氮可利用性对东北不同类型湿地土壤有机碳矿化的影响  

Effects of Exogenous Nitrogen Availability on Carbon Mineralization of Different Wetland Soil Types in Northeast China

作　　者：李英臣[1,2] 宋长春 侯翠翠[1,2] 王宪伟[1] 孙晓新[1] 

机构地区：[1]中国科学院东北地理与农业生态研究所,吉林长春130012 [2]中国科学院研究生院,北京100049

出　　处：《地理科学》2011年第12期1480-1486,共7页Scientia Geographica Sinica

基　　金：国家自然科学重点基金项目(40930527;40771189);国家重点基础研究发展计划(973)项目(2009CB421103);中国科学院重要方向性项目(KZCX2-YW-JC301)资助

摘　　要：2010年6～10月，在中国东北连续多年冻土区，岛状多年冻土区和季节性冻土区采集典型湿地土壤，通过室内分析和模拟试验研究了不同冻土区湿地土壤有机碳矿化及其微生物活性对不同氮可利用性的响应特征。试验设置4个氮处理水平，分别为0mg／g（N0），0．1mg／g（N1），0．2mg／g（N2），0．5mg／g（N3）。结果表明，培养结束后3种土壤在NO处理下的有机碳累计矿化量分别为5646mg／kg，2103mg／kg和1287mg／kg，与初始土壤有机碳含量、全氮含量和微生物量碳（MBC）呈显著正相关。3种土壤在氮输入后的有机碳矿化速率和累积矿化量都明显低于NO处理，表明氮输入对有机碳矿化产生抑制作用。随着氮输入量的增大，氮输入对不同土壤有机碳矿化的抑制作用有所差异，表现为：不同氮输入对连续多年冻土区土壤累积矿化量影响无显著差异；岛状多年冻土区土壤在N1和N2处理下的有机碳累积矿化量明显高于N3处理；季节性冻土区土壤在N2和N3处理下的累积矿化量明显低于N1处理。培养结束后，3种土壤微生物量氮（MBN）含量随氮输入量增加而降低，MBC／MBN随氮输入量增加而增加；季节性冻土区草甸沼泽土培养结束后的MBN和MBC／MBN都与累积矿化量存在显著相关关系，表明季节性冻土区草甸沼泽土氮可利用性增加可能改变了微生物的组成或结构，进而对有机碳矿化产生影响。To examine carbon （C） mineralization and microbial activities of different soil types under different levels of exogenous nitrogen （N） availabilities, three types of soil were collected from continuous permafrost, island permafrost and seasonally frozen ground, and incubated under laboratory conditions from June to October in 2010. The experiment was designed with four N levels, the amounts of exogenous N were 0 （NO）, 0.1 mg/g （N1）, 0.2 mg/g （N2）, 0.5 mg/g （N3）. The results indicated that the cumulative C mineralization of three types of soil under NO treatment was 5 646 mg/kg, 2 103 mg/kg and 1 287 mg/kg, respectively, which existed positive correlation with initial amount of soil organic C, total N and microbial carbon （MBC） in the end of incubation. The C mineralization rates and amount of cumulative mineralization of three types of soil under NO treatment were all higher than under N treatment, indicated that exogenous N suppressed soil C mineralization. As the amount of exogenous N increasing, the inhibition of N on cumulative mineralization of different soil types was various. There was no significant difference of cumulative C mineralization of permafrost soil among three N treatments; the cumulative mineralization of island permafrost between N1 and N2 treatment was similar, but was all higher than N3 treatment; the difference of cumulative mineralization of seasonally frozen ground between N2 and N3 treatment was not notable, but was all lower than N1 treatment. After incubation, the values of MBN decreased and MBC/MBN increased along with exogenous N increasing. The cumulate mineralization of seasonal frozen soil positively related with MBN, and negatively related with MBC/ MBN, which indicated that nitrogen availability may affect the carbon mineralization by changing microbial structure and composition.

关 键 词：泥炭土 草甸沼泽土 氮可利用性 有机碳矿化 微生物量碳氮 

分 类 号：X511[环境科学与工程—环境工程]