The role of the initial soil water content in the determination of unsaturated soil hydraulic conductivity using a tension infiltrometer

A theory is presented to calculate hydraulic conductivity from successive measurements of water content profiles for soil in situ. With unsaturated soil, potential gradients are inferred using moisture characteristics, but with saturated soil these gradients must be measured directly. The weight of overburden can affect in situ soil water suction, and a method for determining this effect is given. The theory was applied to a soil profile with marked changes in moisture characteristics and texture, and conductivity was determined for several depths as a function of water content.

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Numerical Modeling of Water Movement from Buried Vertical Ceramic Pipes through Soils

Journal of Engineering ◽

10.31026/j.eng.2018.06.06 ◽

2018 ◽

Vol 24 (6) ◽

pp. 72

Author(s):

Zena Kamil Rasheed ◽

Maysoon Basheer Abid

Keyword(s):

Hydraulic Conductivity ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Transient Flow ◽

Initial Conditions ◽

Irrigation System ◽

Pipe Length ◽

Ceramic Pipe ◽

Initial Soil

The problem of water scarcity is becoming common in many parts of the world, to overcome part of this problem proper management of water and an efficient irrigation system are needed. Irrigation with a buried vertical ceramic pipe is known as a very effective in the management of irrigation water. The two- dimensional transient flow of water from a buried vertical ceramic pipe through homogenous porous media is simulated numerically using the HYDRUS/2D software. Different values of pipe lengths and hydraulic conductivity were selected. In addition, different values of initial volumetric soil water content were assumed in this simulation as initial conditions. Different values of the applied head were assumed in this simulation as boundary conditions. The results of this research showed that greater spreading occurs in the horizontal direction. Increasing applied heads, initial soil water contents and pipe hydraulic conductivities, cause increasing the size of wetting patterns but in a few increases. Also, the results showed that the empirical formulas which can be used for expressing the wetted width and depth in terms of applied head, initial soil water content, application time, pipe hydraulic conductivity, and pipe length, are good and can be used as design equations.

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Numerical Modeling of Water Movement from Buried Vertical Ceramic Pipes through Coarse Soils

Al-Khwarizmi Engineering Journal ◽

10.22153/kej.2017.06.003 ◽

2018 ◽

Vol 13 (4) ◽

pp. 164-173

Author(s):

Zena Kamil Rasheed ◽

Maysoon Basheer Abid

Keyword(s):

Hydraulic Conductivity ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Transient Flow ◽

Vertical Direction ◽

Empirical Formulas ◽

Pipe Length ◽

Ceramic Pipe ◽

Initial Soil

Problem of water scarcity is becoming common in many parts of the world. Thus to overcome this problem proper management of water and an efficient irrigation systems are needed. Irrigation with buried vertical ceramic pipe is known as a very effective in management of irrigation water. The two- dimensional transient flow of water from a buried vertical ceramic pipe through homogenous porous media is simulated numerically using the software HYDRUS/2D to predict empirical formulas that describe the predicted results accurately. Different values of pipe lengths and hydraulic conductivity were selected. In addition, different values of initial volumetric soil water content were assumed in this simulation as initial conditions. Different values of applied head were assumed in this simulation as a boundary conditions. In general, a good agreement was obtained when comparing the predicted results with available measured values. The results of this research showed that greater spreading occur in vertical direction. Increasing applied heads, initial soil water contents, pipe hydraulic conductivities, cause increasing the size of wetting patterns. Also the results showed that the empirical formulas which can be used for expressing the wetted width and depth in terms of applied head, initial soil water content, application time, pipe hydraulic conductivity, and pipe length, are good and can be used as a designing equations.

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Libardi's method refinement for soil hydraulic conductivity measurement

Soil Research ◽

10.1071/sr00027 ◽

2001 ◽

Vol 39 (4) ◽

pp. 851 ◽

Cited By ~ 2

Author(s):

P. L. Libardi ◽

K. Reichardt ◽

K. Reichardt

Keyword(s):

Hydraulic Conductivity ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Conductivity Measurement ◽

Soil Surface ◽

Hydraulic Gradient ◽

Saturated Soil ◽

Soil Hydraulic Conductivity ◽

Soil Hydraulic

The method of Libardi to estimate soil hydraulic conductivity in the field, during the redistribution of soil water, is discussed and improved. It is shown that if the saturated soil water content is measured at the soil surface, values at any other depth can be calculated from the database used to compute hydraulic conductivity. Since the saturated soil water content is difficult to measure and critical to the establishment of the hydraulic conductivity functions, this is an important refinement of the method. It is also shown that the unit hydraulic gradient assumption, which is part of the methodology, does not introduce significant errors in the estimation of soil hydraulic conductivity.

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Use of Tempe cell, modified to restrain swelling, for determination of hydraulic conductivity and soil water content

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts ◽

10.1016/0148-9062(85)93331-5 ◽

1985 ◽

Vol 22 (3) ◽

pp. A77-A78

Keyword(s):

Hydraulic Conductivity ◽

Water Content ◽

Soil Water ◽

Soil Water Content

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Implications of Hysteresis on the Horizontal Soil Water Redistribution after Infiltration

Water ◽

10.3390/w13192773 ◽

2021 ◽

Vol 13 (19) ◽

pp. 2773

Author(s):

George Kargas ◽

Konstantinos X. Soulis ◽

Petros Kerkides

Keyword(s):

Porous Medium ◽

Hydraulic Conductivity ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Soil Matrix ◽

Wetting And Drying ◽

Initial Soil ◽

Water Redistribution ◽

Horizontal Infiltration

Although soil water redistribution is critical for a number of problems, a rather limited study of this process has been reported up to now and especially as regards the implications of hysteresis on horizontal soil water redistribution after infiltration. To this end, a thorough theoretical and numerical investigation of the redistributed soil water content profiles formed after the cessation of a horizontal infiltration is presented. A number of different initial soil water contents before the initiation of the horizontal infiltration and different infiltration depths were analyzed using the HYDRUS-1D software package considering the appropriate hysteretic wetting and drying curves. The effect of neglecting hysteresis was also investigated for the same conditions. The main wetting and drying boundary curves of the studied porous medium and the hydraulic conductivity at saturation were experimentally determined. The theoretical and numerical analysis indicated that the form of the redistributed soil water content profiles in the presence of hysteresis was similar to the original infiltration profile independently of whether the initial soil water content was taken on the boundary wetting or drying curve and independently of the porous medium type. Specifically, in a relatively short time after the initiation of the redistribution process, the magnitude of the soil matrix head gradient tended to zero due to hysteresis, and this resulted in an insignificant soil water movement, although the soil water content and the hydraulic conductivity values were still high. In addition, the redistribution proceeded at a faster rate than the smallest depth of infiltration water prior to the redistribution, and it was faster during the early stages of the redistribution. Accordingly, hysteresis is important for the simulation of horizontal soil water redistribution as it is, for example, in the case of localized irrigation systems’ design and management.

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Effects of initial soil water content and saturated hydraulic conductivity variability on small watershed runoff simulation using LISEM

Hydrological Sciences Journal ◽

10.1080/02626667.2014.903332 ◽

2015 ◽

Vol 60 (6) ◽

pp. 1137-1154 ◽

Cited By ~ 12

Author(s):

Wei Hu ◽

Dongli She ◽

Ming'an Shao ◽

Kwok P. Chun ◽

Bingcheng Si

Keyword(s):

Hydraulic Conductivity ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Saturated Hydraulic Conductivity ◽

Small Watershed ◽

Runoff Simulation ◽

Initial Soil

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Effect of Biochar Application and Re-Application on Soil Bulk Density, Porosity, Saturated Hydraulic Conductivity, Water Content and Soil Water Availability in a Silty Loam Haplic Luvisol

Agronomy ◽

10.3390/agronomy10071005 ◽

2020 ◽

Vol 10 (7) ◽

pp. 1005 ◽

Cited By ~ 2

Author(s):

Lucia Toková ◽

Dušan Igaz ◽

Ján Horák ◽

Elena Aydin

Keyword(s):

Hydraulic Conductivity ◽

Water Content ◽

Bulk Density ◽

Soil Water ◽

Soil Water Content ◽

Soil Bulk Density ◽

Relative Increase ◽

Saturated Hydraulic Conductivity ◽

Soil Drought ◽

Silty Loam

Due to climate change the productive agricultural sectors have started to face various challenges, such as soil drought. Biochar is studied as a promising soil amendment. We studied the effect of a former biochar application (in 2014) and re-application (in 2018) on bulk density, porosity, saturated hydraulic conductivity, soil water content and selected soil water constants at the experimental site in Dolná Malanta (Slovakia) in 2019. Biochar was applied and re-applied at the rates of 0, 10 and 20 t ha−1. Nitrogen fertilizer was applied annually at application levels N0, N1 and N2. In 2019, these levels were represented by the doses of 0, 108 and 162 kg N ha−1, respectively. We found that biochar applied at 20 t ha−1 without fertilizer significantly reduced bulk density by 12% and increased porosity by 12%. During the dry period, a relative increase in soil water content was observed at all biochar treatments—the largest after re-application of biochar at a dose of 20 t ha−1 at all fertilization levels. The biochar application also significantly increased plant available water. We suppose that change in the soil structure following a biochar amendment was one of the main reasons of our observations.

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