The mechanical harvesting of sugarcane (Saccharum officinarum) increases the risks of soil physical degradation. The objective of this study was to determine the least limiting water range (LLWR) and S index to evaluate the physical quality in soils under mechanically harvested sugarcane. Three soils were sampled (layers 0-0.20 and 0.20-0.40 m): clayey Oxisol (clayey LV), loam Oxisol (medium-textured LV) and a sandy Ultisol (sandy PVA). In decreasing order, the LLWR was clayey LV < sandy PVA < medium-textured LV. In the medium-textured LV, the critical bulk density (BDc) was 1.76 and 1.77 Mg m-3, respectively, in the layers 0-0.20 and 0.20-0.40 m. BDc was not observed in the sandy PVA and clayey LV, based on the range of bulk densities of the field soil samples. The S index was > 0.050 for the clayey LV, around 0.024 for the medium-textured LV and S was < 0.033 for the sandy PVA. The LLWR and S values indicated that the physical restrictions to root growth and development under mechanical sugarcane harvesting system were greatest in the medium-textured LV.
least limiting water range; S index; soil bulk density
