This study investigated the impact of soil compaction owing to cotton picker traffic, and the impact of this compaction on cotton yield on a row-by-row basis across the field under both random traffic farming (RTF) and controlled traffic farming (CTF) systems. Measurements of soil water content, dry bulk density and soil penetration resistance were taken and compared with a depth of 80 cm both before and after traffic. It was found that the traffic of JD7760 round-bale cotton picker caused significant compaction in cotton rows and furrows located between, adjacent to, and in wheel tracks under both RTF and CTF systems, particularly for the top 30-cm depth. Because of the soil compaction, the yield was more significantly reduced (7∼10% by the machine-pick method) in the rows between the dual-wheel than in those adjacent to the wheel track. Adopting CTF reduces the area of soil compaction and ensures the maintenance of soil characteristics of the cultivated portions of the farm, hence enhancing cotton yield.