Prediction of Algal‐Available Phosphorus in Runoff Suspensions

Methods for estimating the potential availability of sediment‐P forms are desirable for better assessment of the impact of runoff waters on surface water quality. The P sorbed by resin‐affixed hydroxy‐aluminum equilibrating with simulated sediment suspensions was evaluated for use as a routine means of estimating relative availability of P. A highly significant relationship (r = 0.98**, n = 5) was found between availability estimated by resin extraction and that determined by bioassay. For the soils tested, resin‐extractable P averaged 98% of that found to be available to algae by bioassay.