Differences of Soil Water Characteristic and Above-ground Biomass between Single and Composite Vegetation in Water-Wind Erosion Crisscross Region

Using the method of field investigations,the plots of typical vegetation types were selected in Liudaogou watershed of Shenmu County,Yulin City,Shaanxi Province on August 2013 to study differences of soil water characteristic,biomass,and the influence factors between single vegetation and composite vegetation in water/wind erosion crisscross region on Loess Plateau.The results showed that the canopy height,degree of surface vegetation coverage,leaf area index and aboveground biomass were improved significantly after deep root plants compounded with shallow root plants;the soil water content in surface increased significantly;species richness also showed a trend of increase.The main factors of affecting differences of aboveground biomass between single vegetation and composite vegetation were the differences of absorbing water between compound vegetation root system and the single vegetation root system,and the differences of utilizing soil moisture in different depth between deep root shrubs and shallow root herbaceous plants.Aboveground biomass of herbaceous vegetation increased with the increase of soil water content within 100 cm and showed no significant correlation with bulk density and hydraulic conductivity.Therefore,deep root plants matching with shallow root plants in the process of vegetation restoration construction can utilize limited water resources reasonably and effectively,improve aboveground biomass of vegetation,canopy height and vegetation coverage on surface,and consequently control soil erosion effectively in water/wind erosion crisscross region.