Using DNDC Model to Help Mitigate Ammonia Volatilization from Paddy Fields

Abstract

【Objective】 Reducing nitrogen loss from leaching and emissions is essential to increasing nitrogen fertilizer use efficiency in developing sustainable agriculture. This paper is to propose an optimization of water and carbon to reduce ammonia volatilization from paddy fields. 【Method】 The DNDC model was used to simulate the processes involved in ammonia volatilization; it considered the effects of both water and biochar application. The model was validated against field measurements, and it was then used to investigate the changes in ammonia volatilization from paddy fields under different combinations of irrigation and biochar addition, from which the optimal irrigation and biochar application that gave the least ammonia volatilization and gas emissions was determined. 【Result】 The relative errors between the simulated and measured ammonia volatilization were less than 8%. The model hence accurately captured the fundamental processes underlying ammonia volatilization from paddy fields. When irrigation was the same, increasing biochar addition reduced ammonia volatilization. When biochar addition was the same, reducing irrigation amount reduced the ammonia volatilization. Irrigation and biochar application significantly influenced ammonia volatilization, but ammonia volatilization was more sensitive to irrigation than to biochar addition. 【Conclusion】 Among all treatments we compared, the combination I3+B11 was the optimal irrigation and biochar application for reducing ammonia volatilization from paddy fields. Rationally increasing biochar application combined with a decrease in irrigation amount can effectively reduce ammonia volatilization and gas emissions from paddy fields.

Keywords

• dndc
• ammonia volatilization
• biochar
• controlled irrigation
• paddy fields