互花米草入侵对潮滩土壤活性有机碳组分的影响

Effects of Spartina alterniflora Invasion on Active Soil Organic Carbon in the Coastal Marshes

对外来种互花米草替代本土植物盐蒿后生长8、12、14年的湿地土壤以及盐蒿湿地表层土壤(0～10 cm)的活性有机碳(微生物量碳、可溶性有机碳)特征进行了研究,分析了不同湿地的土壤活性有机碳与土壤总有机碳之间的关系。结果表明:不同类型湿地的土壤活性有机碳组分含量存在显著差异,土壤活性有机碳、土壤总有机碳的变化趋势一致,表现为互花米草湿地>盐蒿湿地,且随着互花米草生长时间增长而明显增加;土壤活性有机碳与土壤总有机碳存在显著正相关关系;土壤活性有机碳与土壤总有机碳的比值则随着互花米草生长时间增长而逐渐减小,表明入侵年限长的互花米草湿地活性有机碳库周转率降低,生物可利用性减小,有利于土壤有机碳的累积。这可能是互花米草生长导致土壤总有机碳含量显著增加的主要原因。

The microbial biomass carbon （MBC） and dissolved organic cm depth profile in four marshes （Suaeda salsa marsh and Spartina carbon （DOC） were investigated over a 0 - 10 alterniflora marsh across an 8, 12 and 14-year chronosequence） in the coastal marshes in Jiangsu Province. The relationship between active SOC and total SOC was analyzed. Active SOC, either MBC or DOC, differed significantly among the four marshes. MBC, DOC and total SOC, which increased with Spartina alterniflora invasion chronsequence, were significantly higher in the Spartina alterniflora marsh than that in Suaeda salsa marsh. MBC and DOC were significantly positively related to total SOC content. However, the ratios of active SOC to total SOC decreased with Spartina alterniflora invasion chronsequence, suggesting that the turnover rate of microbiall active carbon pool and biotic availability of organic matter inputs decreased. This ultimately caused evident increase in total SOC content after Spartina alterniflora invasion of Suaeda salsa marsh.