基于SD模型的湖南省土地利用变化情景模拟

运用系统动力学模型（System Dynamic Model，简称SD）对湖南省不同社会经济发展情景模式下的土地需求进行了模拟预测。结果表明：1）不同发展模式下建设用地需求均呈增长态势，其他各类土地需求变化幅度差异较大，其中以水域与耕地差异最大。2）根据可持续发展战略要求，稳定发展情景模式较为理想，在此模式下，各类土地利用需求与现有土地利用状况较为接近，对各类土地需求均不会造成太大压力。3）土地利用现状完全能满足低速发展模式对各类土地的需求，但其前提是降低消费水平与市场自给率；而高速发展型对耕地、水域需求大大超出现有水平。4）在现有粮食消费结构下，若不能有效提高粮食单产水平，人口和经济增长带来的粮食需求将对耕地造成很大压力。

Land Use Change Scenarios Simulation in Hunan Province Based on the SD Model

The most significant characteristic of system dynamics is that it is able to deal with the high-order, non-linear, multiple-feedback, and complicated time-varying problems of the system. Land use is a non-lineal dynamic process which is correlated with a mutual reaction between natural, social and economic factors. This paper simulated and forecasted the land demand of Hunan province under different development modes by using SD model. The results showed that: 1) The demand for construction land under different development modes tended to increase, and that for other kinds of land varied greatly especially for waters and cultivated land. 2) Model B of stable development situation was the most ideal according to the requirements of sustainable development strategy; under this model, the demands for all kinds of land were similar to the present land use conditions, which did not cause too much stress to the demands for all kinds of land. 3) The present situation of land use in Hunan Province could fully meet the demands for various kinds of land at the low speed development mode, but the premise would be to reduce the level of consumption and market self-sufficiency rate. The demands for farmland and waters would exceed the present level under high speed development mode. 4) Under the present food consumption structure, the increase of food demand due to the population and economic growth would put a lot of pressure to cultivated land demand if we could not improve the yield of grain.