Physical attributes, i.e, water dispersible clay (WDC), available water (AW) and specific surface area (SSA) of surface and subsurface samples of three acne Oxisols from the São Paulo State - Brazil (two dusky red and one Una variant latosol) were studied. WDC decreased markedly with depth and their values were 0 and 2% for the B horizon. In that layer, electric charge density, surface potential and deltapH were close to zero, promoting colloid flocullation. Amounts of AW were low (<6%) in all samples, with exception of the surface layer from one of the dusky red latosols, for which available water was medium (6-12%). Those low values reflected strong microagreggationof the acric Oxisols, whose water retention and movement are similar to sandy soils. SSA had small values, varying from 42 to 104nrVg, as a result of a predominance of kaolinite and oxides in the soil clay fraction. A positive correlation was obtained between SSA and the amounts of organic carbon and iron oxides.
acric Oxisols; water dispersible clay; available water; specific surface area