Yield and Uptake Response of Corn to Zinc, as Influenced by Phosphorus Fertilization1
- P. N. Takkar,
- M. S. Mann,
- R. L. Bansal,
- N. S. Randhawa and
- Harvey Singh2
Zinc deficiency has been reported after P fertilization of corn (Zea mays L.), but reasons for this deficiency are not clear. A field experiment was conducted for 3 years from 1970 to 1973 with a fixed wheat-corn rotation to determine the effect of P and Zn fertilization on corn yield, uptake, and translocation of Zn, and to evaluate the parameters that would monitor best the P-Zn interaction in corn. Five rates of P (0, 22, 44, 66, and 88 kg of P/ha), and four rates of Zn (0, 11, 22, and 44 kg of Zn/ha) were applied to P and Zn-deficient soil (Ustipsamments) using a split-plot design (with P in the main plots and Zn in the subplots). P was applied to all the six crops and Zn only to the first and second crops.
Optimum response of corn to P was observed at 44 kg of P/ha. The high P supply beyond the optimum P rate produced severe Zn-deficiency symptoms in treatments without added Zn and a significant decrease in grain and stover yields. This resulted from a significant decrease of Zn and a significant increase of P concentration in the shoots of the plant with a high P supply. An increase in the supply of Zn alleviated its deficiency symptoms, significantly increased Zn concentration and its uptake and resulted in a significant increase in growth and yield. The requirement of Zn increased at high (66 to 88 kg/ha) rates of P fertilization. The main effect of P on Zn utilization by corn was to reduce the rate of Zn entry into the roots and induce zinc deficiency.
The P-Zn disorder was better related with P/Zn ratio in the soil and in different parts of the corn plant than either with the P or Zn content of the tissues and soil. Values of P/Zn greater than 7.5 in the soil, 245 in grain, 130 in stover, 150 in the leaves (of 25-day-old plants) indicated a severe Zn deficiency in corn and a highly significant response to its application. The P/Zn values 4 to 7.5 in the soil, 150 to 245 in the grain, 90 to 130 in the stover, and 100 to 150 in the leaves indicated moderate Zn deficiency or response to its application.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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