In order to explore effects of vegetation on nutrients in soils, nutrients characters of soils under natural grass, closed grass, abandoned lands, forest lands returned from farmlands and fixed sandy areas in Mu Us Desert were researched. The results indicated that vegetations in varied types have different effects on organic matter, total N, available N and available P, among which the first three were all higher in soils under closed grass, forest lands returned from farmlands, and fixed sandy lands than those under natural grass and abandoned lands. This was totally contrary with contents of available P in soil. In addition, nutrients in soils at 0-20 cm were more influenced by vegetation, than those at 20-60 cm, and Caragana Korshinskii proved better in improving nutrients in soils.
运用MCE-CA和Logistic-CA两种基本的元胞自动机模型作为理论模型，考虑边界到市中心、镇中心、铁路和主要公路等作为区位因素的空间距离约束条件，以及地形和禁止建设区作为区位因素的全局限制约束条件，在地理模拟优化系统（ Geographical Simulation and Optimization System ，GeoSOS ）的支持下，对1990～2000年和2000～2010年辽宁省大连市旅顺口区的城市空间扩展进行了模拟，并取得较好效果。结果表明，MCE-CA模型的Kappa系数分别为0．71和0．64，Logistic-CA模型分别为0．54和0．55，两者均达到较好的模拟精度；MCE-CA模型适用于主观变量较多的CA模型，Logistic-CA模型更适合于客观因素较多的CA模型；利用合理的CA模型模拟旅顺口区城市未来土地利用变化，可为今后的土地规划以及制定有效的土地管理措施和方针政策提供依据。
