Based on reference review, this study investigated ecosystem services supported by 10 typical rice paddies in six rice planting regions of China. The services were primary production, gas regulation, nitrogen transformation, soil organic matter accumulation, and water regulation and flood control. The results indicated that grain production of the 10 rice paddies was between 4.71 and 12.18 t ha^-1 y^-1; straw production was 4.65 to 9.79 t ha^-1 y^-1; gas regulation was calculated to emit O2 ranging from 8.27 to 19.69 t ha^-1 y^-1 and to assimilate greenhouse gases ranging from -2.13 to 19.24 t ha^-1 y^-1 （in CO2 equivalent）; nitrogen transformation was estimated as nitrogen input ranging from 209.70 to 513.93 kg N ha^-1 y^-1 and nitrogen output of 112.87 to 332.69 kg N ha^-1 y^-1; soil organic matter accumulation was calculated to be between 0.69 and 4.88 t C ha^-1 y^-1; water regulation was estimated to consume water resources of 19875 m3 ha^-1 y^-1 and to support water resources of 6430 m3 ha^-1 y^-1; and flood control of several of the rice paddies was calculated to be 1500 m3 ha^-1 y^-1. The integrated economic value of ecosystem services of these rice paddies was estimated at USD 8605–21 405 ha^-1 y^-1, of which 74%–89% of the value can be ascribed to ecosystem services outside primary production. The results also indicated that the integrated economic value of the ecosystem services of the 10 rice paddies was higher when nitrogen fertilizer was applied in the range of 275 to 297 kg N ha^-1. Until now, the economic value of the rice paddy ecosystem has been underestimated as only the economic value of grain and straw production was previously calculated. As more and more forest land and grassland is lost to urban and industrial use, cropland and especially rice paddies, will become more ecologically important to society. The economic value of ecosystem services supplied by rice paddies, outside primary production, are worthy of increased research attention.
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.
