稻田生态系统气体调节功能及其价值

The gas regulation function of rice paddy ecosystems and its value

论文以2002年在上海五四农场稻田生态系统田间实验为基础,运用造林成本法、碳税法和工业制氧法对稻田生态系统气体调节功能及其价值进行研究。研究表明:①稻田生态系统O2释放物理量变化范围为16518～38517kg·hm-2,其价值量也有相同的变化趋势,变化范围是6217～11873元·hm-2;②稻田生态系统对温室气体(CO2、N2O和CH4)调节基本上起着抑制作用,而不是促进作用,在水稻生育期内,稻田温室气体调节物理量的变化范围为-997～2787kgCO2-C·hm-2,价值量变化范围为-751～2098元·hm-2;③稻田生态系统气体调节功能的综合价值变化范围为5467～12842元·hm-2。可见,除了粮食生产和提供秸秆外,农田生态系统还为人类社会提供包括气体调节、养分转化、供观赏的景观等在内的服务功能,共同为人类福利服务。

The welfare served by croplands has been underestimated.Besides supplying food and providing straw,croplands support many other functions and services such as nutrients transforming,pollination,biological control,supplying beautiful scenery,recreation,and so on.In this study,we examined the gas regulation services supported by rice paddy ecosystems,based on the results of field experiments in Wusi Farm of Shanghai in 2002.And the values of gas regulation by paddy rice ecosystems with different N-fertilization treatments were also estimated with ecological economics methods.The results indicated that two kinds of gas regulation were provided by paddy fields:one was O2 emission,and the other was Greenhouse Gases(GHGs) regulation(including CO2 uptake,CH4 and N2O emission).First,in the cultivation period,O2 emission of rice paddy ecosystems ranged from 1.65×104kg·hm-2 to 3.85×104kg·hm-2 along with increment of N fertilizer application,and the values ranged from 6.22×103yuan·hm-2 to 11.87×103yuan·hm-2 in the same trend.Second,rice paddy ecosystems emitted GHGs,but also fixed CO2 from atmosphere.In CO2 equivalent,the quantities of GHGs regulation ranged from -997kgCO2-C·hm-2 to 2 787kgCO2-C·hm-2,and the values ranged from -751yuan·hm-2 to 2 098yuan·hm-2.Third,the integrated values of gas regulation by rice paddy ecosystems ranged from 5 467yuan·hm-2 to 1.28×104yuan·hm-2.In this study,we are trying to provide a fair method to evaluate the values of croplands,to support an effective way to recognize the welfare served by croplands,especially by paddy fields and to promote the sustainability of cropland ecosystems and yet the sustainability of human kinds.