【摘要】 在田间实验的基础上,对上海五四农场稻田生态系统的初级产品生产、气体调节、氮素转化、有机质形成和累积、水调节和环境净化6项生态系统服务进行了评价。研究结果显示,稻田生态系统初级产品生产量及其价值随施氮量的增加而增加;稻田生态系统向大气释放O₂并吸收大气中的CO₂,稻田向大气排放CH₄和N₂O,其中施氮量为375kgN/hm²（N3处理）的稻田生态系统气体调节价值量最高;稻田生态系统中施加化学氮肥是氮素输入的主要途径,水稻收获移出和氨挥发是氮素输出的主要途径,稻田生态系统氮素转化造成了经济损失;稻田有机质累积量及其价值随施氮量的增加而增加;水稻种植消耗了水资源,同时稻田在降雨时具有蓄水功能;稻田生态系统能吸收SO₂和净化污水。综合研究发现,研究区稻田在水稻生育期内提供的生态系统服务价值为（3.83～4.85）×10⁴元/hm²,其中N3处理稻田提供的生态服务价值最高,但是与未施加氮肥的NO处理相比并不具有明显优势。通过分析表明,施加氮肥带来的环境损失削弱了稻田生态系统服务给人类社会带来的效益。因此,应当鼓励水稻种植者采用缓释氮肥、改进施肥技术等提高氮肥利用效率的措施,以促进稻田生态系统服务的发挥,给人类社会带来更多福利。更多还原

【Abstract】 Rice paddies are some of the most important farmland in China,supporting more than one-third of all food production.Rice paddy ecosystems not only provide food,but also support many ecosystem services such as gas regulation,water regulation,flood control,soil organic matter accumulation,nutrient transformation and environment purification.In 2002,we conducted field experiments in the rice paddy ecosystem of Wusi Farm,Shanghai to examine the ecosystem services provided by rice paddies with different levels of nitrogen application.Based on the field experiment data,we investigated primary production,gas regulation,nutrient transformation,soil organic matter accumulation,water regulation and environment purification and their values.For primary production,the rice seeds and stalks and their values increased with N application.In terms of gas regulation,the rice paddies absorbed CO₂ from the atmosphere,and emission of O₂ and N₂O increased with the addition of N,but the CH₄ emissions decreased.The economic value of gas regulation by the rice paddies was highest at the level of 375 kgN·ha^-1.The nitrogen transformation study indicated that,of the different sources of nitrogen inputs,the nitrogen application provided the most nitrogen input,whiel harvest and ammonia volatilization were the most important sources of nitrogen output.According to our study,the nitrogen transformation resulted in economic losses,and these losses increased with nitrogen addition.The soil organic matter content increased with rice planting,and the quantity of soil organic matter accumulation and its value increased with N application.In terms of water regulation,rice planting consumed water resources,and the ridges of the rice paddies controlled flooding as a reservoir with 5cm height.The comprehensive valuation indicated that the ecosystem services provided by the rice paddies in Wusi Farm provided many economic benefits to society,with a range of（3.83～4.85）×10⁴ yuan·ha^-1.The ecosystem services of the rice paddies with 375 kgN·ha^-1 of N application provided the highest economic value.However,the economic values of the ecosystem services of these rice paddies did not have a significant advantage over those without N application.The economic loss of environmental damage due to N application compromised the benefits provided by the rice paddies.Therefore,to maximize the benefits of ecosystem services and to pursue sustainable rice production,the government should adopt effective measures such as applying controlled-release nitrogen fertilizer and improvement of nitrogen application technologies in order to improve the efficiency of nitrogen application.更多还原