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 (8) Citing Articles via Google Scholar Google Scholar Articles by Parkin, T. B. Articles by Kaspar, T. C. Search for Related Content PubMed Articles by Parkin, T. B. Articles by Kaspar, T. C. Agricola Articles by Parkin, T. B. Articles by Kaspar, T. C. Related Collections Soil Microbiology Carbon Sequestration Global Change Experiment Design

DIVISION S-3—SOIL BIOLOGY & BIOCHEMISTRY

Temporal Variability of Soil Carbon Dioxide Flux

Effect of Sampling Frequency on Cumulative Carbon Loss Estimation

USDA-ARS, National Soil Tilth Lab., 2150 Pammel Dr., Ames, IA 50011

^* Corresponding author (parkin{at}nstl.gov). 677 S. Segoe Rd., Madison, WI 53711 USA

It is well known that soil CO₂ flux can exhibit pronounced day-to-day variations; however, measurements of soil CO₂ flux with soil chambers typically are done only at discrete points in time. This study evaluated the impact of sampling frequency on the precision of cumulative CO₂ flux estimates calculated from field measurements. Automated chambers were deployed at two sites in a no-till corn/soybean field and operated in open system mode to measure soil CO₂ fluxes every hour from 4 March 2000 through 6 June 2000. Sampling frequency effects on cumulative CO₂–C flux estimation were assessed with a jackknife technique whereby the populations of measured hourly fluxes were numerically sampled at regular time intervals ranging from 1 d to 20 d, and the resulting sets of jackknife fluxes were used to calculate estimates of cumulative CO₂–C flux. We observed that as sampling interval increased from 1 d to 12 d, the variance associated with cumulative flux estimates increased. However, at sampling intervals of 12 to 20 d, variances were relatively constant. Sampling once every 3 d, estimates of cumulative C loss were within ±20% of the expected value at both sites. As the time interval between sampling was increased, the potential deviation in estimated cumulative CO₂ flux increased such that sampling once every 20 d yielded potential estimates within +60% and –40% of the actual cumulative CO₂ flux. A stratified sampling scheme around rainfall events was also evaluated and was found to provide more precise estimates at lower sampling intensities. These results should aid investigators to develop sampling designs to minimize the effects of temporal variability on cumulative CO₂–C estimation.

Abbreviations: DOY, day of year • IRGA, infrared gas analyzer

This article has been cited by other articles:

				J. Alvaro-Fuentes, M. V. Lopez, J. L. Arrue, and C. Cantero-Martinez Management Effects on Soil Carbon Dioxide Fluxes under Semiarid Mediterranean Conditions Soil Sci. Soc. Am. J., January 11, 2008; 72(1): 194 - 200. [Abstract] [Full Text] [PDF]

				V. E. Turcu, S. B. Jones, and D. Or Continuous Soil Carbon Dioxide and Oxygen Measurements and Estimation of Gradient-Based Gaseous Flux Vadose Zone J., November 11, 2005; 4(4): 1161 - 1169. [Abstract] [Full Text] [PDF]