Improved methods for zinc and boron application to mango (Mangifera indica L.) cv. Kensington Pride in the Mareeba-Dimbulah district of North Queensland

Abstract

Following soil and foliar treatments with zinc and boron, concentrations of leaf microelements were measured in mango trees (Mangifera indica L. cv. Kensington Pride) in order to determine the best method of application. Quarterly foliar application of zinc sulphate (1.0%) was the most cost-effective way to maintain leaf zinc above the critical concentration of 20 mg/kg dry matter. Yearly soil application of 50 g of Solubor per tree maintained leaf boron above the adequate concentration of 50 mg/kg. Single Solubor soil applications of 100 and 200 g/tree.year were phytotoxic to mango trees, with severe leaf burn associated with leaf boron concentrations of 320 mg/kg. In general, mango yield was not significantly (P>0.05) affected by any of the treatments, nor was it significantly (P>0.05) correlated with zinc or boron leaf concentrations.