Phosphate Uptake by Corn as Affected by Soil Characteristics and Root Morphology

Abstract Phosphate uptake by plants growing in soil is influenced by the P uptake properties of the root and the P supply characteristics of the soil. This system may be described by mathematical simulation models. The objective of this research was to determine if a model used successfully for describing K uptake by corn ( Zea mays L.) could be used for describing P uptake. A growth chamber experiment with corn grain on six soils varying widely in physical and chemical characteristics was conducted. Three harvests were made and root morphology and P uptake were measured. The significance of the differences in root morphology and in soil P‐supply parameters of initial P concentration in soil solution, buffer power, and effective diffusion coefficient for P were determined by using them in the Claassen‐Barber simulation model which considers these soil factors, root morphology, and root physiology to predict P uptake by plants. The calculated P uptake, y was correlated ( r = 0.93) with observed P uptake, x . The regression equation, y = 1.09 x + 27.3 indicated a 9% overprediction of P uptake which was probably because the model did not consider root to root competition for P. The parameters used in this objective simulation model appear to be the important ones determining P absorption by plants from soil. In this study, root morphology varied with soil and was highly correlated with P uptake ( r = 0.88). This simulation model should be a useful tool in P fertilization research.