中文摘要：

耕地不断流失的根本原因在于耕地农业利用的比较收益低下,所以建立耕地保护机制的主要途径在于：一方面提高耕地利用的比较收益,另一方面通过提高耕地征用的价值补偿来抑制乱占耕地行为.这两条途径归结于重建耕地资源的价值.本文提出耕地资源具有经济产出价值、生态服务价值和社会保障价值,并尝试用市场价格分别加以评估.耕地资源的经济产出价值为耕地年收益与贴现率之商,生态服务价值为耕地生态服务年价值与贴现率之商,社会保障价值是耕地提供的养老保险和就业保障价值之和.分别选择广东省潮安县、河南省淮阳县和甘肃省会宁县三个县作为案例的评价,以显示我国东、中、西部之间的区域差异.结果表明：耕地资源价值量在各地区之间呈现东高西低的差异;在耕地资源价值构成中,社会保障价值在三个案例区都占60%以上,但所占比重从东到西渐增,说明农民对耕地资源的依赖程度与社会经济发展水平呈反相关.耕地资源的经济产出价值在总价值中所占比重则从东到西递减,主要源于自然和经济生产率的差异.生态服务价值所占比重也表现出东低西高的特点,反映出生态系统从复杂到简单的变化使得农田生态系统对于西部地区生态环境显得更加重要.农业用地为社会提供了大量外部效益,这可成为实行农业补贴的一大理由,也是计算补贴量的一种依据;更可作为提高征地补偿标准的依据.在我国现阶段,耕地是大多数农民赖以生存的主要资源,在农村社会保障体系不完善甚至不存在的情况下,耕地的社会保障功能不可忽视.

英文摘要：

The basic cause of continuous cultivated land conversion is the comparatively low benefit of its agricultural use. Therefore, the main approaches to establishing the conservation mechanism of cultivated land are to heighten the comparative income of agricultural use of cultivated land on the one hand, and to enhance the cost of cultivated land conversion on the other hand. The two approaches are summarized into the re-evaluation of cultivated land resource. This article argues that cultivated land resource is actually provided with economic output value, ecological service value and social guarantee value, and all of them can be re-evaluated by market price respectively. The economic output value of cultivated land is the quotient of its annual benefit divided by discount rate. The ecological service value of cultivated land is the quotient of its annual ecosystem service value divided by discount rate. The social guarantee value of cultivated land is the sum of its provisions of endowment insurance for the aged and of guarantee for employment. Three cases representing various environmental conditions and social development levels are studied respectively in the article so as to reveal the regional differentiation among the east, the middle and the west of China. They are Chao＇an county of Guangdong Province, Huaiyang county of Henan Province and Huining county of Gansu Province. The results show that the values of cultivated land resource are obviously different among the three case areas and present the higher feature in the east and the lower in the west. Regarding the composition of values of cultivated land resource, social value makes up more than 60% of the total in all of the three areas. Yet the proportion of social value is higher in the west and lower in the east, demonstrating that the dependent degree of peasant upon cultivated land resource reversely relates with the level of socio-economic development. The proportion of economic output value to the total value is higher in the east and lower in t