Litter chemistry, soil microbial priming and community composition regulate the accrual and chemical composition of subtropical forest soil organic carbon

Background/Question/Methods

Large uncertainties remain concerning the factors that control the retention of litter-derived carbon (C) in soils. A study using various tree species selection was design to change chemistry of tree litter input. The effects of different chemical properties of litter; between coniferous and broadleaved tree species, and their roles of soil microbial priming and microbial community composition on soil organic carbon (SOC) quantity and composition in forest ecosystems; remain unclear. A manipulation field experiment was set up using diverse litter in stable environmental and soil conditions. Four tree species litter was added to the surface of soil in a subtropical Pinus massoniana plantation to assess the effect of different functional litter input on the accrual and chemical composition of SOC.

Results/Conclusions

The soils that received litter input had all very similar C concentration, compared to the soils without litter input. Concentrations of SOC were lower in broadleaved litter (Castanopsis hystrix and Erythrophloeum fordii) input than those in coniferous litter (P. massoniana and Cunninghamia lanceolata). Concentration of SOC was positively related to litter C content and litter C/nitrogen ratio. Characteristic of SOC chemical composition was separated into coniferous litter and broadleaved litter input. The proportions of SOC chemical composition were not related to litter C chemical composition, whereas they were obviously related to soil fungi/bacteria ratio across different litter treatments. Our findings highlight the different effects of litter input with different chemical properties on the accrual and chemical composition of SOC. The larger microbial priming of SOC under input of the broadleaved litter than coniferous litter lead to more native soil C loss. Soil microbial community composition regulated by litter chemistry played a crucial role in the formation of chemical compositions of SOC. This study aims to predict the C potential of tree species shifts under global change and land management.