Soil solution P level is believed to be important in determining P uptake rates from soil. The objective of this research was to investigate the relation between initial P concentration in the soil solution and P flux into the root. Millet (Panicum milaceum) was grown on five soils each of which was adjusted to six Clilevels by addition of P. Millet was also grown in solution culture and P influx vs. P concentration in solution measured. There was a curvilinear relation between P influx and relative yield of the Clilevels on each soil (R2=0.74). A P influx of at least 16 pmoles cm‐1sec‐1was needed to obtain 90% of maximum yield. However, yield response was not correlated with Cli, indicating Cliwas not a suitable indicator of P availability on these soils. Influx of P on soils with Cliless than 6 μMwas greater than occurred at similar P concentrations in solution culture indicating P influx was increased by the effect of the root on the soil.