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季节性冻融对东柳沟流域风沙土分离能力的影响

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季节性冻融是影响我国内蒙古地区风沙土侵蚀的重要因素之一,为研究冻融作用与水动力条件对风沙土分离能力的影响,本文采用正交实验的方法,通过人工冻融和室内放水冲刷实验,对内蒙古东柳沟流域的风沙土分离能力的变化特征进行研究.结果表明:1)坡度、流量、土壤含水量、冻融循环次数和土层深度对土壤分离能力均具有显著影响(P<0.05),风沙土分离能力对各因素敏感程度大小为:坡度>流量>冻融循环次数>土壤含水量>土层深度;2)风沙土分离能力与流量和坡度呈正线性相关(R2 >0.94),土壤分离能力的临界流量是0.07 L/min,临界坡度是6%;3)土壤含水量、冻融循环次数和土层深度主要是通过改变土壤性质来间接影响风沙土分离能力:土壤含水量较高较低都会导致土壤分离能力增加,当土壤含水量为6%时,风沙土分离能力最小.土层深度对土壤分离能力的影响与土壤含水量的影响基本一致,中间土层分离能力较小.土壤分离能力随冻融循环次数的增加显著增加,但是10次循环后逐渐减小并趋于平缓.研究结果表明,冻融作用增大了风沙土分离能力,可导致季节性冻融区春季解冻期土壤侵蚀量增加.本研究可为季节性冻融区风沙土侵蚀机理的研究提供参考.
Effect of seasonal freeze-thaw on the detachment capacity of aeolian sandy soil in Dongliugou watershed
[Background] Soil detachment is the initial phase of soil erosion,and is of great significance to studies in regions that are characterized by seasonal freeze-thaw regimes.However,this process remains unclear because limited research on soil physical properties and soil detachment capacity has been carried out to date under freeze-thaw conditions.Thus,the aims of this study were to determine and compare the effects of slope gradient,flow discharge,moisture content,soil depth and freeze-thaw cycles on soil detachment capacity.[Methods] The soil samples were collected from the 0-20 cm soil layer in an abandoned cropland.It is located in Dalad Banner,Inner Mongolia which is the crisscross region of Hobq Desert and the Loess Plateau.In this study,in order to elucidate the effects of freeze-thaw on aeolian sandy soil detachment capacity,a series of artificial freeze-thaw simulations in combination with flume experiments were conducted by using the orthogonal method.[Results] 1) Slope,flow discharge,moisture,freeze-thaw cycles and soil depth had significant influence on soil detachment capacity (P < 0.05).The sensitivity degree of each factor on aeolian sandy soil detachment capacity was:slope > flow > freeze-thaw cycles > soil moisture content > soil depth,and slope and flow discharge were main affecting factors.2) The aeolian sandy soil detachment capacity was linearly correlated with flow discharge and slope (R2 > 0.94).The critical value of flow discharge and slope affecting aeolian sandy soil detachment capacity was 0.07 L/min and 6 %,respectively.3) Soil moisture,freeze-thaw cycles and soil thawing depth influenced aeolian sandy soil detachment capacity indirectly by changing soil physical properties.The process,range and degree of freeze-thaw were restricted by soil moisture content and occurrence condition.If soil moisture content was too higher or lower,it would lead to the increase of aeolian sandy soil detachment capacity.When the soil moisture was 6%,the aeolian sandy soil detachment capacity reached the minimum value.Freeze-thaw cycles resulted in the redistribution of soil moisture.The effect of soil depth on soil detachment capacity was basically consistent with soil moisture content,and aeolian sandy soil detachment capacity of middle depth was the smallest.The aeolian sandy soil detachment capacity increased obviously with the number of freeze-thaw cycles increased,but gradually tended to flat trend after 10th cycles.[Conclusions] The above results indicated that seasonal freeze-thaw increased aeolian sandy soil detachment capacity and it will lead to the increase of soil erosion in spring of the seasonal freeze-thaw area.This research results may provide reference for the study of erosion mechanism of seasonal freeze-thaw areas.The effect of freeze-thaw on the soil detachment capacity,however,requires further investigation in regions where this process occurs seasonally.

freeze-thaw actionfreeze-thaw cyclessoil detachment capacityorthogonal experiment

肖俊波、孙宝洋、马建业、刘晨光、孙艳、王敏、李占斌

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西北农林科技大学水土保持研究所,712100,陕西杨凌

广西壮族自治区水利科学研究院,530023,南宁

西北农林科技大学资源环境学院,712100,陕西杨凌

冻融作用 冻融循环 土壤分离能力 正交试验

国家自然科学基金重点项目西北农林科技大学大学生创新训练项目广西水利科技项目

41330858201610712035201214

2017

中国水土保持科学
中国水土保持学会

中国水土保持科学

CSTPCDCSCD北大核心
影响因子:0.902
ISSN:1672-3007
年,卷(期):2017.15(6)
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