Arkansas research has shown foliar feeding a fast-fruiting cotton variety with potassium (K) increased yield and improved fiber quality. Research was initiated in 1991 at the West Tennessee Experiment Station at Jackson evaluating the effect of foliar-applied surfactants in combination with KNO₃ on K uptake. Research was established on a Lexington-Loring-Calloway soil complex having a high Mehlich I extractable K level. The research was continued in 1992 on a high K Lexington silt loam and a medium K Collins silt loam and continued in 1993 on the Collins soil. The cultivar DPL 50 was planted by mid-May. The experimental design was a randomized complete block replicated five times in 1991 and 1993 but replicated four times in 1992. Foliar treatments included a check (no foliar applications), 4.4 lb/A KNO₃ applied in water, 4.4 lb/A KNO₃ applied with Penetrator Plus, 4.4 lb/A KNO₃ applied with X-77, 2.2 lb/A KNO₃ applied with Penetrator Plus, and 2.2 lb/A KNO₃ applied with X-77. Surfactants were applied at labeled rates. In 1992, the surfactant X-77 was replaced with Kinetic. Foliar treatments were applied at early bloom plus two weeks on a two week interval for a total of four applications. Leaves and petioles were collected from the first mature leaf 1, 3, 7, and 14 days after each application. Plant materials were washed, dried, and ground for K analysis. Cotton was produced no-tillage (NT) in 1991 and produced both conventional (CT) and NT in 1992 and was conventionally produced in 1993. For CT plots, fertilizers were broadcast prior to planting and disked into the soil while NT plots were fertilized immediately after planting. All plots were fertilized by broadcasting 80 lb/A of N and 60 lb/A P₂O₅ using ammonium nitrate and concentrated super-phosphate. Muriate of potash was broadcast applied at 30 lb/A K₂O on the high testing K soils and 60 lb/A K₂O on the medium testing K soils. All recommended production practices were utilized in establishing, growing, and harvesting the crops.

Cotton yields were unaffected by foliar K applications. In 1991, leaf and petiole K concentrations following the 2nd foliar application were increased by foliar KNO₃ with surfactants relative to applying KNO₃. Applying KNO₃ with Penetrator Plus generally resulted in the highest leaf and petiole K concentrations relative to other treatments. Applying KNO₃ with X-77 increased leaf and petiole K concentrations when compared with applying KNO₃ in water or the check. Applying 2.2 lb/A KNO₃ with either surfactant resulted in leaf and petiole K concentrations equal to applying 4.4 lb/A K₂O as KNO₃ in water. In 1992 and 1993, leaf and petiole K concentrations were unaffected by foliar treatments. The data suggest that under certain conditions surfactants may increase leaf and petiole K concentrations, but additional research is needed for further evaluation.