Desorption Kinetics of Legacy Soil Phosphorus: Implications for Non-Point Transport and Plant Uptake

Soil phosphorus (P) solubility and kinetics partly control dissolved P losses to surface water uptake by plants. While previous studies have focused on batch techniques for measuring soil desorption kinetics, flow-through are more realistic because they simulate removal from the system, akin runoff, leaching, plant uptake. The objectives were measure a technique at two flow rates several methods, utilize both understanding how rate impacts thermodynamics of desorption. Desorption obeyed first-order in different phases: an initial rapid phase followed gradual release. was limited equilibrium physical processes as demonstrated interruption test. Dilution-promoted occurred with increasing cumulative volume, which increased via kinetics. tests that simulated solution volume time similar results; however, methods overestimated due less limitations diffusion. Fast desorbed P, but greater speed than slow rates. differences contact time, ultimately controlled potential chemical reactions be realized through processes. interaction between these will quantity buffer non-point drainage