Nitrous oxide and dinitrogen losses from flooded fen peat with and without reed canarygrass (Phalaris arundinacea L.) and common reed (Phragmites australis (Cav.) Trin. ex Steud.) plants

Abstract

There is little information about the effect of wetland plants on N turnover and N gas emission (N2O, N2) in recently reflooded minerotrophic mires (fens). We carried out lab model experiments with two typical wetland plants, reed canary grass (Phalaris arundinacea L.) and common reed (Phragmites australis (Cav.) Trin. ex Steud.) on fen peat substrate using the 15N gas flux method. The reflooded fen peat substrate and the tested plants influenced the amount of gaseous N losses, its composition, and the way of its emission from the peat substrate to the atmosphere in a differentiated manner. Irrespective of plants the denitrification losses were between 49.9 to 74.5 % of the applied N. Whereas common reed narrowed the ratio between N2 and N2O up to 11:1, red canary grass caused a strong expansion of this ratio up to 343:1. The denitrification N gas liberation through the shoots of reed canary grass was not significant. In case of common reed approx. 20% of the fertiliser derived N2 and approx. 10% of the fertiliser derived N2O were exhaled by the plants.