广州城市代谢与土地利用变化指标评价

Analysis of the indicators between urban metabolism and land use change in Guangzhou

土地利用变化与城市代谢间的研究为全球变化的核心计划,是当前生态环境研究的热点问题。本研究以Odum的能值评估方法为分析工具,以广州生态-经济-社会系统为研究范围,以19902006年的资源流动量核算17年来广州城市代谢的演变情况,并在此基础上从整体角度探讨了广州城市代谢与土地利用变化的互动关系,结果表明：（1）广州市近年来各类土地使用面积变化尤其是建设用地的增长,大大影响了广州城市代谢过程中的各项物质流与能量流,能量由自然地区与农业地区向城市地区集中,代谢强度增大给代谢过程带来压力,广州城市代谢效率呈现出下降趋势。（2）外界输入资源在代谢中扮演重要角色,伴随产业的转型,广州市在城市扩张的过程中,消耗了大量的石油等矿物燃料、水泥等建材资源,增加了城市的环境负荷,能值可持续性指数逐渐降低。（3）广州市1990年以来农地面积虽然逐渐减少,农地的能值密度呈下降趋势,但农地的总能值效益得到提高,这主要是由于近年来农业生产逐渐由低能值转换率的水稻生产转变为高能值转换率的蔬菜等产品为主。本文可为广州市土地规划与管理提供重要依据和新的思路。

The study on the interaction between land use change and urban metabolism,which is the core of Global Change Programme,has currently come into lively discussion in the field of ecological research.On the whole ecologic-economic-social system of Guangzhou,this paper analyzes the emergy-based urban metabolism in the past 17 years with reference to the resource flows from 1990 to 2006 and investigates this interaction of the metabolism and land-change of Guangzhou.It finds out the truth that various types of land-use changes had remarkable influence on the material and energy flows during the metabolic course,especially the fast rise of the construction land.The more construction land the city increases,the more total solar emergy it consumes,which makes a decline in the emergy sustainable indices.The per unit area energy consumption also increases in the process of urban expansion with a large amount of depletion of minerals,fuels and building resources.Because of the growing environmental load,the emergy yield ratio is decreasing year by year.At the same time,the emergy efficiency of farmland has been enhanced while there has been a decrease in the amount of farmland and a downward trend of emergy density since 1990.The results can provide an important basis and new ideas for the land planning and management of Guangzhou.