LI, YIQING; XU, MING; ZOU, XIAOMING 2006. Effects of nutrient additions on ecosystem carbon cycle in a Puerto Rican tropical wet forest. Global Change Biology 11, :1-10,.
Abstract:
Wet tropical forests play a critical role in global ecosystem carbon (C) cycle, but C
allocation and the response of different C pools to nutrient addition in these forests
remain poorly understood. We measured soil organic carbon (SOC), litterfall, root
biomass, microbial biomass and soil physical and chemical properties in a wet tropical
forest from May 1996 to July 1997 following a 7-year continuous fertilization. We found
that although there was no significant difference in total SOC in the top 0–10cm of the
soils between the fertilization plots (5.42 0.18 kgm2) and the control plots
(5.27 0.22 kgm2), the proportion of the heavy-fraction organic C in the total SOC
was significantly higher in the fertilized plots (59%) than in the control plots (46%)
(Po0.05). The annual decomposition rate of fertilized leaf litter was 13% higher than that
of the control leaf litter.We also found that fertilization significantly increased microbial
biomass (fungi1bacteria) with 952 48mgkg1soil in the fertilized plots and
755 37mgkg1soil in the control plots. Our results suggest that fertilization in tropical
forests may enhance long-term C sequestration in the soils of tropical wet forests.