基于USLE模型的祁连山南坡土壤保持量评估

发布时间：2018-04-25 01:20

本文选题：土壤侵蚀 + 土壤保持量　；参考：《青海师范大学》2017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,土地的保护亦成为关注的重点。土壤侵蚀会造成一系列的环境问题,威胁社会环境和经济的协调发展,因此土壤保持工作一直备受关注。近几十年来,“3S”技术发展迅速,利用“3S”技术,结合土壤侵蚀模型,对于研究土壤侵蚀机理及土壤保持量具有十分重要的意义。祁连山南坡在祁连山区发挥着重要的生态保护作用。为掌握祁连山南坡近10年的土壤保持量的时空变化规律,分布情况及其影响因素。本文采用“3S”技术,结合USLE模型,利用祁连山南坡DEM数据、Landsat系列数据、青海省土壤类型图和祁连山南坡周边站点降雨数据,分别计算了研究区2004年、2009年、2014年三期的现实土壤侵蚀量和土壤保持量,分析了土壤侵蚀与坡度、海拔、植被覆盖度关系,探讨了土壤保持量与坡度、海拔、植被覆盖度及土地利用方式的关系。获得如下结论:(1)研究区土壤侵蚀易发生区域为海拔4000～5000m,坡度在25°左右区域、植被覆盖度为中覆盖度区域;研究区内的现实土壤侵蚀量与坡度、海拔、植被覆盖度三个环境因子相关性明显,现实土壤侵蚀级别及平均侵蚀模数随着坡度与海拔的升高而增加,随着植被覆盖度的提高而降低;现实土壤侵蚀量随着年际变化整体呈减小趋势。(2)从植被覆盖度(中覆盖度、中高覆盖度、高覆盖度)、海拔、坡度不同年际间平均土壤保持量模数和土壤保持量来看,是逐步稳升的;随着坡度及植被覆盖度的增加,平均土壤保持量模数呈增加趋势,随海拔的增加呈下降趋势;研究区平均土壤保持量模数较大区域为3000～4000m的海拔范围内、缓坡以上、高覆盖度区域,应加强此区域的生态治理工作,以达到更加良好的生态环境。(3)林地及草地构成了祁连山南坡生态系统土壤保持量的主体;应重点防护3000～4000m的海拔范围内,缓坡以上的林地及草地生态系统,来稳定研究区的土壤保持量。近10年的土壤侵蚀量整体减小,2004年、2009年、2014年三期的现实土壤侵蚀量分别为2.11×107t/a、2.48×107t/a、1.54×107t/a;土壤保持量逐年增加,2004年、2009年、2014年三期的土壤保持量分别为1.20×107t/a、1.86×107t/a、3.71×107t/a。表明祁连山南坡生态环境在不断的改善。
[Abstract]:Land is the most basic natural resource for human survival. With the increasingly prominent contradiction between human beings and environmental resources, the protection of land has become the focus of attention. Soil erosion will cause a series of environmental problems and threaten the harmonious development of social environment and economy. In recent decades, "3s" technology has developed rapidly. It is of great significance to study soil erosion mechanism and soil conservation by using "3s" technology and soil erosion model. The southern slope of the Qilian Mountains plays an important role in ecological protection in the Qilian Mountains. In order to understand the temporal and spatial variation of soil conservation in the last 10 years on the southern slope of Qilian Mountains, the distribution of soil conservation and its influencing factors were studied. In this paper, using "3s" technique, combining with USLE model, using DEM data of the south slope of Qilian Mountain, the soil type map of Qinghai Province and rainfall data of the station around the south slope of Qilian Mountain are used. The actual soil erosion and soil conservation were calculated in 2004, 2009 and 2014, respectively. The relationships between soil erosion and slope, elevation and vegetation coverage were analyzed, and the relationship between soil conservation and slope and elevation was discussed. The relationship between vegetation coverage and land use patterns. The results are as follows: (1) the area where soil erosion is easy to occur in the study area is 4 000 ~ 5 000 m above sea level, the slope is about 25 掳, and the vegetation coverage is the area of medium coverage. The correlation of three environmental factors of vegetation coverage was obvious. The real soil erosion level and average erosion modulus increased with the increase of slope and altitude, and decreased with the increase of vegetation coverage. The actual soil erosion decreased with the interannual variation. (2) the vegetation cover (middle, high, high cover, elevation, slope, average soil conservation modulus and soil conservation between different years) was observed. With the increase of slope and vegetation coverage, the modulus of average soil conservation increased and decreased with the increase of altitude. Over the gentle slope and high coverage area, the ecological management work in this area should be strengthened in order to achieve a better ecological environment. 3) the forestland and grassland constitute the main body of soil conservation of the ecosystem on the south slope of Qilian Mountains. In order to stabilize the soil conservation in the study area, the forest land and grassland ecosystem above the gentle slope should be protected at the altitude of 3000 ~ 4000m. The amount of soil erosion decreased in the last 10 years, and the actual soil erosion in 2004, 2009 and 2014 was 2.11 脳 10 ~ 7t / a, 2.48 脳 10 ~ (7) t 路a ~ (-1) 脳 10 ~ (7) t / a, and the soil conservation increased year by year. In 2004, 2009, and 2014, the soil erosion was 1.20 脳 10 ~ (7) t / r ~ (-1) 1.86 脳 10 ~ (7) t / r ~ (-1) 3.71 脳 10 ~ (7) t / a. It shows that the ecological environment of the south slope of Qilian Mountain is improving continuously.
【学位授予单位】：青海师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S157

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