Ditch Sediments Research Articles

The Effect of Nitrate on Nitrous Oxide Reduction in Organic Soils and Sediments

AbstractInhibition of N2O reduction by NO3‐ in cultivated Pahokee muck was determined by measuring N2O accumulation in soil samples incubated in the presence and absence of acetylene. At NO3‐‐N levels of 40 mg/liter or greater, nearly 100% of the gaseous denitrification products were N2O in Pahokee muck. Reduction of the accumulated N2O proceeded rapidly after the NO3‐ was exhausted from the soil. In comparison, N2O was readily reduced in ditch sediment samples in the presence of comparable concentrations of NO3‐. With NO3‐‐N concentrations in the ditch sediments ranging from 90 to 39 mg/liter, < 10% of the gaseous denitrification products were N2O. Similarly, NO3‐ levels in soil samples from a vegetable field which had been flooded 22 days had negligible effect on N2O reduction. These data demonstrate that the inhibitory effect of NO3‐ on N2O reduction was less in sediments and in organic soils that had been subjected to prolonged flooding than in the cultivated soils.