未完全解冻层对黑土坡面降雨侵蚀的影响

春季解冻期土壤侵蚀受未完全解冻层影响较大,以东北黑土为研究对象,通过室内降雨模拟试验,分析未完全解冻层对土壤侵蚀总量及侵蚀速率的影响.结果表明:在所选水平内,低含水率黑土侵蚀总量随着初始解冻深度增加而减少;高含水率黑土在h=10mm水平上侵蚀总量最大;侵蚀速率均呈现先增大后减小的变化趋势,在20min降雨时间内,总会出现一个侵蚀速率峰值,不同初始解冻深度峰值出现时间并不完全相同;当h=5mm和h=10 mm时,未完全解冻层阻水作用都比较明显,侵蚀量差异主要在试验初始阶段,也就是说,土壤含水率只是在试验最初阶段起着一定作用,随着入渗量增多,土壤逐渐达到饱和,二水平之间侵蚀量差异较小,相反这一阶段未完全解冻层隔离作用被充分体现.

Effects of Incompletely Thawed Layer on Black Soil Slope Rainfall Erosion

Incompletely thawed layer have a greater impact to the soil erosion of spring thaw period.Based on the black soil in northeast as the research object,by indoor simulation rainfall tests,analyzed the different initial thaw depth on the total impact of soil erosion and rainfall process to the erosion rate.Results:in the chosen level,erosion amount of soil with low moisture content reduced with the initial thaw depth increases.High moisture content soil,the total erosion is most when the thaw depth of black is 10 mm ; Erosion rate increased first and then showed a decreasing trend,in 20 min period of rainfall.there was always appeared a peak erosion rates,and the peaks appeared different with the difference of the depth of the initial thawing depth.time is not initial thawing peak time also does not appear peak depth exactly the same;Incompletely thawed layer of water has a obvious effect when h=5 mm and h=10 mm,difference between the amount of erosion,mainly in the initial pilot phase,that is,soil moisture content is only played a certain role in the initial stage,with the increase of infiltration amount,the soil gradually reaching saturation,the difference between the level of erosion was reduced,on the contrary,at this stage the role is not incomplete thawed layer of isolation has been fully embodied.