基于DNDC模型的稻田氨挥发模拟及减排模式

Using DNDC Model to Help Mitigate Ammonia Volatilization from Paddy Fields

【目的】优化稻田氨挥发减排的水炭调控模式。【方法】基于田间实测数据,利用DNDC模型构建并验证了水炭调控稻田氨挥发过程模拟模型,分析不同灌溉模式及生物炭添加水平对稻田氨挥发损失量的影响特征,最终优选出稻田氨挥发减排的水炭调控模式。【结果】基于DNDC模型构建的水炭调控稻田氨挥发过程模拟模型在稻田分蘖肥后1周、穗肥后1周、整个稻季的氨挥发量模拟值和实测值的相对误差均在±8%以内,能够较好地模拟控制灌溉稻田不同生物炭添加量后土壤氨挥发损失特征。随着生物炭添加量的增加,相同灌溉处理稻田氨挥发损失量呈小幅递减趋势;相同生物炭添加水平下,稻田氨挥发损失量随灌水下限的降低出现小幅下降。灌水和添加生物炭均显著影响稻田氨挥发损失量,灌水处理是主要影响因素,对稻田氨挥发的作用明显强于添加生物炭。【结论】I3B11处理为稻田水炭调控最优模式,在降低稻田灌溉下限的基础上适当增施生物炭可以有效降低稻田氨挥发量。

【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.