Evaluation of Surfactants in Foliar Feeding Cotton with KNO3

D.D. Howard, P.E. Hoskinson, and R.C. Gerstenecker


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.

Reprinted from Proceedings of the 1994 Beltwide Cotton Conferences pg. 1575
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998