N2O emission and sorption in relation to soil dehydrogenase activity and redox potential

A b s t r a c t. Two soils: a peaty-muck soil (Eutric Histosol) and a brown soil (Eutric Cambisol) developed from sand) were incubated anaerobically with addition of KNO 3 (100 mg NP 3 --N kg -1 and 2% C 2 H 2 ) for the determination of N 2 O emission or with addition of 1% N 2 O for the determination of N 2 O sorption. The rates of nitrous oxide, nitrate, dehydrogenase activity, redox potential and CO 2 production at 20°C were measured over 14 days. The peaty-muck soil showed about 4 times higher denitrification activity (as measured by N 2 O emission and NO 3 - depletion) and on average 27 times higher dehydrogenase activity than the brown sandy soil. In turn, the brown sandy soil was characterized by better capacity for nitrous oxide sorption and more intensive respiration activity. Production of CO 2 and redox potential were not influenced by the form ofN which was added. Dehydrogenase activity in the organic soil was significantly higher with N 2 O-treatment than with nitrate-treatment (P<0.001).