Temperature effects on N2O and N2 denitrification end-products for a New Zealand pasture soil

Denitrification results in the formation of two gaseous end-products: radiatively active greenhouse gas nitrous oxide (N2O) and radiatively inert di-nitrogen (N2). Measuring N2 produced by soil microorganisms has historically been difficult because of interference by high background concentrations (780,840 ppm) of atmospheric N2. Here, we applied a new automated technique for simultaneous measurement of the denitrification end-products N2O and N2. We tested the hypothesis that the temperature response function (defined here as Q10) for N2O was greater than for N2 under anaerobic conditions in the laboratory. The Q10 for N2O was 2.0 and the Q10 for N2 was 1.4, indicating differences in sensitivity to temperature. Denitrified-N shifted towards N2O as temperature increased. While moisture strongly controls the relative abundance of denitrification end-products, additional experiments are needed to determine how a wider range of temperatures may affect N2O and N2. Results could enhance understanding of temper...