冻融交替作用对黄土高原三种典型土壤可蚀性影响

Influence of Freeze-Thaw Alternation on the Erosibility of Three Typical Soils in the Loess Plateau

为研究冻融交替作用对黄土高原北部土壤可蚀性的影响,选取黄土高原北部季节性冻融区的三种典型土壤(灌淤土、黄绵土和风沙土)作为研究对象,设计室内冻融模拟试验,利用基于机械组成和有机质含量的EPIC模型与Dg模型估算土壤可蚀性K值,系统分析冻融交替作用对土壤机械组成、有机质含量及土壤可蚀性K值的影响。结果表明:(1)冻融交替作用使三种供试土壤粘粒含量显著减少(P<0.05),土壤质地粗化;(2)土壤有机质含量随冻融交替次数的增加总体呈先增加后减小再增加的趋势;(3)相同冻融条件下,利用EPIC模型与Dg模型估算出的土壤可蚀性K值具有显著差异(P<0.05),利用EPIC模型估算时,土壤可蚀性K值大小表现为风沙土>灌淤土>黄绵土,利用Dg模型的估算结果与之相反。

In order to study the influence of the alternation of freezing and thawing on the soil erodibility in the northern Loess Plateau, three typical soils(irrigated silt soil, loess soil and aeolian sand soil) in the seasonal freezing and thawing area of the northern Loess Plateau were selected as the research objects, and an indoor freeze-thaw simulation was designed in the experiment, the EPIC model and the Dg model based on mechanical composition and organic matter content are used to estimate the soil erodibility K value, and the influence of freeze-thaw alternation on soil mechanical composition, organic matter content and soil erodibility K value is systematically analyzed. The results showed that:(1) The freeze-thaw alternation effect significantly reduced the clay content of the three types of soils(P<0.05), and the soil texture became coarser;(2) The soil organic matter content increased first and then decreased with the increase in the number of freeze-thaw alternations.(3) Under the same freezing and thawing conditions, the soil erodibility K value estimated by the EPIC model and the Dg model are significantly different(P<0.05). When the EPIC model is used to estimate the soil erodibility, the K value of soil erodibility is in the order of aeolian sandy soil> irrigated silt soil> loessal soil, and the estimation result using the Dg model is contrary to this.