草甸土近地表解冻深度对融雪侵蚀影响模拟研究

Study on Sloping Land Snowmelt Erosion Affected by Thaw Depth of Near-surface Meadow Soil

采用室外人工模拟融雪水冲刷试验,研究了春季解冻期近地表草甸土解冻深度对坡面融雪水冲刷侵蚀过程的影响。结果表明:土壤解冻深度对产流及侵蚀有较大影响。由于冲刷过程中冻土层逐渐向下移动,解冻土层厚度增加,坡面产流和侵蚀也随之经历着此消彼长的复杂过程。对同一冲刷强度,解冻深度愈小,坡面初始产流时间愈早,前期侵蚀率愈大,冲刷后期侵蚀率增幅减小。初始解冻深度越大,坡面初始产流时间愈晚,前期侵蚀率较为稳定,但随冲刷时间的延长,坡面随解冻深度不同发生不同程度的细沟侵蚀,侵蚀量急剧增大,冲刷过程中侵蚀率大小的变化受细沟发育程度的影响较大。

In this paper the effects of near-surface meadow soil thaw depth in the spring thaw period on sloping land erosion process was studied,using outdoor artificial simulated snowmelt experiment.The results showed that the soil thaw depth have great effects on run-off and erosion.As the frozen soil layer moved down gradually in the scour process,the soil thaw depth increased,surface runoff and soil erosion have also experienced a shift in the process.Under the same scour intensity,the smaller the thaw depth,the sooner the initial slope runoff time,the greater the rate of pre-erosion,soil erosion volume was also greater,but the growth rate of erosion in the late scour was decreased.The larger the thaw depth,the later the initial slope runoff time,the rate of pre-erosion was stable,but the rate of erosion growth rapidly when rill erosion development.The fluctuations in the rate of erosion have been influenced mainly by the degrees of rill development.