The effect of varying water tables on the oxidation rate of pyrite in pyrite-containing alluvial soils is being monitored. Preliminary results indicate that pyrite oxidation proceeds at a rapid rate at the onset of drainage and begins to slow down after a period of time. The pH decreases accordingly in the initial stages and begins to decrease with time, when the pyrite oxidation rate slows down. The pH in the freely drained plots is considerably lower than in both the controlled water table plots or the control plots. This trend is especially clear in the plot away from the sea. Coconut yields in the freely drained plot away from the sea are significantly lower.