广西能源作物木薯种植的可能规模：自然适宜性与社会限制性评价

木薯是我国的非粮作物,是生产生物乙醇的主要原料之一。广西是木薯的传统种植区域,随着木薯需求量持续增长,其种植潜力问题越来越受到研究机构与政府部门重视。本文从广西木薯种植的气候适宜性、土壤适宜性、地形适宜性和土地利用的社会经济限制性出发,较为系统地评估了广西木薯种植的自然适宜性和社会限制性,定量揭示了广西木薯种植的土地潜力、可能规模及其地域格局。研究结果表明,广西木薯种植的主要限制因素是地形条件,其次是土壤因素;若不考虑土地利用的社会经济限制性,广西3/5的土地适宜木薯种植;但考虑到土地利用的社会限制性,广西适宜木薯种植的土地则只有115.5万hm2;与目前已种植木薯22.3万hm2相比,尚有约4倍的土地种植潜力;从地域格局看,广西未来木薯发展的重点将在柳州和来宾地区。

Potential Capacity of Cassava Planting in Guangxi: Assessment of Natural Suitability and Socio-Economic Restrictions

Because of the fast consumption of fossil energy and associated environmental problems, governments have paid increasing attention to the development of the bio-energy industry. The Chinese government has formulated a series of policies to improve the bio-energy industry. In order to ensure the food security, the Chinese government has claimed that bio-ethanol could only be produced by non-food crops such as sweet sorghum and cassava. Cassava is a type of non-food crops and one of main materials of bio-ethanol production. With the increasing demands for cassava in Guangxi Zhuang Autonomous Region, which is the most important traditional cassava planting area, relevant institutions and government departments are paying increasing attention to the cultivation potential of cassava. In this paper, based on climate suitability, soil suitability, terrain suitability, and socio-economic restrictions of land use, we used the AHP method to evaluate the suitability of each index. Then, the suitability of comprehensive indexes was evaluated. At last, an assessment of its natural suitability and social restrictions of cassava planting in Guangxi was conducted, with its land production potential, potential capacity, and spatial distribution being quantitatively analyzed. Results show that among all indexes, the terrain condition was the leading limiting factor of cassava planting potential, followed by the soil condition. If the socio-economic restrictions of land use were not accounted for, 60% of the land area in Guangxi was suitable for cassava planting. On the contrary, the suitable land area would decrease to 1 155 ×10³ ha. Compared with current plating area of 223 × 10³ ha, there were up to 4 times cultivation potential. Concerning the spatial distribution, the key areas of cassava planting in the future are in the region of Liuzhou and Laibin. It is suggested that developing the bio-ethanol industry based on cassava in Guangxi would be a right choice, but the development speed should keep appropriate and the extensive mode of production has to be shifted to an intensive mode. Second, although the main areas of cassava planting are in Nanning, Wuzhou, and Guigang, the potential planting areas are Liuzhou and Laibin. Third, more emphasis should be placed on the environment and economy of cassava planting, because much waste grassland and unutilized land were not fully utilized to plant cassava, they would cause serious soil erosion. Its influence on other industries of cassava cultivation should be evaluated.