生态脆弱带波动性、人口压力、脆弱度之间的关系

中国北方农牧交错带自然经济系的高波动性是生态脆弱带的显著特征之一。系统的波动性、人口压力、脆弱性三者之间在空间分布和成因上均有密切的联系。坝上后山地区粮食单产的波动性高，并自南向北递增；而以农牧业总产值为代表的土地生产力的波动性与粮食的波动性正好相反，从牧区向农牧区逐渐加大，在张北尚义一带形成高中心。在温饱型的热量营养标准下，人口的绝对和相对超载状况同土地生产力的波动性成正比，线笥相关在０．８３以

An approach to the fluctuation relation among land productivity,population pressure and weakness in ecotone

The relationship is analyzed among land productivity,population pressure and weakness to the compound system we take counties of southeast Inner Mongolia plateau as an example,which is characterized by the most fragile part of ecotone,as desertification develops rapidly,natural disasters gather heavily.The fluctuation of the system can be described as following:the fluctuation of main crop decreases from north to south due to rain,but the accumulated population overloading under nutrition criteria of calorie is directly proportional to that of total outpnt value of agriculture.It points out that,the higher the proportion of farming in agriculture,the higher the fluctuation of land productivity,the higher the population overloading,the lower the level of economic development.in the end,the paper comes to a conclusion that the high fluctuation of the ecotone is a response to climate as well as irrational land use,and fluctuation of economic development is a scientific and practical index to weakness degree.As it synthetically reflects the land structure of reasonable utilization,situation of poputation overloading,and the level of economic development.