In order to determine the index of soil shearing strength

soil moisture content

bulk density

dry density

total porosity

organic matter and soil aggregate MWD value (which containing dry and wet screening)

five types of land use

including conifer and broad-leaved mixed forest

shrub forest

field

sloping farmland and wasteland

had been taken into consideration and the field survey and laboratory experiment under different grades (10°

15°and 20°) were conducted

besides

the fuzzy close-degree analysis and stepwise regression analysis had both been used

for analyzing the influencing factors on soil shearing strength under those land use types. The results showed that in the same land use type

soil cohesion force increased firstly then decreased with slope degree increasing gradually. In conifer and broad-leaved mixed forest

the close degree was greatest between wet-screening MWD value and soil cohesion force

but this degree was comparatively greater between bulk density

dry density and this force in shrub forest

field and sloping farmland

in wasteland

this force was affected mostly by the organic matter. In conifer and broad-leaved mixed forest

shrub forest and wasteland

the calculating results of 4 kinds of close degrees showed that the main impacting factor on soil internal friction angle was total porosity

while in other two land use types

the main factors were bulk density and dry density. In conifer and broad-leaved mixed forest

the equations of soil shear strength based on dry density and bulk density were established (R2=0.865). In sloping farmland

the predicting model

which was based on dry density

bulk density and dry-screening MWD value

was established (R2=0.964). In shrub forest

field and wasteland

the factors affecting soil shear strength were dry density

dry-screening MWD value and bulk density.