Effect of stones on soil hydraulic properties: measurement and modeling

Stony soils are soils that contain a high amount of stones and are widespread all over the world. &#160;The effective soil hydraulic properties (SHP), i.e. the water retention curve (WRC) and the hydraulic conductivity curve (HCC) are influenced by the presence of stones in the soil. This influence is normally neglected in vadose zone modeling due to the considerable measurement challenges in stony soils. The available data on the effect of stones on SHP is scarce and there is not a systematic modeling approach to obtain the effective SHP in stony soils. Most of the past studies are limited to the effect of stones on the WRC and saturated hydraulic conductivity and low and medium stone contents (up to 40 % v/v). We investigated the effect of stone content on the effective SHP of stony soils through a series of evaporation experiments. Two soil materials a) sandy loam and b) silt loam as background soils were packed with different volumetric contents (0, 10, 30 and 60 %) of medium stones were in containers with a volume of 5060 cm3. Volumetric stone contents were chosen in a way to present stone-free, moderately stony and highly stony soils. All of the experiments were carried out in two replicate packings with an almost identical bulk density. Packed samples were saturated with water from the bottom and subjected to evaporation in a climate-controlled room. During the evaporation experiments, the pressure head and soil temperature were continuously monitored and the water loss from the soil columns was measured with a balance. The dewpoint method provided additional data on the WRC in the dry soil. The resulting data were evaluated by inverse modeling with the Richards equation to identify effective SHP and to analyze the effect of stone content on the evaporation rate, soil temperature, the effective WRC and the effective HCC. The applied methodology was successful in identifying effective SHP with high precision over the full moisture range. The results reveal a quicker transition from stage I to stage II of evaporation in highly stony soils. Evaporation rate reduces with the increase of the volumetric stone content. The existence of a high amount of stone content shorten stage II of evaporation driven by the vapor diffusion through the restricted soil evaporative surface.

Further tests of the HYPROP evaporation method for estimating the unsaturated soil hydraulic properties

Journal of Hydrology and Hydromechanics ◽

10.1515/johh-2017-0046 ◽

2018 ◽

Vol 66 (2) ◽

pp. 161-169 ◽

Cited By ~ 14

Author(s):

Camila R. Bezerra-Coelho ◽

Luwen Zhuang ◽

Maria C. Barbosa ◽

Miguel Alfaro Soto ◽

Martinus Th. van Genuchten

Keyword(s):

Hydraulic Conductivity ◽

Unsaturated Soil ◽

Hydraulic Properties ◽

Water Retention ◽

Measurement Techniques ◽

Richards Equation ◽

Water Retention Curve ◽

Evaporation Method ◽

AbstractMany soil, hydrologic and environmental applications require information about the unsaturated soil hydraulic properties. The evaporation method has long been used for estimating the drying branches of the soil hydraulic functions. An increasingly popular version of the evaporation method is the semi-automated HYPROP©measurement system (HMS) commercialized by Decagon Devices (Pullman, WA) and UMS AG (München, Germany). Several studies were previously carried out to test the HMS methodology by using the Richards equation and the van-Genuchten-Mualem (VG) or Kosugi-Mualem soil hydraulic functions to obtain synthetic data for use in the HMS analysis, and then to compare results against the original hydraulic properties. Using HYDRUS-1D, we carried out independent tests of the HYPROP system as applied to the VG functions for a broad range of soil textures. Our results closely agreed with previous findings. Accurate estimates were especially obtained for the soil water retention curve and its parameters, at least over the range of available retention measurements. We also successfully tested a dual-porosity soil, as well as an extremely coarse medium with a very high van Genuchtennvalue. The latter case gave excellent results for water retention, but failed for the hydraulic conductivity. In many cases, especially for soils with intermediate and highnvalues, an independent estimate of the saturated hydraulic conductivity should be obtained. Overall, the HMS methodology performed extremely well and as such constitutes a much-needed addition to current soil hydraulic measurement techniques.

Testing an infiltrometer methodology to investigate water impact effects on both soil sealing and hydraulic properties of a loam soil under conventional tillage and no-tillage

10.5194/egusphere-egu2020-22632 ◽

2020 ◽

Author(s):

Mirko Castellini ◽

Simone Di Prima ◽

Anna Maria Stellacci ◽

Massimo Iovino ◽

Vincenzo Bagarello

Keyword(s):

Hydraulic Conductivity ◽

Hydraulic Properties ◽

Water Retention ◽

Soil Management ◽

Water Retention Curve ◽

Retention Curve ◽

Soil Sealing ◽

Loam Soil ◽

Testing new experimental procedures to assess the effects of the drops impact on the soil sealing formation is a main topic in soil hydrology.In this field investigation, the methodological approach proposed first by Bagarello et al. (2014) was extended to account for a greater soil infiltration surface (i.e., about 3.5 times higher), a higher range and number of heights of water pouring and to evaluate the different impact on soil management. For this purpose, the effects of three water pouring heights (low, L=3 cm; medium, M=100 cm; high, H=200 cm) on both no-tilled (NT) and conventionally tilled (CT) loam soil were investigated by Beerkan infiltration runs and using the BEST-procedure of data analysis to estimate the soil hydraulic properties.Final infiltration rate decreased when perturbing runs (i.e., M and H) were carried out as compared with the non-perturbing (L) ones (by a factor of 1.5-3.1 under NT and 3.4-4.4 under CT). Similarly, the water retention scale parameter, hg, increased (i.e., higher in absolute terms) by a factor 1.6-1.8 under NT and by a factor 1.7 under CT. Saturated hydraulic conductivity, Ks, changed significantly as a function of the increase of water pouring height; regardless of the soil management, perturbing runs caused a reduction in soil permeability by a factor 5 or 6. Effects on hydraulic functions (i.e., soil water retention curve and hydraulic conductivity function), obtained with the BEST-Steady algorithm, were also highlighted. For instance, differences in water retention curve at fixed soil pressure head values (i.e., field capacity, FC, and permanent wilting point, PWP) due to perturbing and non-perturbing runs, were estimated as higher under NT (3.8%) than CT (3.4%) for FC, and equal to 2.1% or 1.6% for PWP.Main results of this investigation confirm that a recently tilled loamy soil, without vegetation cover, can be less resilient as compared to a no-tilled one, and that tested water pouring heights methodology looks promising to mimic effects of high energy rainfall events and to quantify the soil sealing effects under alternative management of the soil.AcknowledgmentsThe work was supported by the project &#8220;STRATEGA, Sperimentazione e TRAsferimento di TEcniche innovative di aGricoltura conservativA&#8221;, funded by Regione Puglia&#8211;Dipartimento Agricoltura, Sviluppo Rurale ed Ambientale, CUP: B36J14001230007.&#160;ReferencesBagarello, V., Castellini, M., Di Prima, S., Iovino, M. 2014. Soil hydraulic properties determined by infiltration experiments and different heights of water pouring. Geoderma, 213, 492&#8211;501. https://doi.org/10.1016/j.geoderma.2013.08.032

The role of biochar particle size and hydrophobicity in improving soil hydraulic properties

10.5194/egusphere-egu21-4117 ◽

2021 ◽

Author(s):

Ifeoma Edeh ◽

Ondřej Mašek

Keyword(s):

Particle Size ◽

Hydraulic Conductivity ◽

Soil Water ◽

Hydraulic Properties ◽

Water Retention ◽

Sandy Loam ◽

Particle Sizes ◽

Soil Water Retention ◽

The physical properties of biochar have been shown to dramatically influence its performance as a soil amendment. Biochar particle size is one of key parameters, as it controls its specific surface area, shape, and pore distribution. Therefore, this study assessed the role of biochar particle size and hydrophobicity in controlling soil water movement and retention. Softwood pellet biochar in five particle size ranges (>2 mm, 2 &#8211; 0.5 mm, 0.5 &#8211; 0.25 mm, 0.25 &#8211; 0.063mm and <0.063 mm) was used for the experiment. These particle sizes were tested on 2 soil types (sandy loam and loamy sand) at four different application rates (1, 2, 4 and 8%).&#160; Our results showed that biochar hydrophobicity increased with decreasing biochar particle size, leading to a reduction in its water retention capacity. The effect of biochar on soil hydraulic properties varied with different rate of application and particle sizes. With increasing rate of application, water retention increased while hydraulic conductivity decreased. Water content at field capacity, permanent wilting point, and the available water content increased with increasing biochar particle size. The soil hydraulic conductivity increased with decreasing particle sizes apart from biochar particles <0.063mm which showed a significant (p&#8804;0.05) decrease compared to the larger particle sizes. The results clearly showed that both biochar intra-porosity and inter-porosity are important factors affecting soil hydraulic properties. Biochar interpores affected mainly hydraulic conductivity, both interpores and intrapores controlled soil water retention properties. Our results suggest that for a more effective increase in soil water retention in sandy loam and loamy sand, the use of hydrophilic biochar with high intra-porosity is recommended.

The influence of microplastic on soil hydraulic properties

10.5194/egusphere-egu2020-9337 ◽

2020 ◽

Author(s):

Patrizia Hangele ◽

Katharina Luise Müller ◽

Hannes Laermanns ◽

Christina Bogner

Keyword(s):

Hydraulic Conductivity ◽

Soil Water ◽

Hydraulic Properties ◽

Water Retention ◽

Pore Space ◽

Water Retention Curve ◽

Soil Water Retention ◽

Soil Hydraulic Conductivity ◽

The need to study the occurrence and effects of microplastic (MP) in different ecosystems has become apparent by a variety of studies in the past years. Until recently, research regarding MP in the environment has mainly focused on marine systems. Within terrestrial systems, studies suggest soils to be the biggest sink for MP. Some studies now started to explore the presence of MP in soils. However, there is a substantial lack of the basic mechanistic understanding of the behaviour of MP particles within soils.This study investigates how the presence of MP in soils affects their hydraulic properties. In order to understand these processes, experiments are set up under controlled laboratory conditions as to set unknown influencing variables to a minimum. Different substrates, from simple sands to undisturbed soils, are investigated in soil cylinders. MP particles of different sizes and forms of the most common plastic types are applied to the surface of the soil cylinders and undergo an irrigation for the MP particles to infiltrate. Soil-water retention curves and soil hydraulic conductivity are measured before and after the application of MP particles. It is hypothesised that the infiltrated MP particles clog a part of the pore space and should thus reduce soil hydraulic conductivity and change the soil-water retention curve of the sample. Knowledge about the influence of MP on soil hydraulic properties are crucial to understand transport and retention of MP in soils.

Direct measurement of the soil water retention curve using X-ray absorption

Hydrology and Earth System Sciences ◽

10.5194/hess-8-2-2004 ◽

2004 ◽

Vol 8 (1) ◽

pp. 2-7 ◽

Cited By ~ 19

Author(s):

A. Bayer ◽

H.-J. Vogel ◽

K. Roth

Keyword(s):

Soil Water ◽

Hydraulic Properties ◽

Capillary Rise ◽

Water Dynamics ◽

Richards Equation ◽

Water Retention Curve ◽

X Ray ◽

Soil Hydraulic ◽

X Ray Absorption

Abstract. X-ray absorption measurements have been explored as a fast experimental approach to determine soil hydraulic properties and to study rapid dynamic processes. As examples, the pressure-saturation relation θ(Ψ) for a uniform sand column has been considered as has capillary rise in an initially dry sintered glass column. The θ(Ψ)-relation is in reasonable agreement with that obtained by inverting a traditional multi-step outflow experiment. Monitoring the initial phase of capillary rise reveals behaviour that deviates qualitatively from the single-phase, local-equilibrium regime described by Richards’ equation. Keywords: X-ray absorption, soil hydraulic properties, soil water dynamics, Richards’ equation

Reference material for the measurement of soil hydraulic properties

10.5194/egusphere-egu21-12164 ◽

2021 ◽

Author(s):

Axel Lamparter ◽

C. Florian Stange

Keyword(s):

Quality Control ◽

Hydraulic Conductivity ◽

Reference Material ◽

Hydraulic Properties ◽

Saturated Hydraulic Conductivity ◽

Water Retention Curve ◽

Retention Curve ◽

Sintered Glass ◽

Quality control of the measurement of soil hydraulic properties (water retention curve, saturated hydraulic conductivity) using soil cores is not very common in soil physics laboratories. The missing quality control in the labs might be due to the lack of a suitable reference material for the measurement of soil hydraulic properties (SHP). However, a standardized quality of these measurements is needed, especially when generated data from different laboratories are used.So far no satisfying reference material has been presented that can be used for quality control during the measurement of SHP. Reference material should have a rigid pore system and pore surfaces properties that do not change over time. Additionally, the reference material should be very sensitive to provide a sufficient quality control for the measurement of SHP.We present sintered glass cylinders with a defined pore size distribution that were tested in the laboratory for reproducibility. After a standardized cleaning procedure of the glass cylinders, water contents after equilibration at -63 hPa (field capacity) showed reasonably low standard deviations. Thus, it seems promising that these cylinders can be used as reference material for the measurement of the water retention curve.First Results of repeated saturated hydraulic conductivity measurements (Ks) of the same sintered glass cylinders showed larger variability and an increasing trend over the time. Currently the reason for this trend is unknown. Therefore, it is worked on standardizing procedures of using the reference cylinders and on cleaning the cylinders to improve the reproducibility. The results show how sensitive the measurement of saturated hydraulic conductivity is and that we need to put more emphasis on quality control in our work.&#160;

Rapid and accurate measurement methods for determining soil hydraulic properties: A review

Journal of Hydrology and Hydromechanics ◽

10.2478/johh-2021-0002 ◽

2021 ◽

Vol 69 (2) ◽

pp. 121-139

Author(s):

Mirko Castellini ◽

Simone Di Prima ◽

David Moret-Fernández ◽

Laurent Lassabatere

Keyword(s):

Data Analysis ◽

Hydraulic Conductivity ◽

Hydraulic Properties ◽

Field Experiments ◽

Theory And Practice ◽

Water Retention Curve ◽

Great Effort ◽

Single Ring ◽

Abstract The determination of soil hydraulic properties is important in several environmental sciences but may be expensive and time consuming. Therefore, during the last decades, a great effort has been made in soil sciences to develop relatively easy, robust, and inexpensive methods for soil hydraulic characterization. In this manuscript, we reviewed and discussed different infiltrometer techniques in light of the available experimental applications. More specifically, we considered the simplified falling head (SFH) infiltrometer technique and the single-ring infiltration experiment of the Beerkan type. Concerning this latter method, we considered different algorithms for data analysis: two simplified methods based on the analysis of transient (TSBI) and steady (SSBI) Beerkan infiltration data, and the Beerkan Estimation of Soil pedoTransfer parameters algorithm (BEST), that allows to estimate the soil characteristics curves, i.e., the soil water retention curve and hydraulic conductivity functions. For a given method, after dealing briefly theory and practice, available literature references were reported to account for specific applications in order to provide findings on method validation and application. With the aim to provide practical information on available tools for a simpler application of the reviewed methods, several video tutorials were reported to show i) how to conduct correctly field experiments and ii) how to calculate saturated hydraulic conductivity or soil hydraulic functions using user-friendly tools for data analysis. Finally, details on a new automated single-ring infiltrometer for Beerkan infiltration experiments (i.e., construction, assembly and field use) were presented.

Hyphal colonization of Rhizophagus irregularis increases unsaturated hydraulic conductivity of a loamy sand distant from roots

10.5194/egusphere-egu21-4564 ◽

2021 ◽

Author(s):

Michael Bitterlich ◽

Richard Pauwels

Keyword(s):

Hydraulic Conductivity ◽

Water Content ◽

Hydraulic Properties ◽

Volumetric Water Content ◽

Rhizophagus Irregularis ◽

Loamy Sand ◽

Unsaturated Hydraulic Conductivity ◽

Soil Hydraulic ◽

Root Exclusion

Hydraulic properties of mycorrhizal soils have rarely been reported and difficulties in directly assigning potential effects to hyphae of arbuscular mycorrhizal fungi (AMF) arise from other consequences of AMF being present, i.e. their influence on growth and water consumption rates of their host plants that both also influence soil hydraulic properties.We assumed that the typical nylon meshes used for root-exclusion experiments in mycorrhizal research can provide a dynamic hydraulic barrier. It is expected that the uniform pore size of the rigid meshes causes a sudden hydraulic decoupling of the enmeshed inner volume from the surrounding soil as soon as the mesh pores become air-filled. Growing plants below the soil moisture threshold for hydraulic decoupling would minimize plant-size effects on root-exclusion compartments and allow for a more direct assignment of hyphal presence to modulations in soil hydraulic properties.We carried out water retention and hydraulic conductivity measurements with two tensiometers introduced in two different heights in a cylindrical compartment (250 cm&#179;) containing a loamy sand, either with or without the introduction of a 20 &#181;m nylon mesh equidistantly between the tensiometers. Introduction of a mesh reduced hydraulic conductivity across the soil volumes by two orders of magnitude from 471 to 6 &#181;m d-1 at 20% volumetric water content.We grew maize plants inoculated or not with Rhizophagus irregularis in the same soil in pots that contained root-exclusion compartments while maintaining 20% volumetric water content. When hyphae were present in the compartments, water potential and unsaturated hydraulic conductivity increased for a given water content compared to compartments free of hyphae. These differences increased with progressive soil drying.We conclude that water extractability from soils distant to roots can be facilitated under dry conditions when AMF hyphae are present.&#160;

Stabilization of soil hydraulic properties under a long term no-till system

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832014000400024 ◽

2014 ◽

Vol 38 (4) ◽

pp. 1281-1292 ◽

Cited By ~ 11

Author(s):

Luis Alberto Lozano ◽

Carlos Germán Soracco ◽

Vicente S. Buda ◽

Guillermo O. Sarli ◽

Roberto Raúl Filgueira

Keyword(s):

Hydraulic Conductivity ◽

Physical Properties ◽

Hydraulic Properties ◽

Sandy Loam ◽

Soil Physical Properties ◽

Water Retention Curve ◽

Mean Values ◽

Tillage System ◽

Crop Sequence

The area under the no-tillage system (NT) has been increasing over the last few years. Some authors indicate that stabilization of soil physical properties is reached after some years under NT while other authors debate this. The objective of this study was to determine the effect of the last crop in the rotation sequence (1st year: maize, 2nd year: soybean, 3rd year: wheat/soybean) on soil pore configuration and hydraulic properties in two different soils (site 1: loam, site 2: sandy loam) from the Argentinean Pampas region under long-term NT treatments in order to determine if stabilization of soil physical properties is reached apart from a specific time in the crop sequence. In addition, we compared two procedures for evaluating water-conducting macroporosities, and evaluated the efficiency of the pedotransfer function ROSETTA in estimating the parameters of the van Genuchten-Mualem (VGM) model in these soils. Soil pore configuration and hydraulic properties were not stable and changed according to the crop sequence and the last crop grown in both sites. For both sites, saturated hydraulic conductivity, K0, water-conducting macroporosity, εma, and flow-weighted mean pore radius, R0ma, increased from the 1st to the 2nd year of the crop sequence, and this was attributed to the creation of water-conducting macropores by the maize roots. The VGM model adequately described the water retention curve (WRC) for these soils, but not the hydraulic conductivity (K) vs tension (h) curve. The ROSETTA function failed in the estimation of these parameters. In summary, mean values of K0 ranged from 0.74 to 3.88 cm h-1. In studies on NT effects on soil physical properties, the crop effect must be considered.

Pore-morphology-based simulations of drainage and wetting processes in porous media

Hydrology Research ◽

10.2166/nh.2011.058 ◽

2011 ◽

Vol 42 (2-3) ◽

pp. 128-149 ◽

Cited By ~ 3

Author(s):

T. P. Chan ◽

Rao S. Govindaraju

Keyword(s):

Porous Media ◽

Hydraulic Properties ◽

Pore Space ◽

Water Pressure ◽

Theoretical Models ◽

Hysteretic Behavior ◽

Water Retention Curve ◽

Pore Morphology ◽

Soil hydraulic properties relating saturation, water pressure, and hydraulic conductivity are known to exhibit hysteresis. In this paper, we focus on the determination of the water retention curve for a porous medium through a novel pore-scale simulation technique that is based on mathematical morphology. We develop an algorithm that allows for the representation of three-dimensional randomly packed porous media of any geometry (i.e. not restricted to idealized geometries such as spherical or ellipsoidal particles/pore space) so that the connectivity-, tortuosity-, and hysteresis-causing mechanisms are represented in both drainage and wetting processes, and their role in determining macroscopic fluid behavior is made explicit. Using this method, we present simulation results that demonstrate hysteretic behavior of wetting and non-wetting phases during both drainage and wetting cycles. A new method for computing interfacial surface areas is developed. The pore-morphology-based method is critically evaluated for accuracy, sample size effects, and resolution effects. It is found that the method computes interfacial areas more accurately than existing methods and allows for (i) examination of relationships between water pressure, saturation and interfacial area for hysteretic soils, and (ii) comparisons with previously developed theoretical models of soil hydraulic properties. The pore-morphology-based method shows promise for applications in vadose zone hydrology.