TILLAGE AND CROP RESIDUE MANAGEMENT EFFECTS ON LOSSES OF CHEMICALS FROM SOILS

Tillage and crop residue management both influence the losses of nutri ents and crop-protection chemicals from the soil to the aqueous enviro nment. Tillage is performed to control weeds, to modify the soil struc ture and often to incorporate straw, which can no longer be burnt in E uropean Community countries. The resulting changes in the soil alter b oth the pathways for water flow and the activities of microbes. This p aper reviews their effects on water movement and the microbial and phy sico-chemical processes that influence the vulnerabilities of nutrient s and crop-protection chemicals to leaching. It also suggests some pos sible options for limiting losses of these substances from the soil. T here remains considerable scope for cooperation between tillage specia lists and those with an interest in the management of nutrients and cr op-protection chemicals.