Short-term changes in soil nutrients during wetland creation

This study examined changes in pH and extractable nutrients in soilsfollowing wetland creation. Sample plots were established in two areas: (1) an old-field with parts that were flooded during wetland creation, and (2) a native wetland in a floodplain of the Ohio River called Green Bottom Swamp. Soils were sampled before inundation and eight months afterwards. Compared to old-field soils in the pre-inundation period, swamp soils exhibited: (1) higher acidity, (2) lower NO3 and higher NH4 concentrations, (3) higher extractable P, Fe, and Mn, and (4) lower Ca, Mg, and Zn concentrations. Eight months after inundation, the old-field soil redox decreased from +210 mV in the old field –290 mV, and extractable NO3 and Ca decreased and extractable NH4 and Fe increased, but pH and extractable P, Mn, Mg, and Zn changed either slightly or not at all. These results suggest that eight months is an insufficient period of time for a complete change. Other results suggest that the response of nitrogen during the wetland creation processes may be extremely rapid.