昆山市22年来耕地流失研究

RESEARCH ON FARMLAND LOSS OF KUNSHAN IN TWO DECADES

以昆山市1985～2006年共22a间的耕地面积变化及与之相关的总户籍人口、非农业人口、第一产业从业人口、地区生产总值、人均地区生产总值、第一产业生产总值、第二产业生产总值、粮食总产量和社会固定资产投资等9种社会经济指标为研究对象,采用变化率相关分析、主成分阶段分类等新方法对目前耕地流失研究中常用的相关分析、主成分分析等数学方法进行改进。研究结果表明:(1)新方法在耕地流失主要驱动因素分析和阶段划分方面具有独特的优势,同时能够通过回归方程的验证,所得结论可信度较高;(2)昆山市耕地流失的首要驱动因素为以人均地区生产总值为代表的社会经济水平的提高,同时人口增长和第二产业的发展加剧了耕地流失状况;(3)昆山市耕地流失按照所受压力对农业发展的影响可以分为3个阶段,分别为1985～1994年的未限制阶段、1995～1997年制约平衡阶段和1998～2006年限制阻碍阶段。

A case study of Kunshan using data of farmland area and other nine social economic indices,such as total population, nonagricultural population, employments in primary industry, gross domestic product, per capita gross domestic product, value added of primary industry, value added of secondary industry, grain output and social fixed asset investment from 1985 to 2006,was held to research the farmland loss and its driving factors. In order to decrease the disadvantages in the application of mathematical methods of direct correlation analysis and principal component analysis （for example, the variations of social economic indices with time were similar, and it was difficult to get useful information by direct correlation analysis, and some researchers often mistaken principal component analysis for a method distinguishing relative importance of driving factors）, new methods, such as correlation analysis on the changing rate of indices and segmentation of farmland loss process by principal component analysis were taken. Results showed that the new methods had distinct advantages in main driving factor analysis and process segmenting of farmland loss, and the conclusions were proved to be credible and reliable by testing the regression equations. Farmland loss in Kunshan was primarily due to the rapid development of social economics represented by the index of per capita gross domestic product, and was hastened by the development of the second industry and the increase of total population. The farmland loss process of Kunshan should be divided into three stages according to whether farmland loss handicapped the development of agriculture or not： not handicapped stage from 1985 to 1994,balanced stage from 1995 to 1997 and handicapped stage from 1998 to 2006.