Potassium Fertilization of Prune Trees under Drip Irrigation1

Abstract Fertilization with K 2 SO 4 resulted in good uptake of K by trees of French prune (Prunus domestica L. cv. Agen) whether K was applied in drip water or dry K 2 SO 4 was placed on the soil under the emitter and then drip irrigated. These methods were much more effective than applying K 2 SO 4 in trenches alongside the trees and then sprinkler-irrigating. K fertilization with a drip system resulted in K movement to depths of 60 to 75 cm, where the soil is wet from drip irrigation and roots are abundant, enhancing K uptake.