不同放牧制度草场产流产沙过程模拟试验

Simulation Experiment of Process of Runoff and Sediment Yield in Grasslands of Different Grazing Systems

为研究不同降雨条件下不同放牧制度对水土流失的影响,通过在呼伦贝尔沙质草原不同放牧制度草场进行人工模拟降雨试验,得到产流及产沙过程的变化特征,同时测定土壤流失的主要成分,并对产流量及产沙量进行回归分析。结果表明:休牧、轮牧、自由放牧草场的产流率随降雨历时的增加而逐渐增大,并最后达到稳定状态,产沙过程与产流过程相反,3种放牧草场的径流总量及产沙总量均为自由放牧草场>轮牧草场>休牧草场,放牧制度及雨强与产流率、产沙量间存在显著的正效应。3种放牧草场的产流量与泥沙含量间存在二项式相关。在相同降雨强度下,休牧草场对水土流失的调控能力明显优于轮牧及自由放牧草场,但随降雨强度增加,但其调控优势随降雨强度的增加在逐渐变弱。放牧制度对土壤流失的质地产生显著影响,自由放牧草场粉粒及粘粒流失严重,容易出现土壤沙化现象。

In order to explore the influence of different grazing systems on water and soil loss under different rainfall intensity,we selected sandy grasslands in Hulun Buir under different grazing patterns as research area to carry out simulated rainfall experiment.The characteristics of runoff and sediment yield process and the composition of soil loss were investigated.The regression analysis of runoff and sediment yield was also conducted.The results showed that the runoff yielding rate increased with the increase of rainfall duration and finally reached a steady state in no grazing grassland,rotational grazing grassland and continuous grazing grassland.The process of sediment yield was opposite to the runoff process.The total runoff and sediment yield in different grazing systems followed the order of continuous grazingrotational grazingno grazing.There were significant positive effects of rainfall intensity and grazing intensity on runoff yielding rate and sediment yield.There was binomial relation between runoff yield rate and sediment yield in grasslands of 3grazing systems.Under the same rainfall intensity,no grazing grassland was better than grasslands of the other 2grazing systems at the ability of controlling water and soil loss,but the ability decreased with the increase of rainfall intensity.Grazing system had a significant impact on the quality of the soil loss.In the continuous grassland,the loss of soil silt was serious,which could easily cause soil desertification.