HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Arah, J. R. M. Search for Related Content PubMed Articles by Arah, J. R. M. Agricola Articles by Arah, J. R. M.

New Formulae for Mass Spectrometric Analysis of Nitrous Oxide and Dinitrogen Emissions

Soil Science Dep., Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG, Scotland, U.K.

* Corresponding author.

ABSTRACT

Formulae currently used in mass spectrometric studies of N₂ and N₂O emissions require the initial atmosphere to be in a state of isotopic equilibrium with a ¹⁵N atom fraction equal to that of the global background (). This is not always the case (e.g., in sequentially sampled incubations and those conducted under artificial atmospheres). Here I present new formulae that are valid whatever the initial conditions. These formulae are simpler than previous versions. They are expressed directly in terms of the ¹⁵N atom fractions and ³⁰N₂ molecular fractions of two gas samples (taken before and after emission). I have provided secondary expressions for converting the instrumental output of any (single- or dual-inlet, double- or triple-collector) mass spectrometer into the atomic and molecular fractions required. In common with previous treatments, my new calculations hypothesize a homogeneous soil N pool. I have proven that where this hypothesis is false the calculated value of the apparent pool enrichment is wrong (too high where the actual enrichment exceeds that of the atmosphere; too low in the exceptional case where the atmospheric enrichment exceeds that of the pool) and the flux is invariably underestimated. Computer simulations suggest that this underestimation may be relatively constant (about 25%) if the atmosphere is initially at isotopic equilibrium with ¹⁵N fraction , but that it may be larger (about 40%) and more variable where this is not the case.

Received for publication June 18, 1991.

This article has been cited by other articles:

				I. Wolf and R. Brumme Dinitrogen and Nitrous Oxide Formation in Beech Forest Floor and Mineral Soils Soil Sci. Soc. Am. J., November 1, 2003; 67(6): 1862 - 1868. [Abstract] [Full Text] [PDF]

				R. J. Laughlin and R. J. Stevens Evidence for Fungal Dominance of Denitrification and Codenitrification in a Grassland Soil Soil Sci. Soc. Am. J., September 1, 2002; 66(5): 1540 - 1548. [Abstract] [Full Text] [PDF]

				T. T. Bergsma, G. P. Robertson, and N. E. Ostrom Influence of Soil Moisture and Land Use History on Denitrification End-Products J. Environ. Qual., May 1, 2002; 31(3): 711 - 717. [Abstract] [Full Text] [PDF]

				T. T. Bergsma, Q. C. Bergsma, N. E. Ostrom, and G.P. Robertson A Heuristic Model for the Calculation of Dinitogen and Nitrous Oxide Flux from Nitrogen-15-Labeled Soil Soil Sci. Soc. Am. J., November 1, 1999; 63(6): 1709 - 1716. [Abstract] [Full Text] [PDF]