秸秆覆盖对降雨入渗影响的试验研究

为研究作物秸秆覆盖对改善农田自然降水利用效果的作用 ,采用人工降雨的方法模拟小雨、中雨和大雨 3种不同降雨强度 ,对雨后玉米、小麦秸秆覆盖地与裸地 0～ 2 0cm土层土壤含水率分布情况进行了试验。结果表明 :小雨后 ,由于秸秆覆盖阻滞入渗的作用 ,秸秆覆盖地 0～ 5cm土层土壤含水率短时间内低于裸地 ,但降雨后 2 4h玉米秸秆覆盖地已与裸地持平 ,以后逐渐高于裸地 ,降雨后 5 2h小麦秸秆覆盖地已高于裸地 ,且裸地水分蒸发量高于秸秆覆盖地 ;中雨后 ,秸秆覆盖阻滞入渗作用表现在土壤 5～ 2 0cm土层 ;大雨后 ,秸秆覆盖阻滞入渗作用表现在10～ 2 0cm土层。秸秆的吸水性会暂时阻滞雨水的入渗 ,但随着时间的延长 ,以及秸秆覆盖抑制水分蒸发的作用 ,秸秆覆盖地雨水入渗效果均高于裸地 ,秸秆覆盖在降雨小的情况下仍然有利于雨水的利用。

Experimental study on effect of mulch cover on rainwater infiltration

In order to study effect of the mulching on improving rainfall use efficiency, simulation was conducted using the artificial rainfall of sprinkle, moderate rain and downfall were simulated. The 0-20cm layer soil water content distribution was compared within 3 treatments, corn mulch cover, wheat mulch cover and no residue cover. The result shows that water content with mulch cover in 0-5cm layer is temporarily lower than that with no residue cover ones after sprinkle because of mulch cover blocking rainfall infiltration. But the soil water content with corn mulch cover is almost the same as no residue cover' after 24 hours, then higher than no residue cover' later. The water evaporation with no residue cover is higher than with mulch cover. After moderate rain, blocking effect of mulch cover on leaching is mainly happened in 5-20cm layer, but chiefly in 10-20cm layer after downfall. The water holding capacity of mulch cover's blocked rainfall infiltration temporarily. However, because of low evaporation, rainfall infiltration effect of mulch cover on water infiltration are higher than that of no residue. Even under the small amount rainfall mulch cover still benefits the rainwater use.