水蚀风蚀交错区复合植被与单一植被土壤水分特征及其地上生物量差异

采用野外调查的方法,于2013年8月选取位于黄土高原水蚀风蚀交错区的陕西省榆林市神木县六道沟流域典型植被类型样地,研究复合植被与单一植被的土壤水分特征、生物量差异及其影响因素。结果显示:深根型植物与浅根型植物复合后其冠层高度、地表植被盖度、叶面积指数和地上生物量都有显著提高;土壤表层含水量显著增加;物种丰富度也呈增加趋势。影响复合植被和单一植被地上生物量差异的主要因素是其根系对水分吸收利用的差异,以及深根型灌木和浅根型草本植物对不同深度土壤水分的利用差异。草本植被地上生物量随100 cm内土壤含水量的增加而增加,而与容重和导水率相关性不显著。因此在植被恢复建设过程中,深根型植物宜与浅根型植物搭配种植,可以合理有效利用有限水资源,提高植被地上生物量、冠层高度和地表植被盖度,从而可以有效控制水蚀风蚀交错区的土壤侵蚀。

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.