【作者】 史纪安；

【导师】 史俊通； 陈利顶；

【作者基本信息】 西北农林科技大学 ， 作物栽培学与耕作学， 2003， 硕士

【摘要】 水土流失是黄土高原地区严峻的生态环境问题，不合理的土地利用是引发和加剧水土流失的重要原因之一，土地利用变化驱动机制和土地利用空间格局与水土流失关系是其研究的重要方面。本文以无定河流域为典型研究地区，借助地理信息系统(GIS)技术，结合社会经济统计资料和实地调查的数据，探讨无定河流域土地利用变化的驱动机制和流域内不同尺度土地利用类型空间分布格局与水土流失的关系，初步结论如下： 1．土地利用类型的特征变化。20世纪80年代至20世纪90年代，无定河流域典型地区(榆林地区)不同土地利用类型面积和土地利用类型空间格局变化比较剧烈，特别是西北部地区，土地利用格局由以农田和林地为主导向以林地、草地为主导的格局转变。 2．典型区(榆林地区)耕地变化主要驱动力是总人口、农民人均年收入和农业人口比重，而总人口、粮食总产量、农村社会总产值和社会总投入与耕地面积呈负相关。 3．地形地貌决定土地利用的空间分布格局，土地利用的空间分布特征与研究尺度有关。风沙区和丘陵沟壑区决定了土地利用类型的空间分布格局的总体特征，不同空间尺度的土地利用类型分布特征有差异。 4．径流变化和泥沙变化有协同性。径流模数和侵蚀模数多年平均值之间没有直接的相关性，而径流模数的变化和侵蚀模数的变化之间有很好的协同性，径流模数变异大的集水区对应的侵蚀模数变异也大。 5．土地利用类型的空间分布格局决定了径流和泥沙的年际变化特征。集水区内土地利用类型空间分布均匀，则该集水区对应的径流模数和侵蚀模数年际变化小；反之，土地利用类型空间分布格局不均匀的集水区，径流和泥沙的年际变化则大。 6．土地利用类型空间分布格局对径流和泥沙的影响随集水区空间尺度的变化而有所不同。在相近条件的同尺度集水区之间比较发现，小尺度集水区土地利用类型的坡位分布格局对径流和泥沙变化有较直接的影响，中尺度集水区土地利用类型的坡度分布格局和大尺度集水区的土地利用类型的距离分布格局对径流和泥沙土地利用空间分布格局对侵蚀产沙过程的影响的变化影响较大。对不同尺度集水区研究发现，不同集水区具有共性，即土地利用类型的空间分布越不均匀，对应的集水区的径流和泥沙年际变化就越大。更多还原

【Abstract】 Soil erosion is the most serious ecological environmental problem in Loess Plateau of China. Unreasonable land use practice is identified as one of the most important reasons for triggering and aggravating soil erosion, and the driving mechanisms for land use change and the relationship between land use spatial pattern and soil erosion are the important aspects for the study about soil erosion. By integrating GIS, social and economic statistical and field investigating data, taking Wudinghe River watershed as the case study area, we discussed the driving mechanisms for the watershed land use change and the relationship between land use spatial distribution pattern and soil erosion at different scales. The results as follows:1. From 1980’s to 1990’s, different land use area and land use spatial pattern had changed relatively dramatically in the representative region of the Wudinghe watershed, Yulin region, especially for the northwest part, where land use pattern changed from farmland and forest as a major characteristic to forest and grassland.2. The major driving factors for farmland change in Yulin region are total population, the average farmer income and the proportion of agricultural labors, and there is a negative correlation between farmland area and the factors including total population, total crop production, total rural social production value and total social input.3. The topography was a decisive factor for the spatial distribution pattern of land use, and the study scale also have some impacts on it. The region in the sand region had a totally different general characteristic for land use spatial distribution pattern from the region in hilly and ravine region, and the pattern also had some variation at different scales.4. There was a strong consistency between runoff variation and sediment variation. There was no direct correlation between runoff module and erosion module, but there was an obvious consistency between runoff module variation and erosion module variation. The catchments with large runoff module variation also had a large erosion module variation.5. The land use spatial distribution pattern had a decisive impact on the inter-year variation characteristics of both runoff and sediment. The catchments, which had even land use spatial distribution, had small inter-year variation of both runoff and sediment, and vice versa.6. The impact of the spatial distribution pattern of land use on runoff and sediments would differ at different catchments scales. Comparing the catchments with the same conditions at the same scales, we found that at the small scale catchments, the factor directly impacting the runoff variation and sediment variation was the relative distribution location at sloping fields, and at the median scale catchments, was the slope distribution of land use components, while at the large scale catchments, the distance distribution of land use components. Comparing the catchments at different scales, we found that there was a common characteristic between catchments at different scales, that the more uneven the spatial distribution of land use was, the larger runoff variation and sediment variation in the corresponding catchments were.更多还原