| Qinghai Lake watershed is located in the Qinghai-Tibetan plateau area with aperennial low temperature, great temperature difference between day and night, widedistribution of minority groups, and economy development by grazing. With theprogress of socio-economy, the quantity of cattle and sheep is also constantlyincreasing. Moreover, insect pest damage to the grassland leads to declination of soilfertility and even destruction of the soil structure and surface integrity which is soserious that the annual amount grass yield drop and the soil erosion has increaseddramatically.Now,soil erosion is one of the most serious environmental problems and the mainform of damaging the ecological environment. Serious soil erosion has alreadyrestricted fast, stable and healthy development of the national economy. Therefore,evaluating the soil erosion degree of Qinghai Lake watershed from a large scale canhelp us understand the causes of soil erosion scientifically and comprehensively, andat the same time provides scientific foundation for the control of watershed and theprotection of regional ecological environment.The remote sensing data, geographic information system and spatial analysistechnology for data technology platform. According to soil erosion model (USLE),factors of precipitation, soil erodibility, terrain, vegetation coverage and managementmeasures are selected as evaluation standard of Qinghai Lake watershed soil erosion.Each of these erosion factors is analyzed, Raster Data Structure of each factor ismapped out and at last a modulus graph is reached by calculations and analyses ofRaster Data Structures. By the modulus graph of Qinghai Lake watershed erosion aquantitative analysis on current situation of erosion and its spatial distribution isconducted. The main research results are as follows:1) After studying the strengths and weaknesses of the major domestic andoverseas soil erosion models, the author chooses the American general soil lossequation as the basic framework. Through analysis and calculation of the parametersinvolved with the soil loss equation, a basic database of Qinghai lake watershed soilerosion model is established. And get the soil erosion quantity and spatial distributionin a certain period of Qinghai Lake watershed.2）According to the statistical analysis of the USLE model can be concludedthat:In Qinghai Lake watershed, The coverage degree is inversely proportional to erosion. Therefore, micro degrees of soil erosion occupy most of the erosion. whichowns28.56%of the total erosion areas. mild erosion degree with14.54%of the totalerosion areas. The moderate erosion degree occupies11.64%of the total. The strongerosion degree occupies10.5%of the total has the least area among all the erosionareas. The extreme strong erosion degree with17.42%of the total. And the wilderosion degree occupies17.33%of the total.3) In Qinghai Lake watershed, Micro and mild erosion are mainly distributed in theareas with slope generally less than15°and the vegetation coverage above60%.Moderate erosion and Strong erosion are distributed around the Qinghai Lake areaswith steep slope between15°~25°and the vegetation coverage between30%to60%.which are Scattered distributed around the mild erosion and extreme strong erosion.Extremely strength erosion is centralized distributed in the vegetation coverage under30%, in the ditch slope and slope belt area with slope between25°~35°; The wilderosion is mainly distributed in the valley of the inferior vegetation coverage, under about15%, and the slope is above35°in the west of Qinghai Lake watershed. |
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