Response of Corn to Time and Rate of Phosphorus and Zine Application
1972
Keefer, R. F. | Singh, R. N. | Horvath, D. J. | Henderlong, P. R.
Corn (Zea mays L.) was grown in the greenhouse on two soils—Monongahela, a Typic Fragiudult (I) and Wharton, an Aquic Hapludult (II), which differed in available Zn, available P, exchangeable Mg, total Zn, and organic matter (OM). Dry matter yield and Zn concentration and content of plant parts were increased where Zn either as ZnSO₄ or ZnEDTA was applied with P regardless of time to soil I (low in available Zn, total Zn, exchangeable Mg and OM). Zinc-EDTA seemed to be a better source of Zn since it increased Zn concentration in leaves and stems more than ZnSO₄ on soil I. However, with soil II (higher in available Zn, exchangeable Mg, and OM), response to ZnSO₄ application was obtained only when P was applied at high rates 8 weeks before planting. Application of ZnEDTA produced no significant response by corn on soil II, probably due to instability of ZnEDTA under acid conditions resulting in appreciable amounts being fixed on the clays in this soil. The relative response to Zn with increasing levels of P (0 to 200 mg P/kg soil) was greater on soil I than on the soil II. Addition of Zn in the former decreased the percent P and P content in both leaves and stems at high levels of P application; however, application of Zn to the latter did not show any noticeable affect on percent P at all levels of P application.
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