Biogas in organic agriculture: Effects on yields, nutrient uptake and environmental parameters of the cropping systemKurtMöllerauthorWalterStinnerauthorGünterLeitholdauthorSystem effects of biogas fermentation in organic cropping systems with and without livestock (dairy farming) were investigated from 2002-2005. In both systems no differences in yields and nutrient uptake were detected in the legume crops. In the livestock-system non legume crops of the slurry system had no higher yields but a higher nitrogen uptake (6 %) than the stable manure system. Slurry-fermentation had no effect on yields and nitrogen uptake. The inclusion of crop residues in the fermentation system increased the nitrogen uptake about by 10 % and reduced the nitrate leaching potential by ca. 10 %. The inclusion of external substrates lead to a further increase in nitrogen yield of 10 %, but to no significant increase in dry matter yields. Fermentation had no effects on P-availability of manures. In the stockless system fermentation of clover grass, straw and catch crops increased yields and nitrogen content of winter wheat by ca. 10 %, combined with a significant decrease in nitrate leaching potential (10 %) and in emissions of nitrous oxide (ca. 40 %). Air and water emissions Composting and manuring2006Conference paper, poster, etc.