Numerical Evaluation of Static-Chamber Measurements of Soil-Atmosphere Gas Exchange: Identification of Physical Processes

Healy, Richard W.; Striegl, Robert G.; Russell, Thomas F.; Hutchinson, G. L.; Livingston, Gerald P.

doi:10.2136/sssaj1996.03615995006000030009x

Cited by 242 publications

(186 citation statements)

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“…the three areas presented a huge amount of crop residues left after the previous harvest, which occurred between July 29 and august 8, 2005. Measurements of soil Co 2 emission were conducted in each of the studied locations during the afternoon period (between 14 -16 h), using a portable LI-6400-09 chamber (LI-COR, NE, USA) (Healy et al, 1996). the chamber is a closed system, with an internal volume of 991 cm 3 and a contact area with the soil of 71.6 cm 2 that is able to analyze Co 2 concentration inside by means of optical absorption spectroscopy in infrared.…”

Section: Methodsmentioning

confidence: 99%

Spatial variability of soil CO2 emission in different topographic positions

et al. 2010

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the spatial variability of soil Co 2 emission is controlled by several properties related to the production and transport of Co 2 inside the soil. Considering that soil properties are also influenced by topography, the objective of this work was to investigate the spatial variability of soil Co 2 emission in three different topographic positions in an area cultivated with sugarcane, just after mechanical harvest. One location was selected on a concave-shaped form and two others on linear-shaped form (in back-slope and foot-slope). three grids were installed, one in each location, containing 69 points and measuring 90 x 90 m each. the spatial variability of soil Co 2 emission was characterized by means of semivariance. Spatial variability models derived from soil Co 2 emission were exponential in the concave location while spherical models fitted better in the linear shaped areas. The degree of spatial dependence was moderate in all cases and the range of spatial dependence for the Co 2 emission in the concave area was 44.5 m, higher than the mean value obtained for the linear shaped areas (20.65 m). the spatial distribution maps of soil Co 2 emission indicate a higher discontinuity of emission in the linear form when compared to the concave form.Key words: sugarcane, carbon dioxide, geostatistics, kriging, soil respiration, topography. reSUmoVariaBiLidade eSPaCiaL da eMiSSão de Co 2 do SoLo eM diferenteS PoSiçõeS toPográfiCaS a variabilidade espacial da emissão de Co 2 é determinada pela variação de atributos do solo relacionados à produção e ao transporte de Co 2 no interior do solo. Considerando que a distribuição espacial destes atributos ocorre por influência da topografia, o objetivo deste trabalho foi estudar a variabilidade espacial da emissão de CO 2 do solo em três diferentes posições topográficas em área sob cultivo de cana-de-açúcar, após colheita mecanizada da cana crua. Selecionou-se uma área na forma côncava e outras duas em posições contrastantes na forma linear (encosta superior e encosta inferior), nas quais foram instaladas três malhas de amostragem, uma em cada área, contendo 69 pontos e medindo 90 x 90 m cada uma. Caracterizou-se a variabilidade espacial da emissão de Co 2 por meio da semivariância. a estrutura de variabilidade espacial da emissão de Co 2 foi descrita por modelo exponencial na forma côncava e por modelos esféricos nas áreas situadas na forma linear. O grau de dependência espacial foi moderado nas três áreas e o alcance da dependência espacial da emissão na área côncava foi de 44,5 m, superior ao valor médio obtido para as áreas situadas na forma linear (20,65 m). Houve maior descontinuidade da distribuição espacial da emissão de Co 2 do solo na forma linear em relação à forma côncava.

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Section: Methodsmentioning

confidence: 99%

Spatial variability of soil CO2 emission in different topographic positions

et al. 2010

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“…Ci. Solo, 33:325-334, 2009 beginning of CO 2 -C evaluation (Healy et al, 1996). The chamber had an internal volume of 991 cm 3 , with an exposed area to soil of 71.6 cm 2 , and was coupled to a portable infrared gas analyzer (IRGA), which determined the changes in CO 2 concentration inside the chamber by means of optical absorption spectroscopy.…”

Section: Climate Soil and Locationmentioning

confidence: 99%

Carbon dioxide efflux in a rhodic hapludox as affected by tillage systems in southern Brazil

Chávez

Amado

Bayer

et al. 2009

Rev. Bras. Ciênc. Solo

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SUMMARYAgricultural soils can act as a source or sink of atmospheric C, according to the soil management. This long-term experiment (22 years) was evaluated during 30 days in autumn, to quantify the effect of tillage systems (conventional tillage-CT and no-till-NT) on the soil CO 2 -C flux in a Rhodic Hapludox in Rio Grande do Sul State, Southern Brazil. A closed-dynamic system (Flux Chamber 6400-09, Licor) and a static system (alkali absorption) were used to measure soil CO 2 -C flux immediately after soybean harvest. Soil temperature and soil moisture were measured simultaneously with CO 2 -C flux, by Licor-6400 soil temperature probe and manual TDR, respectively. During the entire month, a CO 2 -C emission of less than 30 % of the C input through soybean crop residues was estimated. In the mean of a 30 day period, the CO 2 -C flux in NT soil was similar to CT, independent of the chamber type used for measurements. Differences in tillage systems with dynamic chamber were verified only in short term (daily evaluation), where NT had higher CO 2 -C flux than CT at the beginning of the evaluation period and lower flux at the end. The dynamic chamber was more efficient than the static chamber in capturing variations in CO 2 -C flux as a function of abiotic factors. In this chamber, the soil temperature and the water-filled pore space (WFPS), in the NT soil, explained 83 and 62 % of CO 2 -C flux, respectively. The Q 10 factor, which evaluates CO 2 -C flux dependence on soil temperature, was estimated as 3.93, suggesting a high sensitivity of the biological activity to changes in soil temperature during fall season. The CO 2 -C flux measured in a closed dynamic chamber was correlated with the static alkali adsorption chamber only in the NT system, although the values were underestimated in comparison to the other, particularly in the case of high flux values. At low soil temperature and WFPS conditions, soil tillage caused a limited increase in soil CO 2 -C flux.Index terms: no-till, greenhouse gases, soil temperature, soil moisture. RESUMO: EMISSÃO DE DIÓXIDO DE CARBONO EM LATOSSOLO VERMELHO ALTERADA POR SISTEMAS DE PREPARO NO SUL DO BRASILOs solos agrícolas podem atuar como dreno ou fonte de C atmosférico, dependendo do sistema de manejo adotado. Este estudo foi desenvolvido em experimento de longa duração (22 anos), durante o período de 30 dias do outono, com o objetivo de avaliar o impacto de sistemas de preparo de solo (preparo convencional-PC e plantio direto-PD) nas emissões de C-CO 2 de um Latossolo Vermelho distrófico, em Cruz Alta, RS. As emissões de C-CO 2 do solo foram avaliadas com câmaras dinâmica (Flux Chamber 6400-09, Licor) e estática (com captação em solução alcalina), imediatamente após a colheita da soja. A temperatura e a umidade do solo foram registradas, concomitantemente com as emissões de C-CO 2 , por meio de sensor de temperatura e TDR manual, respectivamente, integrantes do Licor-6400. Estimouse que, em 30 dias, uma quantidade equivalente a menos de 30 % do C aportado pelos resíduos de soj...

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“…For example, Figure 6 illustrates the large effect of differences in 0• when the overlying chamber was homogeneously mixed above a 0.5-cm atmospheric interfacial layer that was not affected by chamber deployment. Smaller effective diffusivity (that is, the product In addition to the differences in tortuosity models and assumed air mixing processes, Figure 5 of Healy et al [1996] also reflects the influence of 0• on near-surface horizontal diffusion beneath chamber walls resting on the soil surface rather than extending 5 cm below it. The resulting much poorer chamber performance emphasizes the importance of inserting the walls to at least the depth that soil gas concentration gradients are significantly perturbed by chamber feedback effects: a conclusion also supported by the comparison of 5-and 50-cm insertion depths in the 300-min simulations described in the previous section.…”

Section: Soil Transport Propertiesmentioning

confidence: 99%

Chamber measurement of surface‐atmosphere trace gas exchange: Numerical evaluation of dependence on soil, interfacial layer, and source/sink properties

Hutchinson¹,

Livingston²,

Healy³

et al. 2000

J. Geophys. Res.

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Abstract. We employed a three-dimensional finite difference gas diffusion model to simulate the performance of chambers used to measure surface-atmosphere trace gas exchange. We found that systematic errors often result from conventional chamber design and deployment protocols, as well as key assumptions behind the estimation of trace gas exchange rates from observed concentration data. Specifically, our simulations showed that (1) when a chamber significantly alters atmospheric mixing processes operating near the soil surface, it also nearly instantaneously enhances or suppresses the postdeployment gas exchange rate, (2) any change resulting in greater soil gas diffusivity, or greater partitioning of the diffusing gas to solid or liquid soil fractions, increases the potential for chamber-induced measurement error, and (3) all such errors are independent of the magnitude, kinetics, and/or distribution of trace gas sources, but greater for trace gas sinks with the same initial absolute flux. Finally, and most importantly, we found that our results apply to steady state as well as non-steady-state chambers, because the slow rate of gas diffusion in soil inhibits recovery of the former from their initial non-steady-state condition. Over a range of representative conditions, the error in steady state chamber estimates of the trace gas flux varied from -30 to +32%, while estimates computed by linear regression from non-steadystate chamber concentrations were 2 to 31% too small. Although such errors are relatively small in comparison to the temporal and spatial variability characteristic of trace gas exchange, they bias the summary statistics for each experiment as well as larger scale trace gas flux estimates based on them.

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Numerical Evaluation of Static-Chamber Measurements of Soil-Atmosphere Gas Exchange: Identification of Physical Processes

Cited by 242 publications

References 0 publications

Spatial variability of soil CO2 emission in different topographic positions

Spatial variability of soil CO2 emission in different topographic positions

Carbon dioxide efflux in a rhodic hapludox as affected by tillage systems in southern Brazil

Chamber measurement of surface‐atmosphere trace gas exchange: Numerical evaluation of dependence on soil, interfacial layer, and source/sink properties

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