湛江市土地资源生态安全评价与限制因素

基于PSR（压力-状态-响应）模型构建了土地资源生态安全评价指标体系，对1996-2008年湛江市土地资源生态安全状况进行了评价，并结合各评价指标的安全指数，分析了影响湛江市土地资源生态安全的限制因素。结果表明:（1）1996-2008年，湛江市土地资源状态子系统总体状况较好，但处于缓慢退化之中，压力子系统和响应子系统的生态安全状况处于逐步改善之中，但总体状况较差，因此湛江市土地资源生态安全综合状况一般。（2）人口增长和不合理的化肥施用是湛江市土地资源压力子系统的主要限制因素，耕地面积不断减少、森林覆盖率较低和农田水利设施差是状态子系统的主要限制因素，第三产业比重偏低和教育科技发展滞后是响应子系统的主要限制因素。

Evalution on Ecological Security of Land Resource and Its Limiting Factors in Zhanjiang City

On the basis of PSR (Pressure-State-Response) model, a system of 26 indexes for evaluating land resource ecological security is established in this paper. Assessment on the ecological security of land resource in Zhanjiang from 1996 to 2008 was carried out and the limiting factors were also analyzed according to the security index. As the results shown, the performance of state subsystem of land resource in Zhanjiang was encouraging as a whole, while which was under slow degradation. Although it was gradually improved, the status of pressure subsystem and response subsystem was still unsatisfactory on the whole. Conclusively, ecological security of land resource in Zhanjiang was at the average level. In addition, population growth and unscientific application of chemical fertilizers were the principle limiting factors of pressure subsystem. Meanwhile, the state system was mainly limited by continuous decrease in cultivated land, relatively low forest coverage and poor irrigation and water conservancy facilities. As for response system, it was mainly restricted by low proportion of tertiary industry and inadequate development of education and technology.