Author(s)

L. Alletto, Y. Coquet, P. Benoit & E. Justes

Abstract

The effects of two tillage treatments and two fallow period managements on water drainage and leaching of isoxaflutole were evaluated over a 4-year period (2005-2008). Tillage treatments were a conventional tillage (CT) with mouldboard ploughing and a conservation tillage (MT) with disk harrowing. Management of the fallow periods were bare soil (BS) or soil sown with a cover crop (CC) after maize harvest. Tillage and fallow period management had significant effects on water flow rate at 40 cm-depth. According to the year and cropping system, cumulated herbicide losses ranged from 2% under MT_CC in 2005 to more than 30% under CT_BS in 2006. Results showed that best agricultural practices, such as conservation tillage and cover crops during fallow period could be an efficient way to reduce herbicide losses at the field scale. Keywords: conventional tillage, conservation tillage, cover crop, leaching, diketonitrile metabolite. 1 Introduction Herbicides are among the most important nonpoint-source pollutants in Europe. The objectives fixed by the EU Water Framework Directive (Directive 2000/60/CE) to prevent and control groundwater pollution by herbicides involve a better assessment of environmental impacts of agricultural practices.

Keywords

conventional tillage, conservation tillage, cover crop, leaching, diketonitrile metabolite