Soil organic matter in podzol horizons of the Amazon region: Humification, recalcitrance, and dating

Author(s)

Tadini, Amanda M. ^{[1, 2, 3]} ; Nicolodelli, Gustavo ^[2] ; Senesi, Giorgio S. ^[4] ; Ishida, Debora A. ^{[5, 6]} ; Montes, Celia R. ^{[7, 6]} ; Lucas, Yves ^[3] ; Mounier, Stephane ^[3] ; Guimaraes, Francisco E. G. ^[8] ; Milori, Debora M. B. P. ^[2]

Affiliation

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, Sao Carlos, SP - Brazil

^[2] EMBRAPA Instrumentacao, Sao Carlos, SP - Brazil

^[3] Univ Toulon & Var, Lab PROTEE, CS 60584, F-83041 Toulon 9 - France

^[4] CNR, Inst Nanotechnol NANOTEC, PLasMI Lab, Bari - Italy

^[5] Univ Sao Paulo, Inst Energia & Ambiente, Piracicaba, SP - Brazil

^[6] Univ Sao Paulo, Nucleo Pesquisa Geoquim & Geofis Litosfera, Piracicaba, SP - Brazil

^[7] Univ Sao Paulo, Ctr Energia Nucl Agr, Piracicaba, SP - Brazil

^[8] Univ Sao Paulo, Inst Fis Sao Carlos, Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Science of The Total Environment; v. 613, p. 160-167, FEB 1 2018.
• Web of Science Citations: 7

Abstract

Characteristics of soil organic matter (SOM) are important, especially in the Amazon region, which represents one of theworld's most relevant carbon reservoirs. In this work, the concentrations of carbon and differences in its composition (humification indexes) were evaluated and compared for several horizons (0 to 390 cm) of three typical Amazonian podzol profiles. Fluorescence spectroscopy was used to investigate the humic acid (HA) fractions of SOM isolated from the different samples. Simple and labile carbon structures appeared to be accumulated in surface horizons, while more complex humified compounds were leached and accumulated in intermediate and deeper Bh horizons. The results suggested that the humic acids originated from lignin and its derivatives, and that lignin could accumulate in some Bh horizons. The HA present in deeper Bh horizons appeared to originate from different formation pathways, since these horizons showed different compositions. There were significant compositional changes of HA with depth, with four types of organic matter: recalcitrant, humified, and old dating; labile and young dating; humified and young dating; and little humified and old dating. Therefore, the humification process had no direct relation with the age of the organic matter in the Amazonian podzols. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 13/07276-1 - CEPOF - Optics and Photonic Research Center
• Grantee: Vanderlei Salvador Bagnato
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 11/03250-2 - Quantification and dynamics of carbon associated with deep spodic horizons of Amazon Forest soils, towards possible climatic changed
• Grantee: Célia Regina Montes
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/51469-6 - Modelling the dynamics of equatorial forest soil deep carbon in changing environments - C-PROFOR
• Grantee: Adolpho José Melfi
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 13/13013-3 - Characterization Humic Substances extracted from Amazonian Soils
• Grantee: Amanda Maria Tadini
• Support Opportunities: Scholarships in Brazil - Doctorate