Soil Carbon Stocks under Amazonian Forest:Distribution in the Soil Fractions and Vulnerability to Emission

作     者：Jean Dalmo de Oliveira Marques Flávio Jesus Luizao Wenceslau Geraldes Teixeira Euler Melo Nogueira Philip Martin Fearnside Max Sarrazin 

作者机构：Federal Institute of EducationScience and Technology of the Amazonas(IFAM)Campus Center of ManausManausBrazil National Institute for Research in Amazonia(INPA)ManausBrazil National Center for Soil ResearchBrazilian Agricultural Research Corporation(EMBRAPA)Rio de JaneiroBrazil IRDUMR BIOEMCORoute de MontaboCayenne CedexFrench Guiana 

出 版 物：《Open Journal of Forestry》 (林学期刊（英文）)

年 卷 期：2017年第7卷第2期

页      面：121-142页

学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学] 

基　　金：the Large-Scale Atmosphere-Biosphere Experiment in Amazonia(LBA),Instituto Nacional de Pesquisas da Amazonia(INPA),Empresa Brasileira de Pesquisa Agropecuaria(EMBRAPA),Conselho Nacional do Desenvolvimento Cientifico e Tecnologico(CNPq:Proc.610042/2009-2,573810/2008-7,610042/2009-2) Fundacao de Amparo a Pesquisa do Estado do Amazonas(FAPEAM Proc.708565)for financial and logistical support 

主　　题：Fractionation of Carbon Carbon Stocks Soil Physics Global Warming Amazon Rainforest Brazil 

摘      要：Transformations of natural ecosystems in tropical regions, which are usually covered by high-biomass forests, contribute to increased atmospheric CO2. Much of the carbon in forest ecosystems is stored in the soil. This study estimates soil carbon stock in a dense forest in central Amazonia from sets of soil samples collected in three topographic positions (plateau, slope and valley bottom). Soil organic matter (SOM) was fractionated by density and particle size, thus obtaining the free light fraction (FLF), intra-aggregated light fraction (IALF), sand fraction (F-sand), clay fraction (F-clay) and silt fraction (F-silt). Soil organic carbon (SOC) stocks on the plateaus (Oxisol), slopes (Ultisol) and valley bottoms (Spodosol) were 98.4 ± 7.8 Mg·ha-1, 72.6 ± 5.4 Mg·ha-1 and 81.4 ± 8.9 Mg·ha-1, respectively. Distribution of carbon in soil fractions was: 112.6 ± 15 Mg·ha-1 (FLF), 2.5 ± 0 Mg·ha-1 (ILAF), 40.5 ± 1.5 Mg·ha-1 (F-silt), 68.5 ± 4.2 Mg·ha-1 (F-clay) and 28.3 ± 1.4 Mg·ha-1 (F-sand), totaling 252.4 ± 22.1 Mg·ha-1 of carbon. Carbon is largely in labile form and near the soil surface, making it liable to release from deforestation or from climate change. Spodosols are more susceptible to soil carbon losses, demonstrating the need to preserve forested areas close to Amazonian rivers and streams.