CO2浓度升高对三江平原典型湿地土壤活性有机碳的影响

选择三江平原典型草甸化小叶章湿地为研究对象，利用开顶箱控制CO2浓度，模拟CO2浓度升高对湿地土壤活性有机碳的影响。结果表明，CO2浓度升高对土壤微生物量碳的影响受土壤氮素水平制约。不施氮和常氮处理，CO2浓度升高对其影响不显著；高氯处理，土壤中可利用的氮相对充足，微生物活性不受氮素限制，土壤微生物量碳显著增加。置于CO2浓度升高环境中的土壤水溶性有机碳含量有增高的趋势，但没有达到统计上显著水平（P〉0．05）。施氮均促进了土壤微生物量碳和水溶性有机碳的增加。图2，参13。

Effects of Elevated CO2 Concentration on Active Carbon in Sanjiang Plain Freshwater Marsh

The freshwater marsh predominated with Calamagrostis angustifolia was chosen in Sanjiang Plain for the study. Open top chamber was used in the controlling of CO2 concentration in order to model the impacts of elevated CO2 concentration on the active carbon of Calamagrostis angustifolia marsh soil. The results showed that the response of microbial carbon to elevated CO2 concentration was strongly dependent on nitrogen supply. The microbial carbon was not increased significantly with NN and MN treatments. Elevated CO2 concentration enhanced the content of microbial carbon with high nitrogen addition because the activities of microbe was not limited by nitrogen supply. Dissolved organic carbon had an increase trend under elevated CO2 concentration, but not significantly （ P 〉 0.05）. Soil microbial carbon and dissolved organic carbon were increased with nitrogen input.