Resumo

WEI, TX  e  LIU, YH. The cover-management factor (C) on woodlands of the hilly areas of the Loess Plateau in North China. Phyton (B. Aires) [online]. 2016, vol.85, n.2, pp.305-313. ISSN 1851-5657.

Soil erosion is one of most serious environmental and production problems on the Loess Plateau in China. The objectives of this study were to quantify the influence of forest vegetation on soil erosion on slope areas in the Loess Plateau. This was made by using the subfactor method to calculate the vegetation cover management factor (C) of the Universal Soil Loss Equation (USLE). Proper local subfactor parameter values were obtained to ofer a theoretical basis and practical guidance for studying the relationship between vegetation and soil erosion on the Loess Plateau. Tree subfactors including prior land use (PLU), canopy cover (CC), surface cover (SC), surface Roughness (SR), soil moisture (SM), and covermanagement factor (C) were observed at three plant growth stages: initial, blooming and end of growing season. All observations and measurements were made on 13 runof plots in the Caijiachuan Watershed. The annual runoff sediment volume, and the subfactor and indirect methods were adopted separately to calculate the vegetation cover and management factor C of each stand, and then carry out comparative tests and comprehensive analyses. The results showed that the cover-management factor (C) calculated by the subfactor and indirect methods were in good agreement. The order refected was forest < Robinia pseudoacacia < Robinia pseudoacacia & Oriental arborvitae < Pinus tabulaeformis < orchard. Subfactors of PLU, CC, SC, SR and SM for soil loss rates of different stand types were not the same and the impact order was PLU>SC>SR>SM>CC. This indicated that plant roots, soil organisms in the surface soil layers and surface cover had a larger impact on soil loss fate than the other subfactors. Stand density was negatively correlated with vegetation cover and management factor C, suggesting that only stand density influenced soil erosion. The stand density of Robinia pseudoacacia ranged from 1200 to 2204 stems/ha. Management factor C ranged from 0.020 to 0.037. The subfactor method could be adopted to monitor the amount of soil erosion in the Loess Plateau, with the parameters being Cb=0.951, Cur=0.004513kg/(ha.cm), Cus=0.001887kg/(ha. cm), Cuf=0.5, b=0.025. The vegetation cover and management factor C of different stands in the Loess Plateau varied between 0.009 and 0.062.

Palavras-chave : Loess Plateau; Forest vegetation; Soil erosion; Universal Soil Loss Equation; Vegetation Cover and management factor.