大宁河流域土地利用变化及其土壤保持效应

发布时间：2018-05-20 22:19

本文选题：土地利用 + 景观格局指数　；参考：《重庆师范大学》2015年硕士论文

【摘要】：土地是人类赖以生存的最基本的自然资源,随着人类与环境资源矛盾的日益突出,LUCC研究成为地理学研究的前沿与热点,对土地利用变化研究也进一步加强。土壤侵蚀会造成土地资源的破坏及土地功能的退化,并可能引发一系列的环境问题,威胁社会环境。由于土壤侵蚀造成的危害较大,因此水土保持研究一直将土壤侵蚀作为重点进行研究,人们也越来越多的关注土壤侵蚀的监测与预报。近几十年来,GIS技术迅猛发展,对土壤侵蚀的机理也进行了不断深入研究,利用GIS技术构建了许多土壤侵蚀模型,对于研究土壤侵蚀具有十分重要的意义。本文以大宁河流域为研究对象,以GIS为平台,建立大宁河的土地利用数据库,系统分析了研究区1988-2010年的土地利用变化,探讨了土地利用变化对景观格局的影响。同时,通过USLE分析大宁河土壤侵蚀,结合In VEST模型得到大宁河流域土壤潜在侵蚀情况,通过分析,评价了土壤保持功能,探讨了土壤保持与坡度、高程、岩性及土地利用方式的关系,获得的结论如下:(1)对大宁河流域1988,1999,2010年三期土地利用数据与其高程,坡度及岩性关系进行分析,结果显示大宁河流域1988—2010年期间,土地利用变化较大,主要以旱地的增加,灌木林的减少,建设用地的增加为主要特征,集中体现在低高程(800 m)、低坡度(25°)下的泥岩砂岩地区。景观多样性指数随着高程的增加而降低,破碎度指数和均匀度指数总体上随着高程的增加而下降,景观多样性指数在坡度上的变化是随着坡度的增加而下降,景观多样性指数在所有岩性地区均持续上升。统计不同土地利用类型的景观多样性指数,结果表明土地利用类型的变化对景观多样性具有较大的影响。(2)在USLE模型的基础上,对大宁河流域的土壤实际侵蚀进行评价,结果表明,大宁河流域平均土壤侵蚀模数在1988,1999和2010年分别为1030.35 t/(km2.a),954.95 t/(km2.a)和878.49 t/(km2.a)。根据水利部颁发的土壤侵蚀强度标准,大宁河流域实际侵蚀以轻度侵蚀为主。叠加分析了土壤侵蚀与坡度、高程及岩性的相关性,发现大宁河流域土壤侵蚀主要发生在8°以上区域,应该划定为水土保持工作的重点开展区域。在高程上,则主要是发生在1200m以下高程地带,土壤侵蚀模数最大的在300-500m高程带,土壤侵蚀在石灰岩地区表现较明显。(3)结合In VEST模型,计算得出大宁河土壤潜在土壤侵蚀的平均侵蚀模数为3740.84 t·km-2·a-1,根据土壤侵蚀强度分级标准,属于中度侵蚀,在1988-2010年的土壤保持功能在逐渐提高。分析了不同的坡度,高程及不同岩性下的土壤保持功能的变化情况,结果表明土壤保持量在15-20°地带最低,在35°以上土壤保持功能较好,在高程上,土壤保持量最大的是在1500-2000m的高程带,其保持面积百分比最大的也是在此高程带,从岩性的角度看,石灰岩保持面积百分比最大,主要是大宁河流域以石灰岩为主,石灰岩地区的保持量较低,仅次于侵蚀模数最高的泥岩。(4)叠加分析统计不同土地利用类型下的土壤保持功能情况,就土壤平均保持量从大到小进行排序,水体灌木林有林地建设用地草地旱地水田。灌木林,有林地及旱地构成了大宁河流域生态系统保持功能的主要部分,结合大宁河流域实际情况,在兼顾经济,环境及社会等综合效益的前提下,提出了水土保持措施的建议。
[Abstract]:Land is the most basic natural resource for human survival. With the increasingly prominent contradiction between human and environmental resources, LUCC research has become the frontier and hot spot of geography research. The study of land use change is further strengthened. Soil erosion will cause the destruction of land resources and the degradation of soil function, and may lead to a series of rings. The environment is a threat to the social environment. Because of the great damage caused by soil erosion, soil erosion has been the focus of research on soil erosion, and more and more attention is paid to the monitoring and prediction of soil erosion. In recent decades, the GIS technology has developed rapidly, and the mechanism of soil erosion has been studied and used in depth. GIS technology has constructed a lot of soil erosion models, which is of great significance for the study of soil erosion. In this paper, taking the great Ninghe River Basin as the research object and taking GIS as the platform, the land use database of great Ninghe was established. The land use change of the study area for 1988-2010 years was analyzed systematically, and the landscape pattern of the land use change was discussed. At the same time, the soil erosion in Daning river was analyzed by USLE and the potential erosion of soil in Daning River Basin was obtained by combining the In VEST model. The soil retention function was evaluated and the relationship between soil retention and slope, elevation, lithology and land use were discussed. The conclusions were as follows: (1) three period soil of the great Ninghe basin for 198819992010 years. The analysis of the relation between the land use data and its elevation, slope and lithology shows that during the period of 1988 to 2010, the change of land use was large, mainly in the increase of dry land, the decrease of shrub forest and the increase of construction land, which was mainly reflected in the mudstone sandstone area under low elevation (800 m) and low gradient (25 degree). With the increase of elevation, the fragmentation index and evenness index decreased with the increase of elevation. The landscape diversity index decreased with the increase of slope, and the landscape diversity index continued to rise in all lithologic areas. The results showed that the change of land use type had a great influence on landscape diversity. (2) on the basis of the USLE model, the soil erosion of the great Ninghe basin was evaluated. The results showed that the average soil erosion modulus of the big Ninghe basin was 1030.35 t/ (km2.a), 954.95 t/ (km2.a) and 878.49 t/ (km) in the year of 2010. 2.a). According to the standard of soil erosion intensity issued by the Ministry of water resources, the actual erosion of the great Ninghe basin is mainly mild erosion. The correlation between soil erosion and slope, elevation and lithology is superimposed. It is found that soil erosion in the big Ninghe basin mainly occurs over 8 degrees, which should be designated as the key area of soil and water conservation work. The soil erosion modulus is the largest in the 300-500m elevation zone, the soil erosion is the most obvious in the limestone area. (3) combined with In VEST model, the average erosion modulus of the potential soil erosion in Ninghe soil is 3740.84 t. KM-2. A-1. According to the classification standard of soil erosion intensity, it belongs to the middle soil erosion. The soil retention function in 1988-2010 years was gradually improved. The changes of soil retention function under different slopes, Gao Cheng and different lithology were analyzed. The results showed that the soil retention was lowest in 15-20 degree zone, and the soil maintained better function over 35 degrees. In Gao Cheng, the largest soil retention was in the 1500-2000m Gao Cheng. The largest percentage of the area is in this area. From the lithologic point of view, the percentage of the limestone area is the largest, mainly in the large Ninghe basin, mainly in limestone area, lower in the limestone area, second only to the mudstone with the highest erosion modulus. (4) superposition analysis and analysis of soil retention work under different land use types According to the situation, the average soil conservation of the soil is sorted from large to small. The water shrubs, shrubs, woodlands, grassland and dryland, shrubs, woodlands and dryland constitute the main part of the conservation function of the great Ninghe River Basin, and in combination with the actual conditions of the great Ninghe basin, under the premise of taking into account the comprehensive benefits of economy, environment and society, Suggestions for soil and water conservation measures were put forward.
【学位授予单位】：重庆师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S157;F301.24

【参考文献】