不同灌溉方式对稻田土中NH_(4)^(+)-N迁移转化途径的影响

Effects of Different Irrigation Methods on NH_(4)^(+)-N Migration and Transformation Pathways in Paddy Soil

为探究不同灌溉方式对稻田土壤中NH_(4)^(+)-N迁移转化途径的影响,采用自制装置模拟稻田,测定土壤施入尿素后在不同灌溉方式下稻田氨挥发量以及土壤、淋溶液中NH_(4)^(+)-N浓度及相关指标的变化.结果表明,常规淹灌方式下,施肥后15 d内以淋溶途径损失的NH_(4)^(+)-N量约为湿润灌溉方式下的2.7倍;湿润灌溉方式下,施肥后15 d内以氨挥发、硝化反应途径损失的NH_(4)^(+)-N量分别约为常规淹灌方式下的16.5倍和2.02倍.研究结果表明,常规淹灌方式下施肥后15 d内NH_(4)^(+)-N主要以淋溶途径进行迁移转化;湿润灌溉方式下施肥后15 d内NH_(4)^(+)-N的迁移转化途径主要为氨挥发.通过分析不同灌溉方式下土壤中NH_(4)^(+)-N的迁移转化途径可为合理灌溉及控制农田面源污染提供技术参考.

In order to explore the effects of different irrigation methods on the migration and transformation of ammonium nitrogen in paddy soil,simulated paddy field experiments were conducted by measuring ammonia volatilization,ammonium nitrogen concentration and related indicators in soil applied with urea and leaching solution under different irrigation methods.The results showed that loss amounts of runoff ammonium nitrogen under conventional flooding irrigation were about 2.7 times as much as that under wet irrigation after urea was applied to the soil for 15 days.Furthermore,after urea was applied to the soil for 15 days,loss amounts of runoff ammonium nitrogen under wet irrigation were about 16.5 and 2.02 times as much as that under conventional flooding irrigation,respectively.Overall,the migration and transformation pathway of ammonium nitrogen was mainly through leaching under conventional flooding irrigation,while ammonia volatilization was the main migration and transformation pathway of ammonium nitrogen under wet irrigation.Therefore,this paper can provide technical reference for rational irrigation and control of non-point source pollution in farmland by analyzing migration and transformation pathways of ammonium nitrogen in soil under different irrigation methods.