III. Response of sweet corn to sources of zinc

Abstract

Pot experiments were done to compare the effectiveness of soil-applied ZnSO₄, ZnO, and ZnEDTA, foliar-applied ZnSO₄ (0.25% solution), and a Zn frit for the correction of Zn deficiency in sweet corn on two calcareous soils and a non-calcareous soil from Niue. Effectiveness was determined from dry matter yields and Zn uptake by sweet corn grown for 43—54 days. Soil-applied ZnSC₄, ZnO, and ZnEDTA resulted in equal dry matter yields on all three soils; foliar-applied ZnSO₄ was equal in effect to soil-applied Zn on two of the soils, but less effective on the more calcareous soil (pH 7.7). The Zn frit was tested on only one soil (pH 7.4) and was less effective than the other Zn sources. Zinc, soil-applied as ZnO and ZnEDTA, was more available to sweet corn than Zn as ZnSO₄.