Comparative Research Of Soil Micromorphological Characters On Typical Crop Land And Artificial Ecological-forest Land In Easten Guanzhong Areas, Shaanxi Province

Through researching and comparing the soil micromorphological characters of different land use patterns,to prove the relation between soil micromorphological characters and land use patterns,so can explore the indicative significances of soil micromorphological characters to land use pattern change.The paper chose crop land and artificial ecological-forest land.as the research.objects in easten Guanzhong areas in Shaanxi province.After observing and describing the soil micromorphological characters under the microscope,this research also apply the software named SISC IAS V 8.0 to analysis the soil micromorphological features of the two different used lands,include soil pedofeatures,the coarse grains,voids and microstructure,and measured quantitatively and done the number simulation,so the information that included in the features of soil micromorphology was released intensively.And also through testing grain size,pH value,magnetic susceptibility and TOC this physical and chemical properties,to discuss the coupling relationship between soil micromorphological features and soil physical and chemical properties,so can get deep interpretation of information of soil micromorphological features.Through comprehensive analyzing the experimental results can gain some recognitions as follow:The construct characteristics of the,two researched soil profiles showed:the crop land soil profile is Ap1-Ap2-BC,and the artificial ecological-forest land soil profile is O-A-BC.The crop land soil profile and artificial ecological-forest land soil profile developed in the same natural enviroment,so the types of soil pedofeatures at the two different soil profiles are nearly same,but the spacial distribution and content of soil pedofeatures at the two different soil profiles have remarkable difference.Compared crop land soil and artificial ecological-forest land soil,the content of illuviation clay in crop land soil are higher than in artificial ecological-forest land soil,and highest at horizon Ap2 in crop land soil profile,but the content of illuviation clay at horizon BC is highest in artificial ecological-forest land soil profile.Calcite exist in crop land soil mainly cryptocrystal calcite and microlite calcite;But in artificial ecological-forest land, soil cryptocrystal calcite,microlite calcite and coarse calcite all can be found.Developed in the same natural enviroment,the minerals assemblage of coarse grains are very similar in the crop land soil and artificial ecological-forest land soil.It is mainly composed of quartz and plagioclase.But the differences in morphological characteristics of coarse grains are obvious:the parameter values such as area,perimeter, width and so on not changed significantly at different depth in the artificial ecological-forest land soil profile;but the parameter values in the crop land soil profile changed significantly at different depth.The different land use pattern can effect the characters of voids:in the crop land soil profile,voids take complicated shapes and have more rough void walls,at the same time,the ratio of voids(28.4%) at horizon Ap1 is the highest,and at horizon Ap2(17.4%) is the lowest.In the artificial ecological-forest land soil profile,the voids are more regular and with more smooth void walls comparatively, the ratio of voids(23.7%) at horizon O is the highest,and at horizon BC(21.2%) is the lowest..The soil physical and chemical characters can response land use patterns remarkablely.The content of clay is higher in the crop land soil profile than in the artificial ecological-forest land soil profile,and at horizon Ap2(22.5%)is the highest;but in the artificial ecological-forest land soil profile the content of clay at horizon BC(22.3%) is the highest.The pH value changed more significant at different depth in the crop land soil profile,and it become smaller with the depth increasing;but in the artificial ecological-forest land soil profile,the pH value become bigger with the depth increasing. The magnetic susceptibility changing with depth increasing in the crop land soil profile is more obviouse than in the artificial ecological-forest profile,and in the crop land soil the mean magnetic susceptibility value at horizon Ap1 is the highest.The content of TOC in the artificial ecological-forest is higher than in the crop land soil,and it.is highest at the horizon near to the surface,and decreasting with depth increasing.The soil physical and chemical properties have some coupling relationship with soil micromorphological characters:The micromorphological characters of coarse have positive correlation with magnetic susceptibility,especially in YSL soil profile,the relative coefficient most above 0.5.The content of clay have negative correlation with C/F_10μm value,and the content of sand have positive correlation with C/F_10μm value,and the relative coefficient also most above 0.5.But the content of silt have negative correlation with C/F_10μm value,and the relative coefficient all below -0.35,so the correlation less significant than with clay and sand.