湘潭农业生态系统的能值分析及其可持续性评价

为提高湘潭市农业生产力水平，促进农业生态系统可持续发展，运用能值分析理论和方法，对湘潭市2000—2008年农业生态系统的能值投入产出、运行效率、ELR进行定量分析。结果表明:湘潭市农业生态系统能值投入以可更新的有机能为主，主要依赖于人力，其所占能值比重由2000年的0.58下降到2008年的0.49，尚处于从传统农业阶段向现代农业阶段转变的过渡时期；能值产出中林业能值产出较大，而种植业和渔业所占比例较小，尤其是渔业，未达到整个能值产出的0.01%；湘潭市农业生态经济环境负载率低，资源空间利用未达到优化配置，具有较大的发展空间。湘潭农业生态系统的可持续发展指数变化较大，波动范围在0.03~0.11之间，说明湘潭农业生态系统属于消费型经济系统。应根据农业的需要合理调整农业产业结构及能值投入结构，促进农业生态经济系统的良性循环。

Analysis on the Energy of Agro-ecosystem and Assessment of Sustainable Development in Xiangtan

In order to improve agriculture productivity, promote agro-ecosystem sustainable development in Xiangtan, the input-output condition, work efficiency, and environmental load of the agro-ecosystem in Xiangtan were systematically assessed based on the theory and method of energy analysis from 2000 to 2008. The results showed that the renewable organic energy dominated over the majority of energy input in Xiangtan, the agro-ecolomic system in Xiangtan still stayed in the period shifting from traditional to modern agriculture, proportion dropped from 0.58 in 2000 to 0.49 in 2008, which mainly depended on man power. The majority of energy output was forestry, while crop cultivation and fishery had a relatively low percentage, especially the fishery, which didn’t reach to 0.01%. Xiangtan had a low environment load ratio and the resources were not fully developed, thus the agroecosystem had a large development potential; the energy-based sustainable index of agroecosystem in Xiangtan was in ascendant trend, the range varied from 0.03 to 0.11, which showed that the agroecosystem belonged to consumer economic system. To promote the virtuous cycle of agro-economic system in Xiangtan, we should gradually adjust the investment proportion of input and output energy.