Water dynamics in a gradually nonhomogeneous soil described by the linearized Richards equation

Barontini, Stefano; Ranzi, Roberto; Bacchi, Baldassare

doi:10.1029/2006wr005126

Cited by 19 publications

(10 citation statements)

References 52 publications

(77 reference statements)

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“…There is still some room for explicit integration of if we expand the exponent there into a Taylor series and retain the first two terms (also see Barontini et al, , for a similar linearization of Richards' equation with the G‐E k ( S ) in transient evaporation models). This linearization reduces to a linear ODE:

\frac{normald p ((), Z)}{normald Z} - \frac{C_{a} v_{Z}}{\sqrt{K_{0} (Z)}} p ((), Z) = 1 - \frac{v_{Z}}{K_{0} ((), Z)}, 0 < Z < D, p ((), 0) = p_{s}, p ((), D) = 0 .

…”

Section: Analytical Solutionsmentioning

confidence: 99%

Minimizing Evaporation by Optimal Layering of Topsoil: Revisiting Ovsinsky's Smart Mulching‐Tillage Technology Via Gardner‐Warrick's Unsaturated Analytical Model and HYDRUS

Kacimov

Šimůnek

2019

Water Resources Research

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Ovsinsky (1899, https://www.rulit.me/books/novaya-sistema-zemledeliya-read-193251-1.html) suggested and tested a water conserving soil no‐till technology for rain‐snow‐fed field crops in a semiarid environment in southern Russia. We model Ovsynsky's unsaturated flow fragment, in which 1‐D steady evaporation and evapotranspiration through a two‐layered soil from a horizontal static water table to a dry soil surface takes place. Gardner's exponential and algebraic functions are used for the unsaturated hydraulic conductivity‐suction head relations. The vertical evaporation flux depends on the dyads and triads (correspondingly) of the parameters of these functions, for example, the saturated hydraulic conductivity and the sorptive number of the two layers. The flux, as a function of the relative thickness of the upper stratum, is analytically found from the solution of one or two nonlinear equations. This relation can be nonmonotonic and exhibits either a minimum or maximum depending on whether this stratum is coarser or finer than the subjacent stratum fed from a horizontal isobar. HYDRUS‐1D simulations confirm these extrema. This explains the experimental results from the literature on mulching/tillage/soil crusting‐sealing, which can increase, decrease, or have no impact on evaporation from a shallow water table. Alterations of the soil's homogeneity to reduce evaporation losses can improve the hydrological balance of soil profiles.

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\frac{normald p ((), Z)}{normald Z} - \frac{C_{a} v_{Z}}{\sqrt{K_{0} (Z)}} p ((), Z) = 1 - \frac{v_{Z}}{K_{0} ((), Z)}, 0 < Z < D, p ((), 0) = p_{s}, p ((), D) = 0 .

…”

Section: Analytical Solutionsmentioning

confidence: 99%

Minimizing Evaporation by Optimal Layering of Topsoil: Revisiting Ovsinsky's Smart Mulching‐Tillage Technology Via Gardner‐Warrick's Unsaturated Analytical Model and HYDRUS

Kacimov

Šimůnek

2019

Water Resources Research

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“…This pattern was proved for exponentially decreasing conductivity in a horizontal soil [5], and cannot be excluded in any case Ks monotonically decreases with depth. Afterwards this pattern was observed by means of a laboratory experiment during which artificial rainfall was poured over a multi-layered soil column characterised by decreasing Ks with depth [15].…”

Section: Geotechnical Implicationsmentioning

confidence: 99%

“…The first condition applies during transient flow, the latter during steady flux. In this case a perched water table can theoretically onset only if the soil is unhomogeneous and if the hydraulic conductivity at soil saturation monotonically decreases with x* [5]. In case (b), as the percolation can take place, if one focuses on distributed processes (viz those related to rainfall or snow-melting infiltration, redistribution and evapotranspiration) and if the depth of the investigated soil layer is almost uniform along the slope (Figure 1), in the Richards equation (1) the condition of uniform flow:…”

Section: Bottom Boundary Conditions and One Dimensional Formulationmentioning

confidence: 99%

On the hydrological properties of mountain soils, from measurement to the geotechnical implications

et al. 2016

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Abstract. Aiming at contributing with a hydrological perspective to the geotechnical investigation in mountain environments, particularly focusing on landslides triggered by perched water tables, we present some findings of a longlasting experimental and theoretical investigation of mountain-soils hydrology. After recalling a theoretical framework suitable to describe the hydrology of shallow, sloping and heterogeneous soils, we discuss some relevant difficulties concerning the measurement of the hydrological properties of heterogeneous and non mature soils, and we finally focus on the role played by the soil heterogeneity in the perched water tables onset.

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“…The Richards equation used the mass conservation law and Darcy's law (Lei et al, 1988). As a physically based model, the Richards equation has been extended into many complex conditions (Brunone et al, 2003, Barontini et al, 2007and Elmaloglou & Diamantopoulos, 2008. Nevertheless, the Richards equation is strongly nonlinear and cannot be solved analytically, especially under complex initial and boundary conditions.…”

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confidence: 99%

Impact of Gypsum Particle Size on Soil Physical Properties of a Saline-Sodic Soil from North Sinai, Egypt

2013

Egypt.J. Soil Sci.

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ATER flow through structured soils can substantially affect …….. local water balance, contaminant transport, and plant-available water. Effect of different gypsum radius on hydraulic conductivity (HC) of saline-sodic soils was assessed. Saline-sodic clay soil from Gelbana Village, Sahl El-Tina plain, Sinai, was mixed with three treatment of gypsum (CaSO 4 .H 2 O) different in there particle size: T1"fine" (< 0.5 mm), T2"medium" (0.5-1 mm) and T3"coarse" (1-2 mm), and subjected to continuous leaching increments, and these treatments were compared by the control. Soil samples were packed in columns to make a 30-cm height with a bulk density of 1.36 Mg.m-3. Leaching was conducted by ponding with a constant head of 5 cm water. Leaching water was of EC 1.50 dSm-1 and SAR of 9.1. Six continuous water increments were performed for each column. To assess and simulate the water flow, to quantify improved management strategies, and to derive updated irrigation standards, the soil-water model HYDRUS-1D code was used. Considerable short-lived increase in HC following addition of gypsum occurred to the soil. It quickly decreased in subsequent leaching increments. The increase amounted to 181, 126 and 117% due to the fine-particles, medium-particles and coarse-particles gypsum, respectively. The increase in HC persisted up to the 4 th leachate; and was particularly marked with the fine-particle gypsum, and this increases up to 275% following the 5 th leachate compared with the 1 st leachate. In soils receiving medium-particle or coarse-particle, increased of the HC was less marked, being up to 56% following 5 th leachate increment. The HYDRUS-1D provided reliable simulation results of infiltration rate and cumulative infiltration. Using the model to analyses management options proved an efficient tool for agro-ecosystem assessment.

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Water dynamics in a gradually nonhomogeneous soil described by the linearized Richards equation

Cited by 19 publications

References 52 publications

Minimizing Evaporation by Optimal Layering of Topsoil: Revisiting Ovsinsky's Smart Mulching‐Tillage Technology Via Gardner‐Warrick's Unsaturated Analytical Model and HYDRUS

Minimizing Evaporation by Optimal Layering of Topsoil: Revisiting Ovsinsky's Smart Mulching‐Tillage Technology Via Gardner‐Warrick's Unsaturated Analytical Model and HYDRUS

On the hydrological properties of mountain soils, from measurement to the geotechnical implications

Impact of Gypsum Particle Size on Soil Physical Properties of a Saline-Sodic Soil from North Sinai, Egypt

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