Bruand A. auteur aut IRD Balbino L.C. auteur aut IRD Volland-Tuduri N. auteur aut IRD Cousin I. auteur aut IRD Reatto Braga A. auteur aut IRD Lopes de Oliveira M.I. auteur aut IRD De Souza Martins E. auteur aut IRD Brossard Michel auteur aut IRD Disnar J.R. auteur aut IRD text conferencePaper eng text/pdf reformatted digital access Ferralsols have a ferralic horizon at some depth between 30 and 200 cm that results from long and intense weathering. Their clay fraction is usually mainly low-activity clay consisting of kaolinite with hematite, goethite and gibbsite in different proportions. Ferralsols show little or no horizonation, and their macrostructure is absent to moderate. On the other hand, they have typically a strong microstructure consisting of microaggregates < 1 mm in size. Because of the lack or small development of macrostructure, porosity of Ferralsols is closely related to the development of microstructure and the assemblage of elementary particles within the microaggregates with a small contribution of large pores resulting from root development and macrofaunal activity. Their physical properties are then closely related to the development of this microstructure. However, there is still no model in the literature that predicts changes of microstructure of these soils using easily accessible soil properties when land-use is modified. The objective of this work was to relate microstructure development to the bulk density (Db) in Ferralsols and then to make possible the use of Db as an indicator of microstructure development. specialized BRESIL 068 Congrès Mondial de Science du Sol, 18., Philadelphie (USA), 2006/07/09-15 141-142 Philadelphie IUSS 2006 https://www.documentation.ird.fr/hor/fdi:010072619 [F B010072619] https://www.documentation.ird.fr/hor/fdi:010072619 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers18-07/010072619.pdf IRD - Base Horizon / Pleins textes 2009-05-13 2018-08-09 fdi:010072619 fre