Turnover and fate of 15N-labelled cattle slurry ammonium-N applied in the autumn to winter wheat

摘要: Abstract The fate of 15 NH 4 -N labelled cattle slurry applied before sowing in September a winter wheat crop was studied on loamy sand soil. aim to quantify immobilization into microbial biomass, the speed at which nitrate derived from transported down soil profile, and utilization by crop. Cattle rate corresponding 75 kg NH -N ha −1 , with very little loss volatilization ( 2 flux, an index activity, over non-amended within first c. 2 weeks, but ceased again after 4 weeks, due depletion easily degradable substances, e.g. volatile fatty acids, slurry. Nitrification fast complete 3 weeks application, this time, maximum biomass (23% -N) also observed, although no significant increase total observed. Rapid turnover quickly diluted assimilated N, only 6% remaining next spring. Downwards transport rapid spite lower than normal precipitation, slurry-derived NO 3 appeared ceramic suction cups installed 60 cm depth already 2 months application. Due unusually low precipitation experimental year, yields were high, recovery N above-ground plant harvest reached 32%. An additional 45% could be found 100 cm (mostly organic form plough layer), indicating that 23% had been lost leaching or gaseous form. It concluded did occur, not sufficient prevent relatively high partly percolation rooting particular site.