ABSTRACT

Deep banding of a low concentration of potassium from 6"-15" deep in the drill approximately 2" wide over a 5-year period (1987-1991) raised soil test K levels in the 10"-15" sample depth 1 lb/A with each 3.02 lb K₂O/A (5.03 lb muriate of potash/A) applied in the deep band. In general, cotton lint yields were increased with a combination of subsoil tillage at a 451 angle to the row and deep banding potassium. Deep banding 80, 120, and 160 lb K₂O/A rates over a 6-year period (1987-1992), significantly increased lint yield over both the non-ripped and ripped (in the drill) treatments without potassium. Lint yields were not significantly increased by ripping in the drill alone. This study shows that potassium (in the low concentrated deep band) significantly increased lint yield in cotton. The nutrient balance values (ratio of soil test K to soil test P) in the 0"-15" soil profile had a higher correlation to percent relative yield than did either soil test P or soil test K values. Over the 5-year period, the K/P nutrient balance ratio accounted for 49.9% of the variability in percent relative yield.