Availability of Zinc, Copper and Iron in Fusions with Sulfur1

Abstract

AbstractA study was made of the uptake of zinc, copper, and iron by four successive crops of corn (Zea mays L.) from applications of trace element‐sulfur fusions to Plainfield sand in pots. The various zinc treatments gave increased total yields, but those with copper gave somewhat reduced yields and those of iron had little or no effect. The concentrations of tissue zinc were inversely related to granule size of the ZnO‐S and ZnCO3‐S fusions and were much lower for banding than mixing with the soil. Both the 20 to 40‐ and 40 to 80‐mesh sizes appeared to be quite favorable for prolonged release of zinc. Similar trends were obtained for tissue copper from the application of CuC2O4‐S fusions. The iron released from the FeS‐S fusions appeared to be precipitated too quickly to be satisfactory in supplying the plants with iron. The inclusion of zinc, copper, or iron compounds in the fusions had little or no effect on the rate of sulfur oxidation. Total recovery of applied elemental sulfur by the crops and as soil sulfate varied inversely with granule size and ranged from 5 to 49%. The data obtained so far suggest that fusions of certain trace element compounds with sulfur hold promise as a means of providing prolonged release of Manganese, zinc and copper for plants.