Denitrification in drained and rewetted minerotrophic peat soils in Northern Germany (Pohnsdorfer Stauung)

Abstract

This study was conducted to assess the nitrogen removal potential of a minerotrophic peatland in Northern Germany, where hydrological conditions were partly restored in the beginning of the 1990s. Actual denitrification and the effect of nitrate (NO3-) and glucose additions on denitrification rates were determined in two flooded and one drained histosols in spring and summer 1998. In the flooded soils, denitrification was insignificant, but the drained field emitted significant rates. Additions of NO3- stimulated denitrification at all sites in spring and summer, whereas glucose additions had no effect. Low NO3- concentration in floodwater was obviously limiting denitrification in the flooded soils. In the drained soil, a coupled nitrification/denitrification might explain the low, but significant denitrification rates. No spontaneous production of nitrous oxide occurred in the flooded soils, whereas at the drained site an increase in spontaneous nitrous oxide concentration was measured during incubation in the summer samples. The suggested introduction of NO3- rich water from a stream flowing through the area would apparently induce denitrification in the flooded fields