Effect of Irrigation, Fruit Load, and Potassium Fertilization on Yield, Quality, and Petiole Analysis of Concord (Vitis labrusca L.) Grapes

A 14-year old Concord vineyard which had received no potassium fertilization since establishment was fertilized with 0 or 450 kg/ha of K under two irrigation and two fruit load regimes. Supplemental irrigation from bloom to véraison increased yields and vine size. Juice soluble solids were reduced by irrigation in a year with near normal rainfall; but in a year of severe drought, soluble solids were improved by irrigation. Increased fruit loads reduced juice quality. Vines receiving K fertilization showed a response the first year of application through increased yeilds and vine size. Juice pH and K content were increased by K fertilization.