Abstract:

The purpose of this study was to study the dynamics of SMBC(Soil microbial biomass carbon) and SWSOC(Soil water soluble organic carbon) along re-vegetation chronosequences on hillslope land with purple soils in Hengyang City of Hunan Province. By using the space for time method, six typical sampling plots(grassplot(GT), meadow thichet (MT), frutex(FX), frutex and arbor (FA), arbor (AR), and top-level vegetation(TV)) were selected to explore the variable regulations of SMBC, SMQ (Soil microbial quotient), SWSOC, SWSOC/SOC, SBR(Soil basal respiration) in 0~10, 10~20 and 20~40 cm soil layers and the relationship between them and soil physio-chemical properties. The six communities were similar and typical, and denoted six different successive stages on hillslope land with purple soils in Hengyang City of Hunan Province. The results showed that:The content of SMBC and SBR decreased with increasing soil depth but increased with the process of re-vegetation; SMQ increased with increasing soil depth and with the process of re-vegetation; SWSOC content decreased with increasing soil depth in different re-vegetation stages; in 0~10 cm soil layer, SWSOC content increased with the process of re-vegetation, while in 10~20 and 20~40 cm soil layers, SWSOC content decreased after an initial increase; SWSOC/SOC increased with increasing soil depth, but decreased with the process of re-vegetation; there were close correlations between SMBC, SMQ, SWSOC and SBR and soil physic-chemical properties. All the results indicated that it was essential to take strong measures to accelerate the re-vegetation and help to improve soil quality and accumulate soil organic carbon on hillslope land with purple soils in Hengyang City of Hunan Province.

Key words: Soil microbial biomass carbon(SMBC), Soil water soluble organic carbon(SWSOC), Soil basal respiration(SBR), Re-vegetation, Purple soils, Hengyang City of Hunan Province

摘要：

为了研究湖南省衡阳市紫色土丘陵坡地恢复过程中土壤微生物生物量碳（SMBC）与水溶性有机碳（SWSOC）的变化特征。采用空间序列代替时间序列的方法，选用立地条件基本相似的草坡阶段（GT）、草灌阶段（MT）、灌丛阶段（FX）、灌乔阶段（FA）、乔木阶段（AR）和顶极阶段（TV），通过调查取样和试验分析，对不同恢复阶段的0~10，10~20和20~40 cm土层土壤的SMBC、土壤微生物熵（SMQ）、SWSOC、水溶性有机碳与土壤有机碳的比值（SWSOC/SOC）、土壤基础呼吸（SBR）的变化规律以及他们与土壤理化性质的关系进行了研究。结果表明：SMBC和SBR随着土层深度的增加而减小，随着恢复的进行而增加；SMQ随着土层深度的增加和恢复进行而增加；在不同的恢复阶段，SWSOC均随着土层深度的增加而减小，在0~10 cm土层，SWSOC随着恢复的进行而增加，在10~20和20~40 cm土层，SWSOC随着恢复的进行先增后减；SWSOC/SOC随着土层深度的增加而增加，随着恢复的进行而减小；SMBC，SMQ，SWSOC，SBR均与土壤理化性质存在密切的相关性。研究表明，植被恢复有利于土壤质量的提高和土壤有机碳库的累积。

关键词: 土壤微生物生物量碳, 土壤水溶性有机碳, 土壤基础呼吸, 植被恢复, 紫色土, 湖南省衡阳市