This report evaluates a vacuum-assisted walled percolation sampler preconditioned in soil, and examines the dynamic response of leachate solutes. The 20-cm walled percolation sampler extracted soil water under tension via a ceramic cup collector imbedded in a silica flour layer, whose upper surface interfaced with field soil. In the laboratory, alternating solutions with high and low NO₃-N (232 or 3.6 mg L^-1), molybdate-reactive P, MRP (1.75 or 0.0 mg L^-1), K⁺ (568 or 3.6 mg L^-1), and Br^- (9.6 or 0.0 mg L^-1) concentrations were delivered directly to the i) sampler ceramic cup; ii) silica flour bed surface, or iii) a 12-mm soil layer placed over the silica flour bed. For input solutions delivered to the silica-flour-bed surface, (i) solute breakthrough (95% equivalency) occurred in 38 h, or 4 pore volumes and was the same for both the high and low concentration input phases of the application, and (ii) concentrations of NO ₃-N, Br-, and MRP in cumulative extracted water volumes were within 5% of those in corresponding input volumes. Alternating nutrient loads from high to low levels in the fixed flow-rate input waters caused excess MRP (1.6x the high-load MRP concentration) to leach from the calcareous soil. The dynamic character of P transport in K-fertilized soils deserves further study and may have important environmental implications.