Cover crops and integrated management reduce pesticide residues in soils and water: Pathways towards cleaner production in Argentine agricultura

Abstract

The potential of cover crops and integrated management as a cleaner production strategy for grain systems in the Argentinian Pampas was assessed in this study. A four-year field comparison of conventional farmer practices with cover crops and integrated management, through practices aimed at reducing pesticide use was conducted. Glyphosate, (2,4-dichlorophenoxy) acetic acid and atrazine were the pesticides most frequently applied under both systems. A 14.9 % lower number of pesticide applications was recorded under cover crops and integrated management, with glyphosate + (2,4-dichlorophenoxy) acetic acid + atrazine being represented as the most common mixture. Clear contamination patterns were observed: (i) in soils, 33 % higher glyphosate concentrations at 0–2 cm depth were detected under conventional farmer practices, while accumulation of transformation products (aminomethylphosphonic acid, hydroxy-atrazine), consistent with enhanced biological degradation, was favoured by cover crops and integrated management; (ii) in leachate water, consistently higher atrazine and (2,4-dichlorophenoxy) acetic acid concentrations were found under conventional farmer practices, whereas no significant differences between systems were detected for glyphosate and aminomethylphosphonic acid; (iii) in groundwater, mixtures of glyphosate, aminomethylphosphonic acid and atrazine were identified, indicating diffuse regional contamination not constrained by management. Through these findings, cover crops and integrated management are positioned as a transitional pathway by which pesticide residues can be reduced without fully removing chemical dependence. However, the persistence of aminomethylphosphonic acid in soils and the presence of pesticide cocktails in groundwater are highlighted as issues requiring complementary monitoring to ensure long-term sustainability. Policy promotion of cleaner agricultural transitions aligned with Sustainable Development Goals 6 (Clean water) and 15 (Life on land) is supported, while critical gaps in the understanding of metabolite dynamics are identified.