Ammonia volatilization and nitric oxide emission from soil during winter wheat season in Taihu Lake region

Field experiments were conducted to evaluate N losses from ammonia volatilization and nitric oxide emission in wheat growing season with different rates of N application in Taihu Lake region. Ammonia volatilization was measured with the continuous airflow enclosure method, while nitric oxide with the static transparent chambers. The results show that the ammonia volatilization in wheat season mainly occurs during the first 7-10 days after each application of fertilizer. Basal fertilization is the main loss stage of ammonia volatilization whose loss varies from N 0.49-9.36 kg/ha which accounts for 60.4% to 74.7% of the wheat observation period. The nitric oxide emission in respond to the urea application mainly takes place during the 30 days after the basal fertilization, the rate of emission is NO-N 0.009-0.304 mg/(m2h), and the accumulative loss is NO-N 0.68-1.23 kg/ha, which accounts for 93% of the total loss during the observation period. The amounts of nitric oxide emission and ammonia volatilization positively correlate with the rate of N application. The accumulative losses from ammonia volatilization during the wheat observation period range from NH3-N 7.6 kg/ha to 12.6 kg/ha, which accounts for 4.62% to 5.26% of the total amount of N application, while the nitric oxide emissions range from NO-N 0.73 kg/ha to 1.3 kg/ha, the loss rates are 0.27% to 0.41%. The results are valuable for evaluating the gaseous loss and environmental effects in wheat season, and have significant meaning for directing rational fertilization.