在公开发表数据基础上,本研究评价了全国6大稻作区10类稻田提供的生态系统服务。研究的服务包括稻田初级产品生产、气体调节、氮素转化、土壤有机质累积以及水调节和洪水控制等5项生态系统服务。研究结果显示,稻田谷物产量为4.71–12.18 t ha-1 y-1,稻草为4.65–9.79 t ha-1 y-1;O2调节量为8.27–19.69 t ha-1 y-1,温室气体调节量为-2 .13–19.24 t ha-1 y-1 (CO2 当量);氮素输入量为209.70–513.93 kg N ha-1 y-1,输出量为112.87–332.69 kg N ha-1 y-1;土壤有机质库变化为0.69–4.88 t C ha-1 y-1;水调节量为-19 875–6430 m3 ha-1 y-1,洪水控制量为1500 m3 ha-1 y-1。研究结果还显示,10类稻田的生态系统服务价值为8605–21 405 美元 ha-1 y-1,除了初级产品生产以外的其他生态系统服务价值仅占74%–89%。在施氮量为275–297 kg N ha-1时,稻田生态系统服务价值相对较高。目前仅以农产品生产来计算稻田生态系统的价值显著低估了稻田生态系统对人类社会的重要性。随着越来越多的森林、草地等转为城市和工业用途,农田特别是稻田生态系统将具有越来越高的生态重要性。农田生态系统农产品生产以外的生态系统服务将受到越来越多的关注。
This paper aims to identify the main driving force for changes of total primary energy consumption in Beijing during the period of 1981-2005.Sectoral energy use was investigated when regional economic structure changed significantly.The changes of total primary energy consumption in Beijing are decomposed into production effects,structural effects and intensity effects using the additive version of the logarithmic mean Divisia index (LMDI) method.Aggregate decomposition analysis showed that the major contributor of total effect was made by the production effect fol- lowed by the intensity effect,and the structural effect was rela- tively insignificant.The total and production effects were all posi- tive.In contrast,the structural effect and intensity effect were all negative.Sectoral decomposition investigation indicated that the most effective way to slow down the growth rate of total primary energy consumption (TPEC) was to reduce the production of the energy-intensive industrial sectors and improving industrial en- ergy intensity.The results show that in this period,Beijing's economy has undergone a transformation from an industrial to a service economy.However,the structures of sectoral energy use have not been changed yet,and energy demand should be in- creasing until the energy-intensive industrial production to be reduced and energy intensity of the region reaches a peak.As sequence energy consumption data of sub-sectors are not available, only the fundamental three sectors are considered:agriculture, industry and service.However,further decomposition into secon- dary and tertiary sectors is definitely needed for detailed investi- gations.
