Effects of Reclamation on the Shift of Wetland Soil Iron

Farmlands reclaimed from natural wetland with different cultivation periods in Sanjing Plain, northeast China, were sampled to analysis the change of soil iron. The results showed that iron is the important soil constituent responding to environmental change sensitively, and its quality and quantity are influenced by reclamation significantly. The total iron (Fet), free iron (Fed), active iron (Feo), and complex iron (Fep) distribution, for example, is significantly different between different cultivation periods, especially for the upper tillage layer (0-10 cm and 10-20 cm). Fet of layer 1 over that of layer 2 changed as an exponential decay curve (Y = 0.95152 + 0.27247exp -1.01493 X, R² = 0.86) after wetland reclamation. This finding conforms that iron can be used to rebuild the past wetland soil environment.