半干旱区城镇周边防沙——以内蒙古乌审旗达布察克镇为例

中国半干旱区城镇众多，风沙灾害频发，开展城镇风沙灾害防治研究势在必行。以毛乌素沙地的乌审旗达布察克镇为例，对其周边沙尘源地和植被进行实地调查；在此基础上，结合单项植物、机械沙障防风原理的风洞模拟结果，提出各种沙尘源地亚类防沙治沙措施的合理配置。根据建立半干旱区城镇防沙工程体系的原则以及城镇周边不同下垫面的防沙治沙措施配置，达布察克镇防沙治沙模式可以概括为城镇周边的“三圈模式”。第一圈是以达布察克镇为核心的绿化景观带，这一圈层大致位于达布察克镇以外600~900 m宽度范围内。第二圈层为沙丘（地）封禁与农牧业生产区，包括两个次级圈层：设施农业次级圈层的宽度约为1 km；远郊沙丘（地）封禁与农牧户独立生产次级圈层的范围较大，这一次级圈层的显著特点是大面积用于生态环境建设和保护，小面积用于农牧业生产。第三圈层是沙丘（地）封禁保护圈。该圈层位于乌审旗的西北位置，圈层内主要包括流动、半流动沙丘链以及平坦流沙地，是达布察克镇上风向主要的沙尘源地，应按照防沙治沙原理对其进行封禁与保护。

Protecting Cities and Towns from Blown-sand Disasters in Semi-arid Area of China-A case study of Dabqig Town in Uxin Banner of Inner Mongolia

Sand-blown disasters frequently occur in semi-arid area of China where cities and towns are relatively densely located. It is imperative to protect cities and towns from sand-blown disasters in semi-arid Area. Based on field survey of sand source and vegetation cover, as well as wind-tunnel measurement of independent vegetation and mechanical windbreaks, a configuration model for sand-blown prevention and control measures are proposed. Based on principles of sand-control engineering system and sand-control measures construction for different underlying surfaces around the towns in semi-arid area, a sand-control model for protecting Dabqig Town of the Uxin Banner from sand-blown disasters can be outlined as a "three-ring" model. The innermost ring is landscape greenbelt zone with Dabqig Town at the core. This zone is located around Dabqig Town with the maximum distance of 600-900 m from the town. The second ring is sand dune enclosure and agriculture-stock production zone, including two sub-zones. The facility agriculture sub-zone has a width of about 1 km. The exurb sub-zone of sand dune/land enclosure and individual agriculture-stock production covers a larger area, and an outstanding feature of this sub-zone is that its main area is used for ecological environment construction as well protection, and a relatively small area is used for agriculture-stock production. The outermost ring is sand dune/land enclosure and protection zone. This zone is located in northwest of the Uxin Banner. It mainly includes mobile and semi-mobile dune chains and flat drifting sand-land, thus is the main sand/dust source for Dabqig Town. Therefore this zone should be enclosed and protected using corresponding sand-control measures.