Ferrolysis induced soil transformation by natural drainage in Vertisols of sub-humid South India


Autoria(s): BARBIERO, L.; KUMAR, M. S. Mohan; VIOLETTE, A.; OLIVA, P.; BRAUN, J. J.; KUMAR, C.; FURIAN, S.; BABIC, M.; RIOTTE, J.; VALLES, V.
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

19/10/2012

19/10/2012

2010

Resumo

In sub-humid South India, recent studies have shown that black soil areas (Vertisols and vertic Intergrades), located on flat valley bottoms, have been rejuvenated through the incision of streambeds, inducing changes in the pedoclimate and soil transformation. Joint pedological, geochemical and geophysical investigations were performed in order to better understand the ongoing processes and their contribution to the chemistry of local rivers. The seasonal rainfall causes cycles of oxidation and reduction in a perched watertable at the base of the black soil, while the reduced solutions are exported through a loamy sand network. This framework favours a ferrolysis process, which causes low base saturation and protonation of clay, leading to the weathering of 2:1 then 1:1 clay minerals. Maximum weathering conditions occur at the very end of the wet season, just before disappearance of the perched watertable. Therefore, the by-products of soil transformation are partially drained off and calcareous nodules, then further downslope, amorphous silica precipitate upon soil dehydration. The ferrolysed area is fringing the drainage system indicating that its development has been induced by the streambed incision. The distribution of (14)C ages of CaCO(3) nodules suggests that the ferrolysis process started during the late Holocene, only about 2 kyr B.P. at the studied site and about 5 kyr B.P. at the watershed outlet. The results of this study are applied to an assessment of the physical erosion rate (4.8x10(-3) m/kyr) since the recent reactivation of the erosion process. (C) 2010 Elsevier B.V. All rights reserved.

ORE-BVET Observatoire de Recherche en Environnemerit - Bassin Versant Experimentaux Tropicaux

IRD/INSU/CNRS

Indo-French Centre for the Promotion of Advanced Research[WA-3000]

Identificador

GEODERMA, v.156, n.3/Abr, p.173-188, 2010

0016-7061

http://producao.usp.br/handle/BDPI/21061

10.1016/j.geoderma.2010.02.014

http://dx.doi.org/10.1016/j.geoderma.2010.02.014

Idioma(s)

eng

Publicador

ELSEVIER SCIENCE BV

Relação

Geoderma

Direitos

restrictedAccess

Copyright ELSEVIER SCIENCE BV

Palavras-Chave #Vertisol #Ferrolysis #Duripan #Calcareous nodules #Physical erosion rate #Late Holocene #South India #RARE-EARTH-ELEMENTS #NORTHEAST THAILAND #TROPICAL REGIONS #CLAY #ROCK #DEGRADATION #PEDOGENESIS #BANGLADESH #MANAGEMENT #LANDFORMS #Soil Science
Tipo

article

original article

publishedVersion