Potential denitrification rates in acid soils under pine forest.

Abstract

Potential rates of N2O production and N2O reduction associated with denitrification were measured from two Dutch soil samples under pine [Pinus] forest, with pH (H2O) 3.6 and 3.8. Undisturbed cores of the surface 15 cm litter and Ah layer were incubated for several weeks in closed pots, of which the gas phase was examined by gas chromatography for O2, CO2, N2O and C2H2. Under anoxic conditions created by soil respiration, average N2O-N production rates in samples from these soils ranged from 9 to 15 mu g cm-2 day-1 and average N2O-N reduction rates from 3 to 6 mu g cm-2 day-1. Rates of N2O production and N2O reduction were measured at two initial nitrate concentrations: N2O production rates were almost the same, but N2O reduction seemed to be delayed by the presence of nitrate. The results indicate that anoxic denitrification peaks might reduce about 1 kg nitrate-N per ha per day in the upper layer of these soils to N2O and/or N2. (Abstract retrieved from CAB Abstracts by CABI’s permission)