The objective of this study was to measure the vertical and horizontal distribution of georeferenced values of cone index (CI) in a no-till field and the influence of soil water content. Data were interpolated to allow for cause and effect analysis. Other important factors as clay and silt content, bulk density, porous space and organic matter content were also measured. A penetrometer mounted on a tractor and equipped with a load cell was used together with GPS receiver, soil auger and computer programs to collect and analyze the data. Analysis was conducted based on maps of interpolated data after choosing the models with the highest determination coefficient (R²) and regressions among them. High CI values were found at depths between 0.10 to 0.15 m. Lower values of CI were associated with place of higher organic matter content, coincident with higher clay and silt content. CI was first influenced by the water content, bulk density and porous space.
soil compaction; geoestatistics; precision agriculture
