On the Visual Evaluation of Soil Structure: The Brazilian experience in Oxisols under no-tillage

The Visual Evaluation of Soil Structure is a helpful tool for assessing the physical quality of soil, since it allows detailed examination of the soil structure as well as identification of layers modified by soil management. The Visual Evaluation of Soil Structure (VESS) method (Ball et al., 2007) has been applied in Brazil because it is simple and relatively objective, giving semi quantitative results quickly. It was used to determine the physical quality of soils under systems of no-tillage. In the present study, the potential for utilization of the VESS method was studied in three field experiments under no-tillage: (i) a comparison between mechanical and biological soil loosening, (ii) a study of changes in soybean yield and soil structural quality along a transect with a soil textural gradient, and (iii) a comparison with Visual Soil Assessment (VS) method (Shepherd, 2009) along the same transect. Overall the use of VESS proved to be an efficient semi quantitative methodology for assessing soil physical quality in Brazilian soils under no-tillage.