Ammonia Volatilization Under Different Water Management and Nitrogen Schemes in a Paddy Field

To provide a theoretical basis for reducing ammonia volatilization from paddy fields, the effects of different water management and nitrogen schemes on ammonia volatilization from paddy soil were studied. A field experiment was conducted to study the dynamics of ammonia volatilization by the closed airflow chamber method under a paddy ecosystem in the Jianghuai Hilly Region from June to September 2016. The results show that 52.92%-90.78% of total ammonia volatilization during the rice growth period occurred within the first 11 days after basal fertilization. A single basal application of slow-release urea combined with common urea reduced ammonia volatilization by 8.27%-14.22%. For conventional fertilization, ammonia volatilization under controlled irrigation decreased by 10.04% relative to that under conventional irrigation. A positive correlation was observed between ammonia volatilization and ammonium-nitrogen concentration in the surface water or 0-10 cm soil. The single basal application of slow-release urea combined with common urea under the water-saving irrigation treatment was identified to be a high-efficiency and environmental friendly model, referred to as the water-nitrogen application coupling management model.