THE EFFECT OF A SUBSURFACE HYDROPHOBIC LAYER ON WATER AND SALT MOVEMENT

1983 ◽  
Vol 63 (1) ◽  
pp. 57-65 ◽  
Author(s):  
E. DE JONG
Keyword(s):  
Key Words ◽  
Water Retention ◽  
Capillary Rise ◽  
Salt Content ◽  
Water Repellency ◽  
Uncontaminated Soil ◽  
Hydrophobic Layer ◽  
Water And Salt Movement

Experiments were conducted on the effect of a hydrophobic layer, a 1:4 mixture of crude oil:soil, on water and salt movement in columns of brine-contaminated and uncontaminated soil. The mixing of oil with soil lowered water retention at low suctions, and increased saturated permeability and water repellency of the mixture. The hydrophobic layer reduced capillary rise, and increased waterholding capacity of the overlying soil. After 6 wk of intermittent leaching the salt content of the soil above and below the hydrophobic layer was lower than in the absence of this layer. The hydrophobic layer prevented resalinization of the overlying soil during a subsequent 4-wk evaporation period. The thickness of the hydrophobic layer (0.5 or 1.0 cm) did not seem important. Key words: Salt movement, hydrophobic layers, redistribution of water and salt

Solonetzic soils of Canada: Genesis, distribution, and classification

2011 ◽  
Vol 91 (5) ◽  
pp. 889-902 ◽  
Author(s):  
J. J. Miller ◽  
J. A. Brierley
Keyword(s):  
Capillary Rise ◽  
Salt Content ◽  
Septic Systems ◽  
Flow Conditions ◽  
Anisotropic Flow ◽  
Hydraulic Gradients ◽  
Total Salt Content ◽  
Pedogenic Processes ◽  
Capillary Movement ◽  
Zonal Soils

Miller, J. J. and Brierley, J. A. 2011. Solonetzic soils of Canada: Genesis, distribution, and classification. Can. J. Soil Sci. 91: 889–902. Soils of the Solonetzic order are defined as having a Solonetzic B horizon designated as a Bn or Bnt horizon. The Solonetzic Order includes four great groups: Solonetz, Solodized Solonetz, Solod, and Vertic Solonetz. Solonetzic soils are thought to develop via the stepwise pedogenic processes of salinization, solonization (desalinzation and alkalization), and solodization. Soluble salts are brought into the soil pedon of Solonetzic soils by capillary movement and evaporation from spring to fall, and upward water flow from the water table to the freezing zone in the winter deposits salts upon freezing. Solonization proceeds when desalinization lowers the total salt content and alkalization is initiated by high exchangeable Na. Solodization occurs when anisotropic flow conditions or a change in vertical hydraulic gradients prevent capillary rise and replenishment of soluble Na in the Bn horizon. Two common Solonetzic catenas are found in the prairies. In the first sequence, Gleyed Solonetz or Solonetz occur in the depressional areas of the landscape, and soils then grade through Solodized Solonetz, Solods, and in some cases, Chernozems or normal zonal soils at higher elevations. In the second sequence, Solods are found in the lowest topographic position, while Solodized Solonetz, Solonetz and Chernozems are found at progressively higher slope positions. Solonetzic soils have unique properties that adversely affect their use for agriculture and other land uses (e.g., construction, septic systems). Further interdisciplinary research is required to better understand the genesis of these soils at the “meter scale” or local landscape level because of the extreme spatial variability of these soils.

The effects of biochar on soil physical properties and winter wheat growth

2012 ◽  
Vol 103 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Rachel C. Devereux ◽  
Craig J. Sturrock ◽  
Sacha J. Mooney
Keyword(s):  
Pore Size ◽  
Bulk Density ◽  
Water Retention ◽  
Average Pore Size ◽  
Water Repellency ◽  
Soil Bulk Density ◽  
Average Pore ◽  
Wheat Growth ◽  
Wetting Ability ◽  
X Ray Computed

ABSTRACTBiochar has been reported to improve soil quality and crop yield; however, less is known about its effects on the physical and, in particular, structural properties of soil. This study examines the potential ability of biochar to improve water retention and crop growth through a pot trial using biochar concentrations of 0%, 1·5%, 2·5% and 5% w/w. X-ray computed tomography was used to measure soil structure via pore size characteristics; this showed that pore size is significantly affected by biochar concentration. Increasing biochar is associated with decreasing average pore size, which we hypothesise would impact heavily on hydraulic performance. At the end of the experiment, average pore size had decreased from 0·07 mm2 in the 0% biochar soil to 0·046 mm2 in the 5% biochar soil. Increased biochar concentration also significantly decreases saturated hydraulic conductivity and soil bulk density. It was also observed that increased biochar significantly decreases soil water repellency. Increased water retention was also observed at low matric potentials, where it was shown that increased biochar is able to retain more water as the soil dried out. The application of biochar had little effect on short-term (<10 weeks) wheat growth, but did improve water retention through a change in soil porosity, pore size, bulk density and wetting ability.

scholarly journals "An order of deep-fried two-by-fours please!"

2007 ◽  
Vol 83 (4) ◽  
pp. 475-477
Author(s):  
P A Cooper ◽  
J. Wang ◽  
Y T Ung
Keyword(s):  
High Temperature ◽  
Key Words ◽  
Vegetable Oil ◽  
Vegetable Oils ◽  
Dimensional Stability ◽  
Water Repellency ◽  
Thermal Modification ◽  
Oil Stability ◽  
Termite Resistance

Thermal modification of wood by immersion in high temperature vegetable oils and other additives impart significant decay and mould fungi resistance, water repellency and dimensional stability. Key words: thermal modification, wood, vegetable oil, decay, termite resistance, oil stability

SOIL AND SUBSOIL MOISTURE ACCUMULATION DUE TO DRYLAND AGRICULTURE IN SOUTHERN ALBERTA

1985 ◽  
Vol 65 (4) ◽  
pp. 805-810 ◽  
Author(s):  
H. W. CHRISTIE ◽  
D. N. GRAVELAND ◽  
C. J. PALMER
Keyword(s):  
Soil Moisture ◽  
Key Words ◽  
Causative Agent ◽  
Salt Content ◽  
Cultivated Land ◽  
Soluble Salts ◽  
Dryland Agriculture ◽  
Dryland Salinity ◽  
Native Prairie ◽  
Southern Alberta

Subsoil moisture accumulation due to cultivation and particularly summerfallowing is considered as an important causative agent of dryland salinity. However, few studies have been conducted to quantify the magnitude of this accumulation. The amount of additional moisture that had accumulated under cultivated land as compared to adjacent native prairie was determined at two sites in Southern Alberta. In comparison to noncultivated sites, a total of 74.0 cm of additional moisture was found under the cultivated area of a Dark Brown Chernozem and 36.2 cm under a Brown Chernozem to a depth of 6 m. Only relatively insignificant changes in salt content were found. Key words: Dryland salinity, soil moisture, soluble salts

scholarly journals Oil and grease in soils irrigated with greywater and the potential effect on soil water repellency

2007 ◽  
pp. 479-488
Author(s):  
Michael Travis ◽  
Noam Weisbrod ◽  
Amit Gross
Keyword(s):  
Soil Profile ◽  
Water Movement ◽  
Water Drop ◽  
Capillary Rise ◽  
Management Strategies ◽  
Water Repellency ◽  
Potential Effect ◽  
Oil And Grease ◽  
Ongoing Research ◽  
Order Of Magnitude

The reuse of greywater and other wastewaters are important considerations for effectivewater management strategies. It is also imperative that the potential for detrimentalenvironmental effects be investigated. As part of ongoing research into the reuse ofgreywater and oil-rich agro-wastewaters, the potential impact of oil and grease (O&G)to soils irrigated with greywater (GW) was studied. Greywater streams were sampledand analyzed for O&G content. Along with the greywater, soil profile samples werecollected from garden soils irrigated with these waters. The goal was to determine theO&G content of these GW streams, verify ifeO&G was accumulating in the soil profiles,and investigate the effect O&G can have on water movement through O&Gcontaminated soils.Untreated kitchen GW averaged 200 mg/L O&G, over an order of magnitude more thanother GW streams. GW-irrigated soils showed O&G accumulation of up to 200 mg/kgwithin the first 20-cm of depth. GW with low O&G concentration (<! 0 mg/L) stilldemonstrated long-tenn accumulation in the soil profile, with O&G concentration of150 mg/kg. To detennine the potential effects that O&G accumulation may have onwater movement in soil, capillary rise and water drop penetration time (WDPT)experiments were conducted. The results showed up to 60% decrease in capillary rise insand containing 250 mg/kg O&G. Interestingly, no additional reduction in capillary risewas observed at concentrations above 250 mg/kg. WDPT was observed to increaselinearly (from nearly instantaneous to over 2 seconds) with increased O&G content, upto 1000 mg/kg. This work demonstrated that O&G in GW used for irrigation canaccumulate in soil and may lead to a significant water repellency and reduction in thesoils ability to transmit water.

The impact of heating on the hydraulic properties of soils sampled under different plant cover

Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Viliam Novák ◽  
Ľubomír Lichner ◽  
Bin Zhang ◽  
Karol Kňava
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Water ◽  
Water Retention ◽  
Water Drop ◽  
Sampling Site ◽  
Water Repellency ◽  
Saturated Hydraulic Conductivity ◽  
Soil Water Repellency ◽  
The Impact ◽  
Penetration Time

AbstractThe impact of heating on the peristence of water repellency, saturated hydraulic conductivity, and water retention characteristics was examined on soils from both forest and meadow sites in southwest Slovakia shortly after a wet spell. The top 5 cm of meadow soils had an initial water drop penetration time WDPT at 20°C of 457 s, whereas WDPT in the pine forest was 315 s for the top 5 cm and 982 s if only the top 1 cm was measured. Heating soils at selected temperatures of 50, 100, 150, 200, 250 and 300°C caused a marked drop in water drop penetration time WDPT from the initial value at 20°C. However, samples collected in different years and following an imposed cycle of wetting and drying showed much different trends, with WDPT sometimes initially increasing with temperature, followed by a drop after 200–300°C. The impact of heating temperature on the saturated hydraulic conductivity of soil was small. It was found for both the drying and wetting branches of soil water retention curves that an increase in soil water repellency resulted in a drop in soil water content at the same matric potential. The persistence of soil water repellency was strongly influenced by both the sampling site and time of sampling, as it was characterized by the results of WDPT tests.

scholarly journals Influence of the wetting process on estimation of the water-retention curve of tilled soils

Soil Research ◽  
2016 ◽  
Vol 54 (7) ◽  
pp. 840 ◽  
Author(s):  
D. Moret-Fernández ◽  
C. Peña-Sancho ◽  
M. V. López
Keyword(s):  
Water Content ◽  
Water Retention ◽  
Capillary Rise ◽  
Time Domain Reflectometry ◽  
Soil Samples ◽  
Water Retention Curve ◽  
Retention Curve ◽  
Hydraulic Behaviour ◽  
Soil Wetting ◽  
Wetting Process

Correct estimation of the soil-water retention curve (WRC) is of paramount importance to characterise the hydraulic behaviour of soils. This paper studies the influence of two different soil-wetting processes (waterlogging soil, WP; capillary rise to saturation, CRP) on the estimate of the WRC. The two procedures were applied on undisturbed loam soil samples with three degrees of soil structure: (i) consolidated soils under conventional tillage (CT), reduced tillage (RT) and no tillage (NT); (ii) freshly tilled soil under CT and RT; and (iii) CT and RT after secondary tillage plus some intense rainfalls events. WRCs were estimated with time-domain reflectometry (TDR) pressure cells and volumetric water content was measured at saturation conditions (for the WP method) and at pressure heads of 0.5, 1.5, 3, 5, 10, 50, 100, 500 and 1500 kPa. The same cores were used to determine the soil bulk density (ρb), which was subsequently used to estimate the saturated water content under CRP. The ρb value of the consolidated soil under NT was significantly higher (P < 0.001) than under CT and RT. No effect of the wetting process on the WRC of consolidated soils was observed. Only the freshly tilled soil samples under RT were significantly affected by the wetting process. In these cases, the water draining after WP collapsed the more unstable soil macropores and increased the volume of the smaller ones. However, this effect was minimised by the CRP method, which prevented the collapse of the more unstable soil pores. This work demonstrates that the soil-wetting process may have an important effect on the characterisation of the water-holding capacity on freshly tilled soils.

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