【摘要】 人类活动引起的大量的活性氮从大气沉降到生物圈.当前氮沉降对草地生态系统碳循环过程的影响机制仍然存在较大的不确定性.本文综述草地生态系统碳循环过程(植物光合作用、地上生物量、地下生物量、土壤呼吸、凋落物分解和土壤有机碳含量)对添加不同的氮源水平和不同施氮年限的响应,并分析这些过程变化的可能原因,同时,也阐述草地碳循环关键过程对外源碳输入的响应,并进一步分析了外源碳和氮输入对草地碳循环关键过程影响的微生物学作用机制.通过上述总结旨在强调说明碳源可利用性变化作为氮沉降背景下草地生态系统碳循环关键过程重要调控因素之一,开展相关研究对科学的管理我国草地资源配置和增加土壤碳汇方面理论的重要意义.更多还原

【Abstract】 Human activities result in a large amount of active nitrogen(N) depositing from atmosphere to biosphere.Then N deposition has inconsistently influenced in the key process of carbon(C) cycle in the grassland ecosystem.In this paper,we review the processes of C cycle(plant photosynthesis,aboveground and belowground biomass,soil respiration,litter decomposition and soil organic carbon content) responding to different N-addition levels and years in the grassland ecosystem,and analyze possible the causes of various in these processes.Simultaneously,we analysis that these processes respond to exogenous C addition.Furthermore,we analysis the mechanisms of microbes driving these processes under exogenous C and N addition.C availability is one of most controllers in the key processes of C cycle in grassland ecosystems.This paper throughout the above these works strongly emphasizes that conducting the related research will play important roles in scientific managing resources and increasing soil C sink in China.更多还原