info:oai:orgprints.org:12308info:ofi/fmt:xml:xsd:bookMöllerKurtMöller, Dr. KurtStinnerWalterStinner, WalterLeitholdGünterLeithold, Prof. Dr. GünterEffects of Biogas Digestion of Slurry, Cover Crops and Crop Residues on Nitrogen Cycles and Crop Rotation Productivity of a Mixed Organic Farming System2008proceeding