外源稀土镧对茶园土壤有机碳的影响

为揭示外源稀土对土壤有机碳库和土壤生态环境的影响,通过土培实验,研究了不同浓度稀土元素镧(La)处理下,茶园土壤有机碳(SOC)及其活性组分易氧化有机碳(ROC)、水溶性有机碳(WSOC)和微生物量碳(MBC)含量的变化特征。结果表明:外源稀土元素La对茶园土壤有机碳及其活性组分具有显着的影响,随着处理浓度的增加,La对SOC、ROC和WSOC的影响呈现出低促高抑的特征,而对MBC的抑制作用不断增强;随处理时间延长,各浓度La处理SOC和MBC含量总体呈下降趋势,而ROC和WSOC含量总体呈上升趋势。因此,MBC可作为外源稀土元素对土壤有机碳影响监测和评价的敏感指标。

Influence of Exogenous Lanthanum on Soil Organic Carbon in Tea Soil

Rare earth elements have shown beneficial roles in plant growth, yields and quality. However, there is little information available about their effects on soil organic carbon(SOC), an important indicator of soil fertility and soil ecological quality. In this study, a pot experiment was carried out to examine the effects of exogenous lanthanum(La) on SOC and its active components, including readily oxidizable organic carbon(ROC), water-soluble organic carbon(WSOC) and microbial biomass carbon(MBC), in tea garden soil. Lanthanum had significantly effects on SOC and its active components. SOC, ROC and WSOC displayed a promotion at low concentrations but an inhibition at high concentrations, while the inhibitory effect of La on MBC constantly increased with increasing La concentrations. Extending La exposure decreased SOC and MBC content, while it tended to increase ROC and WSOC content. These findings show that MBC can be used as a sensitive index to monitor and evaluate the influence of exogenous rare earth elements on soil organic carbon.