In the research project ÖKOVERS different crops for fermentation were cultivated in a double cropping system at five locations in Germany. The crop yields after half a year and after one and half a year mixture of clover/grass were compared. The second crops were maize, sorghum, sunflowers, buckwheat and others, which have been fertilised with solid and liquid digestate. In one and half a year a yield over 20 t DM ha-1 of clover/grass was realised. The yields of the second crops after a one and half a year clover/grass were clearly higher than after half a year clover/grass. The highest yield of the second crops in the mean of all locations was realised by maize with 11,5 t DM ha-1. The yield of sorghum and sunflowers and a mixture with maize and sunflowers with 10 t DM ha-1 were comparable to the yield of maize. The yield of buckwheat was 6,5 t DM ha-1 only, however this could be an alternative as there was no need for weed control. After digestate application the increases of yields were very low at all crops. The reason for this could be the large C and N ratio and the low fraction of plant available nitrogen
