Soil compaction due to traffic and natural reconsolidation limits the ability of crop roots to expand into deep zones of moisture availability. This study was conducted to determine whether the total absence of traffic substantially improved the resulting soil condition. Extensive cone index measurements were used to evaluate the soil strength resulting from 5 years of a cotton (Gossypium hirsutum L.)-wheat (Triticum aestivum L.) double cropping experiment. Four cotton tillage systems, including a conservation tillage practice of in-row subsoiling and planting into wheat residue stubble, and two traffic systems were analyzed. The USDA-ARS Wide-Frame Tractive Vehicle was used to control traffic in the experimental plots. Contour graphs of cone index were used to determine differences in tillage and traffic systems. Traffic was found to reconsolidate soil that was initially completely disrupted to a 0.51 m depth into a soil condition similar to one that had never received a subsoiling treatment. Traffic was also found to decrease the total soil volume estimated for root growth using a 2 MPa limiting cone index value, but not the maximum rooting depth beneath the row, when an annual in-row subsoiling practice was used.
