The identification of impacts of mechanized sugarcane harvesting on the structure in different soil classes can be an important strategy to minimize compaction effects. The objective of this study was to evaluate the structural changes, preconsolidation pressure and least limiting water range (LLWR) in a Red-Yellow Latosol (LVA) and a Haplic Cambisol (CX), due to harvest operations at different periods during the sugar cane harvesting season. Undisturbed soil samples were collected in the layer 0 to 0.05 m to determine preconsolidation pressure, bulk density, porous space, aggregation and the LLWR. Disturbed soil samples were taken for chemical and physical characterization of the soil. The compaction resistance of CX was higher than that of LVA. The soil water content during the harvest of sugarcane varied in the following order: August 2006 < November 2005 < March 2006, and CX > LVA in each period. The preconsolidation pressure showed that bulk density was sensitive to occurrence of structural changes in the soil. Limiting macroporosity restricted plant growth at compaction levels below the critical bulk density of LLWR. Mechanized sugarcane harvesting at soil water contents of up to 0.16 and 0.21 kg kg-1, for LVA and CX, respectively, did not cause excessive compaction.
Saccharum sp; harvest mechanization; soil structure
