Impact of changes in land-use management on soil hydraulic properties: hydraulic conductivity, water repellency and water retention

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.

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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 ◽

Soil Hydraulic Properties ◽

Retention Curve ◽

Soil Sealing ◽

Loam Soil ◽

Soil Hydraulic

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

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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 Hydraulic Properties ◽

Soil Water Retention ◽

Soil Hydraulic

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.

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Analysis of Hydraulic Properties of Indian Forest Soil

Journal of Civil Engineering and Construction ◽

10.32732/jcec.2018.7.1.12 ◽

2018 ◽

Vol 7 (1) ◽

pp. 12

Author(s):

Shwetha Prasanna

Keyword(s):

Hydraulic Conductivity ◽

Spatial Variability ◽

Soil Properties ◽

Forest Soil ◽

Hydraulic Properties ◽

Water Retention ◽

Saturated Hydraulic Conductivity ◽

Soil Hydraulic Properties ◽

Soil Hydraulic ◽

High Degree

Soils are a product of the factors of formation and continuously change over the earth’s surface. The analysis of the spatial variability of soil properties is important for land management and construction of an ecological environment. Soils are characterized by high degree of spatial variability due to the combined effect of physical, chemical or biological processes that operate with different intensities and at different scales. The spatial variability of soil hydraulic properties helps us to find the subsurface flux of water. The most frequently used hydraulic properties are soil water retention curve and saturated hydraulic conductivity. Both these hydraulic properties exhibit a high degree of spatial and temporal variability. The primary objective of this study was to analyze the spatial variability of hydraulic properties of forest soils of Pavanje river basin. Correlation analysis technique has been used to analyze various soil properties. Spatial variability of the forested hillslope soils at different depths varied considerably among the soil hydraulic properties. The spatial variability of water retention at all the different pressure head is low at the top layers, and increases towards the bottom layers. The saturated hydraulic conductivity is almost same in the top layers, but more in the bottom layers of forest soil.

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Estimating soil hydraulic properties from saturation to complete dryness

10.5194/egusphere-egu21-10481 ◽

2021 ◽

Author(s):

Budiman Minasny ◽

Rudiyanto Rudiyanto ◽

Federico Maggi

Keyword(s):

Soil Moisture ◽

Hydraulic Conductivity ◽

Soil Water ◽

Hydraulic Properties ◽

Water Retention ◽

Pedotransfer Functions ◽

Soil Hydraulic Properties ◽

Soil Moisture Dynamics ◽

Soil Hydraulic ◽

Moisture Dynamics

To study the effect of drought on soil water dynamics, we need an accurate description of water retention and hydraulic conductivity from saturation to complete dryness. Recent studies have demonstrated the inaccuracy of conventional soil hydraulic models, especially in the dry end. Likewise, current pedotransfer functions (PTFs) for soil hydraulic properties are based on the classical Mualem-van Genuchten functions.This study will evaluate models that estimate soil water retention and unsaturated hydraulic conductivity curves in full soil moisture ranges. An example is the Fredlund-Xing scaling model coupled with the hydraulic conductivity model of Wang et al. We will develop pedotransfer functions that can estimate parameters of the model. We will compare it with existing PTFs in predicting water retention and hydraulic conductivity.The results show that a new suite of PTFs that used sand, silt, clay, and bulk density can be used successfully to predict water retention and hydraulic conductivity over a range of moisture content. The prediction of hydraulic properties is used in a soil water flow model to simulate soil moisture dynamics under drought. This study demonstrates the importance of accurate hydraulic model prediction for a better description of soil moisture dynamics.&#160;

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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 Hydraulic Properties ◽

Soil Water Retention ◽

Soil Hydraulic Conductivity ◽

Soil Hydraulic

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.

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Comparison of the Instantaneous Profile Method and inverse modelling for the prediction of effective soil hydraulic properties

Soil Research ◽

10.1071/sr04151 ◽

2005 ◽

Vol 43 (5) ◽

pp. 599 ◽

Cited By ~ 4

Author(s):

Oagile Dikinya

Keyword(s):

Hydraulic Conductivity ◽

Water Content ◽

Sandy Soil ◽

Hydraulic Properties ◽

Water Retention ◽

Pressure Head ◽

Inverse Modelling ◽

Soil Hydraulic Properties ◽

Loamy Soil ◽

Soil Hydraulic

Soil hydraulic conductivity K(θ) and soil water retention θ(h) have been determined from a drainage experiment. Two lysimeters, one filled with a sandy soil and the other with a loamy soil, were set up for a 1-dimensional transient flow experiment. The data were collected after flooding the lysimeters with water. Soil water contents were measured by time domain reflectrometry (TDR) and pressure heads were measured by tensiometers with mercury manometers. The experimental data determined by the instantaneous profile method (IPM) were compared with the results obtained by inverse modelling. The inverse modelling proved to be superior to the IPM methodology in effective prediction of hydraulic properties. The measurable properties water content and pressure head were optimised for the following datasets: water content (WC), pressure head (P-h), and a combination of WC and P-h. For both soils the optimisation of the dataset with both WC and P-h resulted in parameters that corresponded closely to the soil hydraulic data generated by the IPM method. The correspondence for the water retention data was better than for the hydraulic conductivity data. The datasets with WC only or P-h only did not contain enough information to accurately estimate the soil hydraulic properties. In most cases the results indicated that the sandy soil gave better agreement than the loamy soil. This was attributed to the faster drainage of the sandy than the loamy soil.

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Seasonal changes of hydraulic properties of a Chromic Luvisol under different soil management

Biologia ◽

10.2478/s11756-006-0186-6 ◽

2006 ◽

Vol 61 (19) ◽

Cited By ~ 10

Author(s):

Csilla Farkas ◽

Csaba Gyuricza ◽

Márta Birkás

Keyword(s):

Hydraulic Conductivity ◽

Soil Water ◽

Hydraulic Properties ◽

Water Retention ◽

Vegetation Period ◽

Saturated Hydraulic Conductivity ◽

Soil Hydraulic Properties ◽

Soil Water Retention ◽

Tillage Systems ◽

Soil Hydraulic

AbstractIn the present work the effect of five tillage methods on the hydraulic properties and water regime of a brown forest soil was studied. In each treatment, measurements of bulk density and soil water retention characteristics were carried out 3 times (March, June and August) within the vegetation period. Near-saturated hydraulic conductivity and soil water content measurements were performed five and eight times, respectively. Statistically valuable differences were obtained between the soil properties, measured in different tillage treatments. The effect of the tillage treatments on the water retention curves was significant in the low suction range (pF < 2.0) only. Differences between the soil water retention curves, measured at the end of the vegetation period reflected the indirect effect of different tillage systems on soil hydraulic properties. The seasonal variability of both the soil hydraulic functions was proofed. Saturated hydraulic conductivity values, evaluated in the ploughing treatment at the beginning and end of the vegetation period differed up to 4-times. The near-saturated hydraulic conductivity values measured in March were nearly two times higher in all the treatments, except no till, than those, measured in August. The applied tillage systems did not influence the potential amount of water available for the plant; still, valuable differences between the soil water contents were measured. According to the soil hydraulic properties and measured soil water regime, ploughing and deep loosening created the most favourable soil conditions for the plants. The biological activity, however, was the highest in the no till treatment. Further studies on the application of the soil conserving tillage systems under Hungarian conditions are recommended.

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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 ◽

Soil Hydraulic Properties ◽

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;

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