LIVESTOCK IN ORGANIC FARMING – HOW IMPORTANT IS IT FOR SOIL FERTILITY MANAGEMENT?

Stockless management is increasing even in organic farming, but it is not known until now, whether organic matter supply is sufficient in such systems, or which measures are necessary to achieve a sustainable soil organic matter (SOM) management. Results from the long-term Organic Arable Farming Experiment Gladbacherhof (OAFEG) show that after two 6 y rotations, only a “mixed farm” treatment (MF) with fodder legumes in the rotation and cattle manure application corresponding to 1 LU ha-1 was able to maintain, and in the long term perhaps increase, SOM levels. The “stockless farm” with fodder legumes as green manure ley (SFL) was barely able to maintain the SOM level, while the “stockless cash crop farm” where organic matter supply relied on green manure catch crops and straw alone (SFC) showed a significant and considerable SOM decrease. We therefore conclude that the inclusion of fodder legumes is a crucial prerequisite for sustainable soil organic matter management in stockless organic farming, unless new approaches (farm cooperation concerning fodder-manure exchange, biogas with recirculation of residues, considerably extended legume shares by intercropping techniques) provide a full substitution