Ammonia Volatilization from Paddy Fields Under Different Nitrogen Schemes in Tai Lake Region

Pollution arose from ammonia volatilization in paddy field might be reduced by managing nitrogen(N)fertilization. Six nitrogen schemes, i.e. conventional N, Reduced N, Slow-release N(not for wheat season), Organic chemical N combination, controlled release urea and no N, were employed to examine effects of N rates and types on ammonia volatilization. Applying 22%～44% less nitrogen reduced ammonia volatilization by 20.2%～35.3%. The amount of ammonia volatilization was higher in conventional nitrogen during the basal and tillering stages than other stages or other treatments. Organic-chemical N combination could significantly decrease the ammonia volatilization compared with pure urea treatment, while controlled release urea treatment could reduce the ammonia volatilization only at basal stage. Nitrogen application at 210 kg·hm-2 did not affect crop yields and N accumulations. Results suggested that reduced nitrogen fertilizer and organic-chemical combination would be environment-friendly and ecological sustainable schemes for nitrogen management in Tai Lake region.