喀斯特峰丛洼地植被恢复过程中土壤微生物特性

Dynamic changes of soil microbial properties in karst peak-cluster depression area during vegetation restoration

以喀斯特峰丛洼地草丛、灌丛、次生林和原生林生态系统为对象,研究了植被恢复过程中土壤微生物生物量、土壤微生物碳熵、土壤呼吸及其呼吸熵等微生物特性。结果表明:土壤微生物生物量与土壤微生物碳熵随着植被恢复呈增加趋势(P<0.05),土壤呼吸熵变化规律与之相反,土壤呼吸变化不显著,说明随着植被的恢复土壤质量不断提高,顺序为乔木(原生林、次生林)>灌丛>草丛;同一生态系统中土壤微生物生物量氮、土壤呼吸及其呼吸熵均表现为冬季>夏季(P<0.05),土壤微生物碳熵为冬季<夏季(草丛例外)(P<0.05),而土壤微生物生物量碳却未呈现显著性季节变化;土壤微生物生物量氮与微生物碳熵不仅对地上植被及季节变化响应敏感,且与土壤有机质及其他微生物指标相关性较好(P<0.05),可以灵敏表征喀斯特峰丛洼地不同植被恢复土壤质量变化。

In order understand the effects of vegetation restoration in karst peak-cluster depression area on the soil microbial properties, soil samples were collected from tussock （T）, shrub （S）, secondary forest （SF）, and primary forest （PF）, with their microbial biomass carbon （MBC） and nitrogen （MBN）, basic respiration （SR）, ratio of MBC to soil organic carbon （qMBC）, and microbial metabolic quotient （qCO2） analyzed. In the process of vegetation restoration, the soil MBC, MBN, and qMBC had an increasing trend, qCO2 was in reverse, and SR had less change, suggesting that soil quality was gradually improved during vegetation restoration （PF, SFST）. It was also found that the qMBC, SR, qCO2, and MBN varied with season. From summer to winter, the SR, qCO2, and MBN increased, while the qMBC decreased （except for T） （P〈0.05）. The MBC did not change significantly with season. Both MBN and qMBC were correlated with soil organic matter and other microbial properties, and better reflected the changes of soil quality in karst peak-cluster depression area during vegetation restoration.