农田下垫面处理对降雨入渗的影响

Rainfall Infiltration Characteristics of Farmland Underlying Surfaces Treated with Different Practices

为分析田间起垄和覆膜对降雨入渗过程的影响,在内蒙古通辽市开鲁县开展了平整裸地(PL)、平整地面(PZ)、不覆膜起垄(QL)和覆膜起垄(ML)4种下垫面处理的田间降雨入渗监测试验。通过监测玉米生育期5次降雨前后不同处理土壤含水率的变化过程,分析了各下垫面处理对降雨入渗再分配过程的影响。结果表明:(1)起垄和覆膜对农田降雨入渗过程的影响与降雨量直接相关,在雨量较小时垄沟和覆膜对降雨的入渗过程影响不明显,在降雨量达到18 mm以上时,垄沟的集雨增渗作用显现,入渗量及入渗深度都有明显的增加,而当雨量达到33 mm左右及以上时,受降雨类型的影响,入渗雨量并没有随着降雨量的增加而增加;(2)各处理对降水入渗量的影响有明显的差异,QL处理因为垄沟汇集雨水的作用增加了降雨的入渗量及入渗深度,沟中剖面比PZ处理最多可增加入渗量76%;ML处理的覆膜削弱了垄沟的集雨作用,比PZ处理最多可增加入渗量39%;但由于膜的不透水作用使保留在表层土壤的水量相对减少,有更多的雨水向下运移,因此ML处理增加了降雨的入渗深度,比PZ处理的入渗深度增加约30 cm。

In order to analyze the influence of ridge and film mulching on the process of rainfall infiltration,field trials of four underlying surface treatments including the open bare land(PL),leveling ground(PZ),ridge without mulching(QL)and ridge with mulching(ML)were carried out in Kailu County,Tongliao City,Inner Mongolia.The changes of soil moisture contents of different treatments before and after 5 rainfall events in maize growth period and the effects of underlying surface treatment on rainfall infiltration redistribution process were analyzed.The results showed that:(1)the influence of ridge and film on the rainfall infiltration process of farmland was directly related to the amount of rainfall;when the rainfall was small,the influence of furrow and film on the infiltration process of rainfall was not obvious;when the rainfall reached 18 mm or more,the effect of rainwater infiltration increased in the ditch,and the infiltration volumes and infiltration depths increased significantly;when the rainfall reached about 33 mm,the infiltration rainfall decreased due to the types of rainfall;(2)the treatments had different effects on rainfall infiltration;QL treatment could increase infiltration volume and infiltration depth due to the accumulation of rainwater in furrows;the mid-channel profile could increase the infiltration rate up to 76%compared with PZ treatment;the film of ML treatment weakened the rainwater collecting effect of the furrow,which could increase the infiltration amount up to 39%compared with the PZ treatment;however,the amount of water retained in the surface soil was relatively reduced,and more rainwater migrated downward due to the impervious effect of the membrane under ML treatment,which increased the infiltration depth of the rainfall and increased the infiltration depth by about 30 cm compared to the PZ treatment.