Improving nitrogen management in reduced tillage systems by use of green manures and appropriate off-farm inputs: results of TILMAN-ORG

For a successful integration of reduced tillage techniques and green manures in organic cropping systems, a better understanding of nitrogen dynamics and management is essential. We present data of several long- and medium-term European experimental field studies from the TILMAN-ORG project. Nitrogen dynamics and crop performance were investigated in an Estonian and a Spanish trial. A Dutch and a Swiss trial were simulated with the NDICEA-model. The Estonian trial shows that the effect of green manure on yield of the subsequent crop is dependent on green manure and crop type. The Estonian and the Spanish trial indicate that effects of fertilization on crop performance are larger than those of green manure or soil cultivation. The results of the Dutch trial give no reason to assume that soil nitrogen availability is negatively affected by minimum tillage in organic or conventional systems. However also in the ploughed systems, low nitrogen availability in spring warrants attention.