Campus Units

Agronomy

Document Type

Article

Publication Version

Published Version

Publication Date

2015

Journal or Book Title

Soil Science Society of America Journal

Volume

79

Issue

4

First Page

1073

Last Page

1083

DOI

10.2136/sssaj2015.02.0079

Abstract

Soil CO2 production rates and fluxes vary with time and depth. The shallow near-surface soil layer is important for myriad soil processes, yet knowledge of dynamic CO2 concentrations and fluxes in this complex zone is limited. We used a concentration gradient method (CGM) to determine CO2 production and effluxes with depth in shallow layers of a bare soil. The CO2concentration was continuously measured at 13 depths in the 0- to 200-mm soil layer. For an 11-d period, 2% of the soil CO2 was produced below a depth of 175 mm, 8% was produced in the 50- to 175-mm soil layer, and 90% was produced in the 0- to 50-mm soil layer. Soil CO2concentration showed similar diurnal patterns with temperature in deeper soil layers and out-of-phase diurnal patterns in surface soil layers. Soil CO2 flux from most of the soil layers can be described by an exponential function of soil temperature, with temperature sensitivity (Q10) ranging from 1.40 to 2.00 (1.62 ± 0.17). The temperature-normalized CO2 fluxes are related to soil water content with a positive linear relationship in surface soil layers and a negative relationship in deep soil layers. The CO2 fluxes from CGM and chamber methods had good agreement at multiple time scales, which showed that the CGM method was able to estimate near-surface soil CO2 fluxes and production. The contrasting patterns between surface and deep layers of soil CO2 concentration and fluxes suggest the necessity of intensive CO2concentration measurements in the surface soil layer for accurate determination of soil-atmosphere CO2 flux when using the CGM.

Comments

This article is published as Xiao, Xinhua, X. Kuang, T. J. Sauer, J. L. Heitman, and R. Horton. "Bare soil carbon dioxide fluxes with time and depth determined by high-resolution gradient-based measurements and surface chambers." Soil Science Society of America Journal 79, no. 4 (2015): 1073-1083. doi: 10.2136/sssaj2015.02.0079.

Rights

Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.

Language

en

File Format

application/pdf

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