Zinc nutrition of three corn cultivars (Zea mays L.) as affected by environment and zinc rates

Three varieties of corn (Zea mays L.) were grown under two different environmental conditions for 21 days in a growth chamber. The soil used was a Zn deficient Bradyville silt loam which was treated with five rates of Zn fertilizer. Available soil Zn was determined by four different extracting solutions.

The concentration of Zn in the plants, and the available soil Zn, were not changed between the cool and warm environment. However, the warmer environment decreased the number of Zn deficient plants. Phosphorus concentration in the tissue, as well as measured soil P, were lower in the warm condition. This decrease in P may partially alleviate the Zn-P imbalance and result in the reduced number of deficient plants. The Zn concentration and uptake and the P concentration and uptake were similar in all three varieties, yet they varied greatly in development of visual deficiency symptoms. The applied Zn rates increased Zn concentration in the plants, and available soil Zn. All four soil tests correlated well with plant Zn concentrations, but rather poorly with deficiency symptoms. Soil test correlations for both plant Zn and deficiency symptoms were very dependent on the variety of corn and the environmental condition.