衡阳紫色土丘陵坡地植被恢复对土壤活性有机碳库的影响

Effect of Re-vegetation on Active Organic Carbon Pool of Purple Soils on Sloping-land in Hengyang, Hunan Province, China

摘要:

为了解植被恢复对土壤活性有机碳库的影响，采用空间代替时间序列方法，对衡阳紫色土丘陵坡地植被恢复对土壤活性有机碳含量和分布进行研究。结果表明，土壤有机碳（SOC）、微生物量碳（MBC）、水溶性有机碳（DOC）、轻组有机碳（LFOC）和易氧化碳（ROC）含量均以乔灌阶段最高（P<0.05），随土层加深显著减小（P<0.05）。随恢复进程，MBC/SOC、DOC/SOC和ROC/SOC显著增加（P<0.05）；0～20 cm土层，LFOC/SOC随恢复显著增加（P<0.05），而20～40 cm土层，LFOC/SOC的差异不明显（P>0.05）。随土层加深，LFOC/SOC显著减小（P<0.05），DOC/SOC、MBC/SOC和ROC/SOC逐渐增加（P>0.05）。SOC、MBC、DOC、LFOC和ROC间存在极显著正相关关系（P<0.01）。各类活性有机碳库与土壤含水量（SWC）、全氮（TN）、碱解氮（AN）和速效磷（AP）呈显著或极显著正相关关系（P<0.05或P<0.01），与土壤容重（BD）呈极显著负相关关系。因此，植被恢复在一定程度上可提高衡阳紫色土丘陵坡地土壤活性有机碳的形成和积累，增加土壤碳储量。

Abstract:

In order to understand the effect of re-vegetation on soil active organic carbon, the soil active organic carbon content and distribution in purple soils on sloping-land in Hengyang, Hunan Province, China were studied by using method of spatial series replace time series. The results showed that the content of soil organic carbon (SOC), microbial biomass carbon (MBC), dissolved organic carbon (DOC), light fraction organic carbon (LFOC) and readily oxidizable carbon (ROC) were the highest at arbor and frutex stage (P<0.05), and they significantly decreased with soil depth (P<0.05). The ratio of MBC/SOC, DOC/SOC and ROC/SOC significantly increased with the process of re-vegetation (P<0.05). In 0-20 cm soil layer, LFOC/SOC significantly increased with the process of re-vegetation (P<0.05), but that was not obvious change in 20-40 cm soil layer (P>0.05). Along soil depth, LFOC/SOC significantly decreased (P<0.05), DOC/SOC, MBC/SOC and ROC/SOC gradually increased (P>0.05). There were significant positive correlation among SOC, MBC, DOC, LFOC and ROC (P<0.01). All kinds of active organic carbon pool had significant positive correlations (P<0.05 or P<0.01) with soil water content (SWC), total nitrogen (TN), alkali-hydrolyzed nitrogen (AN), available phosphorus (AP), and significant negative correlations (P<0.01) with bulk density (BD). Therefore, re-vegetation could enhance at certain degree formation and accumulation of soil active organic carbon and increased soil carbon storage in purple soils on sloping-land in Hengyang.