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• 基金项目：

• 陈传康
• 北京大学地理系

• 摘要：本文阐述了半干旱和干旱地区的形成条件,分布及环境特征,并对我国这类地区的开发利用,环境保护措施的制定提供了科学依据.

• Abstract：Conditions of their formation and distribution.Semi-arid and arid regions are formed under the following conditions:1. along the west coast and in the interior of the continent, and in tropical trade-wind zone;2. inside the inland interior of the temperate zone;3. in the mountain leeward rain-shadow zone, i. e. with a background of humid and semi-humid climate, local semi-arid climate or climate of transition from semi-arid to semi-humid. The semi-arid and arid climate controls predominantly over northwestern arid zone. The interior of the Qinghai-Xizang Plateau, mainly the Qiangtang Plateau belongs to the semi-arid and arid zone. From the desert in the interior of Northwest, through semi-desert and steppe, to forest steppe belongs to transition from semi-arid to semi-humid climate, and then to monsoonal forest of East Asia.Ⅱ. Environmental features.In view of the formation of semi-arid and arid regions, this background is mainly attributed to dynamic circulation of climate. The factors, such as far from the ocean, the unpenetration of air current into the interior prevented by mountains, greatly affect certain areas. These conditions lead to less precipitation, long sunshine, strong wind and more sands, coarse surface materials, inland drainage, few rivers and less runoff in semi-arid and arid regions, resulting in sparse and low vegetation, and deserts and steppe vegetations. Ⅲ. Strategy for environmental exploitation and protection.The principle of environmental exploitation and protection of these regions can be summarized as follows:1. In the near future, cultivation should be adjusted to developing various kinds of those in conjunction with market information. Animal husbandry as well as melons and fruits and plush cotton should be emphatically developed in the desert zone. The agricultural productivity of oasis should be raised and animal husbandry as well as melons and fruits should be developed in semi-arid zone. The animal husbandry should be developed more emphatically. The cultivated area of dry land should be reduced and the yield per unit area by agricultural irrigation should be increased in steppe zone.2. In the mid-range plan, special attention should be paid to adjustment of regional economic structure, to develop large-scale commodity production on the basis of taking full advantage of regional environmental conditions.3. At a specified future date, special attention should be paid to regional environmental programme. Stress should be focused on protection of afforestation of the surrounding mountains for the environmental programme of semi-arid and arid regions, thus the agricultural irrigation to be stabilized in the oasis of the lower reaches.

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