Dinitrogen and nitrous oxide exchanges from an undrained monolith fen: short-term responses following nitrate addition

作者：Roobroeck D^*; Butterbach Bahl K; Brueggemann N; Boeckx P

来源：European Journal of Soil Science, 2010, 61(5): 662-670.

DOI：10.1111/j.1365-2389.2010.01269.x

Gaseous nitrogen exchanges from undrained peat soils and the effect of external nitrate input are poorly understood. This paper reports net N(2), and N(2)O exchanges as well as the short-term responses to nitrate addition from contrasting tussock and hollow soil habitats in an undrained monolith fen ecosystem located in northeast Poland. Gaseous N exchange rates were quantified by means of a He substitution technique. The net N(2) production in hollows (2.53 mg N m(-2) hour(-1)) was significantly higher than in tussocks (1.04 mg N m(-2) hour(-1)). Hollows also constituted a marked N(2)O sink (-3.04 mu g N m(-2) hour(-1)), while tussocks were a source for atmospheric N(2)O (2.08 mu g N m(-2) hour(-1)). Following amendment by NO(3)(-), at a rate similar to atmospheric NO(3)(-) deposition (wet + dry), hollows showed a drastic shift to net production of N(2)O but a non-significant increase in N(2) production. In tussocks only a minor increase of N(2) and N(2)O production was observed after NO(3)(-) addition. This study emphasizes the influence of physico-chemical conditions and biotic resource competition on the rates and responses of microbial denitrification in undrained fen ecosystems. Inferring a simple field-scale estimation of gaseous N emission suggests that undrained, monolith fen ecosystems constitute substantial sources of N(2) (1.79 mg N m(-2) hour(-1)) and considerable sinks for N(2)O (-0.96 mu g N m(-2) hour(-1)). These findings are of importance to further improve greenhouse gas budgeting and assess the impacts of global change on undrained fen ecosystems.

• 出版日期2010-10