Short-term decomposition of 14C-labelled glucose in a fluvo-aquic soil as affected by lanthanum amendment

摘要

In this study, we investigated the effects of lanthanum (La), one of the rare earth elements (REEs), on microbial biomass C as well as the decomposition of 14C-labelled glucose in a fluvo-aquic soil in 28 days. The soil was collected from the field plots under maize/wheat rotation in Fengqiu Ecological Experimental Station of Chinese Academy of Sciences, Henan Province, China. Application of La decreased soil microbial biomass C during the experimental period, and there was a negative correlation (P < 0.01) between microbial biomass and application rate of La. La increased microbial biomass 14C after 14C glucose addition, and the increase was significant (P < 0.05) at the rates of more than 160 mg kg?1 soil. La slightly increased 14CO2 evolution at lower rates of application but decreased it at higher rates 1 day after 14C glucose addition, while there was no significant effect from days 2 to 28. For the cumulative 14CO2 evolution during the incubation of 28 days, La slightly increased it at the rates of less than 120 mg kg?1 soil, while significantly decreased (P < 0.05) it at the rate of 200 mg kg?1 soil. The results indicated that agricultural use of REEs such as La in soil could decrease the amount of soil microbial biomass and change the pattern of microbial utilization on glucose C source in a short period.