北方土石山区的土地压力及其缓解途径

以北方土石山区27个小流域样本数据为基础,针对流域粮食生产、经济发展和生态保护对土地的需求,构建了土地压力定量评估方法,评估了各流域的土地压力,并将其与实际土地生产力进行了比较,进而从各小流域的经验事实中提取出使两者平衡的有效途径。结果表明,土地压力在空间上具有非均衡性,但相对于土地生产力的相对土地压力则存在空间均衡化的趋势。2000年前后,只有76%的样本小流域能够支撑人均300 kg/a的粮食生产压力,只有约20%的样本小流域能够支撑其经济发展压力,但这些小流域的土地压力最终都得到了有效缓解。劳动力转移、发展经济林果和特色产业等是缓解上述压力的主要途径。

Land Pressure and Its Alleviating Approaches for the Mountainous Region of Northern China

The mountainous region of northern China including mountain areas in the Haihe and Huaihe drainage basins covers an area of 28 × 10~4 km~2, where soil erosion is the overwhelming environment issue. Since the 1950s, soil and water conservation projects, such as those based on small watersheds, have partly improved the situation of soil erosion, but there is still 13.47 × 10~4 km~2 of eroded area due to land use and land cover changes under the pressures of both population growth and economic development. Therefore, to alleviate regional land pressure becomes more important in the restoration of regional environment. In this paper, we evaluate the grain production pressures, economic development pressures and soil conservation pressures for 27 sample watersheds listed in those soil conservation projects, and then compare their land pressures and actual production abilities to find out which alleviating approaches were adopted and which approach performed the most important. Empirical analysis reveals that land pressure was spatially non-balanced, but there was a balancing trend between land pressure and production ability. If none of alleviating approaches had been adopted, only 76% of the watersheds could bear grain production of 300 kg/a per capita, another 24% of the watersheds could only bear grain production of 225 kg/a per capita, while about 18% of the watersheds could bear their economic development pressure that is equal to average labors' alternative cost. Out-migration of labors, fruit production and locally specified tour were the major approaches to alleviate land use pressures, and labors migration performed the most important. Those approaches alleviated not only grain production pressures and economic development pressures of the watersheds, but also soil conservation pressures.