【摘要】 稻田不合理的氮素管理模式造成了氮素资源浪费与水体及大气环境污染。为深入分析中国南方典型稻田的氮素去向特征及其优化管理模式，基于 2017 年湖北省孝昌县高岗村的试验稻田在常规水肥管理下的稻田观测数据，采用了 DNDC 模型对稻田各氮素去向负荷进行了模拟与分析, 包括水稻植株吸氮、氮素渗漏、氨挥发与反硝化。研究结果表明：(1)DNDC 模型能够准确模拟中国南方典型稻田的氮素各去向负荷，其中模型对氮素渗漏与氨挥发动态模拟的拟合度 （R~2） 高达0.649 3～0.860 2，纳什效率系数 （NSE） 高达 0.513 5～0.786 2，经验证后的模型可用于稻田氮素去向的动态与结构特征分析；(2)氮素的气态损失—而非随水流失—是稻田氮素损失的主要途径，其占总氮素损失量的比例高达 83.86%～86.69%，且分蘖肥施用期与水稻黄熟落干期是造成显著气态损失的重要时期；(3)基于情景模拟可提出研究区内具体的氮素优化管理模式，优化施氮量为 100 kg/hm~2，优化施氮方式为秸秆还田处理，该模式比低氮施肥处理提升了 12.67% 的稻谷吸氮量，比高氮施肥与氮肥表施处理减少了 17.64%～65.57% 的氮素气态损失。该研究的结果与稻田氮素去向特征的分析方法可推广至中国南方稻区，以实现高氮利用与低氮污染的可持续发展。更多还原

【Abstract】 The unreasonable nitrogen management in paddy fields has resulted in the waste of nitrogen resources and environmental pollution. To solve this problem, this study analyzed the fate of nitrogen and its optimal management in typical paddy fields in Southern China. Based on the observation data of experimental fields under conventional field management in Gaogang village, Xiaochang County Hubei Province in 2017, the DNDC model was used to simulate and analyze crop nitrogen uptake, nitrogen leakage, ammonia volatilization and denitrification. The results showed that :(1)The DNDC model could accurately simulate different nitrogen outputs from paddy fields, with the fitting degree (R~2) as high as 0.649 3～0.860 2, and the Nash efficiency coefficient (NSE) as high as 0.513 5～0.786 2, which indicated that this model could be used to analyze the dynamic and structural characteristics of nitrogen fate in paddy fields.(2)Gaseous nitrogen loss, rather than water loss, was the main way of nitrogen loss in paddy fields, accounting for 83.86%～86.69% of the total nitrogen loss, and the period during tillering fertilizer application and yellow maturity was stage an important period for significant gaseous loss. (3) According to the scenario simulation, the optimal nitrogen management was to control the nitrogen application rate at 100 kg/hm~2and to return paddy straw to fields, which increased nitrogen uptake of paddy by 12.67% compared with the low nitrogen fertilization, and reduced the nitrogen gaseous losses by 17.64%～65.57% compared with the high nitrogen fertilization and nitrogen surface fertilization method. This study results can be extended to paddy areas in southern China to achieve sustainable development of high nitrogen utilization and low nitrogen pollution.更多还原