scholarly journals Soil Water Measurements Relevant to Agronomic and Environmental Functions of Chemically Treated Soil

2009 ◽  
pp. 117-117-28
Author(s):  
R. E. Sojka ◽  
G. A. Lehrsch ◽  
S. J. Kostka ◽  
J. L. Reed ◽  
A. C. Koehn ◽  
...  
Keyword(s):  
Soil Water ◽  
Treated Soil ◽  
Chemically Treated ◽  
Environmental Functions

scholarly journals Soil Water Measurements Relevant to Agronomic and Environmental Functions of Chemically Treated Soil

2009 ◽  
Vol 6 (1) ◽  
pp. 101497
Author(s):  
R. E. Sojka ◽  
G. A. Lehrsch ◽  
S. J. Kostka ◽  
J. L. Reed ◽  
A. C. Koehn ◽  
...  
Keyword(s):  
Soil Water ◽  
Treated Soil ◽  
Chemically Treated ◽  
Environmental Functions

Rhizobacteria Mediated Changes in Soil Physical and Hydrological Properties

2020 ◽  
Author(s):  
Yan Jin ◽  
Saiqi Zeng ◽  
Fatema Kaniz ◽  
Wenjuan Zheng ◽  
Jacob LaManna ◽  
...  
Keyword(s):  
Drought Stress ◽  
Stress Tolerance ◽  
Soil Water ◽  
Water Retention ◽  
Neutron Radiography ◽  
Soil Samples ◽  
Water Evaporation ◽  
Treated Soil ◽  
X Ray ◽  
Drought Stress Tolerance

<p>Large communities of microbes are associated with plant roots in the rhizosphere, which is a critical interface supporting the exchange of water and nutrients between plants and their associated soil environment. The diverse communities of rhizobacteria mediate plant-soil feedback through a multitude of interactions including those that contribute to plant abiotic stresses. For example, enhancement of plant drought stress tolerance by plant growth promoting rhizobacteria (PGPR) has been increasingly documented in the literature, however, investigations to date have been largely focused on PGPR-root/plant interactions and related plant responses to PGPR activities that induce drought tolerance. Comparatively, much less is known about PGPR’s role in mediating physiochemical and hydrological changes in the rhizospheric soil that may also impact plant drought stress tolerance. Using UD1022, aka Bacillus subtilis FB17, as a model bacterium, we demonstrated via soil water characteristic measurements that UD1022-treated soil samples retained more water, had lower hydraulic conductivity than its controls. In addition, we investigated the effects of UD1022 on soil water evaporation via combined neutron radiography, neutron tomography, and X-ray tomography imaging techniques. Neutron radiography images confirmed greater water retention in UD1022-treated soil samples than their controls due to reduced water evaporation. Combined neutron and X-ray tomography 3D images revealed that water distribution in UD1022-treated soil samples was heterogeneous, i.e., there were more disconnected water pockets compared with the controls where water was distributed more uniformly. Our study provides pore-scale mechanistic explanation for increased water retention and reduced evaporation rate from UD1022-treated soil samples, which is mainly attributed to the production of extracellular polymeric substances (EPS) by UD1022 due to EPS’ hygroscopic and chemical properties (viscosity and surface tension). However, our latest experiments showed similar effects by a UD1022 mutant with eps-producing genes removed, suggesting that the beneficial impacts of rhizobacteria may not be limited to their ability to EPS production alone. These findings have practical implications in, for example, “rhizosphere engineering” to improve/restore soil structure, support sustainable agricultural production, and mitigate climate change.</p>

scholarly journals Experimental Study And Modeling Of Water Retention Curve Of A Silty Soil Compacted And Treated With Cement

2020 ◽  
Vol 9 (3) ◽  
pp. 157-176
Author(s):  
Belal Tewfik ◽  
Ghembaza Moulay Smaine ◽  
Bellia Zoheir
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Degree Of Saturation ◽  
Water Retention Curve ◽  
Experimental Measurements ◽  
Characteristic Curves ◽  
Retention Curve ◽  
Treated Soil ◽  
Water Behavior ◽  
Soil Water Characteristic Curves

The evaluation of unsaturated soils' fundamental properties is ensured by the characteristic water retention curve for a wide range of soil suction values. However, a minimal number of research works have focused on studying the water retention properties of natural soils and treated with hydraulic binders using soil-water characteristic curves (SWCC). The present work is motivated by the lack of experimental evidence of this type. Firstly, experimental measurements of soil-water characteristic curves of a natural loam soil from the region of Sidi Bel Abbes (Algeria), treated with cement and compacted at Standard Optimum Proctor at an ambient temperature of 20 °C, Were carried out using the methods of the imposition of suction, namely the osmotic method ranging from 0 to 0.05 MPa and the method of saline solutions over a suction range from 0.05 MPa to about 343 MPa respectively. The suction used were applied to four studied mixtures (natural soil, + 2%, + 4% and + 6% cement). At the end of the tests on the drainage-humidification path, the water retention curves for the treated soil at different cement dosage allow us to determine the different state parameters of the treated soil: Degree of saturation (Sr), dry weight (d), void ratio (e) and water content (w). The suction imposition range and the cement dosage significantly influence the water behavior of the material studied. On the other hand, we develop a model of the water behavior of soils treated with cement. This model makes it possible to correctly predict the retention curves at different cement dosage from the experimental measurements performed on samples compacted at Standard Optimum Proctor represented in the plans [suction, degree of saturation] and [suction, moisture content].

Empirical method for predicting time-dependent strength and resilient modulus of chemically treated soil

2021 ◽  
Vol 29 ◽  
pp. 100551
Author(s):  
Gerald A. Miller ◽  
Amy B. Cerato ◽  
Donald R. Snethen ◽  
Eric Holderby ◽  
Parnaz Boodagh
Keyword(s):  
Resilient Modulus ◽  
Empirical Method ◽  
Time Dependent ◽  
Treated Soil ◽  
Chemically Treated

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.

scholarly journals Effects of Superabsorbent Polymers on the Hydraulic Parameters and Water Retention Properties of Soil

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Renkuan Liao ◽  
Wenyong Wu ◽  
Shumei Ren ◽  
Peiling Yang
Keyword(s):  
Soil Water ◽  
High Speed ◽  
Water Retention ◽  
Soil Column ◽  
Future Research ◽  
Hydraulic Parameters ◽  
Superabsorbent Polymers ◽  
Treated Soil ◽  
Water Retention Properties ◽  
Properties Of Soil

Superabsorbent polymers (SAPs) are widely applied in dryland agriculture. However, their functional property of repeated absorption and release of soil water exerts periodic effects on the hydraulic parameters and water-retention properties of soil, and as this property gradually diminishes with time, its effects tend to be unstable. During the 120-day continuous soil cultivation experiment described in this paper, horizontal soil column infiltration and high-speed centrifugation tests were conducted on SAP-treated soil to measure unsaturated diffusivityDand soil water characteristic curves. The experimental results suggest that the SAP increased the water retaining capacity of soil sections where the suction pressure was between 0 and 3,000 cm. The SAP significantly obstructed water diffusion in the soil in the early days of the experiment, but the effect gradually decreased in the later period. The average decrease in water diffusivity in the treatment groups fell from 76.6% at 0 days to 1.2% at 120 days. This research also provided parameters of time-varying functions that describe the unsaturated diffusivityDand unsaturated hydraulic conductivityKof soils under the effects of SAPs; in future research, these functions can be used to construct water movement models applicable to SAP-treated soil.

Effects of surfactant treatments on the wettability of a water repellent grass-covered dune sand

Soil Research ◽  
2005 ◽  
Vol 43 (3) ◽  
pp. 383 ◽  
Author(s):  
Louis W. Dekker ◽  
Klaas Oostindie ◽  
Stanley J. Kostka ◽  
Coen J. Ritsema
Keyword(s):  
Surface Layer ◽  
Water Content ◽  
Soil Water ◽  
Water Repellency ◽  
Water Repellent ◽  
Dune Sand ◽  
Untreated Soil ◽  
Treated Soil ◽  
Water Contents ◽  
Wetting Rate

The objective of this study was to evaluate the effectiveness of the surfactant formulation Primer®604 for amelioration and management of soil water repellency in grass-covered dune sand. The soil is severely to extremely water repellent to a depth of >0.50 m during dry periods. Primer®604 was applied 12 times between 22 April and 23 November 1999. During that period, soil samples were taken in the untreated and treated plot—8 times in transects and 2 times in soil blocks. A total of 4950 samples were collected for assessment of the actual water repellency and for the spatial and temporal variability of the water content of the soil. Resistance to wetting was determined by measuring the wetting rate of field-moist samples. Measurements of water repellency revealed that applications of Primer®604 resulted in less persistent water repellency in the surface layer to a depth of 0.05 m. No effects were observed deeper in the soil profile, likely due to adsorption of the surfactant material in the surface layer. In the surface layer (0–0.025 and 0.025–0.05 m), the critical soil water content below which the soil is actually water repellent in the field was lowered distinctly by the application of Primer®604, potentially due to coating of water repellent particle surfaces by the surfactant. This suggests that the surface layer (0–0.05 m) in the Primer®604-treated soil can dry to lower water contents than in the untreated soil before water repellency is induced. The thatch layer (0–0.025 m) of the treated soil was often found to have slightly higher water contents than of the untreated soil. The surfactant did not equalise the uneven moisture distribution in the soil below the surface layer (0–0.05 m). Primer®604 applications increased the wetting rate of field-moist samples from the thatch layer. This may result in a more effective wetting of the root-zone during rain events or irrigation, and a reduction in runoff.

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