scholarly journals Combination of Measurement Methods for a Wide-Range Description of Hydraulic Soil Properties

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1021 ◽  
Author(s):  
Thomas Weninger ◽  
Gernot Bodner ◽  
Janis Kreiselmeier ◽  
Parvathy Chandrasekhar ◽  
Stefan Julich ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Soil Water ◽  
Water Retention ◽  
Measurement Methods ◽  
Water Dynamics ◽  
Conductivity Measurements ◽  
Soil Water Dynamics ◽  
Evaporation Method ◽  
Wide Range

Established measurement methods for hydraulic soil properties cover a limited soil moisture range. Simulations of soil water dynamics based on such observations are therefore rarely representative for all conditions from saturation to drought. Recent technical developments facilitate efficient and cheap collecting of soil water characteristics data, but the quantitative benefit of extended measurement campaigns has not been adequately tested yet. In this study, a combination of four methods to measure water retention and hydraulic conductivity at different moisture ranges was applied. Evaporation method, dewpoint psychrometry, hood infiltrometer experiments, and falling head method for saturated conductivity were conducted at two experimental sites in eastern Austria. Effects of including the particular methods in the measurement strategy were examined by visual evaluation and a 1D-modelling sensitivity study including drainage, infiltration and drought conditions. The evaporation method was considered essential due to its broad measurement range both for water retention and hydraulic conductivity. In addition to that, the highest effect on simulated water balance components was induced by the inclusion of separate conductivity measurements near saturation. Water content after three days of drainage was 15 percent higher and the transpiration rate in a drought period was 22 percent higher without near-saturated conductivity measurements. Based on relative comparisons between different combinations, we suggested combining evaporation method and hood infiltrometer experiments as the basis for representative predictions of soil water dynamics.

Method for Quick Prediction of Hydraulic Conductivity and Soil-Water Retention of Unsaturated Soils

2018 ◽  
Vol 2672 (52) ◽  
pp. 108-117 ◽  
Author(s):  
Shaoyang Dong ◽  
Yuan Guo ◽  
Xiong (Bill) Yu
Keyword(s):  
Finite Element ◽  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Soil Water ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Characteristic Curve ◽  
Soil 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.

Influence of vegetation type and soil properties on soil water dynamics in the Šumava Mountains (Southern Bohemia)

2020 ◽  
Vol 582 ◽  
pp. 124285
Author(s):  
Václav Šípek ◽  
Jan Hnilica ◽  
Lukáš Vlček ◽  
Soňa Hnilicová ◽  
Miroslav Tesař
Keyword(s):  
Soil Properties ◽  
Soil Water ◽  
Vegetation Type ◽  
Water Dynamics ◽  
Soil Water Dynamics

scholarly journals Soil functioning in a toposequence under rainforest in São Paulo, Brazil

2013 ◽  
Vol 37 (2) ◽  
pp. 392-399 ◽  
Author(s):  
Miguel Cooper ◽  
João Carlos Medeiros ◽  
Jaqueline Dalla Rosa ◽  
José Eduardo Soria ◽  
Raul Shiso Toma
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Particle Density ◽  
Morphological Characteristics ◽  
Sao Paulo ◽  
Water Dynamics ◽  
Atlantic Rainforest ◽  
Morphological Properties ◽  
São Paulo ◽  
Soil Water Dynamics

Studies of soil-water dynamics using toposequences are essential to improve the understanding of soil-water-vegetation relationships. This study assessed the hydro-physical and morphological characteristics of soils of Atlantic Rainforest in the Parque Estadual de Carlos Botelho, state of São Paulo, Brazil. The study area of 10.24 ha (320 x 320 m) was covered by dense tropical rainforest (Atlantic Rainforest). Based on soil maps and topographic maps of the area, a representative transect of the soil in this plot was chosen and five soil trenches were opened to determine morphological properties. To evaluate the soil hydro-physical functioning, soil particle size distribution, bulk density (r), particle density (r s), soil water retention curves (SWRC), field saturated hydraulic conductivity (Ks), macroporosity (macro), and microporosity (micro) and total porosity (TP) were determined. Undisturbed samples were collected for micromorphometric image analysis, to determine pore size, shape, and connectivity. The soils in the study area were predominantly Inceptisols, and secondly Entisols and Epiaquic Haplustult. In the soil hydro-physical characterization of the selected transect, a change was observed in Ks between the surface and subsurface layers, from high/intermediate to intermediate/low permeability. This variation in soil-water dynamics was also observed in the SWRC, with higher water retention in the subsurface horizons. The soil hydro-physical behavior was influenced by the morphogenetic characteristics of the soils.

A parameterised equation to estimate soil hydraulic conductivity in the field

Soil Research ◽  
2004 ◽  
Vol 42 (3) ◽  
pp. 283 ◽  
Author(s):  
K. Reichardt ◽  
L. C. Timm ◽  
O. O. S. Bacchi ◽  
J. C. M. Oliveira ◽  
D. Dourado-Neto
Keyword(s):  
Hydraulic Conductivity ◽  
Water Content ◽  
Soil Water ◽  
Water Dynamics ◽  
Water Drainage ◽  
Soil Water Dynamics ◽  
Soil Hydraulic Conductivity ◽  
Exponential Character ◽  
Simplifying Assumptions ◽  
Soil Hydraulic

The description of soil water dynamics using the Darcy–Buckingham approach involves the determination and use of soil hydraulic conductivity K v. soil water content θ functions. Many of the methods developed for the measurement of K are based on simplifying assumptions, such as the unit gradient and the choice of fixed models for the K(θ) relation. The need of quick, simple, and inexpensive methods to measure K(θ) in the field using a large number of replicates has also led soil physicists to develop simple methods. This paper presents a procedure that makes use of parameters of equations used to explain the internal water drainage process, and that naturally leads to the exponential character of the K(θ) relation. Results show that the parameterised equation represents a more rigorous estimation of K(θ), compared with the methods that assume unit gradient.

scholarly journals <i>STH-net</i>: a model-driven soil monitoring network for process-based hydrological modelling from the pedon to the hillslope scale

2021 ◽  
Author(s):  
Edoardo Martini ◽  
Simon Kögler ◽  
Manuel Kreck ◽  
Kurt Roth ◽  
Ulrike Werban ◽  
...  
Keyword(s):  
Soil Properties ◽  
Soil Water ◽  
Spatial Scales ◽  
Monitoring Network ◽  
Time Domain Reflectometry ◽  
Water Dynamics ◽  
Quality Data ◽  
Soil Monitoring ◽  
Soil Water Dynamics ◽  
Local Soil

Abstract. The Schäfertal hillslope site is part of the TERENO Harz/Central German Lowland Observatory and its soil water dynamics is being monitored intensively as part of an integrated, long-term, multi-scale and multi-temporal research framework linking hydrological, pedological, atmospheric and biodiversity-related research to investigate the influences of climate and land use change on the terrestrial system. Here, a new soil monitoring network, indicated as STH-net, has been recently implemented to provide high-resolution data about the most relevant hydrological variables and local soil properties. The monitoring network is spatially optimized, based on previous knowledge from soil mapping and soil moisture monitoring, in order to capture the spatial variability of soil properties and soil water dynamics along a catena across the site as well as in depth. The STH-net comprises eight stations instrumented with time-domain reflectometry (TDR) probes, soil temperature probes and piezometers. Furthermore, a weather station provides data about the meteorological variables. A detailed soil characterization exists for locations where the TDR probes are installed. All data are measured at a 10-minutes interval since January 1st, 2019. The STH-net is intended to provide scientists with high-quality data needed for developing and testing modelling approaches in the context of vadose-zone hydrology at spatial scales ranging from the pedon to the hillslope. The data are available from the EUDAT portal (https://b2share.eudat.eu/records/e2a2135bb1634a97abcedf8a461c0909 ) (Martini et al., 2020).

scholarly journals <i>STH-net:</i> a soil monitoring network for process-based hydrological modelling from the pedon to the hillslope scale

2021 ◽  
Vol 13 (6) ◽  
pp. 2529-2539
Author(s):  
Edoardo Martini ◽  
Matteo Bauckholt ◽  
Simon Kögler ◽  
Manuel Kreck ◽  
Kurt Roth ◽  
...  
Keyword(s):  
Soil Properties ◽  
Soil Water ◽  
Spatial Scales ◽  
Monitoring Network ◽  
Time Domain Reflectometry ◽  
Water Dynamics ◽  
Soil Monitoring ◽  
Soil Water Dynamics ◽  
High Resolution Data ◽  
Local Soil

Abstract. The Schäfertal Hillslope site is part of the TERENO Harz/Central German Lowland Observatory, and its soil water dynamics are being monitored intensively as part of an integrated, long-term, multi-scale, and multi-temporal research framework linking hydrological, pedological, atmospheric, and biodiversity-related research to investigate the influences of climate and land use change on the terrestrial system. Here, a new soil monitoring network, indicated as STH-net, has been recently implemented to provide high-resolution data about the most relevant hydrological variables and local soil properties. The monitoring network is spatially optimized, based on previous knowledge from soil mapping and soil moisture monitoring, in order to capture the spatial variability in soil properties and soil water dynamics along a catena across the site as well as in depth. The STH-net comprises eight stations instrumented with time-domain reflectometry (TDR) probes, soil temperature probes, and monitoring wells. Furthermore, a weather station provides data about the meteorological variables. A detailed soil characterization exists for locations where the TDR probes are installed. All data have been measured at a 10 min interval since 1 January 2019. The STH-net is intended to provide scientists with data needed for developing and testing modelling approaches in the context of vadose-zone hydrology at spatial scales ranging from the pedon to the hillslope. The data are available from the EUDAT portal (https://doi.org/10.23728/b2share.82818db7be054f5eb921d386a0bcaa74, Martini et al., 2020).

Assessment of the Role of Different Soil Properties on Crust Strength by Linear Regression Models

2019 ◽  
Vol 6 (04) ◽  
Author(s):  
MINAKSHI SERAWAT ◽  
V K PHOGAT ◽  
ANIL Abdul KAPOOR ◽  
VIJAY KANT SINGH ◽  
ASHA SERAWAT
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Crop Yields ◽  
Modulus Of Rupture ◽  
Silty Clay ◽  
Linear Regression Models ◽  
Wide Range ◽  
Dispersion Ratio ◽  
Crust Strength

Soil crust strength influences seedling emergence, penetration and morphology of plant roots, and, consequently, crop yields. A study was carried out to assess the role of different soil properties on crust strength atHisar, Haryana, India. The soil samples from 0-5 and 5-15 cm depths were collected from 21 locations from farmer’s fields, having a wide range of texture.Soil propertieswere evaluated in the laboratory and theirinfluence on the modulus of rupture (MOR), which is the measure of crust strength, was evaluated.The MOR of texturally different soils was significantly correlated with saturated hydraulic conductivity at both the depths. Dispersion ratio was found to decrease with an increase in fineness of the texture of soil and the lowest value was recorded in silty clay loam soil,which decreased with depth. The modulus of rupture was significantly negatively correlative with the dispersion ratio.There was no role of calcium carbonate in influencing the values of MOR of soils. Similarly,the influence of pH, EC and SAR of soil solution on MOR was non-significant.A perusal of thevalues of the correlations between MOR and different soil properties showed that the MOR of soils of Haryana are positively correlated with silt + clay (r = 0.805) followed by water-stable aggregates (r = 0.774), organic carbon (r = 0.738), silt (r = 0.711), mean weight diameter (r = 0.608) and clay (r = 0.593) while negatively correlated with dispersion ratio (r = - 0.872), sand (r = -0.801) and hydraulic conductivity (r = -0.752) of soils.

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