New Method for Determining Water-Conducting Macro- and Mesoporosity from Tension Infiltrometer

Bodhinayake, Waduwawatte; Cheng, Bing; Xiao, C.

doi:10.2136/sssaj2004.0760

Cited by 19 publications

(28 citation statements)

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“…Because the method of Watson and Luxmoore (1986) has been reported to overestimate the porosities (Bodhinayake et al, 2004;Buczko et al, 2006), we used the more recent approach of Bodhinayake et al (2004). From the pressure head h, the equivalent pore radius r [L] can be calculated using the equation of capillarity (Vomocil, 1965):…”

Section: Hydraulically Effective Porosities and Flowweighted Mean Pormentioning

confidence: 99%

“…L~']. can be calculated from the hydraulic conductivity in the pressure head interval corresponding to the two pore radii a and b (Bodhinayake et al, 2004): where Tl is the dynamic viscosity of water [ML ' T '], taken here as 0.00115 Pa s for 15°C. Integration of Eq.…”

Section: Hydraulically Effective Porosities and Flowweighted Mean Pormentioning

confidence: 99%

“…The data can be used to obtain the hydraulic conductivity function using Wooding's analytical equation (Wooding, 1968;Reynolds and EIrick, 1991). Subsequently, estimates of near-saturated hydraulic conductivities can be further analyzed in terms of the amount of hydraulically effective macro-and mesopores (Watson and Luxmoore, 1986;Bodhinayake et al, 2004) as well the flow-weighted mean pore radii estimated (Reynolds et al, 1995;Moret and Arrúe, 2007) or the parameters of a soil water retention model inversely estimated (Simunek et al, 1998). Ptevious studies have compared inverse parameter estimation from tension infiltrometer data with retention data obtained from laboratory measurements, and the method has been found to be sound (Angulo-Jaramillo al., 2000;Schwartz and Evett, 2002;Ramos et al, 2006;Yoon et al, 2007;Daraghmeh et al, 2008).…”

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confidence: 99%

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Hydraulic Properties and the Water-Conducting Porosity as Affected by Subsurface Compaction using Tension Infiltrometers

Schwen

Hernandez‐Ramirez

Lawrence‐Smith

et al. 2011

Soil Science Society of America Journal

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Changes in soil physical properties due to compaction are a major concern in agricultural production and modeling of soil water movement and plant growth. The objectives of this study were to measure water infiltration under different compaction levels and to characterize the effects of compaction on the soil's porosity and its associated water-conducting properties. On a silt loam soil, relative to a control, four levels of subsurface compaction were induced: loosening and light, medium, and heavy compaction. Infiltration characteristics were measured in situ using tension infiltrometers. Near-saturated conductivities were calculated using Wooding's equation and further analyzed to derive the hydraulically effective macro-and mesoporosities and the flow-weighted mean pore radii. The data were also used for parameterization ofthe van Genuchten-Mualem model by inverse parameter estimation. A high susceptibility to the applied compaction was found: the saturated hydraulic conductivity of the heavily compacted soil was 81% less than that ofthe loosened soil. This soil property may be used as a proxy for compaction-induced changes in hydraulic characteristics. Increasing compaction also decreased the number of hydraulically effective macropores, reduced the flow-weighted mean pore radius, and the ttyj-parameter ofthe van Genuchten-Mualem model. Our findings give indirect evidence for two main efFects ofthe applied compaction.First, the reduced saturated hydraulic conductivity might be due to distortion of structural flow paths, reducing the connectivity and hydraulic effectiveness of many macropores. Second, compaction rearranged the pore space, resulting in more water-conducting mesopores.

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Section: Hydraulically Effective Porosities and Flowweighted Mean Pormentioning

confidence: 99%

Section: Hydraulically Effective Porosities and Flowweighted Mean Pormentioning

confidence: 99%

mentioning

confidence: 99%

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Hydraulic Properties and the Water-Conducting Porosity as Affected by Subsurface Compaction using Tension Infiltrometers

Schwen

Hernandez‐Ramirez

Lawrence‐Smith

et al. 2011

Soil Science Society of America Journal

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show abstract

“…Macropores play an important role in the rapid transport of water, solutes and pollutants through the soil, not only during infiltration but also in subsurface lateral flow and storm (quick) fiow generation of streams (Beven & Germann 1982;Slogan & Moore 1984;Perroux & White 1988;McDonnell 1990;Jarvis & Messing 1995;Bodhinayaka et al 2004;Moret & Arrúe 2007;Clothier eíaZ. 2008).…”

Section: Introductionmentioning

confidence: 99%

“…earthworms and moles; (ii) pores formed by plant roots; (iii) structural macropores, normally in soils with high 2:1 clay mineral contents; and (iv) natural soil pipes formed due to erosive action of subsurface flow. Pores (i) and (ii) are normally dominant in the A horizon whereas (iii) and (iv) are found in deeper horizons (Beven & Germann 1982;Nieber et al 2000;Lin et al 2006 Macropores can either be non-continuous (dead-ended) or continuous (interconnected), only the latter contribute to fast fiow in soils (Bodhinayaka et al 2004). A high degree of macroporosity does not necessarily mean that the soil has a high hydraulic conductivify, as the pores may be discontinuous.…”

Section: Introductionmentioning

confidence: 99%

Pedotransfer functions to determine water conducting macroporosity in South African soils

Tol

Roux

Hensley

2012

Water Science and Technology

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Macropores play an important role in the rapid transport of water, solutes and pollutants through the soil. Transport through these pores (>0.5 mm) is dominated by gravitational forces (i.e. matrix forces have low impact) resulting in flow rates orders of magnitude higher than rates that would be predicted, posing problems for modelling and understanding water and solute transport through soils. This study aimed to quantify the water conducting macroporosity (WCM) in a range of soils in South Africa and to develop three pedotransfer functions (PTFs) able to predict WCM. Saturated (K(s)) and unsaturated (K₃₀) conductivities were measured in situ on 120 soil profiles using double ring and tension infiltrometers methods. Differences between K(s) and K₃₀ in conjunction with Poiseuille's law and the capillary rise equation were used to calculate WCM. The first two multiple regression functions made use of all available soil properties influencing WCM using a 'best model' and 'backward' analysis approach respectively. The third model used only easily observable soil properties to predict the WCM. The functions were validated using a double-cross method. Results are encouraging with R² values of 0.78, 0.74 and 0.69 for functions 1, 2 and 3 respectively.

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Soil infiltration characteristics and pore distribution under freezing-thawing conditions

Jiang

Liu

et al. 2020

Preprint

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Frozen soil infiltration widely occurs in hydrological processes such as seasonal soil freezing and thawing, snowmelt infiltration, and runoff. Accurate measurement and simulation of parameters related to frozen soil infiltration processes are highly important for agricultural water management, environmental issues, and engineering problems in cold regions. Temperature changes cause soil pore size distribution variations and consequently dynamic infiltration capacity changes during different freeze-thaw periods. To better understand these complex processes and to reveal the freeze-thaw action effects on soil pore distribution and infiltration capacity, black soils, meadow soils, and chernozem were selected as test subjects. These soil types account for the largest arable land area in Heilongjiang Province, China. Laboratory tests of soils at different temperatures were conducted using a tension infiltrometer and ethylene glycol aqueous solution. The stable infiltration rate and hydraulic conductivity were measured, and the soil pore distribution was calculated. The results indicated that for the different soil types, macropores, which constituted approximately 0.1 % to 0.2 % of the soil volume under unfrozen conditions, contributed approximately 50 % of the saturated flow, and after soil freezing, the soil macropore proportion decreased to 0.05 % to 0.1 %, while the saturated flow proportion decreased to approximately 30 %. Soil moisture froze into ice crystals inside relatively large pores, resulting in numerous smaller-sized pores, which reduced the number of macropores but increased the number of smaller-sized mesopores, so that the frozen soil infiltration capacity was no longer solely dependent on the macropores. After the ice crystals had melted, more pores were formed within the soil, enhancing the soil permeability.

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New Method for Determining Water-Conducting Macro- and Mesoporosity from Tension Infiltrometer

Cited by 19 publications

References 0 publications

Hydraulic Properties and the Water-Conducting Porosity as Affected by Subsurface Compaction using Tension Infiltrometers

Hydraulic Properties and the Water-Conducting Porosity as Affected by Subsurface Compaction using Tension Infiltrometers

Pedotransfer functions to determine water conducting macroporosity in South African soils

Soil infiltration characteristics and pore distribution under freezing-thawing conditions

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