EffiZwisch

Nitrate leaching is of great concern in North Rhine-Westphalia. With agriculture and horticulture being the major contributors, means to counteract nitrogen (N) losses are gaining importance. Using cover crops (CC) as catch crops is one strategy propagated. Besides taking up N, CC also contribute to soil organic matter accumulation and soil structure improvement. Therefore, this project aims at quantifying the carbon (C) and N immobilisation capacity of CC and the C and N mineralisation of their residues. A special focus is put on assessing the below-ground biomass, which consists of roots and rhizodeposits and is often neglected. To take C and N losses into consideration, nitrate leaching, nitrous oxide and carbon dioxide emissions will be measured. Results will be used to feed a simple N availability prediction tool for farmers. Moreover, soil structure will be investigated and analysed to elucidate its influence on C and N dynamics. Additionally, C sequestration will be assessed to model market possibilities for carbon credits from cover cropping. The overall objective of the project is to provide farmers and consultants with information on how to improve CC and CC-mixture use, with the aim to reduce nitrate leaching, to sequester C and to improve soil structure.