FERTILIZER AND CROP MANAGEMENT-PRACTICES FOR IMPROVING MAIZE YIELDS ON HIGH PH SOILS

In Nebraska, nearly 0.4 million hectares (ha) of maize (Zea mays L.) a re subjected to varying degrees of iron (Fe) chlorosis from high pH so il. A factorial design with two maize varieties (tolerant and non-tole rant) and seed row applied Fe treatments with four replications was us ed on three soil areas of Cozad silt loam with pHs of 8.6, 8.2, and 7. 7. Iron treatments included a check, seed row applied FeSO4 . 7H(2)O, FeEDDHA, dried granular FeSO4-polyacrylamide gel and foliar sprays of 1.5% FeSO4 . 7H(2)O. Chlorophyll meter readings at V8 and V10 separate d treatment effects on the pH 8.6 site and were highly correlated with yield. In 1993, all Fe treatments on the pH 8.6 site produced signifi cant yield increases on both varieties except the foliar treatment and FeEDDHA on the non-tolerant hybrid. The FeSO4-polyacrylamide gel was especially effective, but was not available in 1994. Most Fe treatment s significantly increased yields on the pH 8.2 and 8.6 sites, but not the pH 7.7 site. In 1994, most Fe treatments produced significantly hi gher yields on the pH 8.6 site, however, the tolerant hybrid consisten tly yielded higher than the non-tolerant. Proper hybrid selection and site-specific treatment on high pH areas with seed row applied FeSO4 . 7H(2)O can significantly improve maize yields on high pH soils.