基于PSR框架的甘肃省环县耕地生态安全评价

以生态退化区甘肃环县为研究区,通过构建"压力-状态-响应"(PSR)模型,从自然、经济和社会3个方面选取20个评价指标,建立耕地生态安全评价指标体系,计算耕地生态安全指数并划分安全等级,对2005-2016年环县耕地生态安全变化状况进行定量分析.结果表明:①基于PSR模型的评价指标体系能够较好地反映耕地生态系统各个要素之间的关联,适用于区域耕地生态安全的综合评价.②2005-2016年期间,环县耕地生态安全水平逐渐提高,生态功能有所改善,耕地生态安全经历了"恶化-敏感-安全"的演变过程.③单项指标的变化表明环县2005-2016年间人口密度、人均耕地面积、土地垦殖率、单位面积耕地化肥施用量、年降水量以及工业废水排放达标率变化明显,是影响区域耕地生态安全状况的关键因素.今后在加强对耕地数量保护的同时,应采取休耕等耕地休养方式加强耕地质量和耕地生态建设与维护,致力于耕地生态系统的恢复和重建,促进区域耕地可持续利用.

Ecological Security Assessment of Cultivated Land in Huan County of Gansu Province Based on PSR Framework

The ecological security of cultivated land is an important guarantee for regional sustainable development. In this paper, the ecological degradation area of Ring County, Gansu province, has been taken as the research area. Through the construction of "pressure state response" (PSR) model, 20 evaluation indexes have been selected from three aspects of natural, economic and social factors, and the evaluation index system of ecological security of cultivated land has been established. The index of cultivated land ecological security has been divided into safety grades, and the change of cultivated land ecological security in Huan County from 2005 to 2016 has quantitatively been analyzed. The results show that:(1) the evaluation index system based on PSR model can better reflect the relationship between the various elements of cultivated land ecosystem, and is suitable for the comprehensive evaluation of the ecological security of the cultivated land. (2) during the period of 2005-2016 years, the ecological security level of cultivated land in the ring county has been gradually improved, the ecological function has been improved, and the ecological security of cultivated land has undergone the process of "deterioration-sensitive-Safety". (3) through the change of single index, it is concluded that the 2005-2016 year population density, per capita cultivated land area, land reclamation rate, fertilizer application amount per unit area, annual precipitation and the rate of industrial wastewater discharge are obvious, which are key factors that affect the ecological safety of cultivated land. While strengthening the protection of cultivated land in the future, we should take the way of recuperation and other cultivated land recuperation to strengthen the quality of cultivated land and the ecological construction and maintenance of cultivated land, strive for the restoration and reconstruction of cultivated land ecosystem, and promote the sustainable utilization of cultivated land in the region.