根据承载力确定土地资源安全度

土地资源安全维系着国民经济的可持续发展，而可持续发展是在不超过生态系统承载力情况下的一种安全发展模式。因此，通过土地资源承载力分析，可以了解土地资源的安全度。由于人类种群的增长可用Logstic模型[SX(]DN[]dt[SX)]=r·N·[JB(（][SX(]{K-N}[]K[SX)][JB)）]加以描述。运用熵理论推导证明[SX(]K[]2[SX)]≤N<[JB（(]1+[SX(]1[][KF(]3[KF)][SX)][JB))]·[SX(]K[]2[SX)]为模型的全局解，可作为区域土地资源的人口安全区间。以江苏省为例，在确定人口承载力的基础上，分别给出了温饱型、小康型和富裕型等三种生活水平下的土地资源安全评价标准。结果表明：目前江苏省土地资源在三种生活水平下均处于安全状况，但在富裕生活水平下人口已接近安全上限，必须控制人口，保护土地资源;提出进一步研究土地资源安全度应解决的几个问题。

EVALUATION OF THE SECURITY OF LAND RESOURCES BY LAND CARRYING CAPACITY——A CASE STUDY OF JIANGSU PROVINCE

After explaining relationships between land carrying capacity and sustainable development, this paper took land carrying capacity as an index to evaluate the security of land resources. The logistic model of [SX(]DN[]dt[SX)]=r·N·[JB(（][SX(]{K-N}[]K[SX)][JB)）]can describe the increase of population. From the model and using the theory of entropy, this paper derived the final solution of [SX(]K[]2[SX)]≤N<[JB（(]1+[SX(]1[][KF(]3[KF)][SX)][JB))]·[SX(]K[]2[SX)], which can be taken as the population security interval for regional land resources. Taking Jiangsu Province as a case study, and after evaluating the land carrying capacity, this paper advanced the assessment standards of land resource security at three levels of living standards, namely simply having enough food and clothing, leading to a relatively comfortable life, and being well off. The result indicated that the current land resources in Jiangsu Province at all the three levels are in safe situation, however, the population at the level of being well off has reached the up limit of the security. Therefore, the control of population and protection of land resources are necessary. Lastly, the paper raised problems needing attention in the further research of land resource security.