Phosphorus Application Rate and Distribution in the Soil and Phosphorus Uptake by Corn1
- I. Anghinoni and
- S. A. Barber2
Evaluation of the effect of P addition and distribution in soil on P uptake by corn (Zea mays L.) plants, requires knowledge of the relation of soil P level to corn root growth rate and morphology. This research was conducted to obtain these relationships so that they could be used with root P influx and soil supply characteristics to calculate P uptake. Corn was grown for 12 and 18 days on two soils, each with five levels of P application, in pots in a controlled climate chamber. Root growth and P uptake were measured. Except for the lowest rate, increased rate of P mixed uniformly with the soil decreased average root length per pot even though shoot growth increased. Placing a common rate of P per pot in part of the soil volume increased root growth in the P-treated soil volume as compared to root growth in the untreated soil. The difference was expressed by the relation y = x0.68, where y was the fraction of total plant root length in x, the fraction of the total soil volume that was P treated. Separate calculation of P uptake from each soil volume showed low P uptake from the untreated soil compared to that from the treated soil. Predicted P uptake per not calculated with a mathematical simulation model was correlated (r = 0.81 and 0.78 for the two soils) with observed P uptake. Information on effect of P on corn root growth and on P influx can be used in mathematical models to investigate relative P uptake from alternate P application practices.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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