尿素深施后模拟水田系统中氮素的迁移转化途径

为探究尿素深施入土壤后氮素在土-水系统中的迁移转化途径，采用自制装置模拟水田并测定土壤及表层水中氮素浓度及相关指标的变化，以此对氮素的迁移途径进行研究。结果表明：尿素深施方式下，氮素在表层水中发生的反应以氨挥发和硝化反应为主，在土壤中主要进行反硝化反应；尿素深施入土壤15天后系统中氮素损失量占总施肥量的14.86%，其损失来源于氨挥发和生物反硝化作用，分别约占总损失量的68.95%和31.05%。尿素深施方式下水田中氮素迁移转化过程十分复杂，通过分析土-水系统中存在的反应和氮素迁移转化途径可为合理施肥及控制农田面源污染提供技术参考。

Migration and Transformation Pathways of Nitrogen in Simulated Paddy Field System with Deep Application of Urea

To explore the migration and transformation pathways of nitrogen in soil and water system after urea was deeply applied to soil, the self-made device was used to simulate paddy field, and the subsequent experiments were carried out by measuring the changes of nitrogen concentration and related indicators in soil and surface water. The results showed that ammonia volatilization and nitrification were the main reactions in surface water, while denitrification was the main reaction in soil. After urea was deeply applied to soil for 15 days, the proportion of nitrogen loss in the system reached 14.86% of the total fertilization, and the loss came from ammonia volatilization and biological denitrification, which accounted for 68.95% and 31.05% of the total loss, respectively. The migration and transformation pathways of nitrogen in urea-treated paddy field are complicated, and the study could offer technical reference for rational fertilization and coping with farmland non-point source pollution by analyzing the reactions and migration pathways of nitrogen in soil and water system.