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伊犁河谷水土流失特征及发生规律研究
李大龙
学位类型硕士
导师杨井 ; 陈亚宁
2016
学位授予单位中国科学院大学
学位授予地点北京
学位专业自然地理学
关键词伊犁河谷 土壤侵蚀评价 Usle 土壤侵蚀因子 回归分析
摘要水土流失危害巨大,作为全球最大的环境问题,已经受到了广泛的关注。我国西北地区干旱少雨,荒漠广布。绿洲作为该地区生存发展的根基,其水土资源的保护迫在眉睫。伊犁河谷因其独特的地形地貌特征,使得该流域温度适宜,降雨充沛,成为新疆乃至整个西北地区重要的农业、牧业生产基地。近年来伊犁河谷社会经济发展迅速,人口数量不断增长,耕地需求量急剧上升,致使草地、林地遭到过度开垦,水资源利用不合理,生态环境问题十分突出:森林资源衰减、草地退化严重、植被减少、水土流失加剧,严重制约着地区经济和社会的发展。探索伊犁河谷水土流失发生规律,削弱当地土壤侵蚀势在必行。本文以通用土壤流失方程USLE为计算模型,借助ArcGIS空间分析功能,选取降水、植被、土壤、地形因子,并对方程中的可变因子降水、植被进行季节区分,对伊犁河谷土壤侵蚀敏感性进行综合评价。 对伊犁河谷土壤侵蚀敏感性研究发现受可变因子的影响,研究区土壤侵蚀敏感性在季节尺度上差异显著,主要表现为:伊犁河谷土壤侵蚀春季最敏感,秋季次之,夏季土壤侵蚀以轻度敏感为主;土壤侵蚀高敏感地区所占面积随季节推进逐渐缩减,春季、夏季、秋季,所占面积比例分别为32.3%,6.1%,6%;空间上土壤侵蚀轻度敏感地区主要分布在河谷盆地及平原地区,中度、高度敏感地区集中分布在山前坡地,以及海拔1500 m以上,坡度20°左右的山区;在可变因子中,植被因子对土壤侵蚀敏感性的影响程度大于降雨因子。 选取人为扰动较为严重的河谷西部山前坡地为研究区域,对该地区不同土地利用类型及不同坡度范围内的土壤侵蚀强度进行分析发现:研究区土壤侵蚀在不同坡度范围内呈现出不同的分布状态,坡度介于0-15°区域内,坡度越大土壤侵蚀越严重,波动幅度显著。坡度值大于15°的区域,土壤侵蚀比较严重,但随着坡度的增加其土壤侵蚀强度分布格局变化并不明显。不同的土地利用方式之间,土壤侵蚀强度存在差异。其中耕地、建设用地主要以微度侵蚀为主,林地及草地集中在轻度侵蚀范围内,也存在部分中度侵蚀区域,未利用地侵蚀强度较大。通过对1995、2005、2013年各土地利用类型土壤侵蚀率的计算分析,可以发现该地区土壤侵蚀率较高,其中林地、草地、未利用地的土壤侵蚀率均高于60%,耕地及建设用地的土壤侵蚀率也在20%以上。 在河谷西部山前坡地获取研究区的坡度,1995年、2005年和2013年的降雨、植被、土地利用和土壤侵蚀强度数据,对土壤侵蚀典型区域进行子流域划分,以子流域为单元,采用相关分析与回归分析方法,对土壤侵蚀强度空间格局与其主要影响因素的动态变化关系进行分析。结果表明,1995年、2005年、2013年3个时期河谷山前坡地土壤侵蚀强度先上升后下降;坡度因子是影响各个时期土壤侵蚀强度格局最主要的影响因素之一,贡献率由1995年的46.6%下降到2005年的45.0%,2013年为47.1%;植被覆盖度对土壤侵蚀格局的影响仅次于坡度因子,其影响程度波动中下降,贡献率由1995年的31.3%下降到2013年的30.2%;随着该地区水土资源的开发,土地利用因子的影响力持续上升,其对土壤侵蚀格局的贡献率由1995年的8.2%,上升到2013年的13.9%;降雨侵蚀力因子的贡献率波动中下降,由1995年的13.9%下降到2013年的8.8%,但由于降水量及极端降水事件的增加,降雨侵蚀力因子的影响力会呈波动上升趋势;在无法改变自然因子对地区土壤侵蚀影响的情况下,建议优先考虑调整土地利用结构,削弱地区土壤侵蚀。
其他摘要As the world's biggest environmental problem, water and soil loss has been a general big concern. As the foundation of the survival and development of northwest region of China, the protection of water and soil resources is imminent. Due to its unique characteristics, especially arable temperature and rainfall, the valley of Yili River Valley has become an important agricultural and animal husbandry production base in Xinjiang and even in the whole northwest region. In recent years, with the development of social economy, it faces a lot of problems, such as increasing population, the attenuation of forest resources, grassland degradation, vegetation reduction, serious soil erosion, etc., which seriously restrict the economic and social development of the region. It is imperative to explore the characteristics of soil and water loss in Yili Valley and reduce soil erosion. Based on the universal soil loss equation (USLE) and spatial analysis functions in ArcGIS, this study evaluated the temporal and spatial characteristics of soil erosion sensitivity according to selected factors (i.e. precipitation, vegetation cover, soil, slope, slope length) in the valley, with the factors of precipitation and vegetation being discriminated in different seasons. The results show that in the study area, the soil erosion was most sensitive in spring, followed by autumn, while it was only slightly sensitive in summer and in the whole year. The total area of soil erosion with high sensitivity had a significant seasonal difference. It was largest in spring (32.3% of the total area), while only 6.1% in summer, and slightly less in autumn than in summer. Spatially, soil erosion area of low sensitivity was mainly distributed in plain area of the valley, while the area of medium and high sensitivity was mainly in the steep field, and in mountain area with elevation above 1500 m and slope about 20°. Furthermore, the influence of vegetation factor on soil erosion was greater than that of precipitation factor. Take west valley hillside where human disturbance seriously as the study area, this work studied the soil erosion intensity in different land use types and different slope ranges and results show: the soil erosion in the study area showed different distributions for different slope range. In the range of 0-15 degree, soil erosion is increasing with the increase of slope, and the change is very obvious. When the slope range is above 15 degree, the soil erosion is more serious, but the distribution pattern of soil erosion intensity is not as obvious as the increase of slope gradient. Between different land use patterns, soil erosion intensities are different. The cultivated land and construction land are mainly minor erosion, the soil erosion intensity of forest land and grassland was mainly concentrated in the light range and the intensity of soil erosion was relatively large. Through the analysis soil erosion rates for landuse types in 1995 and 2005, 2013, it can be found that the region soil erosion rates are higher, including woodland, grassland, unused land soil erosion rate is higher than 60%, cultivated land and construction with soil erosion rate is higher than 20%. Then, the study area was divided into subbasins to study the dynamic relationship between soil erosion intensity distribution and the above factors at the subbasin scale using statistical analysis. The investigation showed that the soil erosion intensity in valley hillside region presented an increase from 1995 to 2005 and then a decrease to 2013. Slope was the most critical factor affecting the distribution of erosion intensity, and its impact is stable. Its contribution rate fell from 46.6% in 1995 to 45% in 2005, and rose to 47.1% in 2013. The vegetation cover factor after the slope factor effect on soil erosion intensity, its impact on the volatility of the fell, its contribution rate fell from 31.3% in 1995 to 30.2% in 2013.With the development of soil and water resources in this area, the influence of land use factors will continue to rise, and its contribution rate rose from 8.2% in 1995 to 13.9% in 2013. The contribution rate of rainfall erosion factor fell from 13.9% in 1995 to 8.8% in 2013. As the precipitation increases, the influence of rainfall erosion factor will continue to rise. Effects of natural factors on soil erosion are hard to change, so it is suggested that adjustment and optimization of land use structure should still be made in this area for the control of soil erosion.
学科领域自然地理学
语种中文
文献类型学位论文
条目标识符http://ir.xjlas.org/handle/365004/14764
专题研究系统_荒漠环境研究室
作者单位中科院新疆生态与地理研究所
推荐引用方式
GB/T 7714
李大龙. 伊犁河谷水土流失特征及发生规律研究[D]. 北京. 中国科学院大学,2016.
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