Cutting Effect Of Caranaga Korshinskii Kom In Semi-arid Loess Hilly Region

Soil drying has been an environmental problem in perennial artificial Caragana shrub land in the semi-arid Loess Hilly region. Cutting management was expected to have an effect on improving soil moisture regulation and thus preventing the problem. In this study, the soil properties, soil moisture and Caragana growth of cutting land and control land of Caragana korshinskii Kom in the Shanghuang experimental station in northwestern China was measured and analyzed, the main results are as follows.(1) With the increase of soil depth, soil bulk density firstly increase and then decrease, soil porosity, the water-holding capacities decrease at the first and increase afterwards. The soil was mainly constituted by silt, then sand, then clay.(2) The canopy interception increased with precipitation, the relationship can be determined by equation: y=0.0782x+0.4126. The surface runoff increased with precipitation.(3) The amounts of soil water recharge in both control and cut plots were positively related to precipitation. Rainfall loss rates through interception and runoff in control and cut plots were exponentially related to their surface soil moisture contents before the rain. After cutting, the recharge depth decreased, and soil moisture in 20-160 cm increased for a short period (about two months in this study). Then the soil moisture in cut plot was close to that in control plot. In rainy year and the year after rainy year, soil moisture in cut land was lower than control and the soil water storage in 0—400 cm soil layer was up to 45.9 mm lower than that in control plot. Cutting recovered soil moisture in the 200—400 cm soil layer but the water loss in the upper layer of 0-200 cm was more significant. Three years later, the effect of cutting on soil moisture became weak.(4) The water use depth and the decreased amount of water storage in dry months in cut land were lower than control. These suggest that cutting can reduce the water consumption of the Caragana shrub.(5) The equation y=0.011 (D2H)1.008 can be used to calculate the biomass of single branch and the equation y=0.1228(D2H BN)0.5525 can be used to calculate the biomass of single clump. After cutting, coppice grow fast, the height grew quickly until the fifth year after cutting, however, the basal diameter grew quickly during all the experiment period. The growth rate of Canagara was affected by precipitation. In July and August, Canagara grew most rapidly.