In Loess area,block cloddy was universal existence in farmland surface.The physical and chemistry properties of block cloddy in plow layer were researched in this study.The results showed that the structure characteristics of block cloddy was with tight surface but loose inner,the bulk density of the crust can be high as 1.39~2.0 g/cm3,which was mainly affect by unreasonable tillage process.The tight surface can not be crushed by nature alternation of drying and wetting.Farming machinery to impact and rotar...
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