【作者】 赵园春；

【导师】 张耀民； 黄小苑；

【作者基本信息】 西安科技大学 ， 测绘工程， 2009， 硕士

【摘要】 水土流失是土地退化的主要原因,也是导致生态环境恶化的最严重的问题,联合国粮农组织将其列为全球土地退化的首要问题。水土流失对土地资源和更广泛环境的影响是深远而严重的,最直接的后果是土地生产力的损失和产量的下降,次要的影响包括河流和水库的淤积、以及由土壤颗粒上吸附的化肥和杀虫剂所引起的水污染。另外,对植被层的损害、以及反射率的相应增加和局部气候的变化而加速沙漠化。可渡河流域位于我国五大水蚀区之一—云贵高原水蚀区,水土流失以水力侵蚀为主。近年来,随着着经济的发展,人为活动强烈,水土流失有进一步加重的趋势。如何准确、快速、动态地查清水土流失现状,进行水土流失预报和动态监测,为水土流失治理和水保规划实施提供科学依据,是土地开发与环境整治的迫切需要。本研究采用基于3S技术的水土流失定量遥感方法,以GIS软件为平台,实现了在GIS平台上3S的集成。本次遥感监测,分析了土地利用、植被覆盖和坡度三因子与土壤侵蚀之间的关系,并获得了该区域土壤侵蚀的动态变化情况。取得了以下结果:(1)从2000年到2007年,可渡河流域土壤侵蚀面积小幅下降,但局部区域侵蚀面积和强度有所增加。可渡河流域土壤侵蚀面积共有1977.92km~2,主要由中度、轻度两类构成,二者共占侵蚀总面积的89.16%。(2)可渡河流域内土地利用类型以林地、草地和耕地为主,主要是林草植被向耕地转化。流域的土地总面积为3140.44km~2。流域内76.38%的土地为林地和草地所覆盖。人口压力促使耕地增加,只能开垦林草地,体现了人口对环境的巨大压力。(3)可渡河流域内植被覆盖率不高,林草植被覆盖度低。可渡河流域内植被覆盖度较低,中低覆盖度植被面积所占比例很大,而高覆盖度植被比例很小;植被覆盖度的高低对流域的生态环境和水土保持具有决定性的作用。因此需加大植树造林种草力度。(4)可渡河流域内土地坡度较大,平缓土地比例较小。可渡河流域内坡度较陡,其中坡度在15°以上的土地面积占土地总面积的一半以上,坡度小于8°的缓坡地面积所占比例仅为15.14%,表明可渡河流域地形坡度总体较陡。陡峭的地形是形成本区域严重水土流失的基础。更多还原

【Abstract】 Water and soil losses is the main cause for the global land degradation and also is the key problem resulting in the ecological environment deterioration, so N.N.FAO takes it as the principal problem of the global land degradation. It is far-reaching and profound for water and soil losses to influence the ecological environment, which main directly brings on land productivity losing and crop yield declining, and also induces that reservoirs or rivers are filled up and water bodies are polluted by adsorbing pesticide or fertilizer with soil granule. In addition to the above threats to ecological environment, soil erosion may speed up land desertification because vegetation is destroyed, land surface becomes bare, reflectivity enhances. Keduhe river is located in of the five water erosion areas in China YunGui Plateau water erosion. The water erosion is the main soil erosion. In the recent years, with the development of economy, the human activities are frequent. The trend of soil erosion will be worse. Therefore, it is the urgent need of land exploiture and environment repair that how to investigate the current situation of soil losses accurately, quickly and dynamically, how to Predict & inspect soil losses, and Provide scientific base for the repair of soil erosion and implement of soil and water conservation Planning.This study uses quantitative remote sensing method on soil losses which based on 3S technique and supported by GIS software to probe into the application of quantitative remote sensing method on soil losses, and realize the 3S technique integration on GIS platform. The remote sensing monitoring analyzes the relationship between soil erosion and the three factors of vegetation cover, land use, slope steepness. We have accessed to dynamic changes of soil erosion, and have drew several conclusions as follows:(1) From 2000 to 2007, the land area of soil erosion declined slightly in Keduhe River watershed, but the intensity of the erosion in local areas has increased. The total area of soil erosion were up to 1977.92km2, mainly composed of the moderate and the mild types, both of which made up 89.16% of the total soil erosion.(2) The main land-use types in Keduhe River watershed are woodland, grassland and arable land, with a changing tendency from the woodland and grassland to the arable land. In Keduhe River watershed, the total land area being 3140.44km2, the woodland and grassland are the main land-use types which account for 76.78% of the whole area. There is a growing tendency that more and more woodland and grassland are being changed into arable land due to the cultivation of increased populations.(3) The vegetation cover rate, esp. the wood and grass cover rate, is relatively low in Keduhe River watershed.The vegetation coverage in Keduhe River watershed is relatively low with a big proportion of low and moderate degree vegetation coverage and a small proportion of high vegetation coverage. Since the vegetation coverage have played a decisive role in ecological environment and water/soil conservation, more trees and grass should be planted in this area to this effect.(4) The slope is steep and the proportion of flat land is small in Keduhe River watershed.The slope is so steep that the area of above 15°made up above 50% of the whole watershed while the area of under 8°only accounts for 15.14%. The steep terrain resulted in the serious soil erosion in this area.更多还原