The Effect of Waterlogging on Distribution of Different Forms of Zinc in Acidic and Alkaline Soils

Due to the importance of zinc in rice plant nutrition, the present study was conducted to determine the effect of waterlogging period on the amount of plant available zinc in acidic and alkaline soils separately based on a completely randomized design. Variation in distribution of different forms of zinc before and after waterlogging was also compared. Soils were submerged for a period of 90 days and then the parameters of Eh, pH and plant available zinc were measured at 0, 7, 15, 30, 45 and 90 days after waterlogging. Different forms of zinc were also determined using sequential extraction method. Generally, the amount of plant available zinc decreased in both acidic and alkaline soils during the waterlogging period. Submergence condition led to a significant decrease in soluble + exchangeable and organic forms of zinc, while at the end of the submergence period, the carbonate form of zinc significantly increased in alkaline soil. In both acidic and alkaline soils, no significant changes were observed in the form of zinc bound to manganese oxide, while the amount of zinc bound to amorphous and crystalline iron oxides increased and the amount of residual zinc significantly decreased. In general, the results showed that the concentration of zinc in waterlogged soils is mainly affected by the changes in various forms of iron. Furthermore, plant available forms of zinc decreased in waterlogged condition which can lead to zinc deficiency in rice plants. Hence, it is recommended that the amount of plant available zinc in soil should be managed via soil or foliare application of zinc fertilizers in a way that its decline during waterlogging period has less negative impact on plant yield.