渭北高原植被保土保肥生态效益的计量研究

CALCULATION ON VEGETATION'S SOIL AND FERTILIZATION CONSERVATION BENEFITS IN WEIBEI PLATEAU

植被保土、保肥、保水功能是陆地生态系统最重要的生态服务 ,对于促进区域农业可持续发展具有基础性作用。该文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 ,测算了渭北高原植被保土、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 ,渭北黄土高原植被每年保持表土 3 6 45× 1 0 8t,按等效应人工保土措施计算 ,植被保土价值量合 2 5 5× 1 0 8元 ;植被在保持表土的同时也保持了土壤有机质及N、P、K等土壤养分 ,按各类土壤养分含量及面积加权计算 ,每年可保持 45 7 2× 1 0 4 t有机质 ,植被保持有机质量相当于 1 3 0 6 2 9m3薪材、合 6 5 3× 1 0 8元 ;每年可保持全氮 3 5 45× 1 0 4 t、全磷 5 4 49× 1 0 4 t、全钾73 6 62× 1 0 4 t,植被保持的N、P、K按化肥市场价格计算 ,分别合 3 42× 1 0 8元、3 0 3× 1 0 8元、43 79× 1 0 8元。将该区植被保土、保持有机质、保持氮磷钾三者加起来 ,该区 4 2 6× 1 0 8km2 的植被整个保土保肥效益约5 9 3 2× 1 0 8元 ,这是植被为本区提供天然生态服务和自然资本。

Vegetation's soil, fertilization and water conservation plays an important role not only in land ecosystem protection but also in the sustainable development of regional agriculture. With the support of GIS, this paper works out the matter amount of the vegetation's soil and fertilization conservation according to the difference of eroding modulus between the naked land and the vegetation-covered land, which are calculated upon the equation of ULSE and the vegetation exponent C. Having the matter amount, we then calculate the benefits of vegetation soil and fertilization conversation according to the equal effect principle. The result show that the vegetation of Weibei plateau can conserve 36.45×10 8t soil, whose value is about 2.55×10 8 Yuan with its corresponding conservative measures. While keeping the topsoil, the vegetation also conserves the soil organism and its N, P, K etcetera nutrient materials. After adding each kind of the soil nutrients' for their contents and proportions, it is concluded that each year vegetation within this region can conserve organism for about 457.2×10 4 t which equals 1306.29 m 3 firewood whose value is 6.53×10 8 Yuan, while with respect to N, P, K, the total weight conserved and its corresponding value are 35.45×10 4t and 3.42×10 8Yuan, 54.49×10 4t and 3.03×10 8Yuan, and 736.62×10 4t and 43.79×10 8Yuan, respectively, according to their current market prices. Altogether the vegetation in Weibei area may produce the soil and fertilizer benefits for about 59.32×10 8Yuan, providing the natural ecological service and capital for this region.