以系统观点讨论中国沙漠化的成因机制及对策

沙漠化已经成为一个威胁人类生存的世界性环境问题。要防治沙漠化，必须先要找出沙漠化的成因。导致土地沙漠化的原因是由于地区生态系统脆弱，外部环境的作用强度很大，超过系统的承受范围而导致系统崩溃。由于全球变化导致气候格局发生变化，中纬度地区趋于干暖化，另上我国境内地形因素的影响，加剧了季风强度，降水分布很不均匀并分布集中，主要集中在7、8两个月份，土地风化淋蚀作用强烈，使得我国西部和北部地区的土地沙漠化现象严重，而人类过度活动和落后的管理体制也在一定程度上加剧了土地的沙漠化。不同地区具有不同的沙漠化特征，从我国实际出发，主要采取适应，预防和治理的策略来防止沙漠化的继续扩展。

Discussion on genetic mechanism and countermeasure of desertification in china viewed from the system theory

Desertification is a world environmental problem at present. We need to find the true reasons of desertification if we want to prevent and cure it. There are some reasons that lead to the desertification. The weak ecosystem is one of them. The change of system elements having exceeded the range that the ecosystem can endure leads to the collapse of whole system following the increasing of active intensity. The second reason is the change of the world climate structure. It has strengthened the monsoon and caused the distributing of precipitation that is asymmetry in space and concentrating in time especially in July and August. Since climate tends to be dry and warm in the mid latitude region and influence of the topography in China, the weathering and erosion of land are very strong. These lead to the phenomena of desertification seriously in north and west of China. The third reason is the excessive human activities and lagging manage mechanism, which can enhance desertification in a certain extent. There are some different characteristics in different areas of China. We can adopt some methods such as adapting, taking precautions and harnessing the desertification, to prevent the continuous expanding of desertification in China.