Shifting application dates on cereal reduces pesticide transfer via subsurface drainage based on water flow forecasts during autumn applications

• Published in: Pest management science 2023-09, Vol.79 (9), p.3058-3070
• Main Authors: Julien, Tournebize, Jeantet, Alexis, Marks‐Perreau, Jonathan, Dutertre, Alain, Maillet‐Mezeray, Julie
• Format: Article
• Language: English
• Subjects: Agriculture; Autumn; autumn application; Contamination; Cropping systems; Drainage; Drainage patterns; Edible Grain; Environmental Sciences; FOCUS scenario D5 La Jaillière; Herbicides; Herbicides - chemistry; Isoproturon; Mathematical analysis; Meteorological data; mitigation measure; Pesticide application; Pesticides; Pesticides - analysis; Risk assessment; Risk management; Risk reduction; Soil - chemistry; Soil contamination; Soil profiles; Soil properties; soil wetness index; Subsurface drainage; Surface water; Water; Water flow; Water Pollutants, Chemical - analysis; Weed control
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.7483

BACKGROUND Thanks to the changes in aquatic risk assessment within the marketing authorization (MA) process in France, the contamination of surface water through the subsurface drainage network is better accounted for. The measure adopted by risk regulations is to prohibit any use of selected pesticides on drained plots. Herbicide solutions on subsurface‐drained plots are becoming scarce due to a limited number of innovations combined with the re‐approvals process. Autumn weed management then becomes a major issue for winter cropping systems on drained plots. Unlike runoff prevention, few risk management measures are available to prevent the risks associated with drained plots. RESULTS We analyzed data from La Jaillière, an ARVALIS experimental site (nine plots, 1993 to 2017), representative of scenario D5 from the EU FOCUS Group, for four herbicides (isoproturon, aclonifen, diflufenican, flufenacet). Our study demonstrates the relevance of the time application management measure by showing the decreasing trend in the transfer of pesticides in drained plots. In addition, it validates, still on the La Jaillière site, the hypothesis of a management measure based on an indicator of soil profile saturation before drainage flow (soil wetness index, SWI). CONCLUSIONS A conservative measure consisting of restricting pesticide applications during autumn, when the SWI is