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

• Published in: Environmental science & technology Vol. 55; no. 5; pp. 2919 - 2928
• Main Authors: Riedo, Judith, Wettstein, Felix E, Rösch, Andrea, Herzog, Chantal, Banerjee, Samiran, Büchi, Lucie, Charles, Raphaël, Wächter, Daniel, Martin-Laurent, Fabrice, Bucheli, Thomas D, Walder, Florian, van der Heijden, Marcel G. A
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 02.03.2021
• Subjects: Abiotic factors; Agricultural ecosystems; Agricultural land; Agriculture; Agrochemicals; agroecosystems; analytical methods; Arbuscular mycorrhizas; Contaminants in Aquatic and Terrestrial Environments; environmental science; Environmental Sciences; Fungi; Fungicides; Herbicides; Insecticides; microbial biomass; Microorganisms; Organic farming; organic production; Pesticide residues; Pesticide Residues - analysis; Pesticides; Pesticides - analysis; Residues; Soil; Soil contamination; Soil management; Soil Pollutants - analysis; Soils; Symbionts; technology; vesicular arbuscular mycorrhizae; fungicides; environmental impact; soil ecology; insecticides; Multiresidue analysis; organic farming; herbicides; no tillage; multiresidue analysis
• ISSN: 0013-936X; 1520-5851; 1520-5851
• DOI: 10.1021/acs.est.0c06405

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.