Effect of Submergence on Copper Fractions in Alfisols

The effect of soil submergence on the redistribution of different copper fractions in 15 Alfisols was studied in laboratory in relation to their soil properties. Upon submergence for 45 days, organically complexed (OC) and crystalline sesquioxides bound (CRYOX) Cu fractions recorded decreases with concomitant increases in water soluble plus exchangeable (WSEX), amorphous sesqwoxides bound (AMOX) and residual (RESID) fractions, the mean magnitude of decreases being 36.4 and 47.1 per cent of their initial contents in OC and CRYOX and that of increases being ISO, 23.3 and 37.0 per cent in WSEX, AMOX and RESID fractions, respectively. The increase in WSEX-Cu was dependent on initial pH of the soils, whereas the decrease in CRYOX-Cu was controlled by initial crystalline Fe-oxides content. The transformation of Cu into RESID fraction was controlled by the Cu released from CRYOX fraction and the changes in soil pH upon submergence. Results indicated major influence of soil pH and crystalline Feoxides content on Cu transformation in Alfisols upon submergence.