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

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Hutchinson, G. L. Articles by Rochette, P. Search for Related Content PubMed Articles by Hutchinson, G. L. Articles by Rochette, P. Agricola Articles by Hutchinson, G. L. Articles by Rochette, P. Related Collections Agroclimatology Air Pollution Soil Methods/Instrumentation Soil Biology

DIVISION S-3—SOIL BIOLOGY & BIOCHEMISTRY

Non-Flow-Through Steady-State Chambers for Measuring Soil Respiration

Numerical Evaluation of Their Performance

^a USDA-ARS, P.O. Box E, Fort Collins, CO 80522, USA
^b Agriculture and Agri-Food Canada, 2560 Hochelaga Blvd., Sainte-Foy, Québec, Canada G1V 2J3

* Corresponding author (glhutch{at}lamar.colostate.edu)

Soil respiration estimates obtained from non-flow-through steady-state chambers (also called static, absorption, or alkali trap chambers) are considered by many investigators to be unreliable. We studied the accuracy, functioning, and design requirements of this chamber type using a gas diffusion model validated for this purpose by demonstrating that it matched the empirical relation between alkali-measured flux and headspace CO₂ concentration. Simulated measurement error depended on (i) magnitude of the soil respiration rate, which spawned positive or negative error depending on the algebraic sign of the change in headspace CO₂, (ii) absorption efficiency of the alkali trap, which was determined by headspace air mixing rates, the thickness of atmospheric interfacial layers, and especially the ratio of exposed alkali surface area to emitting soil surface area, (iii) the effective diffusivity and storage coefficient of CO₂ in underlying soil, which depended on the soil's air-filled porosity (AFP) and pH, respectively, and (iv) the rate of CO₂ leakage between the chamber system and its surroundings. The results also indicated that although no single chamber design is universally applicable, striving for the ideal design in every situation is not required; for example, measurement error associated with the design used in our simulations was usually only 5% despite that headspace concentration rose more than 70% within 2 h. Larger errors occurred for chamber designs less well matched to the soil respiration rate they were intended to measure, but if such serious design deficiencies are avoided, the method offers a simple inexpensive means for obtaining multiple reliable time-integrated estimates of soil respiration, even at remote locations.

Abbreviations: AFP, air-filled porosity (m³ m^-3 soil) • D, binary molecular diffusion coefficient of CO₂ in air • F_a, estimate of CO₂ flux density at the soil-atmosphere boundary obtained from the amount of CO₂ absorbed by the alkali trap in a non-flow-through steady-state chamber • F_c, CO₂ flux density at the soil-atmosphere boundary • F_o, depth-integrated rate of subsurface CO₂ production expressed in units of flux density • FT, flow-through • NFT, non-flow-through • NSS, non-steady-state • SS, steady-state

This article has been cited by other articles:

				R. T. Venterea and J. M. Baker Effects of Soil Physical Nonuniformity on Chamber-Based Gas Flux Estimates Soil Sci. Soc. Am. J., August 20, 2008; 72(5): 1410 - 1417. [Abstract] [Full Text] [PDF]

				G. P. Livingston, G. L. Hutchinson, and K. Spartalian Trace Gas Emission in Chambers: A Non-Steady-State Diffusion Model Soil Sci. Soc. Am. J., August 3, 2006; 70(5): 1459 - 1469. [Abstract] [Full Text] [PDF]