Estimating Hydraulic Properties of Soil Aggregate Skins from Sorptivity and Water Retention

Hydraulic conductivity and soil-water retention are two critical soil properties describing the fluid flow in unsaturated soils. Existing experimental procedures tend to be time consuming and labor intensive. This paper describes a heuristic approach that combines a limited number of experimental measurements with a computational model with random finite element to significantly accelerate the process. A microstructure-based model is established to describe unsaturated soils with distribution of phases based on their respective volumetric contents. The model is converted into a finite element model, in which the intrinsic hydraulic properties of each phase (soil particle, water, and air) are applied based on the microscopic structures. The bulk hydraulic properties are then determined based on discharge rate using Darcy’s law. The intrinsic permeability of each phase of soil is first calibrated from soil measured under dry and saturated conditions, which is then used to predict the hydraulic conductivities at different extents of saturation. The results match the experimental data closely. Mualem’s equation is applied to fit the pore size parameter based on the hydraulic conductivity. From these, the soil-water characteristic curve is predicted from van Genuchten’s equation. The simulation results are compared with the experimental results from documented studies, and excellent agreements were observed. Overall, this study provides a new modeling-based approach to predict the hydraulic conductivity function and soil-water characteristic curve of unsaturated soils based on measurement at complete dry or completely saturated conditions. An efficient way to measure these critical unsaturated soil properties will be of benefit in introducing unsaturated soil mechanics into engineering practice.

Download Full-text

Impact of Soil Amendments on the Hydraulic Conductivity of Boreal Agricultural Podzols

Agriculture ◽

10.3390/agriculture9060133 ◽

2019 ◽

Vol 9 (6) ◽

pp. 133 ◽

Cited By ~ 4

Author(s):

Dinushika Wanniarachchi ◽

Mumtaz Cheema ◽

Raymond Thomas ◽

Vanessa Kavanagh ◽

Lakshman Galagedara

Keyword(s):

Hydraulic Conductivity ◽

Vadose Zone ◽

Hydraulic Properties ◽

Soil Amendments ◽

Dairy Manure ◽

Soil Hydrology ◽

Inorganic N ◽

Infiltration Rates ◽

Agricultural Setting ◽

Properties Of Soil

Hydraulic properties of soil are the basis for understanding the flow and transport through the vadose zone. It has been demonstrated that different soil amendments can alter the soil properties affecting soil hydrology. The aim of this study was to determine the effect of soil amendments on hydraulic conductivity (K) of a loamy sand podzolic soil under both unsaturated (Kunsat) and near-saturated (near Ksat) conditions in an agricultural setting. A field experiment was conducted with two common soil amendments: Dairy manure (DM) in 2016 and 2017 and biochar (BC) once only in 2016. DM and BC were incorporated up to a depth of 0.15–0.20 m at a rate of 30,000 L ha−1 and 20 Mg ha−1, respectively. A randomized complete block experimental design was used and the plots planted with silage corn (Zea mays L.) without irrigation. The treatments were: Control without amendment (0N), inorganic N fertilizer (IN), two types of DM (IN+DM1 and IN+DM2), and two treatments with BC (IN+BC and IN+DM1+BC). Infiltration data were collected using a mini disk infiltrometer under three tension levels in which −0.04 and −0.02 m was ascribed as unsaturated (at the wet end) and −0.001 m as near-saturated condition. Based on the measured infiltration rates, Kunsat and near Ksat hydraulic conductivities were calculated. There were no significant effects of DM and BC on bulk density and near Ksat. Treatments IN+DM1, IN+DM2, and IN+DM1+BC significantly reduced the Kunsat compared to the control. Since these soil amendments can influence soil hydrology such as reduced infiltration and increased surface runoff, carefully monitored application of soil amendments is recommended.

Download Full-text

Root growth and presence of Rhizophagus irregularis distinctly alter substrate hydraulic properties in a model system with Medicago truncatula

Plant and Soil ◽

10.1007/s11104-020-04723-w ◽

2020 ◽

Vol 457 (1-2) ◽

pp. 131-151

Author(s):

Richard Pauwels ◽

Jan Jansa ◽

David Püschel ◽

Anja Müller ◽

Jan Graefe ◽

...

Keyword(s):

Medicago Truncatula ◽

Mycorrhizal Fungi ◽

Hydraulic Properties ◽

Water Retention ◽

Pore Space ◽

Moisture Stress ◽

Model System ◽

Rhizophagus Irregularis ◽

Root Penetration ◽

Mycorrhizal Plants

Abstract Aim We investigated how substrate hydraulic properties respond to the presence of arbuscular mycorrhizal fungi (AMF) in root-containing and root-free substrate zones in a Medicago truncatula-Rhizophagus irregularis model system. Methods Before planting, two compartments constructed from standard soil sampling cores (250 cm3) were implanted into non-mycorrhizal and mycorrhizal pots containing a sand-zeolite-soil mix. One compartment allowed root penetration (1 mm mesh cover) and the other only hyphal ingrowth (42 μm mesh cover). After eight weeks of growth under maintenance of moist conditions, the cores were subjected to water retention measurements. Additionally, we measured water retention of bare substrates before and after drying events to check for successful maintenance of moist conditions in pots. Results Drying of bare substrates decreased water retention, but planting at least sustained it. The parameters of water retention models responded linearly to root morphological traits across mycorrhizal and non-mycorrhizal substrates. Hyphae-only colonization comparatively affected the course of water retention in ways that suggest increased pore space heterogeneity while maintaining water storage capacity of substrates. Conclusions Hence, water contents corresponded to different substrate matric potentials in non-mycorrhizal and mycorrhizal pots. We conclude that changes to water retention in AMF colonized substrates can contribute to a widely observed phenomenon, i.e. that mycorrhizal plants differ in their moisture stress response from non-mycorrhizal plants.

Download Full-text

Bio-improved hydraulic properties of sand treated by soybean urease induced carbonate precipitation and its application Part 1: Water retention ability

Transportation Geotechnics ◽

10.1016/j.trgeo.2020.100489 ◽

2021 ◽

Vol 27 ◽

pp. 100489 ◽

Cited By ~ 1

Author(s):

Yanbo Chen ◽

Yufeng Gao ◽

Charles W.W. Ng ◽

Haowen Guo

Keyword(s):

Hydraulic Properties ◽

Water Retention ◽

Carbonate Precipitation

Download Full-text

Nano Titania Reinforced Limestone Cement: Physico-Mechanical Investgation

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.786.248 ◽

2018 ◽

Vol 786 ◽

pp. 248-257

Author(s):

Mohmoud A. Abuelseoud ◽

Asmaa S. Hamouda ◽

Ibrahim M. Ismail ◽

M.A. El-Sheikh

Keyword(s):

Mechanical Properties ◽

Particle Size ◽

Hydraulic Properties ◽

Water Retention ◽

Physical And Mechanical Properties ◽

Sem Analysis ◽

Cement Clinker ◽

Titanium Silicate ◽

Cement Pastes ◽

Limestone Cement

Studying physical and mechanical properties of limestone cement pastes blended by TiO2 nanoparticles (i.e., particle size less than 100 nm). Three mixes are prepared for this study (5.00, 10.00 and 25.00 wt. % of limestone) partially replaced cement/clinker by TiO2 nanoparticles. Fillers are carefully selected which reinforcing cement workability or water retention they could be inert or have slightly hydraulic properties. Limestone is most common filler that fills the pores between cement particles due to the formation of monocarboaluminate, while nanoparticles increase the hydration C-S-H gel product and calcium titanium silicate which hardened the cement pastes. Nanoparticles show a great effect in reinforcing the mechanical strength of cement pastes due to the fact that TiO2-nanoparticles act as active nuclei site forming C-S-H gel observed as honeycomb-like plus improving cement to water demined (W/C) ratio. SEM analysis proves that the morphology of cement structure is well arranged and compacted.

Download Full-text

Effects of Sugar Foam Liming on the Water-Retention Properties of Soil

Communications in Soil Science and Plant Analysis ◽

10.1080/00103624.2015.1033541 ◽

2015 ◽

Vol 46 (10) ◽

pp. 1299-1308 ◽

Cited By ~ 2

Author(s):

C. Pérez-de-los-Reyes ◽

J. A. Amorós Ortíz-Villajos ◽

F. J. García Navarro ◽

S. Bravo Martín-Consuegra ◽

R. Jiménez Ballesta

Keyword(s):

Water Retention ◽

Water Retention Properties ◽

Properties Of Soil

Download Full-text

Experiments and interpretations on unsaturated hydraulic properties using water retention tests based on the membrane in Korea

10.5194/egusphere-egu2020-3817 ◽

2020 ◽

Author(s):

Seboong Oh ◽

Sungjin Kim ◽

Kwang Ik Son

Keyword(s):

Unsaturated Soils ◽

Hydraulic Properties ◽

Water Retention ◽

Void Ratio ◽

Water Retention Curve ◽

Soil Water Retention Curve ◽

Soil Water Retention ◽

Huge Amount ◽

Retention Curve ◽

Hydraulic Behavior

In unsaturated soils, the soil water retention curve (SWRC) is most important in the fundamental hydraulic properties. In order to measure SWRCs through an alternative method in Korea, high air entry disks were replaced by micro membranes. Micro membranes are thin in which the air entry value is around 100kPa. Tests with the membrane are fast to reduce the duration of infiltration through the high air entry disk.The water retention curves using the membrane were compared with the data using high air entry disks from the volumetric pressure plate extractor and Tempe pressure cell for samples of various sites. As a result, the SWRCs using the membrane were very similar for most cases and the micro membrane was verified as a useful tool to measure SWRCs.The unsaturated hydraulic behavior could be measured easily using the membrane than ceramic disks and the huge amount of data could have been obtained in Korea. Using DB of SWRCs, the hydraulic properties were interpreted based on the parameters of the van Genuchten SWRC model. The void ratio and density are correlated to SWRCs under the same classification soil.Acknowledgements This research is supported by grant from Korean NRF (2019R1A2C1003604) and MOE (79608), which are greatly appreciated.

Download Full-text