PHOSPHATE REACTION MODELS FOR THE LAKEHURST SOIL IN THE NEW JERSEY PINE BARRENS

Abstract

We leached samples of the A1, A2, B2, and C horizons of Lakehurst soil with phosphate solution and measured total phosphorus, labile phosphorus, nonlabile phosphorus, and maximum retention capacity for each horizon. A1 and A2 horizons proved to have a limited capacity for phosphate retention, and the B2 and C horizons were capable of removing phosphate from solution. Experimental results were fitted by a multifactor kinetic model involving a reversible two-step reaction mechanism. The first step, from solution to labile phase, was similar to a second-order kinetic reaction. The second step, from labile to nonlabile phase, was similar to first-order kinetics. The fitting for A2, B2, and C horizons by the model results in the same rate constants and empirical reaction parameters. Different rate constants were fitted for the A1 horizon, probably due to its higher organic matter content than other horizons. The reaction model with measured initial conditions can be used to predict phosphate movement under different concentrations and solution pH values in the Lakehurst soil of the Pine Barrens of New Jersey.