南水北调重要水源地的土地生态安全动态研究 ——以陕西省商洛市为例

土地生态安全对区域可持续发展具有重要影响。论文从影响土地生态安全的自然、 社会、 经济和环境因素方面选取了23个指标,构建商洛市土地生态安全评价指标体系,运用计量模型,对商洛市土地生态安全进行定量综合评价。结果表明:2000—2009年商洛市土地利用结构信息熵从1.031 4降低到0.980 5,土地利用结构均衡度不断降低,并向非均衡态发展;土地生态安全综合指数整体呈上升趋势,土地生态安全状况不断改善,土地生态安全压力尚未得到根本缓解;商洛市土地生态安全的威胁主要源于土地自然生态系统,土地经济生态系统的限制作用逐渐减小;人均耕地面积、 旱涝保收率、 人口自然增长率、 单位面积化肥和地膜施用量等因子成为商洛市土地生态安全的主要限制因素。

Study on Dynamic Security of Land Ecology in Water Source Area of South-to-North Water Diversion Project:A Case Study of Shangluo City,Shaanxi Province

As a research proposition in the field of land science,land ecological security has an important influence on the regional sustainable development.The research of land ecological security plays a significant role in protecting water source area.The paper takes Shangluo City located in Shaanxi Province as a study area,which is an important water source area of South-to-Noorth Water Diversion Project.The data used in this paper is mainly from the statistics of socio-economy and land-use structure in this city from 2000 to 2009.An evaluation index system consisting of 23 indices from the natural,social,economic and environmental factors influencing land ecological security has been established based on comprehensive consideration of land-use structure change.Related mathematical methods and econometric models have been used to make a quantitative and comprehensive appraisal of land ecological security in Shangluo City.The results are as following: 1) The land ecological security of Shangluo City was improved gradually since 2000,although the land ecological security was still in a sensitivity state in 2009.In the past decade,the comprehensive value of land ecological security rose from 0.2516 to 0.6951.But the pressure of land ecological security remained.The land ecological security needs to be further improved in the future.2) There has a stable decline of the information entropy of land-use structure in Shangluo City.From 2000 to 2009,the entropy-value of land-use structure dropped from 1.0314 to 0.9805.At the same time,the land-use structure of original state has been broken.The balance degree of the land-use structure in Shangluo City was dropping gradually,while the order of land-use structure system developed to non-equilibrium.3) The threat to the land ecological security came from the subsystem of land natural ecology and the declining negative influence of the subsystem of land economic ecology on land ecological security.The subsystem of land social ecology and the subsystem of land environmental ecology had less influence on land ecological security.4) The indices of cultivated land per capita,flood insurance yield,natural population growth rate,fertilizer using intensity per unit area and plastic film much using intensity per unit area became major limited factors to the land ecological security.Finally,some measures are proposed to cope with the pressure of land ecological security.