【摘要】：砒砂巖區(qū)由于砒砂巖自身的易蝕性以及干旱風大、降雨集中等惡劣的自然條件,加之人為因素的干擾,水土流失情況嚴峻,被稱為世界水土流失之最。本文選取砒砂巖區(qū)具有典型代表性的陽崖小流域為研究對象,在ArcGis10.0操作平臺下,以30m分辨率的DEM數(shù)據(jù)為基礎對流域內(nèi)的溝道進行提取；通過對2013年遙感影像進行解譯,獲取了流域2013年的土地利用現(xiàn)狀圖；對流域內(nèi)的植被現(xiàn)狀進行外業(yè)調(diào)查；參照我國《1：100萬土地資源圖》土地潛力評價系統(tǒng)對研究區(qū)內(nèi)土地利用潛力進行評價,并結合實地情況對流域內(nèi)坡面、溝沿、溝道以及河岸進行植被緩沖帶的布局與配置。主要研究結論如下：(1)流域內(nèi)一級溝道數(shù)量多,致使水流集中的速度快；溝道密度大,使得地表徑流大量匯集,水流流量增大。因此,流域內(nèi)溝道數(shù)量多、密度大,一級溝道多,所占比重大是流域內(nèi)土壤侵蝕嚴重的重要原因。(2)對流域內(nèi)土地類型和植被現(xiàn)狀進行了調(diào)查。通過對地形因子坡度、坡向的提取與分析,揭示出流域內(nèi)地形條件差,坡度主要集中在5-15°,坡向以陽坡、半陽坡為主,用作農(nóng)用地的改良難度大,適宜用為林業(yè)用地或牧草地。對土地利用現(xiàn)狀的分析說明流域內(nèi)土地利用結構不合理,未利用地占到流域總面積的45.52%,且主要為侵蝕溝道兩側的裸巖與裸地。此外,流域內(nèi)的植被覆蓋度低,種類單一,主要為灌木和草本植物,喬木數(shù)量少且以人工林為主,應該通過布設植被緩沖帶增加流域內(nèi)植被蓋度和生物多樣性,從而達到防治侵蝕的目標。(3)依據(jù)土地潛力評價系統(tǒng)建立土地利用潛力評價表,根據(jù)最弱指標對評價單元的限制作用最大的原則對流域內(nèi)土地潛力進行評價,結果表明流域內(nèi)主要為Ⅲ級和Ⅳ級地,共占流域總面積的78.62%,且主要分布在溝坡以及坡面上,應充分挖掘這部分土地的利用潛力,通過土地利用結構的調(diào)整把其用作林業(yè)用地或牧草地來達到控制土壤侵蝕,增加生態(tài)經(jīng)濟效益的目的。(4)依據(jù)土地潛力評價結果以及土地利用現(xiàn)狀對流域進行植被緩沖帶的布局與配置。緩沖帶主要分布在坡面、溝沿、溝道(溝底、溝坡和溯源侵蝕強烈的溝頭)以及河岸。結合立地條件選擇適宜的植被和整地方式,共設計了油松+檸條、油松+山杏、沙棘+山杏三種帶狀混交模式和沙棘純林、油松純林、以及檸條純林三種純林模式。
[Abstract]:Due to its own erodibility, severe natural conditions such as high drought wind and concentrated rainfall, and the disturbance of human factors, the soil and water loss situation in the arsenopyst area is severe, so it is called the most serious soil erosion in the world. In this paper, the typical representative Yangya small watershed in the soft rock area is selected as the research object, and the channel in the basin is extracted on the basis of 30m resolution DEM data under the ArcGis10.0 operating platform. Through the interpretation of the remote sensing image in 2013, the land use status map of the watershed in 2013 was obtained, and the vegetation status in the basin was investigated in the field. According to the land potential evaluation system of < 1: 1 million land resources map in China, the potential of land use in the study area is evaluated, and the distribution and disposition of vegetation buffer zone along the slope, gully, channel and riverbank in the river basin are analyzed in combination with the actual situation. The main conclusions are as follows: (1) the number of first-order channels in the basin is large, which results in the rapid concentration of water flow, and the high channel density leads to a large amount of surface runoff and the increase of water flow. Therefore, the number and density of channel in the watershed are large, and the proportion of the first channel is large, which is the important reason for the serious soil erosion in the basin. (2) the land types and vegetation status in the basin are investigated. Through the extraction and analysis of the slope and direction of the topographic factors, it is revealed that the terrain condition in the basin is poor, the slope is mainly concentrated in 5-15 擄, the slope direction is mainly sunny slope and semi-sunny slope, so it is difficult to improve agricultural land. Suitable for forestry land or forage land. The analysis of the present situation of land use shows that the structure of land use in the basin is unreasonable, the unused land accounts for 45.52% of the total area of the basin, and it mainly consists of bare rock and bare land on both sides of the erosion channel. In addition, the vegetation coverage in the watershed is low, the species is single, mainly shrubs and herbaceous plants, and the number of trees is small and the artificial forest is the main one. Therefore, vegetation coverage and biodiversity should be increased by planting vegetation buffering zones. In order to achieve the goal of controlling erosion. (3) according to the land potential evaluation system, the evaluation table of land use potential is established, and the land potential in the watershed is evaluated according to the principle that the weakest index has the most limiting effect on the evaluation unit. The results show that there are mainly 鈪，

本文編號：2364997