Analysis of 3D infiltration curves measured with disc infiltrometer in heterogeneous soil profiles: Sequential analysis of infiltration data and estimate of β

2021 ◽  
Author(s):  
David Moret-Fernández ◽  
Borja Latorre ◽  
Laurent Lassabatere ◽  
Simone Di Prima ◽  
Mirko Castellni ◽  
...  
Keyword(s):  
Sequential Analysis ◽  
Sandy Loam ◽  
Lower Layer ◽  
Transient State ◽  
Soil Heterogeneity ◽  
Accurate Estimation ◽  
Practical Reasons ◽  
Wetting Front ◽  
Soil Layering ◽  
Disc Infiltrometer

<p>The 3-D Haverkamp et al. (1994) model for disc infiltrometer measures on homogeneous media involves the following parameters: the soil sorptivity, S, the saturated hydraulic conductivity, Ks, the β parameter and the A= (γ S<sup>2</sup>)/(r<sub>d</sub>*Δθ) term, where r<sub>d</sub> is the disc radius, Δθ is the soil water increase and γ is proportionality constant. Fixed β and A values are commonly used in most cases. S, and Ks can be estimated from the inverse analysis of a cumulative infiltration curve by fitting it the Haverkamp model. For practical reasons, Haverkamp implicit model is replaced by its 4-term (4T) approximate expansion for the transient state. The first part of this work analyzes the influence of layered soils on Ks and S estimates, and designs a new procedure, sequential Analysis of Infiltration curve (SAI), for treating infiltration curves impacted by soil layering. The SAI method analyzes a sequence of increasing dataset for a given infiltration curve and fits to the 4T expansions to estimate Ks, S. Then estimates and RMSE are reported as a function of the number of data points used for the fit. The method was applied on synthetic profiles with homogeneous loam soil, six layered profiles involving a 1, 2 and 3 cm thickness loam layer over silty or sandy loam soils, respectively. Erroneous estimates of Ks and S were obtained when the total infiltration curves were considered for the analysis, regardless of the presence of soil layering. In opposite, estimates were improved using the SAI method for the layered systems. The SAI method relies on the fact that the RMSE increases when the wetting front reaches the interface between the upper layer and the lower layer. Such increase allows (i) the detection of the soil heterogeneity, (ii) the determination of the optimum infiltration time, t<sub>o</sub>, that corresponds to the minimum value of RMSE, and, (iii) accurate estimation the upper layer Ks and S.</p><p>Taking use of the SIA procedure, the second part of this communication studied the relationship between β and A, and proposed a new procedure to improve the estimate of Ks and S and approach β. The analysis was applied on synthetic infiltration curves simulated on homogneneous and layered columns. The results showed that different combinations of β and A resulted in similar Ks. Overall, optimization of Ks, S and A for different β values showed that β had an important effect on A and Ks, but not on S and RMSE.  We propose approaching the optimum β as the β for which is closer to zero, where A and A<sub>exp</sub> are the optimized and measurable parameter, respectively. While the optimum β is calculated, Ks and S are computed by applying the optimum β to the respective quadratic β(Ks) and β(S) relationships. This methodology allowed improving the estimate of Ks giving good approaches of β (36% error) and omitting the erroneous praxis of using constant β and A values.</p><p>Haverkamp, R., et al. 1994. 3. Water Resources Research 30, 2931–2935.</p>

A LABORATORY STUDY ON THE EFFECTS OF SOIL MOISTURE CONTENT, TEXTURE, AND TIMING OF LEACHING ON N LOSS FROM TWO SOUTHERN ALBERTA SOILS

1982 ◽  
Vol 62 (2) ◽  
pp. 407-413 ◽  
Author(s):  
T. G. SOMMERFELDT ◽  
C. CHANG ◽  
J. M. CAREFOOT
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Sandy Loam ◽  
Wetting Front ◽  
N Losses ◽  
Initial Soil Moisture ◽  
N Removal ◽  
Southern Alberta ◽  
Initial Soil

A column study was conducted to determine the effects of soil texture, initial soil moisture content and timing of leaching on N removal from two irrigated soils of southern Alberta. Pelleted NH4NO3 fertilizer (0.639 g N per column = 336 kg∙ha−1) was applied to Lethbridge loam (Leth L) and Cavendish fine sandy loam (CV FSL) at three initial levels of soil moisture: air dry (AD), 0.5 field capacity (0.5 FC), and wet (W, 25 cm suction). Leaching began immediately after the fertilizer application or was delayed 1 wk. Water was applied in 1400-mL (7.6 cm depth) increments every 2nd day for a total of 33 600 mL (175 cm depth). The leachate was collected, measured, and analyzed for NH4-N and NO3-N. The soil was analyzed for N content before and after leaching. More N was leached from CV FSL (0.600 g) than from Leth L (0.521 g). Responses to initial soil moisture were similar for both soils; the NO3-N concentration peak followed the advancing wetting front more closely in the AD than in the W systems and leaching losses were greatest from the 0.5 FC treatment. Delayed leaching did not significantly affect the amount of N leached. N losses, other than from leaching, were greatest in the W and AD treatments, in the AD treatment these losses were attributed to volatilization and, in the W soils, to denitrification.

scholarly journals A Note on One- and Three-Dimensional Infiltration Analysis from a Mini Disc Infiltrometer

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1783 ◽  
Author(s):  
George Kargas ◽  
Paraskevi Londra ◽  
Konstantinos Anastasiou ◽  
Petros Kerkides
Keyword(s):  
Shape Parameter ◽  
Sandy Loam ◽  
Three Dimensional ◽  
Silty Clay ◽  
Soil Hydraulic Properties ◽  
One Dimensional ◽  
Cumulative Infiltration ◽  
The Difference ◽  
Infiltration Tests ◽  
Disc Infiltrometer

Disc infiltrometers are used to characterize soil hydraulic properties. The purpose of this study was to determine the difference between three- and one-dimensional infiltration and to calculate the infiltration shape parameter γ from a proposed analytical infiltration equation. One- and three-dimensional infiltration tests were done on three repacked soils (loam, sandy loam, and silty clay loam) for two negative pressure heads. A mini disc infiltrometer of a radius of 22.5 mm with suction that ranged from −5 mm to −70 mm was used. The difference between experimental three- and one-dimensional cumulative infiltration was linear with time, which confirmed the proposed equation. In this study, the shape parameter γ seems not to be seriously affected by the soil type and acquires values from 0.561 to 0.615, i.e., smaller than the value γ = 0.75, which is widely used. With these values, the criteria proposed for calculating hydraulic conductivity using three-dimensional infiltration data may be fulfilled in most soils.

scholarly journals Feasibility Investigation of Improving the Modified Green–Ampt Model for Treatment of Horizontal Infiltration in Soil

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 645 ◽  
Author(s):  
Ding-feng Cao ◽  
Bin Shi ◽  
Hong-hu Zhu ◽  
Hilary Inyang ◽  
Guang-qing Wei ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Linear Functions ◽  
Moisture Distribution ◽  
Water Infiltration ◽  
Richards Equation ◽  
Accurate Estimation ◽  
Wetting Front ◽  
Size Change ◽  
Moisture Profile ◽  
Horizontal Infiltration

Water infiltration in soil is a complex process that still requires appreciation of interactions among three phases (soil particles, water and air) to enable accurate estimation of water transport rates. To simulate this process, the Green–Ampt (GA) model and the Modified Green-Ampt (MGA) model introduced in the paper “A new method to estimate soil water infiltration based on a modified Green–Ampt model” have been widely used. The GA model is based on the hypothesis that the advance of the wetting front in soil under matric suction can be treated as a rectangular piston flow that is instantaneously transformed after passage of the infiltration front, and the MGA model does not contain the influence of pore size change. This cannot accurately reflect the soil moisture change process from unsaturation to saturation. Due to soil stratification and other inhomogeneity, predictions produced with these models often differ widely from observations. To quickly obtain the soil moisture distribution after passage of the wetting front for horizontal infiltration, an improved modified Green–Ampt (IMGA) model is presented, which estimates the soil moisture profile along a horizontal column in a piecewise manner with three functions. A logarithmic function is used to describe the gradual soil saturation process in the transmission zone, and two linear functions are used to represent the wetting zone. The algorithm of the IMGA model for estimating the water infiltration rate and cumulative infiltration is configured. To verify the effectiveness of IMGA model, a lab model test was performed, and a numerical model was built to solve the horizontal one-dimensional Richards equation using the finite–element method. The results show that the IMGA model is more accurate than the GA and MGA models. The horizontal soil moisture profiles obtained by the IMGA model are closer to the measured data than the numerical simulation results. The relative errors of the MGA and IMGA models decrease with an increase in infiltration time, whereas that of the GA model first decreases and then increases with infiltration time. The primary novelty of this study is nonlinear description of soil moisture content distribution, and derivation of unit transfer coefficient.

Effect of Intermittent Water Application from Trickle Source on The Water Movement and Moisture Distribution in Layered Soil

2020 ◽  
Vol 27 (4) ◽  
pp. 87-97
Author(s):  
haqqi Yasin ◽  
abdul alsattar Al-Dabagh
Keyword(s):  
Sandy Loam ◽  
Soil Depth ◽  
Layered Soil ◽  
Moisture Distribution ◽  
Silty Clay ◽  
Horizontal Distance ◽  
Clay Loam ◽  
Water Application ◽  
Wetting Front ◽  
Silty Clay Loam

The aim of this research is to study the effect of intermittent water application on the wetting pattern and soil moisture distribution for homogeneous and layered soils under trickle source. Thirty experiments were conducted to monitor the advance of the wetting front in the soil profiles. Measurements of soil moisture content were also made at selected locations to evaluate the moisture distribution in soil. Four types of soil profiles were built; the first was sandy loam soil, the second was silty clay loam soil, the third was (silty clay loam/ sandy loam) layered soil, and the fourth was (sandy loam/ silty clay loam) layered soil. Three water application rates were used for each soil profile. Three continuous or intermittent applications were used; continuous applications, equally intermittent applications, and different intermittent applications. In addition, several cylindrical infiltration tests were conducted to describe some characteristics of each soil. Empirical relations to predict each of vertical (under trickle source) and horizontal (at soil surface) wetting front advance were found in this study. Empirical relations to predict the percentage of applied water volume in horizontal strips as a function of soil depth and in vertical strips as a function of horizontal distance from the trickle emitter were also found. The study showed that the wetted soil volume increases as either the water application rate increases, or the intermittent application ratio increases. Also, it showed that the ratio of horizontal advance to vertical advance of wetting front increases as either the water application rate increases, or the intermittent application ratio decreases. The study demonstrated that the accumulated ratio of water application volume at a certain soil depth from trickle source increases as the intermittent application ratio decreases. Also, it demonstrated that the accumulated ratio of water application volume at a certain horizontal distance from trickle source decreases as the intermittent application ratio decreases.

Using HYDRUS 2D/3D to Evaluate Soil Water Movement in Drip-irrigated Young Populus tomentosa Plantations on Sandy Loam Soil

2020 ◽  
Author(s):  
Doudou Li ◽  
Benye Xi ◽  
Liming Jia
Keyword(s):  
Soil Water ◽  
Drip Irrigation ◽  
Water Movement ◽  
Sandy Loam ◽  
Vertical Movement ◽  
Populus Tomentosa ◽  
Sandy Loam Soil ◽  
Wetting Front ◽  
Loam Soil ◽  
Soil Water Movement

<p>     Understanding the rules of soil water movement under drip irrigation can provide data support and theoretical basis for developing precise drip irrigation strategies. In this study, a two-years-old <em>Populus tomentosa </em>plantation under surface drip irrigation on sandy loam soil was selected to measure the dynamics of soil water potential (<span><em>ψ</em></span><em><sub>s</sub></em>), wetting front and soil water content (<span><em>θ</em></span>) during irrigation and water redistribution periods were investigated in field experiments. Then, the observed data in the field were used to evaluate the accuracy and feasibility of the HYDRUS-2D/3D model for simulating the short-term soil water movement. Besides, the validated model was used to simulate the dynamics of wetting front under different initial soil water content (<span><em>θ</em></span><em><sub>i</sub></em>). During irrigation, the variation of <span><em>ψ</em></span><em><sub>s</sub></em>, horizontal and vertical movement distances of the wetting front, and <span><em>θ</em></span> within the wetting volume with irrigation duration could be described by the logistic function (<em>R<sup>2</sup></em> = 0.99), the logarithm function (<em>R<sup>2</sup></em> = 0.99), the power function (<em>R<sup>2</sup></em> = 0.82), and the polynomial function (<em>R<sup>2</sup></em> = 0.99), respectively. At the end of irrigation, the horizontal and vertical movement distances of the wetting front reached 22.9 cm and 37.3 cm, respectively. The <span><em>ψ</em></span><em><sub>s</sub></em> and <span><em>θ</em></span> within the soil wetting volume were 61.6% and 30.9% higher than those at the start of the irrigation, respectively, but the <span><em>ψ</em></span><em><sub>s </sub></em>decreased to its initial level about 120 hours later after the stop of irrigation. The average deviations of the horizontal and vertical wetting radius between the simulated and measured values were 1.3 and 4.5 cm, respectively. The mean RMSE and RMAE of HYDRUS-2D/3D for simulating <span><em>θ</em></span> at the end of irrigation and during water redistribution were 0.021 cm<sup>3</sup>∙cm<sup>-3</sup> and 9.7%, respectively. The movement distances of wetting front in the experimental plantation under various soil drought degrees (soil water availabilities were 40%, 60%, 73% and 80%) were obtained through scenarios simulations using HYDRUS-2D/3D. And it was found that the wetting front could move further under higher <span><em>θ</em></span><em><sub>i</sub></em>, and the movement distance of the wetting front was always smaller in the horizontal direction than in the vertical direction under different <span><em>θ</em></span><em><sub>i </sub></em>conditions. Consequently, HYDRUS-2D/3D can be used to well simulate the short-term soil water movement in drip-irrigated young <em>P. tomentosa</em> plantations on sandy loam soil. In addition, the constructed figure (describes the variations of the horizontal and vertical soil wetting distances with the irrigation duration) can be used to determine the reasonable irrigation duration for the plantations of <em>P. tomentosa</em> and other tree species on sandy loam soil.</p>

Soil moisture content estimation using water absorption bands

GEOMATICA ◽  
2019 ◽  
Vol 73 (3) ◽  
pp. 63-73 ◽  
Author(s):  
Mohammad Reza Mobasheri ◽  
Meisam Amani ◽  
Mahin Beikpour ◽  
Sahel Mahdavi
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Absorption ◽  
Soil Moisture Content ◽  
Mean Squared Error ◽  
Sandy Loam ◽  
Soil Types ◽  
Accurate Estimation ◽  
Absorption Bands ◽  
New Models

Soil moisture content (SMC) is a crucial component in various environmental studies. Although many models have been proposed for SMC estimation, developing new models for accurate estimation of SMC is still an interesting subject. This study aimed to develop new models for SMC estimation using the water absorption bands in the spectral signatures of three different soil types: loam, silty loam, and sandy loam. Based on the three absorption bands (i.e., 1400, 1900, and 2200 nm) and regression analyses, six approaches were considered. These scenarios were generally based on the reflectance value and its logarithm, as well as the difference between the wet and dry reflectance values for the absorption bands. Finally, 24 models were developed for SMC estimation from the three different soil types, as well as the entire soil samples. The most accurate SMC, as indicated by the lowest root mean squared error (RMSE) and the highest correlation coefficient (r), was obtained from the model developed using the logarithm of the average values reflectance in the three water absorption bands for sandy loam (RMSE = 0.31 g/kg, r = 0.99). Overall, using the spectrometry data derived in the lab, the results of the proposed models were promising and demonstrate great potential for SMC estimation using spectral data collected by satellites in the future studies.

scholarly journals Resource Allocation for Lagrangian Tracking

2016 ◽  
Vol 33 (6) ◽  
pp. 1225-1235 ◽  
Author(s):  
Benjamin T. Jones ◽  
Andrew Solow ◽  
Rubao Ji
Keyword(s):  
Particle Tracking ◽  
Sequential Analysis ◽  
Gulf Of Maine ◽  
Transport Model ◽  
Accurate Estimation ◽  
Large Ensemble ◽  
Lagrangian Particles ◽  
Lagrangian Tracking ◽  
The Cost ◽  
Release Location

AbstractAccurate estimation of the transport probabilities among regions in the ocean provides valuable information for understanding plankton transport, the spread of pollutants, and the movement of water masses. Individual-based particle-tracking models simulate a large ensemble of Lagrangian particles and are a common method to estimate these transport probabilities. Simulating a large ensemble of Lagrangian particles is computationally expensive, and appropriately allocating resources can reduce the cost of this method. Two universal questions in the design of studies that use Lagrangian particle tracking are how many particles to release and how to distribute particle releases. A method is presented for tailoring the number and the release location of particles to most effectively achieve the objectives of a study. The method detailed here is a sequential analysis procedure that seeks to minimize the number of particles that are required to satisfy a predefined metric of result quality. The study assesses the result quality as the precision of the estimates for the elements of a transport matrix and also describes how the method may be extended for use with other metrics. Applying this methodology to both a theoretical system and a particle transport model of the Gulf of Maine results in more precise estimates of the transport probabilities with fewer particles than from uniformly or randomly distributing particle releases. The application of this method can help reduce the cost of and increase the robustness of results from studies that use Lagrangian particles.

Numerical analysis of vertical water movement in a bounded profile

Soil Research ◽  
1975 ◽  
Vol 13 (1) ◽  
pp. 1 ◽  
Author(s):  
KK Watson ◽  
AA Curtis
Keyword(s):  
Water Movement ◽  
Sandy Loam ◽  
Air Pressure ◽  
Wetting Front ◽  
Flow Process ◽  
Compression Effect ◽  
Cumulative Infiltration ◽  
Computer Based ◽  
Air Compression ◽  
Made In

The usual assumption made in soil water studies that the effect of the air phase on the flow process is negligible is discussed in relation to certain profile configurations where such an assumption is not valid. A computer-based numerical solution of the equation describing water movement in an unsaturated soil is then modified by the inclusion of a time-dependent boundary condition, thus allowing the modelling of the air compression effect during infiltration. This analysis also satisfactorily models the drainage along primary draining scanning curves which occurs in the upper part of the profile as the air pressure increases. The analysis is limited to the Darcy flow regime which, for the system considered, terminates when the excess air pressure equals the air entry value of the porous material. Detailed results are presented for a sand and a sandy loam. Profile depths of 200 cm and 1000 cm have been analysed, and comparisons made of the effect of the air compression on the shape of the wetting front. The effect on cumulative infiltration is also noted.

Influence of evaporation suppressants on water movement in soils

Soil Research ◽  
1968 ◽  
Vol 6 (1) ◽  
pp. 67 ◽  
Author(s):  
JW Kijne
Keyword(s):  
Soil Water ◽  
Capillary Flow ◽  
Water Movement ◽  
Sandy Loam ◽  
Cetyl Alcohol ◽  
Fatty Alcohols ◽  
Wetting Front ◽  
Treated Soil ◽  
Hydrophobic Character ◽  
Water Diffusivity

The soil-water diffusivity was determined as a function of water content for Urrbrae fine sandy loam treated with two fatty alcohols, two amines, Krilium, polyvinyl alcohol, and Carbowax. The fatty alcohols and dodecylamine had the strongest influence on soil-water diffusivity throughout the whole range of soil-water contents. Treatment with these amendments markedly reduced capillary flow of water to the soil surface. Dodecylamine reduced the rate of infiltration into the soil. Heats of wetting of the treated soil samples indicated that penetration rate and diffusivity near saturation were reduced in accordance with the hydrophobic character of the adsorbed compound. Cetyl alcohol was partly desorbed when water permeated through cetyl-alcohol-treated soil, forming a film on the advancing wetting front. This resulted in a slower rate of penetration than would have been expected from the hydrophobic character of the complex.

Sign in / Sign up

Export Citation Format

Share Document