Influence of soil moisture on codenitrification fluxes from a urea-affected pasture soil

Autor: Timothy J. Clough, Gary J. Lanigan, Cecile A. M. de Klein, Md. Sainur Samad, Sergio E. Morales, David Rex, Lars R. Bakken, Charlotte Johns, Leo M. Condron, Jim Grant, Karl G. Richards
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Scientific Reports, Vol 7, Iss 1, Pp 1-12 (2017)
Druh dokumentu: article
ISSN: 2045-2322
DOI: 10.1038/s41598-017-02278-y
Popis: Abstract Intensively managed agricultural pastures contribute to N2O and N2 fluxes resulting in detrimental environmental outcomes and poor N use efficiency, respectively. Besides nitrification, nitrifier-denitrification and heterotrophic denitrification, alternative pathways such as codenitrification also contribute to emissions under ruminant urine-affected soil. However, information on codenitrification is sparse. The objectives of this experiment were to assess the effects of soil moisture and soil inorganic-N dynamics on the relative contributions of codenitrification and denitrification (heterotrophic denitrification) to the N2O and N2 fluxes under a simulated ruminant urine event. Repacked soil cores were treated with 15N enriched urea and maintained at near saturation (−1 kPa) or field capacity (−10 kPa). Soil inorganic-N, pH, dissolved organic carbon, N2O and N2 fluxes were measured over 63 days. Fluxes of N2, attributable to codenitrification, were at a maximum when soil nitrite (NO2 −) concentrations were elevated. Cumulative codenitrification was higher (P = 0.043) at −1 kPa. However, the ratio of codenitrification to denitrification did not differ significantly with soil moisture, 25.5 ± 15.8 and 12.9 ± 4.8% (stdev) at −1 and −10 kPa, respectively. Elevated soil NO2 − concentrations are shown to contribute to codenitrification, particularly at −1 kPa.
Databáze: Directory of Open Access Journals
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