宜能边际土地开发潜力熵权模糊综合评价——以广东省为例

Fuzzy Entropy Evaluation of Marginal Land Exploitation Potential for Bio-Energy Crop Cultivation: A Case Study of Guangdong Province

利用边际土地种植高效能源作物是我国生物能源发展战略重要的组成部分。开展区域宜能边际土地的空间分布和开发潜力定量评价研究,是区域分布实施能源作物种植,推进生物质能源产业发展的前提和基础。以广东省为例,利用TM/ETM遥感影像通过遥感监督分类和目视人工解译提取疏林地、灌木林地、天然草地和未利用地等边际土地。然后选取影响能源作物种植的边际土地的自身性状和整理难易程度等5类因素建立指标体系,利用熵权模糊综合评判模型,把广东省宜能边际土地开发潜力分成高、中、低和极低4个级别。研究结果表明:广东省共有宜能边际土地105.34×104hm2。其中,高、中、低、极低开发潜力宜能边际土地面积分别占边际土地总面积的41.08%,32.13%,17.22%和9.57%。并且宜能边际土地空间分布呈现内陆地区>西南沿海地区>东南沿海地区的趋势,具有高开发潜力土地在区域内所占比例呈现西南沿海地区>东南沿海地区>内陆地区的趋势。

Utilization of the bio-energy has been widely considered to be one of the solutions to nowadays＇increasingly serious issues such as energy crisis, environmental protection, and rural development etc. In China, the government has declared that exploiting marginal land for cultivating bio-energy crop was going to be an important part of China＇ s biology energy development strategy till 2020. Therefore it is of both theoretical and practical importance to locate the distribution of marginal lands and quantitatively evaluate their exploitation potential. In this study, we present a case study of using fuzzy entropy model to evaluate exploitation potential of marginal lands in Guangdong province. Marginal lands, such as sparse forest, sloping grassland and barren land, were firstly extracted based on classification results of TM/ETM Landsat images. Exploitation potential of marginal lands was then evaluated using the fuzzy entropy model. Factors like slope, surface roughness, land use type, soil type, distance to road, soil thickness, temperature and precipitation etc were used as evaluation indexes for calculation of fuzzy grades matrix. Based on the evaluation results, marginal lands were classified into four categories, namely very low, low, medium and high exploitation potential land. The result shows that there are 1.05 million hm2 of marginal lands in Guangdong, including 41.08% of high potential land, 32. 13% medium potential land, 17.22% low potential land, and 9.57% very low potential land. Spatial distribution of marginal lands in inland region is higher than in coastal region, but lands with high exploitation potential shows an opposite trend. The study also proved the applicability of fuzzy entropy model for evaluating marginal land exploitation potential.