| The soil physical properties of manmade Pinus tabulaeformis forestland in the Loess Plateau at different forest ages had been studied. The results go as follows: Bulk density varies dramatically with tree ages and soil depths; total soil prosity,capillary prosity, non capillary prosity change irregularly with tree age, but greatly with soil depths; max soil moisture capacity,capillary capacity and moisture capacity change greatly with tree ages, and more greatly withs depth, so both tree ages and soil depthes could show the moisture capacity of Pinus tabulaeformis carr forestland. Compared with wastedland, Pinus tabulaeformis carr. Forestland soil bulk density could be reduce through the function of litters and root system, and to some degree, to improve soil prosity, to raise soil moisture capacity. Total prosity, non-capillary prosity, max moisture capacity, capillary capacity, moisture capacity rise respectively by 9.3%36.3%, 40%232.8%, 1%103%, 21.6%46.2%, 22.4%43.7%, and soil capillary prosity changes little. These findings shows that it was favorable to improve soil hydro-physical properties by building plantation forests on the Losss Plateau. |