杭州湾湿地不同植被类型下土壤有机碳及其组分分布特征

土壤有机碳及其活性组分能够敏感地反映土壤碳库的变化。调查采集杭州湾自然滩涂湿地土壤样品(0~10 cm、10~20 cm、20~30 cm),比较分析芦苇、互花米草、海三棱藨草、裸滩的土壤有机碳(SOC)、水溶性有机碳(DOC)、易氧化碳(ROC)和轻组有机质(LFOM)的变化。结果表明:(1)0~30 cm各土层,芦苇、互花米草、海三棱藨草和裸滩的SOC平均含量依次为3.87~5.08 g kg-1,6.46~6.78 g kg-1,4.33~4.48 g kg-1和4.99~5.25 g kg-1,互花米草SOC含量高于相同土层的其他类型;(2)互花米草DOC和LFOM平均含量分别为90.69~98.90 mg kg-1,2.35~2.95 g kg-1,高于相同土层的海三棱藨草、芦苇和裸滩,而裸滩ROC含量(2.06~2.22 g kg-1)却高于相同土层的其他三种类型;(3)芦苇、互花米草和海三棱藨草DOC占土壤有机碳的分配比例无显著性差异,而相同土层的DOC占土壤有机碳的分配比例大小依次为裸滩海三棱藨草芦苇互花米草;(4)SOC和DOC、ROC、LFOM、全氮(TN)、土壤含水量、p H之间均存在极显著关系(p0.01),各指标与p H之间均表现为负相关性。研究表明互花米草的入侵增强了滩涂湿地的固碳能力,有机碳活性组分能够反映有机碳库的变化。

Distribution characteristics of organic carbon and its components in soils under different types of vegetation in wetland of Hangzhou Bay

The soil organic carbon and its labile C can sensitively reflect the changes of soil carbon pool, so this research was carried out to survey natural wetlands and collect soil samples (0~10cm, 10~20cm, 20~30cm) in Hangzhou Bay, analyzing the changes of soil organic carbon (SOC), soil dissolved organic carbon (DOC), soil readily oxidized carbon (ROC) and light fraction organic matter (LFOM) of Phragmites australis, Spartina alterniflora, Scirpus mariqueter, mudflats. The results indicated that: 1) 0~30cm soil layer, the average SOC content of Phragmites australis, Spartina alterniflora, Scirpus mariqueter, mudflats was in the followed by 3.87~5.08g/kg, 6.46~6.78g/kg, 4.33~4.48g/kg, 4.99~5.25g/kg, the SOC content of Spartina alterniflora was higher than the other types in the same soil layer; 2) The DOC and LFOM average content ranges of Spartina alterniflora were 90.69~98.90mg/kg, 2.35~2.95g/kg respectively, and higher than Phragmites australis, Scirpus mariqueter, mudflats in the same soil layer, however, the ROC content of mudflats (2.06~2.22g/kg) was higher than that of other vegetation types; 3) The ratios of DOC to SOC between Phragmites australis, Spartina alterniflora, and Scirpus mariqueter showed no significant differences, and the ratios of ROC to SOC is mudflats > Scirpus mariqueter > Phragmites australis > Spartina alterniflora; 4) SOC was significantly related to DOC, LFOM, TN, soil moisture content, pH (p <0.01), and all the indexes showed negative correlation with pH. As a result, the invasion of Spartina alterniflora can further improve wetlands carbon sequestration capacity and the active component of organic carbon can effectively indicate organic carbon pool changes in the wetlands of Hangzhou Bay.