研究了三江平原小叶章湿地土壤中碳的可利用性对土壤中微生物呼吸的限制作用.结果表明,表土和根层土中的可利用性碳显著限制微生物呼吸作用.在所有的培养土壤中,起始时微生物呼吸速率较高,随之急剧下降,这可能是由于土壤物理化学及生物性质的变化所致.土壤中有机质低于10%时,可以明显影响碳的可利用指数;大于10%以后就几乎没有影响了.微生物生物量碳与碳的可利用指数也存在较为显著的正相关关系.%The limitation of carbon availability on microbial respiration was studied in the Calamagrostis angustifolia soil in Sanjiang Plain. The results suggest that carbon availability limits the microbial respiration in root layer soil and subsoil initially, whereas it does not limit the microbial respiration after 1.5 h incubation for recovery from the disturbance in physical, chemical and biological structure caused by sampling from the field, then after 5 h incubation when the labile carbon has been mineralized the available carbon limits the microbial respiration again. At the same time the results show that the soil organic matter affects carbon availability index significantly when its value is lower than 10%, but the effect is little when the soil organic matter is higher than 10%. The microbial biomass carbon is linearly correlated with carbon availability in the Calamagrostis angustifolia soil.
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