四川“长治”工程对环境人口容量的影响

Effects of soil erosion control project of the Yangtze River on environmental human carrying capacity in Sichuan Province

在水土流失地区,通过水土流失综合治理可以明显提高土地生产力和增加农民的收入,从而提高小流域环境人口容量。长江上游水土流失重点防治工程是我国开展的最大规模的长江流域水土流失综合治理工程,对提高当地生态环境和人口容量有显著的作用。以已竣工的“长治“四期工程为例,利用系统聚类方法将研究区的72个小流域划分为6种类型;分别以价值消费和粮食消费作为人口容量的计算标准,得出了四川省72个小流域治理前后的环境人口容量变化;同时分析了单位面积的治理投资规模与单位面积环境人口容量变化的关系。结果表明：研究区治理后的72个小流域环境人口容量均有显著增加;同一治理投资水平下,人口密度高、单位面积粮食产量高的小流域,其单位面积环境人口容量增加量最为显著。以第3类小流域进行投资分析表明：“长治”四期工程的环境人口容量增加的最佳治理投资规模为11万~12万元/km^2左右,按2013年投资水平计算,“一期”与“四期”工程的最佳治理投资规模相近,均为31.5万元/km^2左右。

In soil erosion area, land productivity and farmer＇ s income can be raised obviously by carrying out the measures of soil erosion control and in the meantime increasing the amount of environmental human carrying capacity. As the most important and the largest soil erosion control project in the Yangtze River, also called ＂ Yangtze River Harness＂ project, it plays an important role for improving the environment and increasing human carrying capacity. Taking the fourth stage of the project in Sichuan Province as an example, we used cluster analysis method and divided the 72 controlled watersheds into 6 groups. The environmental human carrying capacity was calculated in terms of different consumption standards （food consumption and cash consumption）. The results showed that the amount of the carrying capacity had been greatly increased after control. At the same level of harness investment, the small watersheds with higher population density and grain yield per hectare have more increment of carrying capacity. Based on analyzing the typical small watersheds, the proper value of investment for the fourth stage of the project is about RMB 110 000 to 120 000 yuan per square kilometer, at the investment level of the year 1997, for the purpose of increasing environmental human carrying capacity. In comparison, the amount of rational harness investment of the first stage of the project, which is similar to that of the fourth stage, is about RMB 315 000 yuan per square kilometer at present value of 2013.