基于GIS的陕北黄土高原土地生态系统水土保持价值评价

Research on the Value of Soil and Water Conservation in Loess Plateau in Northern Shaanxi Province

【目的】土壤侵蚀是导致人类赖以生存且日趋紧缺的土地资源退化和损失的主要原因,这种损失正在全球悄然进行。定量计算区域土地生态系统水土保持的价值量,为区域土地的持续利用与生态环境和社会经济协调发展提供科学决策依据。【方法】本文根据陕北黄土高原的特点,采用无植被覆盖的潜在土壤侵蚀量来估算各生态系统土壤保持量,然后利用估算的土壤保持量,采用市场价值法、机会成本法和影子工程法从保护土壤肥力、减少表土损失和减轻泥沙淤积3个方面来评价水土保持的经济效益。【结果】而从整个时间段上来看,2000年比1978年的土壤保持量增长94.18%,接近一倍。1978～2000年期间陕北黄土高原水土保持价值是逐渐增加的,1978～1990年期间比1990～2000年期间增加的要快。1978年的陕北黄土高原的水土保持价值为18.503亿元;1990年比1978年陕北黄土高原水土保持价值增加了近8亿元;而2000年比1990年增加了2.414亿元。【结论】近20多年的时间里,1978～1990年时间段增长幅度比1990～2000年的增长幅度要大,这与植被覆盖度有着密切的关系。针对陕北黄土高原所进行的一系列水土保持治理工作,已经取得了巨大的成绩。从空间分布上来看,通过对研究区三类不同地貌类型区进行水土保持价值评价,其结果为,南部低山丘陵区>北部风沙过渡区>中部黄土丘陵区。

【Objective】Soil erosion is the first cause for the degeneration and losses of land resources which is essential for human beings, and this kind of loss gradually becomes a global phenomenon. The purpose of this paper is to quantitatively calculate the value of ecosystem soil and water conservation and provide a scientific decision-making basis for sustainable usage of land and the harmonious development of regional socio-economic development. 【Method】 Based on the characteristics of North Shaanxi Loess Plateau, this paper used potential soil erosion quantity without vegetation cover to evaluate the soil conservation quantity of each ecological system, and then used the estimated soil conservation quantity to evaluate the economic benefit of water and soil conservation from the three aspects of protecting soil fertility, reducing surface soil loss and sediment accumulation with the market value method, opportunity cost method and shadow project approach. 【Result】During the entire time, the maintenance of soil increased by 94.18%, nearly doubled from 1978 to 2000. The conservation value from 1978 to 2000 increased gradually, and the increasing speed between 1978-1990 was higher than that of 1990-2000. The water and soil conservation value of North Shaanxi Loess Plateau in 1978 is $1.8503 billion; and that in 1990 was almost $0.8 billion higher; while the value of 2000 was $0.2414 billion higher than that of 1990. 【Conclusion】 The increase in the period from 1978-1990 is larger than that of 1990 to 2000, this is closely related to the vegetation cover degree, this also shows that in nearly 20 years, a series of water and soil conservation projects in North Shaanxi Loess Plateau has gained huge success. From the special distribution, water and soil conservation values of the three different landscapes were studied, and the result was that the south hill areas>north wind drift sand region>middle loess hills.