青海湖地区耕地演变过程与影响机制分析

通过对青海湖地区耕地总面积、内部结构的变化过程和区域差异的分析，探讨了耕地变化的驱动机制。结果发现该区耕地面积变化呈现出平稳增加、激增、螺旋式增加和锐减的演变趋势，内部结构先呈现水浇地面积的显著增加，浅山地、脑山地相对减少的趋势，然后有出现水浇地和其它类型的耕地此消彼张变化阶段趋势；而耕地变化的区域差异也呈现出全区增长，区域不同步和全区减少的变化趋势。影响研究区耕地变化的原因，除自然因子外，国家大政方针和重大农业政策是导致这种变化的主要原因。

Analysis of Evolution and Impact Mechanism of Cultivated Land in Tsinghai Lake Region

Through analysis of total area of cultivated lands, change in internal structure and regional difference, we discussed the driving mechanism of cultivated land change in the Tsinghai Lake region. Results show that cultivated lands in the region exhibit an evolutionary tendency of steady increase, sharp increase, screw-type increase and sharp decrease. For the internal structure, area of irrigable land has increased greatly, and areas of both nearby mountains and tope mountains have a relatively declined tendency. Areas of irrigable land and other types of cultivated lands change alternately. Regional difference of cultivated lands is characterized by a tendency of increase, non-synchronized change and then decrease in the area for the entire region. Besides natural factors, the major national policies and the agricultural policies are responsible for the changes in cultivated lands of the region.