Changes in SBR and qCO2 at Different Re-vegetation Stages on Slopingland with Purple Soils in Hengyang of Hunan Province, South-central China

Abstract:

In order to understand the changes in soil respiration of sloping-land with purple soils in Hengyang, the soil basal respiration (SBR), metabolic quotient (qCO₂) were studied by using the space series to replace time series, and the relationships between SBR, qCO₂ and soil properties were analyzed. The results showed that SBR and qCO₂ had significant difference at different re-vegetation stages. From bare land stage (Ⅰ), herb community stage (Ⅱ), shrub community stage (Ⅲ) to tree community stage (Ⅳ), SBR significantly increased (P<0.05), while qCO₂ significantly decreased (P<0.05). At every re-vegetation stage, SBR significantly decreased (P<0.05) along 0-20 cm, 20-40 cm, and 40-60 cm soil layers, while qCO₂ significantly increased (P<0.05). From Ⅱ, Ⅲ to Ⅳ stages, SBR of rhizosphere (R) and non-rhizosphere (S) significantly increased (P<0.05), and R/S of SBR significantly decreased (P<0.05), while qCO₂ of R and S gradually decreased (P>0.05), and R/S of qCO₂ gradually increased (P>0.05). SBR and qCO₂ in rhizosphere were bigger than those in non-rhizosphere. Correlation analysis showed that SBR had significantly positive correlation with soil microbial biomass carbon (SMBC) and soil temperature (ST) (P<0.01), and significantly negative with soil bulk density (SBD) (P<0.05). qCO₂ had significantly negative correlation with SMBC (P<0.01) and ST (P<0.05), but significantly positive with SBD and pH value (P<0.05). These would have a theoretical and practical significance for building vegetation restoration technique system.