scholarly journals The structural porosity in soil hydraulic functions – a review

2008 ◽  
Vol 3 (Special Issue No. 1) ◽  
pp. S7-S20 ◽  
Author(s):  
M. Kutílek ◽  
L. Jendele
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Soil Structure ◽  
Water Retention ◽  
Retention Function ◽  
Pore System ◽  
Conductivity Function ◽  
Soil Hydraulic ◽  
Matrix Domains

Products of biological processes are the dominant factor of soil structure formation in A horizons, while in B horizons their role is less expressed. Soil structure influences dominantly the structural domain of the pore system in bimodal soils thus affecting soil hydraulic functions. The form of soil hydraulic functions depends upon the pore size distribution and generally upon configuration of the soil pore system. We used the functions derived for the lognormal pore size distribution and modified them to bi-modal soils. The derived equations were tested by experimental data of catalogued soils. The procedure leads to the separation of two mutually different domains of structural and matrix pores. The value of the pressure head (potential) separating the two domains is not constant and varies in a broad range. For each domain we obtained its water retention function and unsaturated hydraulic conductivity function. The separation of hydraulic functions for the two domains is a key problem in the solution of preferential flow and in controlling lateral flow between the structural and matrix domains. Water retention function is fully physically based while the conductivity function still keeps fitting parameters, too. Their simple relationship to tortuosity and pores connectivity was not confirmed. Since they differ substantially for matrix and structural domains, we suppose that there exists a great difference in configuration of porous systems in structural and matrix domains. The use of uniform fitting conductivity parameters for the whole range of pores is not justifiable.

Particle-size and organic matter effects on structure and water retention of soils

Biologia ◽  
2015 ◽  
Vol 70 (11) ◽  
Author(s):  
Kálmán Rajkai ◽  
Brigitta Tóth ◽  
Gyöngyi Barna ◽  
Hilda Hernádi ◽  
Mihály Kocsis ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Soil Structure ◽  
Water Retention ◽  
Sandy Soils ◽  
Soil Profiles ◽  
Matter Effects

AbstractWater storage and flow in soils are highly dependent on soil structure, which strongly determines soil porosity. However pore size distribution can be derived from soil water retention curve (SWRC). Structural characteristics of cultivated arable fields (693 soil profiles, 1773 samples) and soils covered by treated forest stands (137 soil profiles, 405 samples) were selected from the MARTHA Hungarian soil physical database, and evaluated for expressing organic matter effects on soil structure and water retention. For this purpose the normalized pore size distribution curves were determined for the selected soils, plus the modal suction (MS) corresponding to the most frequent pore size class of the soil. Skewness of soils’ pore size distribution curves are found different. The quasi-normal distribution of sandy soils are transformed into distorted in clayey soils. A general growing trend of MS with the ever finer soil texture was shown. Sandy soils have the lowest average MS values, i.e. the highest most frequent equivalent pore diameter. Silty clay and clay soil textures are characterized by the highest MS values. A slight effect of land use and organic matter content is also observable in different MS values of soils under forest vegetation (’forest’) and cultivated arable land (‘plough fields’). MS values of the two land uses were compared statistically. The results of the analyses show that certain soil group’s MS are significantly different under forest vegetation and cultivation. However this difference can be explained only partly and indirectly by the organic matter of different plant coverage in the land use types.

scholarly journals SWRC fit – a nonlinear fitting program with a water retention curve for soils having unimodal and bimodal pore structure

2007 ◽  
Vol 4 (1) ◽  
pp. 407-437 ◽  
Author(s):  
K. Seki
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Soil Water ◽  
Water Retention ◽  
Distribution Model ◽  
Soil Water Retention ◽  
Nonlinear Fitting ◽  
Soil Hydraulic ◽  
Log Normal

Abstract. The soil hydraulic parameters for analyzing soil water movement can be determined by fitting a soil water retention curve to a certain function, i.e., a soil hydraulic model. For this purpose, the program "SWRC Fit," which performs nonlinear fitting of soil water retention curves to 5 models by Levenberg-Marquardt method, was developed. The five models are the Brooks and Corey model, the van Genuchten model, Kosugi's log-normal pore-size distribution model, Durner's bimodal pore-size distribution model, and a bimodal log-normal pore-size distribution model propose in this study. This program automatically determines all the necessary conditions for the nonlinear fitting, such as the initial estimate of the parameters, and, therefore, users can simply input the soil water retention data to obtain the necessary parameters. The program can be executed directly from a web page at http://purl.org/net/swrc/; a client version of the software written in numeric calculation language GNU Octave is included in the electronic supplement of this paper. The program was used for determining the soil hydraulic parameters of 420 soils in UNSODA database. After comparing the root mean square error of the unimodal models, the van Genuchten and Kosugi's models were better than the Brooks and Corey model. The bimodal log-normal pore-size distribution model had similar fitting performance to Durner's bimodal pore-size distribution model.

scholarly journals Accounting for evolving pore size distribution in water retention models for compacted clays

2014 ◽  
Vol 39 (7) ◽  
pp. 702-723 ◽  
Author(s):  
Gabriele Della Vecchia ◽  
Anne-Catherine Dieudonné ◽  
Cristina Jommi ◽  
Robert Charlier
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Water Retention ◽  
Retention Models ◽  
Compacted Clays

scholarly journals Prediction of soil water retention properties using pore-size distribution and porosity

2013 ◽  
Vol 50 (4) ◽  
pp. 435-450 ◽  
Author(s):  
Christopher T.S. Beckett ◽  
Charles E. Augarde
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Soil Water ◽  
Water Retention ◽  
Adsorbed Water ◽  
Retention Data ◽  
Soil Water Retention ◽  
Pore Size Distributions ◽  
Water Retention Properties

Several models have been suggested to link a soil's pore-size distribution to its retention properties. This paper presents a method that builds on previous techniques by incorporating porosity and particles of different sizes, shapes, and separation distances to predict soil water retention properties. Mechanisms are suggested for the determination of both the main drying and wetting paths, which incorporate an adsorbed water phase and retention hysteresis. Predicted results are then compared with measured retention data to validate the model and to provide a foundation for discussing the validity and limitations of using pore-size distributions to predict retention properties.

scholarly journals Water Retention and Pore Size Distribution of a Biopolymeric-Amended Loam Soil

2019 ◽  
Vol 18 (1) ◽  
pp. 0 ◽  
Author(s):  
Mehdi Rahmati ◽  
Andreas Pohlmeier ◽  
Sara Mola Ali Abasiyan ◽  
Lutz Weihermüller ◽  
Harry Vereecken
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Water Retention ◽  
Loam Soil

scholarly journals Hydraulic Properties of Forest Soils with Stagnic Conditions

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1113
Author(s):  
Stefan Julich ◽  
Janis Kreiselmeier ◽  
Simon Scheibler ◽  
Rainer Petzold ◽  
Kai Schwärzel ◽  
...  
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Soil Samples ◽  
Stagnant Water ◽  
Infiltration Rates ◽  
Retention Characteristic ◽  
Water Conditions

Tree species, e.g., shallow vs. deep rooting tree species, have a distinct impact on hydrological properties and pore size distribution of soils. In our study, we determined the soil hydrologic properties and pore size distribution at three forest stands and one pasture as reference on soils with stagnant water conditions. All sites are located in the Wermsdorf Forest, where historical studies have demonstrated severe silvicultural problems associated with stagnant water in the soil. The studied stands represent different stages of forest management with a young 25-year-old oak (Sessile Oak (Quercus petraea) and Red oak (Q. robur)) plantation, a 170-year-old oak stand and a 95-year-old Norway Spruce (Picea abies) stand in second rotation. We determined the infiltration rates under saturated and near-saturated conditions with a hood-infiltrometer at the topsoil as well as the saturated hydraulic conductivity and water retention characteristic from undisturbed soil samples taken from the surface and 30 cm depth. We used the bi-modal Kosugi function to calculate the water retention characteristic and applied the normalized Young-Laplace equation to determine the pore size distribution of the soil samples. Our results show that the soils of the old stands have higher amounts of transmission pores, which lead to higher infiltration rates and conductance of water into the subsoil. Moreover, the air capacity under the old oak was highest at the surface and at 30 cm depth. There was also an observable difference between the spruce and oak regarding their contrasting root system architecture. Under the oak, higher hydraulic conductivities and air capacities were observed, which may indicate a higher and wider connected macropore system. Our results confirm other findings that higher infiltration rates due to higher abundance of macropores can be found in older forest stands. Our results also demonstrate that an adapted forest management is important, especially at sites affected by stagnant water conditions. However, more measurements are needed to expand the existing data base of soil hydraulic properties of forest soils in temperate climates.

The effect of soil conditioners on pore size distribution and water retention of a calcareous soil

Soil Research ◽  
1978 ◽  
Vol 16 (3) ◽  
pp. 277
Author(s):  
MH Khoury ◽  
AH Sayegh ◽  
NJ Atallah
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Calcareous Soil ◽  
Water Retention ◽  
Available Water ◽  
Soil Conditioners

The application of soil conditioners on a calcareous soil resulted in an increase in the diameter of pores and a decrease in the available water. A diameter of 140 �m was suggested to be the dividing point between micropores and very fine pores.

Water retention of arctic zone soils (Spitsbergen)

2013 ◽  
Vol 27 (4) ◽  
pp. 439-444 ◽  
Author(s):  
J. Melke ◽  
B. Witkowska-Walczak ◽  
P. Bartmiński
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Bulk Density ◽  
Size Distribution ◽  
Water Retention ◽  
Total Porosity ◽  
The Arctic ◽  
Arctic Zone ◽  
Retention Characteristics

Abstract The water retention characteristics of the arctic zone soils ((TurbicCryosol (Skeletic), TurbicCryosols (Siltic, Skeletic) and BrunicTurbicCryosol (Arenic)) derived in different micro-relief forms were determined. Water retention curves were similar in their course for the mud boils, cell forms, and sorted circles ie for TurbicCryosols. For these forms, the mud boils showed the highest water retention ability, whereas the sorted circles - the lowest one. Water retention curves for the tundra polygons (Brunic TurbicCryosol, Arenic) were substantially different from these mentioned above. The tundra polygons were characterized by the lowest bulk density of 1.26 g cm-3, whereas the sorted circles (TurbicCryosol, Skeletic) - the highest: 1.88 g cm-3. Total porosity was the highest for the tundra polygons (52.4 and 55.5%) and the lowest - for the sorted circles (28.8 and 26.2%). Pore size distribution of the investigated soils showed that independently of depths, the highest content of large and medium pores was noticed for the tundra polygons ie 21.2-24.2 and 19.9-18.7%, respectively. The lowest content of large pores was observed for the cell forms (6.4-5.9%) whereas the mud boils exhibited the lowest amount of medium sized pores (12.2-10.4%) (both TurbicCryosols Siltic, Skeletic). The highest content of small pores was detected in the mud boils - 20.4 and 19.0%.

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