EVALUATION OF SURFACTANTS IN FOLIAR FEEDING COTTON WITH KNO3

D.D. Howard, P.E. Hoskinson, and P.W. Blawley

ABSTRACT

Arkansas research has shown foliar feeding a fast-fruiting cotton variety with potassium (K) increased yield and improved fiber quality. This research was initiated at the West Tennessee Experiment Station at Jackson to evaluate the effect surfactants has on K uptake from foliar KNO3 applications. An additional objective was to evaluate the effect of two surfactants applied at two KNO3 rates. Research was initiated in 1991 on a Lexington-Loring-Calloway soil complex having a high Mehlich I extractable K level. The research was continued in 1992 on a Lexington soil also having a high Mehlich I extractable K level. The cultivar "DPL-50" was planted the first two weeks of May. The experimental design was a randomized complete block replicated five times in 1991 and replicated four times in 1992. Foliar treatments included a check (no foliar applications), 4.4lb/A KNO3 applied in water, 4.4 lb/A KNO3 applied with Penetrator Plus, 4.4 lb/A KNO3 applied with X-77, 2.2lb/A KNO3 applied with Penetrator Plus, 2.2 lb/A KNO3 applied with X-77. Surfactants were applied at label 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. The 1991 experiment was produced no-tillage (NT) while in 1992 both conventional (CT) and NT production practices were utilized. Plots were fertilized applied immediately after planting in 1991 by broadcasting 80-60-60 lb/A of N, P2O5, and K20, respectively. In 1992, fertilizers broadcast and disked into the soil prior to planting CT while the NT fertilizers were applied immediately after planting. All recommended production practices were utilized in establishing, growing, and harvesting the crops.

Cotton yields were unaffected either year by foliar K applications. In 1991, leaf and petiole K concentrations following the 2nd application were increased by foliar KNO3 with surfactants. Applying KNO3 with Penetrator Plus generally resulted in the highest leaf and petiole K concentrations when compared with 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 KNO3 in water. In 1992, leaf and petiole K concentrations were unaffected by treatments. The data suggest that under certain conditions surfactants may increase leaf and petiole K concentrations, but additional research is needed for further evaluation.





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Document last modified July 8, 2004