In order to study the relationships between soil settlement and soil bulk density and surface roughness under natural conditions

this paper used ruler

ring sampler and a chain to determine soil settlement

soil bulk density

surface roughness degree of different soil textures in turned over tillage and ridge culture under natural conditions and analyzed soil bulk density

the changes of surface roughness degree and the relationship between soil settlement quantity and soil bulk density

surface roughness degree under different soil textures with tillage measures were not homogeneous soil subsidence

and constructed the soil bulk density and surface roughness prediction formula. The results showed that：（1）With rainfall energy accumulated

the soil settlement decreased under certain rainfall energy conditions. And the soil settlement under ridge tillage were not less than the soil settlement under flatten culture.（2）Soil bulk density increased after reaching to natural soil bulk density with different levels.（3）Surface roughness under the condition of ridge tillage decreased. And the surface roughness of loam soil was not always less than the surface roughness of sandy soil.（4）A good exponential relationship between soil settlement and variation of soil bulk density

the correlation coefficient more than 0.9. Soil settlement and the variation of surface roughness fitted power function relationship

where the correlation of sand than loam was higher

the correlation coefficients were 0.993

0.936 respectively. These research results offered a reference for prediction soil compaction degree

surface smooth degree under natural conditions and tillage.