Characteristics and simulation of ammonia volatilization from paddy fields under different water and nitrogen management

In order to investigate the reasonable water and nitrogen management for reducing ammonia volatilization from paddy field, the effects of ammonia volatilization from paddy field under different water and nitrogen managements were analyzed based on field experiments. In addition, ammonia volatilization from paddy fields with different nitrogen managements under controlled irrigation was simulated. The results showed that joint application of controlled irrigation and site-specific nitrogen managements not only substantially reduced the peak values of ammonia volatilization from paddy fields, but also lowered the ammonia volatilization in the most time of rice growing stage without nitrogen fertilizer input. Nitrogen loss through ammonia volatilization from paddy fields with the joint application of controlled irrigation and site-specific nitrogen management was 39.63 kg/hm2, decreased by 44.69% compared to traditional water and nitrogen management. The processes of ammonia volatilization with different nitrogen managements under controlled irrigation can basically captured by DNDC model. The errors of simulated values and measured values of ammonia volatilization during rice growing stage were less than ±10%. Joint application of controlled irrigation and site-specific nitrogen management significantly reduced nitrogen loss through ammonia volatilization from paddy field. And the contribution of site-specific nitrogen management to the reduction of ammonia volatilization from paddy fields was larger than controlled irrigation. The study results can provide a basis for scientific management of water and nitrogen and reduction of ammonia volatilization from paddy fields.