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.

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>

FRACTAL CHARACTERISTICS OF THE HORIZONTAL MOVEMENT OF WATER IN SOILS

Fractals ◽  
1994 ◽  
Vol 02 (03) ◽  
pp. 465-468 ◽  
Author(s):  
IVAN A. GUERRINI ◽  
D. SWARTZENDRUBER
Keyword(s):  
Brownian Motion ◽  
Soil Water ◽  
Unsaturated Soils ◽  
Water Movement ◽  
Water Saturation ◽  
Horizontal Movement ◽  
Water Diffusivity ◽  
Fractal Characteristics ◽  
Affine Type ◽  
Soil Water Movement

Observed deviations from traditional concepts of soil-water movement are considered in terms of fractals. A connection is made between this movement and a Brownian motion, a random and self-affine type of fractal, to account for the soil-water diffusivity function having auxiliary time dependence for unsaturated soils. The position of a given water content is directly proportional to tn, where t is time, and exponent n for distinctly unsaturated soil is less than the traditional 0.50. As water saturation is approached, n approaches 0.50. Macroscopic fractional Brownian motion is associated with n < 0.50, but shifts to regular Brownian motion for n = 0.50.

EFFECTS OF SOIL WATER MOVEMENT ON ACTUAL EVAPOTRANSPIRATION ESTIMATED FROM THE SOIL MOISTURE BUDGET

1970 ◽  
Vol 50 (3) ◽  
pp. 409-417 ◽  
Author(s):  
WAYNE R. ROUSE
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Movement ◽  
Potential Evapotranspiration ◽  
Sandy Loam ◽  
Spatial Variations ◽  
Actual Evapotranspiration ◽  
Moisture Budget ◽  
Loam Soil ◽  
Soil Moisture Budget

Actual evapotranspiration was estimated from the soil moisture budget for a grass-covered sandy loam soil at Simcoe, Ontario. Soil moisture was measured at 25 sites distributed over a 6-meter-square grid. The coefficient of variation for actual evapotranspiration estimated at all sites averaged 13% and rose as high as 19%. Average actual evapotranspiration exceeded both the Penman and Thornthwaite estimates of potential evapotranspiration for three of the six measuring intervals, due to deep seepage losses. The application of corrections for the vertical water movement, determined from experimentally derived matric suction and hydraulic conductivity data, gave a substantial deep seepage loss for some periods and a capillary uptake of soil water for others. Vertical losses and gains created errors of up to + 28 and − 29%, respectively, in the standard estimates of actual evapotranspiration. The large spatial variations in evapotranspiration estimates resulted from variations in volumetric soil moisture between sample points, apparently creating differences in the magnitude and direction of vertical water movement across the terminal depth. The horizontal flux of water between measuring points was relatively unimportant in accounting for the spatial variations.

Effect of infiltration head on soil water movement of small-diameter tube outflow furrow irrigation under mulch film

2019 ◽  
Vol 16 (2) ◽  
pp. 232-237 ◽  
Author(s):  
H.X. Wu ◽  
Yunxin Zhang ◽  
Lishu Wang ◽  
Dongjuan Chen ◽  
Chao Ma
Keyword(s):  
Soil Water ◽  
Water Movement ◽  
Small Diameter ◽  
Scientific Basis ◽  
Furrow Irrigation ◽  
Wetting Front ◽  
Migration Distance ◽  
Content Type ◽  
Mulch Film ◽  
Soil Water Movement

PurposeThe purpose of this study is to investigate the effect of different infiltration heads on soil water movement using a free infiltration test for small-diameter tube outflow furrow irrigation under mulch film.Design/methodology/approachThe test consisted of small-diameter tube outflow furrow irrigation under mulch film with three different infiltration heads (3, 4 and 5 cm) and furrow drip irrigation under mulch film using an infiltration head of 4 cm (CK).FindingsDuring irrigation, the accumulated infiltration and migration distance of the wetting front increased with time. During the same infiltration time, both the accumulated infiltration and horizontal migration distance of the wetting front increased with the larger infiltration head, whereas the vertical migration distance of the wetting front gradually decreased. With increasing distance from the furrow center, soil moisture content declined, but the uniformity of its distribution increased as the infiltration head increased.Originality/valueThis study can provide scientific basis for the use of small-diameter tube outflow furrow irrigation under mulch film.

Performance of HYDRUS-1D for simulating water movement in water-repellent soils

2018 ◽  
Vol 98 (3) ◽  
pp. 407-420 ◽  
Author(s):  
Xiaofang Wang ◽  
Yi Li ◽  
Yichen Wang ◽  
Chuncheng Liu
Keyword(s):  
Soil Water ◽  
Water Movement ◽  
Water Dynamics ◽  
Dynamics Simulation ◽  
Water Repellent ◽  
Efficiency Coefficient ◽  
Wetting Front ◽  
Statistical Parameters ◽  
Volumetric Soil Water Content ◽  
Hydrus 1D

Soil water repellency affects soil water movement during infiltration significantly. The HYDRUS software has been popularly applied in soil water dynamics simulation for many years, but its performance in water-repellent (WR) soils has not been assessed thoroughly. Our objectives are to assess the performance of HYDRYUS-1D for cumulative infiltration (CI), wetting front (Zf), and volumetric soil water content (θv) during horizontal imbibition and vertical infiltration in wettable, slightly WR, and strongly WR soils. The key parameters of α and n in water retention curves were inversely estimated by RETension Curve software. The α and n were calibrated inversely until the observed data fitted the simulated values well enough. The α and n were then used for validation using three statistical parameters including relative root-mean-square error, R2, and Nash–Sutcliffe efficiency coefficient. The performances of calibration and validation for wettable, slightly, and strongly WR soils were good enough to be used for further simulations (RRMSE ≤20.2% for calibration and ≤21.1% for validation). Soil water movements for strongly WR soils of variable ponded depth during vertical infiltration were simulated. For Lou soil, as the ponded depth increased from 4 to 10 cm, the CI and Zf increased 2.08 and 5.5 cm, respectively. The simulations for the other three soils also showed gradually increased CI and Zf values. In conclusion, the performances of HYDRUS-1D in four different soil types with changing WR levels were good, which confirmed the application of HYDRUS-1D in WR soils.

Influence of active aluminium oxides on water movement in soils

Soil Research ◽  
1969 ◽  
Vol 7 (3) ◽  
pp. 325 ◽  
Author(s):  
CK Tweneboah ◽  
JW Kijne ◽  
DJ Greenland
Keyword(s):  
Sodium Chloride ◽  
Soil Water ◽  
Water Retention ◽  
Water Movement ◽  
Soil Water Retention ◽  
Water Diffusivity ◽  
The Stability ◽  
Soil Pores ◽  
Water Contents ◽  
Soil Water Contents

Active aluminium oxides were removed from several soils by treatment with 0.5M calcium chloride or lM sodium chloride at pH 1.5. Soil-water retention and soil-water diffusivity were determined and contrasted with the values for these properties obtained after treatment with neutral salts. The changes resulting from the removal of aluminium oxides were relatively small in calcium saturated systems, but in sodium saturated systems soil-water diffusivity was drastically reduced by the prior removal of aluminium oxides. The results are discussed in terms of the influence of aluminium oxides on the stability of soil pores at different soil-water contents.

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.

scholarly journals Effect of Organic Matter and Initial Moisture Content on Water Transmission Characteristics of Alfisols of Assam

Agropedology ◽  
2019 ◽  
Vol 27 (1) ◽  
Author(s):  
M. K. Nayak ◽  
◽  
D. K. Patgiri ◽  
T. C. Baruah ◽  
◽  
...  
Keyword(s):  
Organic Matter ◽  
Moisture Content ◽  
Soil Water ◽  
Initial Moisture Content ◽  
Mean Diffusivity ◽  
Wetting Front ◽  
Transmission Parameters ◽  
Increase With Increase ◽  
Water Diffusivity ◽  
Water Transmission

A study was conducted to study the effect of organic matter and initial moisture content on water transmission behaviour of three texturally different Alfisols. Saturated hydraulic conductivity showed a variable increase with increase in organic matter. Soil water diffusivity D (θ) showed an irregular trend with increasing levels of organic matter while sorptivity (s) increased with increasing levels of organic matter, penetrability (P) of wetting front decreased. Weighted mean diffusivity did not show any particular trend amongst the treatments, however, it was found to be higher in treated soils as compared to untreated control. Specific water capacity increased with increasing levels of organic matter, while capillary conductivity (k) did not show any definite trend. All the water transmission parameters except sorptivity were found to be increased with an increase in initial moisture content. Diffusivity was in general higher at lower initial moisture content indicating that soil water diffusivity was greatly influenced by initial moisture content. Prediction of D (θ) was, by and large, satisfactory in coarse textured soils and inconclusive in case of K (θ) relation in most of the soils.

scholarly journals Laboratory Experiments on the Effect of Microtopography on Soil-Water Movement: Spatial Variability in Wetting Front Movement

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Leif Sande ◽  
Xuefeng Chu
Keyword(s):  
Soil Water ◽  
Smooth Surface ◽  
Laboratory Experiments ◽  
Unsaturated Flow ◽  
Water Movement ◽  
Experimental Studies ◽  
Soil Profiles ◽  
Wetting Front ◽  
Front Movement ◽  
Soil Water Movement

The effect of microtopography on soil-water movement is a topic of interest for a range of disciplines, with experimental studies investigating the relationship between the two lacking. Laboratory experiments were conducted by simulating rainfall across packed soil surfaces to investigate the effect of microtopography on wetting front movement within experimental soil profiles. In small soil box experiments, the observed wetting fronts for soil profiles showed considerably deeper movement beneath a smooth surface than depressions for 12–60 min rainfalls. For large soil box experiments, the wetting front reached moisture sensors installed at 5 and 10 cm depths and corresponding to various rough and smooth surface features at significantly different times, with movement being most rapid beneath the smooth surface. Wetting front movement was “quicker” beneath surface peaks than depressions for the rough surface as attributed to 2D/3D unsaturated flow. This study provides valuable experimentally based insight into the effect of microtopography on soil-water movement.

Modeling Soil Water Movement in Pedostructure

2006 ◽  
Author(s):  
Rabi H. Mohtar ◽  
Erik Braudeau
Keyword(s):  
Soil Water ◽  
Water Movement ◽  
Soil Water Movement
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