How much greenhouse gases do grass-clover crop sequences emit?

Background and Objective

There is a lack of data regarding the impact grass-clover cropping on nitrous oxide  (N₂O) emission from crop ssequences. The project aimed to derive N₂O emission factors for grass-clover and wheat crop sequences. Emission factors are used to estimate N₂O emission in dependence on nitrogen input.

Specific project aims were measurement and modelling of N₂O fluxes in the central part of the organic farming crop sequences: grass-clover, incorporation of grass-clover and the following wheat in comparison to conventional cropping of winter wheat. Farm specific methods of grass-clover incorporation were investigated and compared regarding their effect on crop yield an potential for mitigation of N₂O emission.

Target Group

The project is geared towards agricultural praxis and consulting. Results will improve the German emission inventories and the Thünen institute's consulting of policy makers.

Approach

4 field trials were established in different regions of Germany, comprising rotations with grass-clover followed by wheat in different treatments. Fluxes of nitrous oxide and several soil and environmental parameters were measured for two years.

Results

see the publications for results