Shrinkage of microaggregates in Brazilian Latosols during drying: significance of the clay content, mineralogy and hydric stress history

Adriana Reatto-Braga 1, 2 Ary Bruand 1 E.M. Silva 3 Régis Guégan 1 Isabelle Cousin 4 Michel Brossard 5 E.S. Martins 3
1 ISTO - Institut des Sciences de la Terre d'Orléans
2 Embrapa Cerrados - Empresa
3 EMBRAPA CERRADOS - EMBRAPA Cerrados
4 Unité de Science du Sol
5 Eco&Sols - Ecologie fonctionnelle et biogéochimie des sols et des agro-écosystèmes
Abstract : Latosols are characterized by a poor differentiation of the horizons, a weak macrostructure and a strong submillimetric granular structure resulting in microaggregates 50 to 300 µm in size. The shrinkage properties of these microaggregates that are generally considered as very weak or absent are still under discussion. The objective of our study is the analyze the shrinkage properties of microaggregates in diagnostic Bw horizons collected in a set of Latosols varying in their particle size distribution and mineralogical composition according to their location in a regional toposequence across the Brazilian Central Plateau. We measured the water retention properties at 300 and 1500 kPa by using the centrifugation method. The morphology and size of the elementary particles was studied by using transmission electron microscopy and determining the specific surface area (SSA) with the BET method. We determined also the pore size distribution of the microaggregates by combining mercury intrusion and nitrogen desorption isotherm. Our results showed that the microaggregates of the Latosols studied are not rigid but shrink during drying. The pore volume of the microaggregates at –300 and –1500 kPa as well as the pore volume of the dried microaggregates are closely related to the clay content. The SSA is also closely related to the clay content. Consequently, the mineralogy of the <2 µm would play at the most a marginal role in the properties studied. Finally, our results showed that the shrinkage of the microaggregates between –300 kPa and the shrinkage limit and between –1500 kPa and the shrinkage limit varies with the location of the Latosols in the Landscape. Thus, the microaggregates of the Latosols located on the SAS shrink less than those of the Latosols located on the VS. This difference might be related to a difference of hydric stress history of the Latosols.
Type de document :
Article dans une revue
European Journal of Soil Science, Wiley, 2009, 60, pp.1106-1116. 〈10.1111/j.1365-2389.2009.01189.x〉
Liste complète des métadonnées

Littérature citée [35 références]  Voir  Masquer  Télécharger
https://hal-insu.archives-ouvertes.fr/insu-00414419
Contributeur : Nathalie Pothier <>
Soumis le : jeudi 9 septembre 2010 - 07:00:06
Dernière modification le : lundi 3 juillet 2017 - 09:00:32
Document(s) archivé(s) le : vendredi 10 décembre 2010 - 02:16:13

Fichier

EJSS_Reatto_et_al_2009.pdf
Fichiers produits par l'(les) auteur(s)

Identifiants

Collections

INSU | IRD | ISTO | UNIV-ORLEANS | INRA | OSUC | AGROPOLIS | CIRAD

Citation

Adriana Reatto-Braga, Ary Bruand, E.M. Silva, Régis Guégan, Isabelle Cousin, et al.. Shrinkage of microaggregates in Brazilian Latosols during drying: significance of the clay content, mineralogy and hydric stress history. European Journal of Soil Science, Wiley, 2009, 60, pp.1106-1116. 〈10.1111/j.1365-2389.2009.01189.x〉. 〈insu-00414419〉

Exporter

BibTeX TEI DC DCterms EndNote
Rdf

Partager

Métriques

Consultations de
la notice

355

Téléchargements du document

126

Contact

support.ccsd.cnrs.fr
hal.support@ccsd.cnrs.fr
Logo CCSD