Comparison of Nitrogen Loss Weight in Ammonia Volatilization, Runoff, and Leaching Between Common and Slow-Release Fertilizer in Paddy Field

Nitrogen (N) loss from paddy fields contributes to air and water pollution, which has been a serious challenge to agriculture and the environment. In situ field experiments were conducted to monitor ammonia (NH 3 ) volatilization, surface runoff, and leaching loss in common nitrogen fertilizer and slow-release nitrogen fertilizer treatments. The total N loss by ammonia volatilization, leaching, and runoff was 38.27 ± 4.23~113.54 ± 7.66 kg ha −1 among the different treatments. Results indicated that slow-coated urea could reduce ammonia volatilization (24.69~29.54%), N surface runoff loss (20.05~25.37%), and leaching loss (21.86~38.05%) compared with common fertilizer. Of the different nitrogen loss pathways monitored in paddy fields, ammonia volatilization was the greatest (68.98~75.27% of the total N loss), followed by (in descending order) runoff (16.43~23.07%) and leaching (7.67~8.86%). Ammonia volatilization and N runoff loss were predominantly attributed to surface ammonium nitrogen (NH 4 + -N) concentration and precipitation. In addition, 42 ± 2.48% of N runoff loss was a result of wet deposition, while 58 ± 3.11% was attributed to nitrogen hydrolysis. There is obvious vertical nitrogen migration in the soil profile, among which NO 3 − -N leaching loss is the predominant form (69.94~90.12%).