野外模拟降雨条件下径流小区产流产沙试验研究

Experimental Study on Runoff and Sediment Yield in Runoff Plot Under Field Simulated Rainfall Condition

降雨引起的侵蚀产沙,是全球性的严重环境问题之一,在我国黄土区表现尤为突出。降雨及其产生的径流是引起黄土高原土壤侵蚀的主要动力,开展黄土区降雨产流产沙过程研究可为土壤侵蚀过程模型研发奠定基础,为水土保持与生态建设提供科学依据。利用野外模拟降雨试验研究了不同坡度、土地利用类型和雨强下径流、侵蚀产沙规律及相关关系。结果表明:在降雨过程中,产流时间随坡度、雨强的增大而变短,裸耕地产流时间短于自然草地。径流量随产流历时增加而增大,且坡度、雨强越大其值越大。产流过程中侵蚀产沙量呈先陡增、再陡减、最后趋于稳定的现象;坡度、雨强越大产沙量的峰值越大,峰值出现时间也相应提前。自然草地侵蚀产沙量极少,草地起着重要的固沙作用。建立径流与产沙回归关系,产沙量与径流量呈二次多项式函数关系,揭示了降雨过程中产流产沙变化规律。

Rainfall and runoff are the main dynamic factors which cause soil erosion on the Loess Plateau.Research on processes of rainfall,runoff and sediment yield can serve as development of process-based mode of soil erosion,soil and water conservation,and ecology construction on the loess region.The rule of erosion sediment and runoff infiltration relation was studied under different site conditions using field simulated rainfall.The results show that the runoff time becomes shorter when the slope and rain intensity increase and the time of runoff occurrence in bare arable land is shorter than that of natural grassland in the rainfall process.The volume of runoff increases when the duration increases,besides,the greater slope and rainfall intensity are,the larger the value is.The sediment-carrying capacity of the runoff first steeply increased,and then decreased sharply,and finally stabilized.The greater the slope is,the greater the rainfall intensity is,and the more advanced peak appearance time is.The natural grassland plays an important role in stabilizing the soil because the sediment-carrying capacity is very tiny in the grassland.Establishing a regression relation between runoff and sediment shows that the sediment yield and runoff follows the quadratic polynomial function,which reveales the variation rule of runoff and sediment yield during rainfall process.