Copper Lability in Soils Subjected to Intermittent Submergence

Reducing conditions in soils can have signifi cant infl uences on the availability of nutrient and toxic metals, through their remobilization, their release through reductive dissolution of oxide phases, and from the formation of precipitates. In the literature, contrasting results are reported on the eff ects of temporary waterlogging conditions on the availability of metals. In the present study, changes in the “labile” or “potentially available” pool of copper (Cu) in soils as a consequence of up to three intermittent soil submergence cycles was investigated using isotopic dilution. The soils (an Oxisol and an Inceptisol) selected were amended in the field with both biosolids-Cu and salt-Cu. Intermittent soil submergence was found to have a significant eff ect on the lability of Cu in soils, with Etotal values generally increasing in all the treatments with the different submergence cycles, the highest lability of Cu observed in the Cu-salt treatment. The presence of nonexchangeable colloidal forms of Cu, influenced by treatments and submergence cycles, was also reported.