Nitrous oxide emission from soil with different fertilizers, water levels and nitrification inhibitors

The effects of urea, (NH4)(2)SO4, KNO3, and NH4NO3 on nitrous oxide (N2O) emission from soil at field capacity and submerged condition were studied during 120 days in the laboratory. Soils in both moisture regimes gave higher emissions in the beginning, which were reduced later. Total emission of N2O was higher at submergence as compared to field capacity regardless of fertilizer type. At field capacity soil fertilized with urea emitted the highest amount of N2O (1903 mug N2O-N kg(-1) soil) during 120 days while at submerged condition, soil with NH4NO3 gave the highest emission (4843 mug N2O-N kg(-1) soil). In another study, the efficacy of seven nitrification inhibitors in reducing the emission of N2O-N from soil fertilized with urea was tested in the laboratory. Nitrapyrin, 2-amino-4-chloro-6-methylpyrimidine (AM), and dicyandiamide (DCD) reduced the emission to 12, 24, and 63% that of urea, respectively, whereas sodium thiosulphate, sulphur, acetylene, and thiourea had no effect on emission of N2O. In submerged conditions none of the inhibitors reduced the emission.