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 Denmead, O. T. Search for Related Content PubMed Articles by Denmead, O. T. Agricola Articles by Denmead, O. T.

Chamber Systems for Measuring Nitrous Oxide Emission from Soils in the Field¹

ABSTRACT

Recent concern over N₂O losses from soils has highlighted the need for new techniques for measuring N₂O exchange in the field. Two systems are described, in which nondispersive infrared gas analysis is used to measure the change in N₂O concentration of air passing through a cylindrical chamber driven 0.1 m into the ground. When interfering gases are removed from the air stream, the infrared analyzer has a resolution of ± 12 ppb N₂O.

In one system, air circulates in a closed loop between the chamber air space and the gas analyzer; in the other, open system, outside air is drawn continuously through the chamber space and its N₂O enrichment or depletion measured.

Two operational problems (common to many emission chambers) were encountered: the development of a low pressure in the chamber when air is withdrawn, which induces a mass flow of N₂O from the soil in addition to the diffusive flow; and a readjustment of the N₂O concentration in the soil air whenever the N₂O concentration in the chamber air changes from ambient. These can lead to incorrect estimates of the flux. The former problem was overcome by chamber design. The latter appeared to be insurmountable in the closed system, but could be reduced to acceptable proportions in the open system by choice of air flow rate.

The open system permits relatively rapid equilibration, automatic and continuous operation, a discrimination less than 2 ng N m^–2 sec^–1, and the maintenance of environmental conditions within the chamber close to those in the field.

¹ Contribution from CSIRO, Australia.

² Senior Principal Research Scientist, CSIRO Division of Environmental Mechanics, P.O. Box 821, Canberra City, A.C.T. 2601, Australia.

Received for publication April 10, 1978. Accepted for publication October 2, 1978.

This article has been cited by other articles:

				P. Rochette and N. S. Eriksen-Hamel Chamber Measurements of Soil Nitrous Oxide Flux: Are Absolute Values Reliable? Soil Sci. Soc. Am. J., March 1, 2008; 72(2): 331 - 342. [Abstract] [Full Text] [PDF]

				S. Bernal, A. Butturini, E. Nin, F. Sabater, and S. Sabater Leaf Litter Dynamics and Nitrous Oxide Emission in a Mediterranean Riparian Forest: Implications for Soil Nitrogen Dynamics J. Environ. Qual., January 1, 2003; 32(1): 191 - 197. [Abstract] [Full Text] [PDF]

				B. P. Horgan, B. E. Branham, and R. L. Mulvaney Direct Measurement of Denitrification Using 15N-labeled Fertilizer Applied to Turfgrass Crop Sci., September 1, 2002; 42(5): 1602 - 1610. [Abstract] [Full Text] [PDF]

				B.P. Horgan, R.L. Mulvaney, and B.E. Branham Determination of Atmospheric Volume for Direct Field Measurement of Denitrification in Soil Cores Soil Sci. Soc. Am. J., March 1, 2001; 65(2): 511 - 516. [Abstract] [Full Text] [PDF]