辽宁省重点防治区土壤侵蚀估算方法对比及优化

发布时间：2018-05-01 06:15

本文选题：土壤侵蚀 + 三因子模型　；参考：《沈阳农业大学》2017年硕士论文

【摘要】：精准估算一定区域内土壤侵蚀状况是开展区域水土保持工作的基础,也是有效防治水土流失的关键。而当前一定区域范围内的水土流失量不能直接测量,往往需要借助遥感、土壤流失模型、抽样调查等方法间接实现。为了提高区域土壤侵蚀调查工作的精确度,本研究以辽宁省国家重点治理区和重点预防区典型县为研究对象,分别按三因子模型和六因子模型(USLE)提取因子并进行土壤侵蚀量计算,将不同土壤侵蚀模型计算结果与径流小区实测数据对比分析,并采用遗传算法进行优化,找到适合辽宁省重点防治区土壤侵蚀估算的方法。主要结论如下:(1)三因子模型中,从土地利用因子提取结果看,西丰、朝阳土地利用类型主要为林地、旱地,宽甸土地利用类型主要为林地;从植被覆盖度因子提取结果看,西丰、宽甸高覆盖、中高覆盖面积较大,朝阳高覆盖、中高、中覆盖面积较大;从坡度因子的提取结果可见,西丰、朝阳坡度分布主要集中在8-25°之间,宽甸坡度主要在15°以上。USLE中,西丰、朝阳降雨侵蚀力较低,宽甸降雨侵蚀力较高;各县土壤可蚀性因子最大值主要集中在林地、旱地;坡长坡度因子最大值主要集中在林地。(2)运用三因子模型计算得出,西丰县土壤侵蚀面积1051.71km~2延续修改,占西丰总面积的39.89%,以轻度侵蚀为主;朝阳县土壤侵蚀面积1629.98km~2,占朝阳总面积的43.36%,以中度和强烈侵蚀为主;宽甸土壤侵蚀面积1546.78km~2,占宽甸总面积的25.29%,以轻度和中度侵蚀为主。(3)运用USLE计算得出,西丰县土壤侵蚀面积616.40km~2,占西丰总面积的22.96%,以轻度和中度为主;朝阳土壤侵蚀面积1918.72km~2,占朝阳总面积的50.99%,以轻度和中度为主;宽甸土壤侵蚀面积2685.69km~2,占宽甸总面积的43.92%,以轻度和剧烈为主。西丰平均土壤侵蚀模数为1469.93t/km~2.a,朝阳平均土壤侵蚀模数为1496.84t/km~2.a,宽甸平均土壤侵蚀模数为1667.29t/km~2.a,土壤侵蚀强度分级均属于中度侵蚀。(4)从土壤侵蚀强度及模数比较,治理区(朝阳与西丰)采用USLE的计算结果更接近实测数据,均以轻度和中度为主。预防区宽甸采用三因子土壤侵蚀模型的计算结果更接近实测数据,均以轻度和中度为主。可见,USLE更适合治理区,而三因子模型更适合预防区。(5)利用USLE计算的土壤侵蚀估算值(西丰与朝阳)与研究区的径流小区实测值进行比较,建立了辽宁典型治理区模型估算值和实测值之间的差异函数:Y = 1×10~(-4)X,+ 0.666X_2 + 0.0896 X_3 + 0.0001 X_4-2.6864X_5。从优化函数输出的结果可以看出,水土保持措施因子对实测值与模型估算值的影响最大。通过对USLE的优化,将研究区实测值与采用USLE计算的土壤侵蚀估算值之间的差异由优化前的平均23.48%缩减到优化后的8.57%。
[Abstract]:Accurate estimation of soil erosion in a certain area is the basis of regional soil and water conservation, and also the key to effectively control soil and water loss. However, the amount of soil and water loss can not be measured directly in a certain area at present. It often needs remote sensing, soil loss model, sampling investigation and so on. In order to improve the accuracy of regional soil erosion investigation, this study took the typical counties in the state key control area and the key prevention area of Liaoning Province as the research objects. According to the three factor model and six factor model, the factors were extracted and the soil erosion amount was calculated. The calculated results of different soil erosion models were compared with the measured data of runoff plot, and the genetic algorithm was used to optimize the soil erosion quantity. To find a suitable method for estimating soil erosion in key control areas of Liaoning Province. The main conclusions are as follows: (1) in the three-factor model, from the results of land use factor extraction, the main types of land use in Xifeng, Chaoyang and Kuandian are forest land, dry land and Kuandian land use. Xifeng, Kuandian high coverage, medium and high coverage area, Chaoyang high coverage, middle and high coverage area, from the slope factor extraction results, Xifeng, Chaoyang slope distribution mainly in the range of 8-25 掳, The slope of Kuandian is above 15 掳. USLE, Xinfeng, Sunrise rainfall erosivity is lower, Kuandian rainfall erosivity is higher, the maximum value of soil erodibility factor is mainly concentrated in woodland, dryland; The maximum slope factor of slope length is mainly concentrated in forestland. 2) by using the three-factor model, the soil erosion area of Xinfeng County is continuously modified by 1051.71km~2, which accounts for 39.89% of the total area of Xifeng, with slight erosion as the main factor. The soil erosion area of Chaoyang County was 1629.98km2, accounting for 43.36% of the total area of Chaoyang, mainly of moderate and intense erosion, and the soil erosion area of Kuandian was 1546.78km2, accounting for 25.29% of the total area of Kuandian. The soil erosion area of Xinfeng County is 616.40 km2, accounting for 22.96% of Xinfeng's total area, mainly light and moderate, and 1918.72 km / m ~ (-2) of Chaoyang soil erosion area, accounting for 50.99% of the total area of Chaoyang, which is mainly mild and moderate. The soil erosion area of Kuandian was 2685.69 km2, accounting for 43.92% of the total area of Kuandian, mainly light and violent. The average soil erosion modulus of Xifeng was 1469.93 t / kg 路m ~ (2) a, the average soil erosion modulus of Chaoyang was 1496.84 t / kg / m ~ (2) a, the average soil erosion modulus of Kuandian was 1667.29 t / kg ~ (2) a, and the soil erosion intensity was classified as moderate erosion. (4) the soil erosion intensity and modulus were compared in terms of soil erosion intensity and modulus. The calculated results of USLE in the governance area (Chaoyang and Xifeng) were more close to the measured data and were mainly mild and moderate. The calculation results of Kuandian with three factors soil erosion model were closer to the measured data and were mainly mild and moderate. It can be seen that usle is more suitable for control area, while three-factor model is more suitable for prevention area. 5) soil erosion estimated value (Xifeng and Chaoyang) calculated by USLE is compared with the measured value of runoff plot in the study area. The difference function between the estimated value and the measured value of the typical governance area model in Liaoning Province is established. The function: y = 1 脳 10 ~ (-4) -4X, 0.666X_2 0.0896 X _ 3 0.0001 X _ 4 _ 4 _ (68) 4X _ 5. It can be seen from the output of the optimization function that the factors of soil and water conservation measures have the greatest influence on the measured value and the estimated value of the model. Through the optimization of USLE, the difference between the measured value and the estimated value of soil erosion calculated by USLE was reduced from 23.48% before optimization to 8.57% after optimization.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S157.1

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