沼泽湿地垦殖对土壤碳动态的影响

Cultivation Effects on Soil Organic Carbon Dynamics in Sanjiang Plain,Northeast China

在中国科学院三江平原湿地生态试验站选取相邻的、土壤类型相同的小叶章沼泽化草甸以及不同开垦殖年限的已垦湿地农田，综合运用多种微生物指标，全面地评价沼泽湿地垦殖后土壤有机碳的动态。结果表明，沼泽湿地垦殖初期（1—3年），土壤微生物量碳（MBC）、微生物商以及基础呼吸（BR）都迅速降低，而代谢商（qCO2）、PR／BR和PR／MBC比值却不断升高。表明湿地垦殖后，有机碳的可利用性下降，微生物对碳源的利用效率降低，造成土壤有机碳的大量损失。各种微生物指标之间有密切的相关关系，练合这些微生物指标能够全面地、准确地评价沼泽湿地垦殖后土壤有机碳的动态。

We selected adjacent Deyeuxia angustifolia meadow and farmland cultivated 1,3,5,9,15,25 and 35 years, to study cultivation effects on soil biological properties and organic matter dynamics in the Sanjiang Plain in Northeast China. The results showed that cultivation resulted in decrease in the microbial biomass carbon （MBC）, microbial quotient（ MQ）, and basal respiration （BR）. While, metabolized quotient （ qCO2 ）, potential respiration/basal respiration（ PR/BR）, and PR/MBC ratios obviously increased with cultivation. Converting wetland soil into agriculture soil resulted in significant decline in carbon availability and efficiency of microbial populations in conserving C. There are clear relationships between soil microbial properties. The method evaluating more parameters simultaneously can provide complete and true information about the soil microorganisms and carbon dynamics.