Title:	CO2-driven cation leaching after tropical forest clearing.
Authors:	MARKEWITZ, D. FIGUEIREDO, R. de O. DAVIDSON, E. A.
Affiliation:	DANIEL MARKEWITZ, The University of Georgia RICARDO DE OLIVEIRA FIGUEIREDO, CPATU ERIC A. DAVIDSON, The Woods Hole Research Center.
Date Issued:	2006
Citation:	Journal of Geochemical Exploration, v. 88, n. 1/3, p. 214-219, 2006.
Description:	The objective of this study was to investigate the role of dissolved CO2 (H2CO3*) as a mechanism of cation removal from surface soils under secondary land uses in the tropics. Soil leachate columns were prepared with 0?10 cm soils from mature and secondary forest, and managed pastures, and extracted with H2CO3* from deionized water equilibrated with 0%, 0.5%, 1%, and 10% CO2 (g). Extraction of soil cations slowed over time following an exponential form for the cumulative data. The rate of cation concentration decline varied as a function of CO2 concentration with the 10% solution resulting in a greater percent decline with extraction volume. Potassium removal from the exchange sites of all soils and for all solutions was nearly complete ranging from 85% to 97% while removals of Mg (31% to 71%) and Ca (12% to 42%) were lower. The asymptotic patterns of cation loss observed in this study suggest that H2CO3* acid-driven losses of cations may become self-limiting over time. Other stronger acids from atmospheric deposition or organic sources may serve to perpetuate cation removal, and re-forestation on these cleared lands would certainly re-distribute cations from soils to vegetation.
Thesagro:	Cálcio Potássio
NAL Thesaurus:	Amazonia
DOI:	10.1016/j.gexplo.2005.08.042
Type of Material:	Artigo de periódico
Access:	openAccess
Appears in Collections:	Artigo em periódico indexado (CPATU)