The Linkage of Soil CO2 Emissions in a Moso Bamboo (Phyllostachysedulis (Carriere) J. Houzeau) Plantation with Aboveground and Belowground Stoichiometry

Abstract

Understanding the effects of soil stoichiometry and nutrient resorption on soil CO2 emissions is critical for predicting forest ecosystem nutritional demands and limitations tooptimal forest growth. In this study, we examined the effects of above- and belowground stoichiometry on soil CO2 emissions and their mediating effect on soil respiration in subtropical moso bamboo (Phyllostachys edulis) plantations. Our results showed that the soil respiration rate did not differ significantly among four bamboo stands. Nitrogen (N) and phosphorous (P) concentrations were higher in bamboo leaves than litter, whereas the C:N and C:P ratios showed the opposite trend. Significant positive correlations of soil cumulative CO2 emission with litter C:P (p = 0.012) and N:P (p = 0.041) ratios indicated that litter stoichiometry was a better predictor of soil respiration than aboveground stoichiometry. Cumulative soil CO2 emissions were significantly negatively correlated with soil microbe C:N (p = 0.021) and C:N (p = 0.036) ratios, and with soil respiratory quotients (p < 0.001). These results suggest that litter and soil stoichiometry are reliable indicators of the soil respiration rate. This study provides important information about the effects of ecosystem stoichiometry and soil microbial biomass on soil CO2 emissions and highlights them editing role of soil nutritional demands and limitations in the association between soil respiration rates and aboveground plant tissues.