Nitric oxide emission from a Norway spruce forest floor

Abstract

Abstract. Although the available data on soil NO emission are increasing, only few measurements have been made in temperate forests. Emissions from these forests are generally low, but recent studies have shown that NO emission from N-affected forests can be much higher. In this study the emission of NO from the floor of a moderately N-affected Norway spruce forest in Denmark was measured using dynamic chambers during two seasons (April 1995 and September 1995). At the same time, fluxes of CO2 and NO2, soil water content inside and outside the chambers, soil temperature at 10 cm depth, soil surface temperature and air temperature were recorded. The emission of NO in April was low (< 0.3 ng N m -2 s-•), whereas it was significantly higher in September (21 ng N m -2 s -1 with a range 0-82 ng N m -2 s -1). In April the soil surface temperature was low (< 6øC) and the soil moisture was high (26% vol/vol). In September the soil surface temperature was high (16øC) and soil moisture was significantly lower (14% vol/vol) than in April. There was a high correlation between CO2 emission and NO emission. The fluxes of NO2 were very small and not related to NO emission. Generally, the variation within a single plot was small, whereas the variation between plots was large. About half of the total variation of NO emission in September could be explained by a combination of soil moisture, distance to tree trunks, and moss cover. No significant relationship could be found between NO emission and soil surface temperature or soil temperature. Other parameters such as the C/N dynamics in the soil must be taken into account to provide a better mechanistic understanding of the NO emission. An annual emission of 3.15 kg NO-N ha-• yr-• was estimated by the amount of NH4 + in throughfall. Compared to most of the previous published measurements of NO emission from temperate forest soils, the values presented here are high and of the same magnitude as found in N-affected forests in Central Europe.

Factors controlling regional differences in forest soil emission of nitrogen oxides (NO and N&lt;sub&gt;2&lt;/sub&gt;O)

“…35%), but the exchange of nitrogen oxides (NO, N 2 O and NO 2 ) has so far only been investigated in a few European forests. These studies in N-affected forests in Central (Butterbach-Bahl et al, 1997;van Dijk and Duyzer, 1999;Brumme and Beese, 1992;Gasche and Papen, 1999) and Northern Europe (Pilegaard et al, 1999;Skiba et al, 1998) have shown that European forests have a much higher NO and N 2 O emission than other temperate forests in the world (Williams et al, 1992;Castro et al, 1993). It has been suggested that the high emissions found in European forests are due to the high atmospheric N-input to these forests.…”

“…Butterbach-Bahl et al, 1997;Pilegaard et al, 1999;van Dijk and Duyzer, 1999). NO was measured with dynamic chambers and the flux was estimated by comparing the steady-state concentration in the chamber with a reference measurement or by using the full mass balance equation (Altimir et al, 2002).…”

“…Kreutzer, 1995) and/or in form of N-gas emissions (N 2 O, NO, N 2 ) into the atmosphere (e.g. Butterbach-Bahl et al, 1997;Pilegaard et al, 1999;van Dijk and Duyzer, 1999;Skiba et al, 1998).…”

The relationship between NH&lt;sub&gt;3&lt;/sub&gt; emissions from a poultry farm and soil NO and N&lt;sub&gt;2&lt;/sub&gt;O fluxes from a downwind forest

“…At the three closest sites (A-C) 2 square automatically closing dynamic PTFE chambers (18 l) were installed for hourly NO, (NO x -NO) and O 3 flux measurements per site. The chamber system is described in detail by Pilegaard et al (1999). Two small fans stirred the air in each chamber.…”

Nitric oxide emissions from black soil, northeastern China: A laboratory study revealing significantly lower rates than hitherto reported

“…Nitric oxide in soil is produced through biological processes of nitrification and denitrification, as well as chemical decomposition of HNO 2 (Firestone and Davidson, 1989;Remde and Conrad, 1991;Conrad, 1996;Gödde and Conrad, 2000;Russow et al, 2009). Temperature, soil moisture, soil texture, fertilization and land-use have all been shown to be key factors controlling NO emission from soils (Gut et al, 1999Pilegaard et al, 1999;Venterea and Rolston, 2000;Venterea et al, 2005;Williams and Fehsenfeld, 1991;Yu et al, 2008). The approximate ranking of NO emission levels sources, viz.…”