不同棉田暗管布置方式对氮素流失影响的模拟分析

为了研究不同棉田暗管布置方式对暗管排水中硝态氮流失量的影响,结合2007—2009年在湖北荆州丫角排灌试验站的控制排水试验,采用DRAINMOD田间水文模型进行数值模拟。结果表明,暗管出口高程和暗管间距对暗管排水中的硝态氮流失量均有极显著的影响,是进行农田控制排水设计的关键因素。具体而言,暗管排水中硝态氮的流失量随着暗管出口高程的减小而减小,随着暗管间距的增大而减小。因此,在进行农田控制排水设计时,应根据当地的环境要求以及作物的具体生长要求,调整暗管的出口高程和暗管间距,做到作物高产和环境保护的统一。

Simulation Analysis of Cotton Fields Nitrate-nitrogen Loss under Different Underground Pipe Layout

For studying rules of nitrate-nitrogen loss in controlled pipe drainage under different underground pipe layout in cotton fields,we combined the controlled drainage experiment during 2007—2009 in Yajiao,Jingzhou,Hubei Province and used DRAINMOD model to simulate the designed experiment schemes.The results showed that both exit water depth and space of underground pipe have very significant impact for the nitrate-nitrogen loss in underground pipe drainage;therefore,these two factors play important roles in the design of farmland controlled drainage systems.To be more specific,the amount of pipe nitrate-nitrogen loss may decrease by reducing the exit water depth and increasing the space of the underground drainage pipe.In this condition,based on the requirements of local environment and crop,we can modify the exit water depth and the space of underground drainage pipe to pursue the uniform of the high crop yield and environmental protection.