Nitrification potential of marsh soils from two natural saline-alkaline wetlands

Few studies have been carried out on nitrification potential of marsh soils in natural saline wetlands with high alkalinity. The nitrification potentials of a closed wetland and an open wetland were monitored by an aerobic incubation at 25 degrees C for 28 days. The relative nitrification index (RNI, NO(3)-N/NO(3)-N+NH(4)(+)-N) rapidly increased with time in both wetlands and decreased with depth in soil profiles in both wetlands within the first 21 days. Nitrification proceeded much faster in the closed wetland than in the open wetland. The higher rate of nitrogen removal in closed wetlands than open wetland was probably due to the fast nitrification followed by denitrification or leaching loss.