秦巴山区植被土壤保持生态价值研究

Study on the Ecological Value of Soil Conservation of Vegetation in the Qinling-Daba Mountains

在地理信息系统支持下,以通用土壤侵蚀方程(ULSE)及植被指数(C)为依据,按裸地侵蚀模数减植被覆盖侵蚀模数,测算了秦巴山区植被保土、保肥的物质量。以保土、保肥物质量为基础,按等效应原则测算了植被保土、保肥的价值量。结果显示:秦巴山区植被因防止土壤侵蚀而减少废弃地的总价值为4.23×106元;全区植被保持营养物质的总价值为2.24×109元,其中,N为4.37×108元,P为1.86×108元,K为1.62×109元;陆地植被减轻泥沙淤积灾害方面的总价值为1.45×107元。秦巴山区植被防止土壤侵蚀的总生态经济价值为三者之和,共计2.26×109元,这是植被为本区提供的天然生态服务和自然资本。

The study area, Oinling-Daba Mountains （31°42＇-34°45＇N, 105°46＇- 111°15＇E） covers three morphologic units, i. e., the Qinling Mountains, Hanjiang Valley-basin and Daba Mountains, its east-west length and south-north width are 400-500 km and 180-380 km respectively, and its total area is 8.71 × 10^5 km^2. In the study area the annual temperature, monthly temperatures in July and January and annual accumulated temperature ≥10 ℃ vary in ranges of 12-15 ℃,23.4-26.7℃,0-3.6 ℃ and 3 812-5 537.4 ℃respectively; the annual precipitation varies in a range of 709.5- 1 400 mm, the rainy season is from April to October, and the precipitation in rainy season occupies 75% of the annual one; and the biological resources are more than 6 000 species. In general, the Qinling-Daba Mountains is characterized the diversified floras, complicated ecological conditions, rich plant species, significant vertical zones, and complete and typical spectrum dif- ferentiation of vertical zones. Soil and water conservation and soil fertilization are the most important ecological services of continental ecosystems, which play a basic role in promoting regional agricultural sustainable development. In this paper, the values of soil conservation and fertilization of vegetation in the Qinling-Daba Mountains are estimated by subtracting the erosion modulus of soil covered with vegetation from the erosion modulus of soil without vegetation coverage based on the equation of soil erosion and the vegetation indexes under GIS support. The results show that the total value of vegetation in controlling soil erosion in the Qinling-Daba Mountains is 4.23 × 10^6 yuan RBM; the total value of vegetation in soil fertilization is 2.24 × 10^9 yuan, in which the values of N, P and K are 4.37× 10^8 yuan, 1.86 ×10^8 yuan and 1.62× 10^9 yuan respectively; and the total value of vegetation in reducing filling-up is 1.45 × 10^7 yuan. The total ecological value of vegetation in controlling soil erosion in the Qinling-Daba Mountains is 2.26 × 10^9 yuan.