NH3 and N2O Emissions after Landspreading of Slurry as Influenced by Application Technique and Dry Matter-Reduction. I. NH3 Emissions

Ammonia volatilization from slurry is undesirable because of environmental N eutrophication and loss of fertilizer value. The dry matter content of slurry, the application technique and the weather conditions are the main factors influencing NH₃ losses from landspread slurry. In a field of winter wheat a two factor plot experiment was conducted to study single and combined effects of slurry separation and application techniques, including broadcast and banded application, as well as incorporation by injection and the flexible harrow. Ammonia volatilization from all treatments could be measured simultaneously, and at ambient climatic conditions by an indirect, open measurement technique. The experiment was repeated four times. Due to varying weather conditions and treatment effects, cumulative NH₃ volatilization from the slurry during the first 48 hours ranged from 4 to 90% of total ammoniacal nitrogen (TAN). Both separation and incorporation significantly decreased NH₃ losses, but only the combination of dry matter reduction and injection or harrowing reduced NH₃ volatilization to about 30% of TAN in all weather conditions. Banding alone did not efficiently conserve slurry N, but even enhanced NH₃ volatilization in wet conditions.