Stickstoffdüngewirkung und Stickstofftransfereffizienz von Düngemitteln auf Basis von Kleegrasbiomasse im Gefäßversuch mit Weidelgras (Lolium perenne)

Summary in the original language of the document

The aim of our research was to compare the N fertilizer value of different clover-grass (CG) based fertilizers. A pot trial was set up with 8 treatments with Lolium perenne:
fresh CG, ensiled CG, compost from CG, solid manure and liquid manure from dairy cows fed with CG, biogas digestate, an unfertilized and a mineral fertilizer control. Our
hypothesis was that compared to composting, and to other treatments (e.g. silage) biogas digestates allow for a more efficient N fertilization due to a lower C/N ratio and
a higher share of NH4 +. Dry matter yield, C/N ratio, N concentration, N release and Nitrogen use efficiency (NUE) were examined. The results show the highest overall
NUE, N release and yield in the treatment with biogas digestate and the lowest in the compost treatment. The overall efficiency of a treatment approach was also influenced by the N transfer rates during the entire treatment chain. The short-term N fertilizer
efficiency was mainly influenced by the characteristics of the amendments used, while the long-term N fertilizer efficiency is mainly influenced by the transfer factors during the chain harvesting treatment fertilization. In conclusion, any approach for a more efficient N use from the clover grass biomass-N should focus on reduction of N-losses
while the chemical characteristics of the obtained fertilizer product is less relevant.