Corn Response to Time and Rate of Phosphorus Applications
1963
Seatz, Lloyd F. | Sterges, Athan J.
A greenhouse experiment was conducted to study the effects of rate and time of P applications on the growth and P uptake of corn. Different initial rates of P were applied and supplementary P was applied to make all treatments equal to the highest initial rate of 105 pounds P per acre. These supplementary applications were made to one set of each initial treatment at weekly intervals for 7 weeks after planting. In most cases the yield was lower if the supplementary P was not applied within 4 weeks after planting. The higher the initial rate of P the longer the supplementary application could be delayed without yield reduction. In most instances the total P uptake was greatest when the supplemental P was applied 5 or more weeks after planting. A critical period no doubt exists in the development of corn before which P must be available if it is to increase plant growth. If P becomes available after this critical period it will be absorbed by the plant and will be reflected in a higher percentage P composition.
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