贵州喀斯特山区坡面产流产沙机理及影响因子研究

发布时间：2018-02-03 00:17

本文关键词： 坡面土壤侵蚀产流产沙影响因子贵州　出处：《南京大学》2015年硕士论文　论文类型：学位论文

【摘要】：贵州喀斯特山区生态系统脆弱,地貌类型多样,坡耕地比重大且土层浅薄,人地矛盾突出。自然因素与人为因素共同作用导致区域内出现严重的水土流失及石漠化现象,土地退化威胁当地的粮食安全与生态安全。坡面是土壤侵蚀发生的基本地表单元,是喀斯特山区侵蚀泥沙的主要源地,定量评价喀斯特山区坡面土壤侵蚀是防治该地区水土流失、保证粮食安全的关键。本文针对贵州喀斯特山区坡面土壤侵蚀机理及水土流失预报研究相对薄弱的现状,利用黔南龙里、遵义浒洋水及毕节石桥3个小流域2012-2014年的野外径流小区径流泥沙观测数据和降雨资料,基于水文学、水力学、土壤侵蚀科学、水土保持学和环境科学等学科理论,运用数理统计、回归分析和地理综合分析等方法,探讨贵州喀斯特山区坡面产流产沙规律,并计算了贵州喀斯特山区土壤侵蚀影响因子值,构建了降雨因子值和地形因子值估算公式。主要研究结论如下:(1)大雨和暴雨条件下,坡面产流量分别占年产流量的16.6%和59.8%,产沙量分别占年产沙量的10.1%和65.6%;高雨强型降雨的雨量占年降雨量的28.8%,但坡面产流量和产沙量分别占年产流量和年产沙量的44.1%和61%。(2)坡度从5°增加到15°时,坡面产流与产沙量随坡度增加显著增加;坡度从15°增加到20°时,坡面产流与产沙量大幅度下降,坡度从20°增加到25°时,坡面产流与产沙量又小幅度增加。(3)坡面产流随坡长的增加呈现先减小后增大再减小的波动变化趋势,多年平均产沙量呈现随坡长的增加逐渐增大的趋势。(4)不同植被减流减沙作用表现为:经果林的减流作用草地,耕地与水保林的减流作用差异不明显;经果林的减沙作用草地,水保林的减沙作用耕地。(5)降雨侵蚀力因子R的估算公式为:R=0.13P1.943,地形因子LS值估算公式为:LS =(0.348E1.04λ)(7.301+sin1.426θ),主要土壤可蚀性因子 K 值的范围:0.0072-0.0151,植被覆盖与管理因子C值范围:0.00047-0.00851和水土保持措施因子P值范围:0.00047-0.0872。
[Abstract]:Guizhou karst mountain ecosystem is fragile, the geomorphology type is diverse, the proportion of sloping farmland is large and the soil layer is shallow. The contradiction between man and land is prominent. The joint action of natural factors and human factors leads to serious soil erosion and rocky desertification in the region. Land degradation threatens local food security and ecological security. Slope is the basic surface unit of soil erosion and the main source of erosion and sediment in karst mountain area. Quantitative evaluation of soil erosion on slope in karst mountain area is to control soil erosion in this area. In view of the relatively weak research on soil erosion mechanism and soil erosion prediction in karst mountainous area of Guizhou Province, this paper uses Longli, southern Guizhou Province, to ensure food security. Runoff and sediment data and rainfall data from 2012 to 2014 in three small watersheds of Huyang River and Bijie Shiqiao in Zunyi are based on hydrology, hydraulics and soil erosion science. By means of mathematical statistics, regression analysis and geographical comprehensive analysis, the laws of runoff and sediment yield on slope in karst mountainous area of Guizhou Province were discussed. The influence factors of soil erosion in karst mountainous areas of Guizhou were calculated, and the estimation formulas of rainfall factors and topographic factors were established. The main conclusions are as follows: 1) under heavy rain and rainstorm. The runoff of sloping land accounts for 16.6% and 59.8% of the annual yield, and the sediment yield accounts for 10.1% and 65.6% of the annual sediment yield, respectively. The rainfall of high rainfall intensity type accounts for 28.8% of the annual rainfall, but the slope increases from 5 掳to 15 掳when the runoff and sediment yield on the slope account for 44.1% and 61% of the annual runoff and sediment yield, respectively. The runoff and sediment yield on the slope increased significantly with the increase of slope. When the slope is increased from 15 掳to 20 掳, the runoff and sediment yield on the slope decreases significantly, and the slope increases from 20 掳to 25 掳. The runoff and sediment yield on the slope increased by a small margin with the increase of slope length. The annual average sediment yield showed a trend of increasing gradually with the increase of slope length. (4) the effect of reducing flow and sediment of different vegetation was as follows: through the reducing effect of fruiting forest on grassland, there was no significant difference between cultivated land and water conservation forest in reducing flow and sediment; The estimation formula of rainfall erosivity factor R is: 1 / R 0.13P 1.943. The estimation formula of the LS value of the topographic factor is 0.348E1.04 位 and 7.301 sin1.426 胃. The range of K value of main soil erodibility factor is: 0.0072-0.0151. The range of C value of vegetation cover and management factor is: 0.00047-0.00851 and the range of soil and water conservation measure factor P is: 0.00047-0.0872.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S157

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