春季解冻期白浆土融雪侵蚀模拟研究

Simulated Snowmelt Runoff on Lessive in Spring Thawing Period

采用室内人工模拟融雪水冲刷试验,研究了春季解冻期冻融温差、循环次数、土壤初始含水率、融雪水流量和解冻深度这5个控制因子对白浆土侵蚀的影响。结果表明,影响土壤侵蚀的首要因素为融雪水流量。春季解冻期土壤发生侵蚀主要集中在前15次冻融循环过程中,之后即使冻融循环次数增加,侵蚀量增幅也不明显。土壤含水率变化与侵蚀量之间线型关系不明显,初始含水率较小的土壤侵蚀量大于初始含水率较大的侵蚀量。在径流冲刷过程中,融雪流量的大小和土壤冻层的存在,共同影响解冻深度与侵蚀量大小之间的关系。当融雪流量较小时,土壤解冻深度越小侵蚀量越大,二者间呈负相关关系;反之,当融雪流量较大时,土壤解冻深度与侵蚀量之间呈正相关关系。

In order to research the impact of lessive soil erosion under the freeze-thaw condition in spring thaw period,freeze-thaw temperature,freeze-thaw cycles,initial water content,snowmelt water flow,thaw depth were selected to study the effects of these five factors on soil erosion by using indoor artificial simulated snowmelt experiment.The results showed that the primary factor was snowmelt water flow.The erosion was mainly happened in the first 15 freeze-thaw cycles in spring thaw period,even though the cycles increase after that,the erosion wasn′t increase at all.There was not a significant linear relationship between soil moisture and erosion,but the erosion of relatively small initial soil moisture was greater than the larger amount of initial soil moisture.During the process of scouring runoff,the size of snowmelt water and the existence of soil frozen layer,which both affect the relations between the thaw depth and erosion.When the snowmelt water flow was smaller,the less depth of soil was thawed,the more amount of soil will be eroded,that appear a negative correlation between the two;however,when the snowmelt water flow was greater,that appeared a positive correlation.