Abstract
A field experiment was established on a heavy clayey Oxisol in the Amazon region near Manaus, Amazonas, Brazil, to compare the effects on soil physical properties of two different methods of clearance of tropical rainforest: (a) traditional slash-and-burn clearance and (b) mechanical clearance using bulldozers. Comparisons were made with adjacent virgin forest soils. Removal of topsoil, mechanical impedance, dry bulk density, porosity, moisture content and infiltration capacity were measured. The clearing of the forest by bulldozer resulted in considerable topsoil removal and deterioration of the soil structure. The hand-felling and burning method of clearing produced conditions little changed from those under virgin forest.
