We conducted an experiment in 27 large columns to determine the impact of soil type (sandy loam, silt loam and clay), salinity of irrigation water (1.5, 3.0, and 6.0 dS m−1), and leaching fraction (drainage/irrigation, 0.09, 0.18, and 0.27) on oxygen diffusion rate measurements (ODR) taken with platinum electrodes. Electrodes were left in place (15, 30, and 60 cm deep), and ODR was measured over a 6-mo period. At the end of 6 mo, electrodes were removed and observed under a low-magnification microscope for the presence or absence of precipitate. Selected electrodes were then photographed under a scanning electron microscope, analyzed using x-ray diffraction techniques, and analyzed for percentage of atom composition using x-ray photoelectron spectroscopy. Results indicated that soil type, salinity, and leaching fraction all influenced ODR measurements. The formation of precipitate on the platinum electrodes was observed equally in all three soils, but to a greater extent under high salinity and low leaching fraction conditions at the greater depths. Precipitate composition was similar to soil composition in both the silt loam and clay soils, but poor agreement was observed in the sandy loam soil, as indicated by Si/Al and C/O ratios. Results would suggest that aluminosilicates were either incorporated into calcium carbonate as it precipitated out of solution onto the platinum or platinum oxides in the presence of high salinity and calcium were bridged to aluminosilicates through a charged exchange reaction.