The heterogeneity in soil compaction induced by different traffic intensities can reduce the productivity of citrus trees. The objective of this research was to quantify the compression index (CI) and the preconsolidation pressure (sigmap) in different sampling positions (row, between wheel track, wheel track, and canopy projection) to evaluate the compaction heterogeneity in a Haplustox under an orange orchard. The sampling was carried out at forty randomly distributed sites (ten samples in each position). The samples were water saturated and equilibrated at a water potential (psi) of -10 kPa. Thereafter, they were weighed and submitted to a uniaxial compression test under the following pressures: 25, 50, 100, 200, 400, 600, 800, 1,000, 1,300, and 1,600 kPa. The results indicated that the sigmap was the most sensitive indicator to evaluate the compaction heterogeneity induced by the traffic of agricultural machinery in areas cultivated with citrus trees. Soil compaction increased in the following order: row, between wheel tracks, at the wheel track, and canopy projection position.
compression index; preconsolidation pressure; sampling position
