| On the basis of ecological environment science, this paper applies systematic dynamics to optimize the crop structure in Changling County, Jilin Province which lies in the arid and semiarid area, and constructs the systematic dynamic imitation model by the qualitative and quantitative ways. Several scenarios including natural development, economic benefit, ecological protection and harmonious progress are simulated and analyzed. As a result, the "harmonious progress" project is determined, and the strategies and the approaches to realize it is also brought forward. |