Because of the unfavourable natural conditions,China s semiarid areas has low-level economy development and low-degress social development, which lead to deficiency of interior impetous.

• 中国半干旱区由于自然条件比较严酷,不仅经济发展水平低下,而且社会发育程度低,引发社会结构变迁的内部动力不足。