Effects of nutrient additions on ecosystem carbon cycle in a Puerto Rican tropical wet forest |
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| Authors: | YIQING LI † MING XU ‡ XIAOMING ZOU†§ |
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| Institution: | Department of Ecology, Evolution and Natural Resources, Rutgers University, 14 College Farm Road, New Brunswick, NJ 08901-8551, USA,;Xishuangbanna Tropical Botanical Garden, The Chinese Academy of Sciences, 88 Xuefu Road, Kunming, Yunnan 650223, China,;College of Forestry, The Northwest Sci-Tech University of Agriculture and Forestry, Yangling, Shaanxi 712100, China,;Institute for Tropical Ecosystem Studies, University of Puerto Rico, San Juan, PR 00931, USA |
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| 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 0–10 cm of the soils between the fertilization plots (5.42±0.18 kg m?2) and the control plots (5.27±0.22 kg m?2), 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%) (P<0.05). 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 (fungi+bacteria) with 952±48 mg kg?1soil in the fertilized plots and 755±37 mg kg?1soil 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. |
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| Keywords: | decomposition forest floor mass litterfall long-term carbon microbial biomass soil carbon |
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