尕海湿地沼泽化草甸中不同积水区土壤活性有机碳含量

Contents of Active Organic Carbon in Soils of Different Flooding Areas in Marshy Meadow in Gahai Wetlands

2014年5~9月,以尕海湿地沼泽化草甸中不同积水区(无积水区、季节性积水区和常年积水区)的土壤为研究对象,测定土壤中的活性有机碳含量,分析沼泽化草甸不同积水区土壤活性有机碳组分差异。研究结果表明,积水状况对土壤活性有机碳组分影响显著。0~40 cm深度土壤活性有机碳含量最大值出现在常年积水区,季节性积水区的土壤活性有机碳含量次之,最小值出现在无积水区。在不同土壤深度,20~40 cm深度土壤有机碳和微生物量碳含量在季节性积水区最大,在无积水区最小,其它深度土壤有机碳、微生物量碳和易氧化有机碳含量都在常年积水区最大,在无积水区最小,说明常年积水区活性有机碳及组分具有更加明显的表聚性。在不同采样日,各积水区的土壤有机碳、微生物量碳、微生物熵和易氧化有机碳含量都有显著变化(p<0.05)。各活性有机碳组分与土壤有机碳含量显著正相关(p<0.01),各活性有机碳含量都随着土壤有机碳含量增加而增加。

In the study, we selected different flooding areas of marshy meadow in Gahai （no flooding, seasonal flooding, perennial flooding area） wetlands as the research areas. The active organic carbon contents in soils were determined in May to September of 2014 and the diversities of components of active organic carbon in different flooding areas were analysed. The result showed that different flooding changes significantly influ- ence on soil active organic carbon components of marshy meadow in Gahai wetlands, the maximum contents of active organic carbon of 0-40 cm depth soils appeared in the perennial flooding area, followed by the sea- sonal flooding area. The soil organic carbon （SOC） and microbial biomass carbon （MBC） contents of 20-40 cm depth were highest in the seasonal flooding area, and lowest in no flooding area. Soil organic carbon, mi- crobial biomass carbon, easily oxidated carbon （EOC） contents of other layers showed that in the perennial flooding area were highest and in the no flooding area were lowest, which indicated that perennial flooding ac- tive organic carbon contents and components had obvious properties of surface-aggregation. In different sam- pling days, the soil organic carbon, microbial biomass carbon, microbial quotient and easily oxidated carbon in different flooding areas were all changed significantly （p〈0.05）. Active organic carbon ingredient were posi- tively correlated with contents of soil organic carbon （p〈0.01）. Active organic carbon contents increased with the increase of soil organic carbon.