AbstractThe method developed in Part I was used with mixtures of A1 and B1 or A1 and 3C1 horizons of varying ratios to predict the potential of horizons from an eroding urban soil for the phosphorus enrichment of streams. A 1:9 mixture of A1 and 3C1 horizons sorbed greater or similar amounts of added inorganic P (0 to 200 µg P/liter) than a 1:9 mixture of A1 and B1 horizons at a solution/ soil ratio of 400:1. Nomograms were constructed to illustrate the relationship between initial inorganic P concentration (0 to 150 µg P/liter), equilibrium inorganic P concentration, and varying mixtures of these soil horizons using a 400:1 solution/soil ratio. Predictive ability is maximized because the data can readily be extrapolated to a wider solution/soil ratio (1000:1) which is more realistic in terms of a stream environment. Mixtures containing the A1 and 3C1 horizons maintained lower equilibrium P concentrations than those containing the A1 and B1 horizons. Calcium ions released from the calcareous 3C1 horizon apparently reduced the dissolution of P from the moderately soluble calcic P fertilizer‐soil reaction product present in the A1 horizon. The validity of the adopted method is discussed with reference to conditions existing in stream environments.