Nitrogen mineralization from mature bio-waste compost in vineyard soils - I. Long-term laboratory incubation experiments

摘要

The steadily increasing utilization of bio-waste compost in German viticulture requires a more detailed investigation of nitrogen (N) mineralization parameters for mature bio-waste compost applied to vineyard soils. N mineralization kinetics were described with two superposing exponential equations. Long-term aerobic laboratory incubation experiments of 12 soil-compost substrates revealed that 5+/-2.8% of its total N content could be released from a rapidly decomposable fraction (half-life period t(50) 41 d at 15degreesC) and another 60+/-2.9% from a slower decomposable fraction (t(50) = 490 d). The remaining proportion (35%) is considered not to be released in the medium term. The obtained potentially mineralizable nitrogen of 65% of total compost N significantly differs from current fertilizer recommendations, which were adopted from calculations for agricultural conditions. For fertilizer recommendations in viticulture, we recommend the consideration of a higher N-mineralization potential for organic fertilizers.