成都粘土可蚀性K值及其对土地利用的响应研究

Soil Erodibility K Value of Chengdu Clayand Its Response to Land Utilization

基于EPIC模型计算土壤可蚀性K值,探讨了3种地类对成都粘土上发育土壤的理化性质、土壤可蚀性的影响。结果发现:(1)研究区土壤是以粉粒为主的粉土、粉壤土;荒草地的粉粒含量显著高于旱地和林地,林地和旱地的砂粒、有机质含量、磁化率显著高于荒草地,粘粒含量和硅铝铁率在3种地类中无明显差异。(2)研究区土壤可蚀性K值介于0.0226~0.0563,均值为0.0398,具有较高的土壤侵蚀潜在性;根据土壤可蚀性K值分级标准,3种地类中荒草地土壤属于高可蚀性,林地和旱地土壤属于较高可蚀性。(3)不同土地利用方式下土壤可蚀性K值大小表现为荒草地>旱地>林地;随土壤深度增加,土壤可蚀性K值越大,土壤抗蚀能力越弱。(4)土壤粒度组成、有机质、Saf和地球化学元素中的Al_(2)O_(3)、SiO_(2)和TiO_(2)是影响研究区土壤可蚀性K值的主要因素,土壤pH、碳酸盐和磁化率对其影响不显著。

K value of soil erodibility is calculated and the effects of three land types on the soil developed on Chengdu clay is discussed from the physical and chemical properties as well as the soil erodibility by EPIC model in this paper.The results show as follows.(1)The main soil in the study area is silty soil and silty loam with silty grains.The content of powder grains in the barren grassland is significantly higher than that in the dryland and forest;the sand grains,organic matter content and magnetization rate in the forest and dryland are significantly higher than those in the grass wasteland;the clay grain content and silica-aluminium-iron rate are not significantly different among the three land types.(2)The soil erodibility K in the study area ranges from 0.0226 to 0.0563,with a mean value of 0.0398,indicating that the soil has a high potential for soil erosion;according to the grading standard of soil erodibility K,among the three land types,the grass wasteland soils are of higher soil erodibility,and the forest and dryland soils are of high soil erodibility.(3)Soil erodibility K values of different land types have differed significantly in the sequence of grass wasteland>dry land>forest land.As the soil depth increases,the higher the K value of soil erodibility,the weaker the erosion resistance of the soil.(4)Soil particle size composition,organic matter and geochemical elements of Al_(2)O_(3),SiO_(2) and TiO_(2) are the main factors affecting the K value of soil erodibility in the study area,while soil pH,carbonate and magnetisation rate have no significant effect.