Auswirkungen zweijähriger Düngung mit NAWARO-Biogasgülle auf chemische und physikalische Bodeneigenschaften

Summary

Using biomass from intercrops as feedstock for biogas production makes it possible to produce renewable energy without compromising food production. In order that using intercrops for biogas and fertilizing with liquid digestate is sustainable, it must be secured that this practice does not have adverse effects on soil fertility. Two-year randomised field experiments were conducted on two different soil types near Bruck/Leitha (A). On chernozem soil, soil pH and composition of the cation exchange complex were hardly influenced by liquid digestate. Also on a parachernozem with pH 5.9 short-term effects of liquid digestate were small due to the low salt content and high C/N ratio of the digestate. Nevertheless the distinct increase in soil K content shows that if fertilization with liquid digestate is continued at rates clearly above K offtake by crops, K percentage on the exchange complex will exceed the critical value of 5% soon. Aggregate stability of the parachernozem was increased by the organic matter applied via digestate. Aggregate stability and infiltration rate of the chernozem were not affected. For a long-term sustainable use of intercrops for biogas and recycling of liquid digestate as a fertilizer, it is necessary that the rate of digestate fertilization corresponds to the amount of intercrop biomass harvested, and that digestate fertilization is adjusted to the potassium requirements and potassium uptake of the crops.