双层暗管排水布置方式对农田水氮运移的影响及模拟

Effect and Simulation of Double-layer Subsurface Pipe Drainage Layout on Water and Nitrogen Transport of Farmland

南方平原河网地区农田地下水位高、排水速度慢,氮素易随地表排水流失。为了有效减少农田氮素流失,控制农业面源污染,进行了麦秸秆和沸石组合外包材料条件下的双层暗管布置方式排水试验,并做了数值模拟。试验结果表明,双层暗管布置方式明显增加了排水流量,试验时间内排水总量比单层暗管布置方式多33.9%;氮素流失量上有所减少,其中硝态氮流失量减少了13.6%,氨氮流失量变化不大;数值模拟值与实测值吻合较好。研究成果说明双层暗管排水方式结合外包材料对农业面源污染的控制有一定的作用和实际应用价值。

The high water table and slow drainage are the characteristics of the southern plain river network region in Chi-na ,and the nitrogen is easy to lose with surface drainage .The drainage experiments and numerical simulation of double-layer subsurface pipe layout were done in the conditions of combined envelope materials of wheat straw and zeolite so as to reduce farmland nitrogen loss and control agricultural non-point pollution .The results show that the double-layer subsur-face pipe layout could significantly increase the drainage flow by 33 .9% ,which would be more than that of single-layer pipe arrangement in total test time .The amount of nitrogen loss was decreased ,the NO3 - -N loss was decreased by 13 . 6% ,and the NH4＋ -N loss was changed little .The simulated and measured values agreed well in the accuracy .The research results show that the double-layer subsurface pipe drainage combined with envelope materials has a certain effect and practical application value to control the agricultural non-point pollution .