黄河流域土壤侵蚀及植被水保效益研究

Study on Soil Erosion and Vegetation Effect on Soil Conservation in the Yellow River Basin

基于土壤侵蚀快速评估法,以最小图斑为研究单元,评估了黄河流域20世纪90年代末土壤侵蚀的状况,并分析了黄河流域土壤侵蚀的分布特点.在此基础上,设定流域不同植被覆盖度情景,计算了不同植被覆盖度下黄河流域的土壤侵蚀状况,获得了1.1km分辨率条件下的植被覆盖度变化对水保效益的影响,给出了对应于产生显著水保效益的植被覆盖度变化范围.研究表明,从黄河流域整体上来看,当流域较低植被覆盖度提高到15%以上时会产生显著的水保效益,在25%处显著性开始降低,而超过45%时水保效益的增加则很不显著.综合考虑经济投入及当地环境限制,最佳水保效益对应的植被覆盖度约为25%.

Based on the rapid soil erosion assessment approach, the soil erosion intensity of the Yellow River basin at the end of 1990s is assessed using minimum polygon as study units. The distribution characteristics of soil erosion in the Yellow River basin are analyzed. Based on the assessment results, a parameter study investigates the soil conservation effects of vegetation coverage with a resolution of 1. 1 km. And the vegetation coverage range that could generate obvious soil conversation effect is obtained. It is indicated that, on the whole view of the basin, the lower and upper threshold of vegetation coverage for obvious soil conservation effect respectively are 15% and 45% ,and the best vegetation coverage is 25%.