退化喀斯特植被恢复过程中土壤基础呼吸及代谢熵的变化

Changes of Soil Basal Respiration and qCO_2 along Successional Processes of Degraded Karst Vegetation

以不同植被恢复阶段的土壤样品作为研究对象,采用微生物培养法、生化活性试验法及氯仿熏蒸法分析了退化喀斯特植被恢复过程中不同层次、不同生境、根际和非根际土壤基础呼吸及代谢熵(qCO2)的变化特征。结果表明:退化喀斯特植被恢复过程中土壤基础呼吸及qCO2存在较大差异。随着退化喀斯特植被的恢复,土壤基础呼吸明显增强,表现为乔木群落阶段>灌木群落阶段>草本群落阶段>裸地阶段,但qCO2明显下降,反映出土壤质量在逐渐恢复;土壤基础呼吸及qCO2在土壤剖面上均表现明显的垂直变化特征,即随土层深度的增加,呈递减趋势,具体表现为A层>B层的特点;土壤基础呼吸及qCO2的变化特征在不同生境间表现为:除裸地恢复阶段外,其它三个阶段总体上表现为石沟比石槽和土面两个小生境偏大的特点,这是因为石沟生境的特点有利于微生物类群及土壤动植物群体的繁殖;根际和根外变化明显,表现为根际>非根际。因此,创造了更好的土壤条件更有利于退化喀斯特植被的恢复。

The soil samples in different restoration stages in the researched area were taken as the study object.The microbial incubation methods and experimental means of the bio-chemical activity were used.The changes of the soil basal respiration and qCO2 different soil layers,microhabitats and Rhizosphere,Non-rhizosphere were studied during the process of degraded Karst vegetation restoration.The results showed that the soil basal respiration and qCO2 had obvious difference.With degraded Karst vegetation restoration,the soil basal respiration were ascending obviously,taking on arboreal community stage〉shrubby community stage〉herbaceous community stage〉bare land stage.But the change of qCO2 was just opposite.It decreased with the vegetation restoration,which indicated the soil quality has been restored gradually.The soil basal respiration and qCO2 took on the characteristic of vertical change in the soil profile,which decreased with the increase of the soil depth,presenting A〉B.The changes of the soil basal respiration and qCO2 in different habitats overall performed the characteristics which stone gully was higher than soil surface and stone-groove.It was because stone gully habitat characteristics were advantageous to breed soil microorganisms and animal and plant groups.They were different between the rhizosphere and none-rhizosphere,which means that they created better soil conditions to improve the vegetation restoration of degraded Karst.