川中丘陵区耕地变化及其驱动力研究--以四川省盐亭县为例

Study on Cultivated Land Change and Its Driving Force in Hilly Area of Central Sichuan Basin——A Case Study of Yanting County,Sichuan Province

以四川省盐亭县为例,分析了川中丘陵地区近50年来耕地变化的基本特征.根据土地利用政策变化,将该区近50年来的耕地变化划分为两个时段(1950-1980年和1981-2001年).分别从第一时段和第二时段中选取9个影响耕地变化指标因子的22年和10年数据作为样本数据,通过主成分分析进行驱动力判定,并建立相应的驱动力多元回归模型.用黑箱方法计算两个时段人类活动对耕地面积变化贡献率的差异.结果显示,川中丘陵地区耕地变化是自然因素、社会因素和经济因素综合作用的产物.一方面,近50年来该区主要粮食作物的单产与耕地面积变化有较大的正相关;另一方面,随着生产力水平的提高和其他因素的影响,人类活动对耕地变化的贡献率不断增大,耕地变化影响因子的作用也存在明显的时间差异.在第一时段(1950-1980年)该区人均粮食占有量与气候条件对耕地面积变化的影响作用较大,而在第二个时段(1981-2001年)农民人均纯收入的影响作用较大,气候条件的作用依然明显,但在程度上比第一个时段略有下降.

Taking Yanting county, Sichuan Province for an example, this paper analyzes the fundamental characteristics of cultivated land change in the hilly area of central Sichuan for fifty years. In the light of land use policy change, the cultivated land change of hilly area of central Sichuan basin in recent 50 years is divided into two periods （ 1950-1980 and 1981-2001 ）. Taking 9 kinds of factors affecting cultivated land change as indexes for principal component analysis, indexes data of 22 years from the first period and 10 years from the second period are selected as sample data, driving force of cultivated land is analyzed through method of principal component analysis. Then multiple linear regression model of driving force is established. The result shows that cultivated land change is comprehensively affected by natural environment, social conditions and economic factors. On one hand, in recent 50 years there is a positive relationship between per unit area yield of main grain crops and cultivated land change of hilly area of central Sichuan basin. On the other hand, with enhancement of productive forces and change of other affecting factors, the proportion of human activities affecting on cultivated land continuously increases. During the first period （ 1950-1980 ） , the effect of per capita grain and climatic conditions on cultivated land is obvious. However, during the second period （ 1981-2001 ） , the effect of per pure income of peasants on cultivated land is obvious, and the effect of climatic conditions is also important, but is less than that in the first period.