Fertilizing strategy and spreading technology for cattle slurry -grass yield and ammonia emissions

摘要

Swedish nitrogen (N) fertilizer recommendations need to be evaluated to match current grass ley production. The aim of this study was to identify fertilizer strategies for cattle slurry concerning time, applied N amounts and spreading technologies that decrease ammonia losses (NH^-N) and increase dry matter (DM) yield and N efficiency in ley with three cuts per year. The three-year grass ley trial used a complete randomized block design with four replications on clay soil. In three of the treatmentschemical N fertilizer in spring was combined with cattle slurry after the first ley harvest. In one treatment cattle slurry was spread at spring and chemical N fertilizer spread after the first ley harvest. Slurry was applied with bandspreading and shallow injection after first cut and NH^-N emissions were measured. Shallow injection decreased NH, emissions by more than 50% when compared with band spreading, but did not give a significant higher DM yield. On average, N use efficiency was 50% when spreading chemical N at spring and cattle slurry after first cut. This was higher than spreading slurry at spring and chemical N after first cut.