Ergebnisse zur Anwendbarkeit der neuen VDLUFA-Methode für die Humusbilanzierung im ökologischen Landbau

Summary

Recently a revised version of the German standard method for humus balancing according to VDLUFA has been published. In contrast to the preceeding version, the method now shall be applicable not only in conventional, but also organic farming systems. In this contribution, we try to define the scope of the three levels of organic matter demand parameters for crops applied in the method, as an applicable definition is missing in the VDLUFA method description. We do so by calculating crop uptake of mineralized humus-N from the balance parameters, and by linking N uptake to yield levels of crops. Further, we calculate humus balances for farming system treatments in the Organic Arable Farming Experiment Gladbacherhof (Villmar,Germany) and test the ability of the VDLUFA method to differentiate between treatments with regard to their effect on humus levels in relation to each other. We confirm that the method in principle is applicable in organic farming systems, even though the specific scope of the parameter levels should be defined more explicitly. Further, the parametrization of crops (and fertilizers?) should be evaluated in detail, especially with regard to cereals and perennial legumes.