Strategic nutrient management in stockless organic cropping systems integrated with biogas production

In regions with a small organic livestock production the lack of certified organic nutrients resources is a barrier for increased conversion to organic farming. Stockless organic farmers include green manuring crops in their rotations, which may result in significant losses of nitrogen via ammonia volatilization and nitrate leaching. Furthermore it is a challenge for organic farming to reduce the dependence on fossil fuels and become self-reliant in renewable energy, while reducing the impact on the climate and the environment. The aim of this project is to determine the effects of strategic application of a biogas digestate on the N-demanding crops in a rotation for food production. The digestate is derived from anaerobic digestion of a legume-grass mixture, catch crops and crop residues within the same system. The anaerobic digestion management is compared to in situ or redistributed placement of the biomass resources within the rotation. We will study the effects of nutrient management on the dry matter yield of the harvest, nitrogen accumulation and quality of food crops, the nitrogen dynamics in soils including the potential for nitrate leaching, ammonia volatilization and nitrous oxide emissions and the energy balance and economy related to the management methods and biogas production. The experiments will be carried out in an organic certified cropping system at SLU Alnarp and in collaboration with Lunds University.

Foundings: No Foundings

Project responsible Erik Steen Jensen, Project leader: PhD student Tora Råberg.
Other staff: assistant professor Georg Carlsson, university lecturer Sven-Erik Svensson.
Collaborating partner Lund University: postdoc Emma Kruger and professor Lovisa Björnsson