陕西省安塞县土壤侵蚀状况研究

发布时间：2018-07-17 00:43

【摘要】：陕西省安塞县地处黄土高原西北内陆,位于鄂尔多斯盆地边缘地带。安塞县以其独特的土壤特质、地形坡度以及夏季多雨的气候条件,以及剧烈的农业和人类活动,导致该地区水土流失严重。水土流失导致土地退化,土壤肥力下降,耕地减少,阻碍社会的可持续发展。黄土高原成为水土流失的重灾区,水土流失如此严重,动态观测土壤侵蚀状况刻不容缓。针对陕西省安塞县水土流失状况,本论文采用Arc GIS的宏观研究,并且运用WEEP软件分析安塞县最主要的侵蚀方式—细沟侵蚀的侵蚀影响因子对水土流失的影响状况。对安塞县水土流失状况的宏观观测需要结合“3S”技术,运用安塞县的高程数据,利用Arc GIS软件对分辨率30米的DEM数据进行对无洼地提取,水流方向提取,累积流量提取,矢量化栅格河网,生成河网连接,生成集水流域,确定流域盆地,主要流域重分类,各个流域沟壑密度提取这些步骤得到各个流域的沟壑密度,对各流域沟壑密度进行统计分析计算得出各流域沟壑密度,将各流域沟壑密度与《土壤侵蚀分级分类标准》(SL190-2007)中的沟蚀分类标准,进行比较,《土壤侵蚀分级分类标准》(SL190-2007)中将侵蚀强度划分为轻度、中度、强烈、极强烈和剧烈共5各级别,可得出安塞县各个流域的土壤侵蚀非常严重,属于剧烈级别。因为黄土高原土壤侵蚀的主要侵蚀类型是细沟侵蚀,细沟侵蚀产生的泥沙含量大约是整个流域的70%。而WEEP软件主要是用来模拟细沟侵蚀的水蚀模型,所以运用WEEP模型,利用安塞地区2015年的气候状况,安塞地区黄绵土的土壤特征,运用不同坡度、不同坡长、不同耕作物的耕作区进行土壤侵蚀模拟,得出各个作物耕作区的土壤侵蚀量不尽相同。在相同条件下,草地耕作区的土壤侵蚀量最小,然后冬小麦的耕作区的土壤侵蚀量大于草地耕作区的土壤侵蚀量,大豆和玉米的作物耕作区的土壤侵蚀量大体相同且大于冬小麦的作物耕作区的土壤侵蚀量,最后,休耕地耕作区没有任何作物的耕作区的土壤侵蚀量最大。由此可知,有植被保护的土壤的地区,其土壤侵蚀量远远小于休耕地没有作物保护的耕作区,由此可知,作物保护对水土保持的重要性。
[Abstract]:Ansai County, Shaanxi Province is located in the northwest of the Loess Plateau and the margin of the Ordos Basin. Ansai County has serious soil erosion due to its unique soil characteristics, topographic slope, rainy climate conditions in summer, and intense agricultural and human activities. Soil erosion leads to land degradation, soil fertility decline and cultivated land decrease, which hinders the sustainable development of society. The Loess Plateau is a serious disaster area of soil and water loss, so it is urgent to observe soil erosion dynamically. Aiming at the situation of soil and water loss in Ansai County, Shaanxi Province, this paper adopts the macro research of Arc GIS, and analyzes the influence of erosion factors of rill erosion on soil and water loss by using WEEP software. The macroscopical observation of soil and water loss in Ansai county should be combined with "3s" technique, using the elevation data of Ansai County, using Arc GIS software to extract the Dem data with resolution of 30 meters, extracting the direction of water flow, and extracting the cumulative flow rate. Vectorization of grid river networks, generation of river network connections, generation of catchment basins, determination of basin basins, re-classification of major basins, extraction of gully densities from each watershed, The gully density of each watershed was calculated by statistical analysis. The gully density of each watershed was compared with the gully erosion classification standard in soil erosion Classification Standard (SL190-2007). In comparison, the soil erosion classification standard (SL190-2007) classifies the erosion intensity into five grades: mild, moderate, intense, extremely strong and intense. It can be concluded that the soil erosion in Ansai county is very serious and belongs to severe grade. Because the main erosion type of soil erosion on the Loess Plateau is rill erosion, the sediment content produced by rill erosion is about 70% of that of the whole basin. The WEEP software is mainly used to simulate the water erosion model of rill erosion, so using the WEEP model, using the 2015 climate situation in Ansai region, the soil characteristics of loess in Ansai area, using different slopes and different slope lengths, Soil erosion was simulated in different tillage areas, and the amount of soil erosion was different. Under the same conditions, the soil erosion amount in the grassland tillage area was the least, and the soil erosion amount in the winter wheat tillage area was higher than that in the grassland tillage area. The amount of soil erosion in soybean and corn cultivation areas is about the same and larger than that in winter wheat cultivation areas. Finally, the soil erosion amount is the largest in cultivated areas without any crops. Therefore, the amount of soil erosion in the soil with vegetation protection is much smaller than that in cultivated land without crop protection, which shows the importance of crop protection to soil and water conservation.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S157.1

【相似文献】