氮素形态对泥炭沼泽土壤有机碳矿化的影响  

Effects of Nitrogen Forms on Carbon Mineralization in Peatland Soils

作　　者：陶宝先[1] 宋长春 

机构地区：[1]聊城大学环境与规划学院,山东聊城252059 [2]中国科学院东北地理与农业生态研究所,吉林长春130102

出　　处：《生态环境学报》2015年第3期372-377,共6页Ecology and Environmental Sciences

基　　金：国家自然科学基金项目(41125001;40930527);中国科学院战略性先导科技专项-应对气候变化的碳收支认证及相关问题(XDA05050508;XDA05020502);中国科学院知识创新工程重要方向项目(KZCX2-YW-JC301);山东省自然科学基金(ZR2014DQ015);聊城大学博士启动基金(318051430)

摘　　要：大气氮沉降是全球变化的主要因素之一。硝态氮、氨态氮是大气氮沉降的两种主要氮素形态,且两者在大气氮沉降中的比例具有较大的空间变异性。目前,多数研究侧重于探讨氮输入量与土壤碳循环过程之间的关系,很少有研究关注不同氮素形态对沼泽湿地土壤有机碳矿化的影响。以东北地区多年冻土区及季节冻土区泥炭沼泽为例,利用室内模拟实验,在100%土壤最大持水量条件下,将土样于15℃好氧培养60 d,研究不同形态氮输入对泥炭沼泽土壤有机碳矿化的影响。结果表明,多年冻土区和季节冻土区泥炭沼泽0-30 cm深度的土壤有机碳贮量分别为17.60、13.06 kg·m^-2。多年冻土区泥炭沼泽土壤有机碳的累积矿化量显著大于季节冻土区（P〈0.001）。同一泥炭沼泽中,表土（0-15 cm）有机碳累积矿化量显著大于下层（15-30 cm;P〈0.001）。氨态氮抑制土壤有机碳矿化,使多年冻土区泥炭沼泽土壤有机碳累积矿化量下降12.08%-14.90%,季节冻土区下降7.28%-12.57%,而硝态氮及硝酸氨对土壤有机碳矿化无显著影响。此外,氮素形态、土壤深度及泥炭沼泽类型对土壤有机碳矿化有显著的交互作用（P〈0.05）。因此,区分不同氮素形态对土壤碳排放的影响是非常有必要,有利于深入了解大气氮沉降对泥炭沼泽土壤碳库稳定性的影响。Nitrogen （N） deposition is one of the most significant environmental change factors for terrestrial ecosystems. The N deposition could be in two forms as ammonium and nitrate, while the proportions of these two N forms in atmospheric N depositon have great spatial variation. How various N forms affect carbon （C） mineralization is critically important while is lacking of investigation. In this study, an incubation experiment was carried out to investigate the effects of N forms on C mineralization using peat samples collected from permafrost （PR） and seasonally frozen region （SFR） in Northeast China. The samples were incubated for 60 days under the conditions of 15℃ and 100% water holding capacity. We found that the storage of C was larger in PR （C 17.60 kg·m^-2） than that in SFR （C 13.06 kg·m^-2）. The cumulative CO2 production was larger in PR compared with those in SFR, while the surface peat layer （0-15 cm） produced more CO2 than subsurface peat layer （15-30 cm） within the same peatland. Ammonium addition suppressed C mineralization, and the cumulative CO2 production was decreased ranging from 12.08% to 14.90% in PR, and from 7.28% to 12.57% in SFR. However, nitrate and ammonium nitrate additions produced neutral effect on C mineralization. Moreover, soil depth, peatland types and N forms had significant and interactive effects on C mineralization. This study highlights the importance of distinguishing nitrate and ammonium when estimating/projecting C fluxes in response to N addition. The ecosystem models should separately simulate nitrate and ammonium when estimating the effects of N addition on C storage.

关 键 词：氮形态 有机碳矿化 泥炭沼泽 东北地区 

分 类 号：S153[农业科学—土壤学]