Effect of Row Proximity to In-Row Subsoiled Zones on Cotton Productivity

Producers in the Coastal Plain of the southeastern United States manage soil compaction in conservation tillage systems by in-row subsoiling prior to planting. However, planting directly over the loosened zone of soil can be difficult in high-residue conservation tillage systems where cover crop production is maximized, because the loosened soil is often covered by the large amounts of cover crop residue. Tractors equipped with guidance systems could assist with placement of in-row subsoiling and planting operations, but little is known about the accuracy necessary to maximize rooting development, reduce succeeding soil compaction, and optimize crop yield. An experiment was conducted in south-central Alabama to determine the maximum distance in-row subsoiling performed by three different implements could be from the cotton row without reducing cotton growth and increasing soil compaction. Results showed that if the cotton row was within 5.1 cm of in-row subsoiling, the relative seed cotton yield is 44% greater than a corresponding no-subsoiling treatment. No significant differences were found between the three in-row subsoiling implements used in the experiment. Recommendations resulting from this experiment indicate that to maximize crop yields and minimize soil compaction in the row, the subsoiled zone should be kept within 5 cm of the row.