RESEARCH ADVANCES OF VEGETATION EFFECT ON SOIL AND WATER CONSERVATION IN CHINA
我国植被水土保持功能研究进展

Research on the effect of vegetation on soil and water conservation in China can be divided into three main aspects. The first is the research of contrast, which is the research of vegetation benefits on blocking runoff and sediment by contrasting field observation data of runoff and soil erosion in vegetation cover land with those of bare land or farmland. The results showed that natural vegetation has a remarkable effect on soil and water conservation and this effect increases from the natural grassland to shrubbery and forest. The situation is more complicated for artificial vegetation, whose effect on soil and water conservation is influenced by many factors. The second is research of mechanism. Raindrop strike and runoff scour is the power of soil and water loss. Analyzing the energy reduction process of rainfall and runoff throughout the vegetation layers, the researchers discovered the internal mechanism of vegetation effect on soil and water conservation. The research showed that the external effect of vegetation on soil and water conservation is a combined effect of rainfall interception and runoff blockage by different vertical layers of vegetation so as to reduce the erosive energy of raindrop strike and runoff scour. All the vertical layers of vegetation are important to soil and water conservation. The third is research of evaluation. In order to evaluate vegetation effect on soil and water conservation, the evaluation index is firstly put forward, then quantitative relationships between evaluation index and runoff as well as soil erosion are analyzed. For a long time, this evaluation research in China focused on the single evaluation index, vegetation cover (for forest, it is forest cover ratio). With the development of mechanism research, many scholars put forward different evaluation index systems to comprehensively evaluate vegetation effect on soil and water conservation. The single index proved unable to completely reflect the difference of effects of different vegetation on soil and water conservation. The new comprehensive evaluation index systems need to be developed and validated, and are currently unable to be applied in practice.