Distribution and eco-stoichiometry of carbon and nitrogen of the plant-litter-soil continuum in evergreen broad-leaved forest

Abstract

ABSTRACT In order to understand the nutrient distribution characteristics and eco-stoichiometry of the evergreen broad-leaved forest in Dagang Mountain of Jiangxi Province, China, we investigated the distribution and stoichiometry of carbon and nitrogen along the plant-litter-soil continuum in evergreen broad-leaved forest. The total N concentration of the fine roots and litter had a high coefficient of variation of,16.22% and 9.17%, with a high spatial heterogeneity, respectively. The relationship between the carbon and nitrogen concentration and the functional traits of leaves and roots of constructive species was analyzed. The total C and N concentrations in leaves and roots were positively related. C concentration in the leaves and fine roots of S. discolor was relatively high, as 418.16 g·kg−1 and 381.82 g·kg−1, leading to the strong carbon storage capacity in the whole plant. A. fortunei had low leaf and fine root C: N ratios (14.94 and 19.96), mainly causing its high growth rate. Compared to evergreen tree species, deciduous tree species had higher nitrogen concentration in leaves and roots, larger specific leaf area, smaller root surface area, and root length. With the increase of soil depth, the concentration of soil SOC, ROC, total N, alkali nitrogen, NH4 +-N and NO3 –N decreased, but the variation of NH4 +-N and NO3 –N was minor. Among the components, alkaline N had a strong relation with soil C and N, and ROC was highly related with soil ammonium and nitrate nitrogen. The result in this study reveals the different survival strategies and relative adaptive mechanism of different species.