Comportement de la phase argileuse lors de la dessiccation dans des Ferralsols microagrégés du Brésil : rôle de la microstructure et de la matière organique.Report as inadecuate




Comportement de la phase argileuse lors de la dessiccation dans des Ferralsols microagrégés du Brésil : rôle de la microstructure et de la matière organique. - Download this document for free, or read online. Document in PDF available to download.

1 EMBRAPA ARROZ E FEIJãO - EMBRAPA Arroz e Feijão 2 Unité de Science du Sol 3 ISTO - Institut des Sciences de la Terre d-Orléans 4 VALPEDO - Actualisation et valorisation des données pédologiques tropicales et méditerranéennes. Contributions à la recherche, à l-expertise et à l-aide à la gestion des ressources 5 Universidade Estadual de Londrina, Department of Agronomy

Abstract : Behaviour of the clay fraction during desiccation in microaggregated Ferralsols from Brazil: role of microstructure and organic matter. The physical properties of the microaggregates of Ferralsols are still under discussion. Two sites were selected for study: in each site, one soil under a native savannah Cerrado and another one under pasture were studied. Samples were analysed in the laboratory by using scanning electron microscopy and mercury porosimetry and by measuring the water content at −0.1 and −1.5 MPa potential. Results showed the presence of microaggregates 50 to 300 μm in size and bigger ones 500 to 1 000 μm in size. The latter were often packed in dense volumes 2 to 20 mm in size, which were numerous in the top soil under pasture. These dense volumes are casts and would result from an imbalance in the faunal population as a consequence of deforestation. Results showed also a shrinkage of the clayey phase for drying and this shrinkage increased with the carbon content of the soil. These results showed that microaggregates are not rigid fabrics and the significant role of organic matter in physical properties of the soils studied.  2001 Académie des sciences - Éditions scientifiques et médicales Elsevier SAS

Keywords : microaggregate shrinkage clay cerrado organic carbon termite cast Brazil





Author: Luíz Carlos Balbino - Ary Bruand - Michel Brossard - M. F. Guimarães -

Source: https://hal.archives-ouvertes.fr/



DOWNLOAD PDF




Related documents