人口增长对荒漠化的驱动作用

Driving Action of Population Increaseon Desertification

以毛乌素沙区为例 ,分析沙区几十年来人口增长与荒漠化发展之间的关系 ,揭示荒漠化发展的人为驱动力。毛乌素沙区解放以来人口平均以 3 %的速率快速增长 ,在较高的人口增长压力下 ,一方面导致了对粮食需求的增加 ,在比较原始落后的生产方式下 ,投入低 ,粮食单产增长速度远远低于人口增长速度 ,为了满足粮食需求 ,必然导致对草地的大量开垦 ,该地区解放以来人口增长率和垦殖指数的变化规律是一致的。当地自然条件恶劣 ,土壤含沙量大 ,开垦后的旱作农业 ,在强劲的风力下 ,风蚀严重 ,土地很快发生退化。人口增长另一方面导致燃料需求的增加 ,该地区燃料的 5 0 %以上依靠砍烧天然植被 ,加剧了天然植被的破坏 ,对荒漠化发展有促进作用。典型地区荒漠化监测资料和人口变化资料进行的相关分析说明 ,当地荒漠化发生发展速率与人口密度存在相关关系。控制人口增长、减轻土地压力、退耕还牧和保护植被是促进当地荒漠化土地逆转所必须的。

Relationships between population increase and desertification in Maomusu Sandy Land were analyzed and the driving forces on desertificaton were revealed in this paper. The population had been increasing by 3% since liberation The higher population rate would resulted in the increasing demands for the food. With the backward production manners and low investment,the increase rate of food production per unit yield was much slower than that of population. For satisfying the food need, much grassland were cultivated. Since the poor natural conditions and sandy soil, dry land was erosed under strong wind and degraded in a short time. On the other hand, the higher population rate would resulted in the increasing demands for the fuels. More than 50% fuel was from cutting natural vegetation. The natural vegetation were so quickly destroyed that desertification development was promoted. It is essential to control population increase to lighten the burden on the land,to withdraw the farmland to the grassland and to protect thd vegetation for anti-desertification.