Organic matter, heterotrophic activity, and NO· consumption in soils


  • Peter F. Dunfield,

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      Current address: Max Planck Institut für Terrestrische Mikrobiologie, Karl-von-Frisch-Str., Marburg, D-3550, Germany.

  • Roger Knowles

    1. Department of Natural Resource Sciences, McGill University, Macdonald Campus, 21111 Lakeshore Rd., Ste. Anne de Bellevue, Quebec, H9X 3V9, Canada
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  • 1In accordance with IUPAC nomenclature, we adopt this term over the vulgar ‘nitric oxide’ (Koppenol & Traynham 1996).

R. Knowles, tel +1/514-398-7751,
fax +1 514–398–7990, e-mail


When the effect of water content was minimized, soil CO2 evolution and soil organic matter content were good predictors of aerobic NO. uptake rate constants across a wide range of soil types. Field manure application to a Gleysol stimulated NO. uptake rate constants and lowered NO. compensation points compared to unfertilized or NH4NO3-fertilized soil. This effect lasted for months after manure application. In a laboratory experiment, addition of manure reduced the NO. efflux associated with nitrification of NH4 Cl fertilizer, and manured soils had a greater capacity to remove NO. from polluted air. Evidence is presented that these observations result from NO. oxidation during heterotrophic microbial activity in soil.