IRON-DEFICIENCY IN WHEAT GROWN ON THE SOUTHERN PLAINS

Extensive areas of chlorotic winter wheat (Triticum aestivum L.) were observed on calcareous soils in western Oklahoma. Spraying severely chlorotic wheat with ferrous sulfate (FeSO4) resulted in greening within a week and doubled herbage yield a month later. Intensive grazing of wheat prior to jointing induced no to severe chlorosis in 33 wheat cultivars tested over three years. After peak intensity in early April, the chlorosis diminished and was not visible when the wheat was fully headed in May. Overall, we believe increased iron (Fe) deficiency in wheat on the Southern Plains is due to increased use of Fe-inefficient cultivars and stress induced by grazing. Wheat cultivars less susceptible to Fe deficiency are commercially available.