Allantoin-induced changes of microbial diversity and community in rice soil

The effects of slurry application method and weather conditions after application on ammonia volatilisation are well documented, however, the effect on slurry N recovery in herbage is less evident due to large variability of results. The objective of this field experiment was to determine the recovery of cattle slurry NH₄-N in herbage and soil in the year of application as affected by application method (trailing shoe versus broadcast) and season of application (spring versus summer), using ¹⁵N as a tracer. In 2007 and 2008, ¹⁵N enriched slurry was applied on grassland plots. N recovery in herbage and soil during the year of application was determined. Both spring and trailing shoe application resulted in significantly higher herbage DM yields, N uptake and an increased recovery of ¹⁵NH₄-N in herbage. Additionally, the recovery of slurry ¹⁵NH₄-N in the soil at the end of the growing season was increased. Spring and trailing shoe application reduced the losses of slurry ¹⁵NH₄-N by on average 14 and 18 percentage points, respectively, which corresponded closely to ammonia volatilisation as predicted by the ALFAM model. It was concluded that slurry N recovery in temperate pasture systems can be increased by adjusting the slurry application method or timing.