A Statistical Approach to Define Soil, Aeration in Respect to Denitrification1

Flühler, H.; Stolzy, L. H.; Ardakani, M. S.

doi:10.1097/00010694-197608000-00008

Cited by 53 publications

(14 citation statements)

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“…The Pt tip might be located either along a macropore, enabling enhanced O 2 diffusion, or embedded within a fine-textured soil matrix, retarding the entrance of O 2 to increase E H . This concept of 'non-aerated' and 'aerated' soil volume was discussed by Flühler et al (1976) with suggestions to use a binomial function to approximate real soil conditions rather than a simple dual differentiation. Overall, even though Pt aeration might exceed a certain threshold, it must be expected that microsites of anoxia are still present.…”

Section: Single Aeration Experimentsmentioning

confidence: 99%

Soil aeration: the relation between air‐filled pore volume and redox potential

Dorau

Luster

Mansfeldt

2018

European J Soil Science

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Summary The soil water content affects rates of oxygen diffusion and redox potentials (EH). When water‐saturated soils become aerated, a switch from reducing to oxidizing conditions occurs. However, limited information is available on the air‐filled pore volume (ϵ) at which this shift happens. To obtain values of ϵ, undisturbed soil cores were taken from a Fluvisol and a Gleysol that differed in structure and clay content. Experiments on submergence and drying following a new experimental design were performed in the laboratory. After submergence, the cores were sealed with a glass hood to exclude oxygen and to achieve reducing conditions (EH < −100 mV). We then aerated the sample by removal of glass plugs in the hood and measured EH consecutively by platinum (Pt) electrodes and ϵ by matric potential readings on an hourly basis. From the drying curve we determined two characteristic values: (i) ϵPt reaction indicates the air‐filled pore volume at which a response of the Pt electrode to contact with oxygen occurs (i.e. EH increase > 5 mV hour−1) and (ii) ϵPt aeration indicates when oxidizing soil conditions are present (i.e. EH > 300 mV at pH 7). The Fluvisol was characterized by an ϵPt reaction value of 0.036 ± 0.006 cm3 cm−3 and an ϵPt aeration value of 0.047 ± 0.005, whereas for the Gleysol these values were 0.048 ± 0.008 and 0.085 ± 0.007 cm3 cm−3, respectively. We aimed to obtain such characteristic values for different soils to estimate the aeration status of a soil when ϵ is known, but EH measurements were unavailable. Highlights We studied the relation between EH and air‐filled pore volume (ϵ) for two soils varying in texture. Two characteristic ϵ values are proposed: ϵPt reaction (EH increases > 5 mV hour−1) and ϵPt aeration (EH > 300 mV at pH7). ϵPt aeration was larger for a clayey Gleysol than a sandy Fluvisol, but ϵPt reaction was similar. Small‐scale heterogeneity in soil structure had no effect on the EH–ϵ relation.

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Section: Single Aeration Experimentsmentioning

confidence: 99%

Soil aeration: the relation between air‐filled pore volume and redox potential

Dorau

Luster

Mansfeldt

2018

European J Soil Science

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“…Differences in the sampling volumes of various aeration sensors and actual differences in soil 0 2 status over short distances within the soil led Flühler et al (1976) to conclude that soil aeration is most appropriately characterized by a statistical expression of microsite spatial heterogeneity. Average profile 0 2 status may be irrelevant to the particular 0 2 status at a microsite near a root hair or single-celled microorganism.…”

Section: B Water In Soil Poresmentioning

confidence: 99%

Effects of Flooding on Plant Disease

Stolzy

1984

Flooding and Plant Growth

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“…1) vary with external conditions thereby constantly affect microbial community size and composition (Fierer et al, 2003b(Fierer et al, , 2009Eilers et al, 2012). The resulting growth conditions in soil may vary in space and time giving rise to episodic anoxic hotspots where much of the anaerobic microbial processes (e.g., denitrification) take place (Fl€ uhler et al, 1976;Groffman et al, 2009;Eilers et al, 2012;Kuzyakov & Blagodatskaya, 2015). Evidence suggests that even at the aggregate-scale microbial community structure and self-organization may vary considerably within an aggregate and along the soil profile (Nunan et al, 2002;.…”

Section: Introductionmentioning

confidence: 99%

Microbial community dynamics in soil aggregates shape biogeochemical gas fluxes from soil profiles – upscaling an aggregate biophysical model

Ebrahimi

2016

Global Change Biology

129

142

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Microbial communities inhabiting soil aggregates dynamically adjust their activity and composition in response to variations in hydration and other external conditions. These rapid dynamics shape signatures of biogeochemical activity and gas fluxes emitted from soil profiles. Recent mechanistic models of microbial processes in unsaturated aggregate-like pore networks revealed a highly dynamic interplay between oxic and anoxic microsites jointly shaped by hydration conditions and by aerobic and anaerobic microbial community abundance and self-organization. The spatial extent of anoxic niches (hotspots) flicker in time (hot moments) and support substantial anaerobic microbial activity even in aerated soil profiles. We employed an individual-based model for microbial community life in soil aggregate assemblies represented by 3D angular pore networks. Model aggregates of different sizes were subjected to variable water, carbon and oxygen contents that varied with soil depth as boundary conditions. The study integrates microbial activity within aggregates of different sizes and soil depth to obtain estimates of biogeochemical fluxes from the soil profile. The results quantify impacts of dynamic shifts in microbial community composition on CO2 and N2 O production rates in soil profiles in good agreement with experimental data. Aggregate size distribution and the shape of resource profiles in a soil determine how hydration dynamics shape denitrification and carbon utilization rates. Results from the mechanistic model for microbial activity in aggregates of different sizes were used to derive parameters for analytical representation of soil biogeochemical processes across large scales of practical interest for hydrological and climate models.

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A Statistical Approach to Define Soil, Aeration in Respect to Denitrification1

Cited by 53 publications

References 0 publications

Soil aeration: the relation between air‐filled pore volume and redox potential

Soil aeration: the relation between air‐filled pore volume and redox potential

Effects of Flooding on Plant Disease

Microbial community dynamics in soil aggregates shape biogeochemical gas fluxes from soil profiles – upscaling an aggregate biophysical model

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