This study was conducted to investigate the influence of waterlogging on availability of nutrients in paddy soils. The five soils were incubated under a waterlogged condition at 30 C for 12 weeks. The EC, Eh, pH, NH4, K, Na, Ca, Mg, Cl, P, Fe, and Mn of soil solutions were monitored over the waterlogged period. The Eh values generally dropped to the lowest point within 14 days of waterlogging, then increased, and reached equilibrium after 8 weeks of waterlogging. The soil pH decreased in the first 2–4 weeks of waterlogging. The EC values increased partly due to dissolution of soluble salts in the first 2 weeks. The concentrations of soluble NH4 were significantly increased with waterlogging, reached maximum values at week 4–6, and then declined to the initial level. Waterlogging increased the concentration of soluble K, Ca, Mg, Fe, and Mn ions, the magnitudes of changes were greatly affected by soil properties. Increases in soluble Na, K, Ca, and Mg were attributed to the increase in solubility of insoluble salts and increase in competition for the exchange sites. Increases in soluble Fe and Mn induced by waterlogging were attributed to the dissolution of Fe and Mn oxides under reduced conditions.
