中文摘要：

为探究粮食生产核心区内土地生态安全状况及其障碍因子,破解河南省三大国家战略规划实施过程中的土地困境提供支持。本文采用改进PSR模型、相对熵赋权法、障碍因子诊断模型对河南省周口市的土地生态进行评价与障碍因子分析。结果表明：（1）12年间系统压力呈现缓慢上升-快速下降-逐渐上升的变化趋势;系统状态呈现快速下降-逐渐上升-缓慢下降的变化态势;系统响应与系统压力呈现出拉锯式循环增减变化态势;系统综合指数从2001年的0.3456下降到2003年的0.3230,又快速上升到2009年的0.4534,再缓慢下降到2012年的0.4394,相应的安全等级也经历了从敏感级到一般安全级再到临界安全级的倒＂U＂型变化;（2）有55.5%的障碍因子集中在系统压力层,主要障碍因子包括人均耕地、地均化肥和农药负荷、农林水务和环保治理支出比重等指标。研究地域和研究方法的创新丰富了土地生态安全评价研究,为类似区域提供参考借鉴;河南省土地生态安全保护必须从系统压力入手,以构筑绿色和谐的国土空间格局为着眼点,以转变经济发展方式为落脚点,以增加＂三农＂和环保项目的财政支持为发力点,走一条不以牺牲粮食生产和生态环境的＂三化＂协调＂五化＂同步之路。

英文摘要：

To explore the situation of land eco-security and its obstacle thctors in the core area of grain production, and provide support＇ for the land dilemma in implementation process of the three national strategic planning of Henan Province. This paper took methods including the improved PSR model, relative entropy weight method and obstacle factor diagnosis model. The result showed that（l） press index showed a gradually rise- rapid fall- gradually rise fluctuation trends during 12 years; State index showed a rapid decline -gradually increase-slowly downward trends; Response index and the press index showed a seesaw circulation trends; Composite index decreased from 0.3456 in 2001 to 0.3230 in 2003, then quickly increased to 0.4534 in 2009, finally drop to 0.4394 in 2012. The security levels also experienced from sensitive to general safety level then became critical safety level--presented a inverted U shape change. （2）The obstacle factors mainly concentrated in the system pressure layer. It included the per capital cultivated land, fertilizer and pesticide load, the proportion of agriculture and environmental protection spending. It concluded that the innovation of region and methods not only enriched the study of land eco-security evaluation; but also provided a ret＇erence for the similar regions. Henan Province must start from the system pressure tO construct green and harmonious land spatial patterns, enlarge financial support to the ＂three rural＂ and environmental protection and transform economic developing mode. It should exploit a path of three-agriculture coordination and five-oriented synchronization rather than did it at the cost of grain production and the ecological environment.