Zinc Availability for Corn as Related to Source and Concentration in Macronutrient Carriers1
- P. M. Giordano and
- J. J. Mortvedt2
Zinc oxide, ZnSO4, and ZnS were tested as sources of Zn at rates of 1, 2, and 4 ppm Zn for two successive crops of corn (Zea mays) grown on Nolichucky sandy clay loam (pH 7.3). Each source was mixed throughout the soil as finely ground material, incorporated into granules of ammonium nitrate (AN) or ammonium polyphosphate (APP) by pressure granulation, and into granules of concentrated superphosphate (CSP) during the granulation stage of the manufacturing process. When mixed with the soil ZnO and ZnSO4 were more effective than when incorporated with a macronutrient carrier. Both ZnO and ZnSO4 were markedly superior to ZnS. Ammonium nitrate and APP were comparable carriers when ZnSO4 was the source, but APP was superior to AN when ZnO was used. A higher concentration of Zn in the CSP granules resulted in poorer response to this carrier. Zinc oxide was pressure granulated with CSP, AN, APP, or Nolichucky soil to contain 0.5, 2.0, or 8.0% Zn. Soil granules and CSP were applied at 1, 2, and 4 ppm Zn while AN and APP were applied at 2 ppm only. Forage yields and Zn uptake varied inversely with concentration of Zn in all carriers.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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