land use, land use history and cultivated crops. Pesticides can prevail much longer than predicted by their half-lives, and were found in soils even decades after conversion from conventional to organic farming. Corresponding residual fractions can be in the order of a few percent of the originally applied amounts. We further found negative associations of pesticide residues with the abundance of beneficial soil life, underpinning their potential risk to the fertility of agricultural soils. Traces of pesticides are also detected in soils to which they were never applied, indicating contamination, e.g., via spray drift or atmospheric deposition. These results confirm the general notion of both scientists and legislators that prospective risk assessments (RA; as executed during registration and use authorization) should be confirmed and adjusted by retrospective RA (e.g., by environmental monitoring studies of currently used compounds) to jointly lead to an overall reduced environmental risk of pesticides

Soil contamination in nearby natural areas mirrors that in urban greenspaces worldwide

Soil contamination is one of the main threats to ecosystem health and sustainability. Yet little is known about the extent to which soil contaminants differ between urban greenspaces and natural ecosystems. Here we show that urban greenspaces and adjacent natural areas (i.e., natural/semi-natural ecosystems) shared similar levels of multiple soil contaminants (metal(loid)s, pesticides, microplastics, and antibiotic resistance genes) across the globe. We reveal that human influence explained many forms of soil contamination worldwide. Socio-economic factors were integral to explaining the occurrence of soil contaminants worldwide. We further show that increased levels of multiple soil contaminants were linked with changes in microbial traits including genes associated with environmental stress resistance, nutrient cycling, and pathogenesis. Taken together, our work demonstrates that human-driven soil contamination in nearby natural areas mirrors that in urban greenspaces globally, and highlights that soil contaminants have the potential to cause dire consequences for ecosystem sustainability and human wellbeing

Publisher Correction: Soil contamination in nearby natural areas mirrors that in urban greenspaces worldwide

Correction to: Nature Communications, published online 27 March 2023 In the version of this article originally published, the current affiliation 25, “CEAZA, Universidad Católica del Norte, Coquimbo, Chile,” initially appeared as the last affiliation, offsetting all author footnotes from 25-39. The affiliation order has been restored in the article.Peer reviewe