ARS | Publication request: Comparison of soil carbon dioxide flux measurements by static and portable chambers in various management practices

Submitted to: Soil and Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 2, 2011
Publication Date: December 21, 2011
Citation: Sainju, U.M., Caesar, T., Caesar, A.J. 2011. Comparison of soil carbon dioxide flux measurements by static and portable chambers in various management practices. Soil and Tillage Research. 118:123-131.

Interpretive Summary: Portable chamber using infrared analyzer, because of its simplicity, rapidity, inexpensiveness, has been increasingly used to measure emissions of soil carbon dioxide (CO2), a greenhouse gas responsible for global warming. Its effectiveness and precision compared with the static chamber using gas chromatograph, however, is not well known. Experiments were conducted to compare the portable and static chamber methods of measuring soil CO2 fluxes from May to October, 2008 under various soil, climatic, and management practices in dryland and irrigated cropping systems in eastern Montana and western North Dakota, USA. Treatments in eastern Montana were dryland no-tilled continuous malt barley (NTCB), no-tilled malt barley-pea (NTB-P), and conventional-tilled malt barley-fallow (CTB-F), each with 0 and 80 kg N ha-1 applied to Williams loam. Similarly, treatments in western North Dakota were no-tilled malt barley with N fertilizer (NTBFN), no-tilled malt barley with no N fertilizer (NTBON), no-tilled malt barley-pea with N fertilizer (NTB-PN), conventional-tilled malt barley with N fertilizer (CTBFN), and conventional-tilled malt barley with no N fertilizer (CTBON), each with irrigation and non-irrigation applied to Lihen sandy loam. At both locations, CO2 flux during the summer peaked following substantial precipitation and/or irrigation (>15 mm), increasing soil water content, regardless of treatments and measurement methods. The flux varied with treatments more in the portable than in the static chamber. In eastern Montana, CO2 flux, averaged across measurement dates, was greater in NTCB than in NTB-P and was 1.2 times greater in the portable than in static chamber. In western North Dakota, CO2 flux varied among treatments and was 2.4 times greater in the portable than in the static chamber. The CO2 fluxes in portable and static chambers were linearly to exponentially related (R2 = 0.68 to 0.77, P = 0.01, n = 40 to 56). Measurements of CO2 fluxes between the portable chamber using infrared analyzer and the static chamber using gas chromatograph were closer in loam soil under dryland cropping systems than in sandy loam soil under dryland and irrigated cropping systems. Portable chamber may provide a reliable measurement of CO2 flux compared with static chamber in dryland than in irrigated cropping systems.

Technical Abstract: Portable chamber using infrared analyzer provides simple, rapid, and inexpensive measurement of emissions of soil carbon dioxide (CO2), a greenhouse gas responsible for global warming, but its effectiveness and precision compared with the static chamber using gas chromatograph is not well known. The measurement of soil CO2 flux was compared between a portable chamber using infrared analyzer and a static chamber using gas chromatograph under various management practices from May to October, 2008 in eastern Montana and western North Dakota, USA. Treatments in eastern Montana were dryland no-tilled continuous malt barley (Hordeum vulgaris L.) (NTCB), no-tilled malt barley-pea (Pisum sativum L.) (NTB-P), and conventional-tilled malt barley-fallow (CTB-F), each with 0 and 80 kg N ha-1 applied to Williams loam (fine-loamy, mixed, superactive, frigid, Typic Argiborolls). Similarly, treatments in western North Dakota were no-tilled malt barley with N fertilizer (NTBFN), no-tilled malt barley with no N fertilizer (NTBON), no-tilled malt barley-pea with N fertilizer (NTB-PN), conventional-tilled malt barley with N fertilizer (CTBFN), and conventional-tilled malt barley with no N fertilizer (CTBON), each with irrigation and non-irrigation applied to Lihen sandy loam (sandy, mixed, frigid, Entic Haplustolls). At both locations, CO2 flux during the summer peaked following substantial precipitation and/or irrigation (>15 mm), increasing soil water content, regardless of treatments and measurement methods. The flux varied with treatments more in the portable than in the static chamber. In eastern Montana, CO2 flux, averaged across measurement dates, was greater in NTCB than in NTB-P and was 1.2 times greater in the portable than in static chamber. In western North Dakota, CO2 flux varied among treatments and was 2.4 times greater in the portable than in the static chamber. The CO2 fluxes in portable and static chambers were linearly to exponentially related (R2 = 0.68 to 0.77, P = 0.01, n = 40 to 56). Measurements of CO2 fluxes between the portable chamber using infrared analyzer and the static chamber using gas chromatograph were closer in loam soil under dryland cropping systems than in sandy loam soil under dryland and irrigated cropping systems. Portable chamber may provide a reliable measurement of CO2 flux compared with static chamber in dryland than in irrigated cropping systems.