Management of vegetable crop residues for reducing nitrate leaching losses in intensive vegetable rotations

Crop residues of field vegetables are often characterized by large amounts of biomass with a high N content. Even when these are incorporated in autumn, high rates of N mineralization and nitrification still occur causing important N -losses through leaching. Crop residues thus pose a possible threat to maintaining water quality objectives, but at the same time they are a vital link in closing the nutrient and organic matter cycle of soils. Appropriate and sustainable management is needed to fully harness the potential of crop residues. In this research, two fundamentally different management strategies are investigated, namely i) removal of crop residues followed by a useful and profitable application or ii) on-field treatment of crop residues in order to prevent N -losses and maintain soil quality. We here present the preliminary results of these experiments, and more comprehensive results will be presented during the conference.