scholarly journals Comparison of different estimation procedures for the hydraulic properties of horticultural substrates by One-Step technique

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Carlo Bibbiani ◽  
Carlo A. Campiotti ◽  
Luca Incrocci ◽  
Alberto Pardossi
Keyword(s):  
Hydraulic Conductivity ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Water Retention Curve ◽  
Step Method ◽  
Retention Curve ◽  
Van Genuchten Model ◽  
One Step ◽  
Conductivity Function ◽  
The One

The improved iterative method for the simultaneous determination of the hydraulic properties of growing media from One-Step experiment by Bibbiani, is performed and compared with simplified equations by Valiantzas and Londra. Brooks and Corey equation for water retention, and Kozeny power equation for hydraulic conductivity characterized the hydraulic properties of the porous media. The iterative procedure is applied on pure peat, pumice, and their mixes. The One- Step method has been previously optimized: processing the mean cumulative outflow curves recorded versus time, an estimation of diffusivity, and therefore of the hydraulic functions, is derived. Estimated water retention curve is compared with nine experimental data, and with the estimation of the Van Genuchten model, via the RETC code. Bibbiani’s and Van Genuchten’s models overlap except for the “very wet” range near saturation, whereas the Valiantzas and Londra’s procedure didn’t get satisfactory results. In regard to diffusivity, a good similarity between Bibbiani’s and Van Genuchten-Mualem’s curves can be assessed, while Valiantzas and Londra’s procedure generally results in higher values. Due to the lack of estimation of the water retention curve, Valiantzas and Londra’s procedure fails to estimate the hydraulic conductivity function, whereas Bibbiani’s and Van Genuchten-Mualem’s curves match together in most cases.

scholarly journals Determination of the water diffusivity of horticultural substrates: comparison of different approaches for the one-step outflow data analysis

2014 ◽  
Vol 44 (4) ◽  
pp. 160
Author(s):  
Carlo Bibbiani ◽  
Carlo A. Campiotti ◽  
Luca Incrocci ◽  
Alberto Pardossi
Keyword(s):  
Hydraulic Conductivity ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Pressure Head ◽  
Water Retention Curve ◽  
Water Diffusivity ◽  
One Step ◽  
Set Up ◽  
The One

The improved iterative method for the simultaneous determination of the hydraulic properties of growing media from one-step experiment by Bibbiani, was performed on pure peat, pure pumice, and peat/pumice (1peat:1pumice by volume) mix, and compared with simplified equations by Valiantzas and Londra, who set up a new two-point method for calculating the water diffusivity, and with Van Genuchten- Mualem model. Brooks and Corey equations for water retention and hydraulic conductivity characterized the hydraulic properties of the porous media in relation to the iterative procedure. In the present work, the estimated water retention curves are compared with nine experimental data, and with the estimation of the Van Genuchten- Mualem model, via the RETC code, taking into account retention and diffusivity data. Bibbiani’s and Van Genuchten-Mualem’s estimations overlap except for the very wet range near saturation (R<sup>2</sup> equals to 0.9997, 0.9999, 0.9998 for pure pumice, 1peat:1pumice mix, and pure peat respectively, for Bibbiani’s estimation; R<sup>2</sup> equals to 0.9923, 0.9541, 0.9993 for pure pumice, 1peat:1pumice mix, and pure peat respectively, for Van Genuchten-Mualem’s estimation), whereas the Valiantzas and Londra’s procedure didn’t get satisfactory results, apparently because of different requirements related to the final pressure head applied in one-step experiment. In regard to diffusivity, a good similarity between Bibbiani’s and Van Genuchten-Mualem’s curves can be assessed, being the mean ratio values of the D(θ) from Valiantzas equation divided by D(θ) from Bibbiani equation equal to 1.20, 1.10, and 1.31 for pure pumice, 1peat:1pumice mix, and pure peat respectively, while Valiantzas and Londra’s procedure generally results in higher values. Due to the lack of estimation of the water retention curve, Valiantzas and Londra’s procedure fails to estimate the hydraulic conductivity function, whereas Bibbiani’s and Van Genuchten-Mualem’s curves match together in most cases.

scholarly journals Determining hydraulic properties of concrete and mortar by inverse modelling

2012 ◽  
Vol 1475 ◽  
Author(s):  
Sébastien Schneider ◽  
Dirk Mallants ◽  
Diederik Jacques
Keyword(s):  
Hydraulic Conductivity ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Inverse Modelling ◽  
Degree Of Saturation ◽  
Water Retention Curve ◽  
Retention Data ◽  
Capillary Suction ◽  
Near Surface ◽  
Van Genuchten Model

ABSTRACTThis paper presents a methodology and results on estimating hydraulic properties of the concrete and mortar considered for the near surface disposal facility in Dessel, Belgium, currently in development by ONDRAF/NIRAS. In a first part, we estimated the van parameters for the water retention curve for concrete and mortar obtained by calibration (i.e. inverse modelling) of the van Genuchten model [1] to experimental water retention data [2]. Data consisted of the degree of saturation measured at different values of relative humidity. In the second part, water retention data and data from a capillary suction experiment on concrete and mortar cores was used jointly to successfully determine the van Genuchten retention parameters and the Mualem hydraulic conductivity parameters (including saturated hydraulic conductivity) by inverse modelling.

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

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

&lt;p&gt;Testing new experimental procedures to assess the effects of the drops impact on the soil sealing formation is a main topic in soil hydrology.&lt;/p&gt;&lt;p&gt;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.&lt;/p&gt;&lt;p&gt;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, h&lt;sub&gt;g&lt;/sub&gt;, 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, K&lt;sub&gt;s&lt;/sub&gt;, 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.&lt;/p&gt;&lt;p&gt;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.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Acknowledgments&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;The work was supported by the project &amp;#8220;STRATEGA, Sperimentazione e TRAsferimento di TEcniche innovative di aGricoltura conservativA&amp;#8221;, funded by Regione Puglia&amp;#8211;Dipartimento Agricoltura, Sviluppo Rurale ed Ambientale, CUP: B36J14001230007.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;&amp;#160;&lt;/strong&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Bagarello, 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&amp;#8211;501. https://doi.org/10.1016/j.geoderma.2013.08.032&lt;/p&gt;

scholarly journals Effect of Chia Seed Mucilage on the Rhizosphere Hydraulic Characteristics

2021 ◽  
Vol 13 (6) ◽  
pp. 3303
Author(s):  
Faisal Hayat ◽  
Mohanned Abdalla ◽  
Muhammad Usman Munir
Keyword(s):  
Hydraulic Conductivity ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Numerical Models ◽  
Chemical Properties ◽  
Water Retention Curve ◽  
Soil Drying ◽  
Retention Curve ◽  
Unsaturated Hydraulic Conductivity ◽  
Chia Seed

The rhizosphere is one of the major components in the soil–plant–atmosphere continuum which controls the flow of water from the soil into roots. Plant roots release mucilage in the rhizosphere which is capable of altering the physio-chemical properties of this region. Here, we showed how mucilage impacted on rhizosphere hydraulic properties, using simple experiments. An artificial rhizosphere, treated or not with mucilage, was placed in a soil sample and suction was applied to mimic the negative pressure in plant xylem. The measured water contents and matric potential were coupled with numerical models to estimate the water retention curve and hydraulic conductivity. A slower loss of water was observed in the treated scenario which resulted in an increase in water retention. Moreover, a slightly lower hydraulic conductivity was initially observed in the treated scenario (8.44 × 10−4 cm s−1) compared to the controlled one in saturated soil. Over soil drying, a relatively higher unsaturated hydraulic conductivity was observed. In summary, we demonstrated that mucilage altered the rhizosphere hydraulic properties and enhanced the unsaturated hydraulic conductivity. These findings improve our understanding of how plants capture more water, and postulate that mucilage secretion could be an optimal trait for plant survival during soil drying.

scholarly journals How does PTF Interpret Soil Heterogeneity? A Stochastic Approach Applied to a Case Study on Maize in Northern Italy

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 275 ◽  
Author(s):  
Angelo Basile ◽  
Antonello Bonfante ◽  
Antonio Coppola ◽  
Roberto De Mascellis ◽  
Salvatore Falanga Bolognesi ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Spatial Variability ◽  
Soil Water ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Pedotransfer Functions ◽  
Water Retention Curve ◽  
Real Field ◽  
Retention Curve

Soil water balance on a local scale is generally achieved by applying the classical nonlinear Richards equation that requires hydraulic properties, namely, water retention and hydraulic conductivity functions, to be known. Its application in agricultural systems on field or larger scales involves three major problems being solved, related to (i) the assessment of spatial variability of soil hydraulic properties, (ii) accounting for this spatial variability in modelling large-scale soil water flow, and (iii) measuring the effects of such variability on real field variables (e.g., soil water storage, biomass, etc.). To deal with the first issue, soil hydraulic characterization is frequently performed by using the so-called pedotransfer functions (PTFs), whose effectiveness in providing the actual information on spatial variability has been questioned. With regard to the second problem, the variability of hydraulic properties at the field scale has often been dealt with using a relatively simple approach of considering soils in the field as an ensemble of parallel and statistically independent tubes, assuming only vertical flow. This approach in dealing with spatial variability has been popular in the framework of a Monte Carlo technique. As for the last issue, remote sensing seems to be the only viable solution to verify the pattern of variability, going by several modelling outputs which have considered the soil spatial variability. Based on these premises, the goals of this work concerning the issues discussed above are the following: (1) analyzing the sensitivity of a Richards-based model to the measured variability of θ(h) and k(θ) parameters; (2) establishing the predictive capability of PTF in terms of a simple comparison with measured data; and (3) establishing the effectiveness of use of PTF by employing as data quality control an independent and spatially distributed estimation of the Above Ground Biomass (AGB). The study area of approximately 2000 hectares mainly devoted to maize forage cultivation is located in the Po plain (Lodi), in northern Italy. Sample sites throughout the study area were identified for hydropedological analysis (texture, bulk density, organic matter content, and other chemical properties on all the samples, and water retention curve and saturated hydraulic conductivity on a sub-set). Several pedotransfer functions were tested; the PTF‒Vereckeen proved to be the best one to derive hydraulic properties of the entire soil database. The Monte Carlo approach was used to analyze model sensitivity to two measured input parameters: the slope of water retention curve (n) and the saturated hydraulic conductivity (k0). The analysis showed sensitivity of the simulated process to the parameter n being significantly higher than to k0, although the former was much less variable. The PTFs showed a smoothing effect of the output variability, even though they were previously validated on a set of measured data. Interesting positive and significant correlations were found between the n parameter, from measured water retention curves, and the NDVI (Normalized Difference Vegetation Index), when using multi-temporal (2004–2018) high resolution remotely sensed data on maize cultivation. No correlation was detected when the n parameter derived from PTF was used. These results from our case study mainly suggest that: (i) despite the good performance of PTFs calculated via error indexes, their use in the simulation of hydrological processes should be carefully evaluated for real field-scale applications; and (ii) the NDVI index may be used successfully as a proxy to evaluate PTF reliability in the field.

scholarly journals Water retention curve and hydraulic conductivity function of highly compressible materials

2007 ◽  
Vol 44 (10) ◽  
pp. 1200-1214 ◽  
Author(s):  
Serge-Étienne Parent ◽  
Alexandre Cabral ◽  
Jorge G. Zornberg
Keyword(s):  
Hydraulic Conductivity ◽  
Water Retention ◽  
Void Ratio ◽  
Silty Sand ◽  
Water Retention Curve ◽  
Volume Changes ◽  
Retention Curve ◽  
Conductivity Function ◽  
K Function ◽  
Compressible Materials

A model capable of describing the suction-induced consolidation curve (void ratio function) and water retention curve (WRC) of highly compressible materials (HCM) is developed, validated, and finally applied to describe the WRC of deinking by-products (DBP). DBP are a highly compressible by-product of paper recycling used in geoenvironmental applications. Validation is conducted by modelling the WRC and the void ratio function for a well documented silty sand from Saskatchewan, Canada. The WRC and void ratio function were used to predict its hydraulic conductivity function (k-function). The water content, suction, and volumetric deformation data of DBP are obtained using an experimental technique that allows determination of the WRCs of HCMs that is suitable for prediction of the DBP k-function. The results show that volumetric water contents are underestimated if volume changes are not accounted for, leading to inaccuracies in the WRCs, thus inaccurately predicted k-functions. It is shown that the newly developed model is better suited for HCMs than currently available models, in particular for HCMs that continue to undergo significant volume changes when the applied suction exceeds the air-entry value.

Determination of the Soil-Water Retention Curve and the Hydraulic Conductivity Function Using a Small Centrifuge

2011 ◽  
Vol 34 (5) ◽  
pp. 103590
Author(s):  
L. D. Suits ◽  
T. C. Sheahan ◽  
Rodrigo Martins Reis ◽  
Wagner Nogueira Sterck ◽  
Artur Bastos Ribeiro ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Water ◽  
Water Retention ◽  
Water Retention Curve ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Retention Curve ◽  
Conductivity Function

scholarly journals Water retention and transfer properties of a Green roof volcanic substrate

2020 ◽  
Vol 195 ◽  
pp. 03011
Author(s):  
Filip Stanic ◽  
Pierre Delage ◽  
Yu Jun CUI ◽  
Emmanuel DE LAURE
Keyword(s):  
Hydraulic Conductivity ◽  
Water Retention ◽  
Green Roof ◽  
Water Retention Curve ◽  
Retention Curve ◽  
Column System ◽  
Paris Area ◽  
Conductivity Function ◽  
Transfer Properties

The water retention curve and the hydraulic conductivity function of a volcanic coarse granular material used as a substrate in an urban green roof in the Paris area was carried out on a newly developed device, in which low suctions were controlled. In the same cell, a hanging column system was used for controlling smaller suctions (up to 32 kPa) and the axis translation technique for larger suctions (up to 50 kPa). Water exchanges were monitored in connected tubes by using a high accuracy differential pressure transducer. The step changes in suction were also used to determine the hydraulic conductivity function by means of Gardner’s method, accounting for the impedance effects due to the high air entry value ceramic porous disk with Kunze and Kirkham’s method. van Genuchten and Brooks and Corey models were used for the water retention curve, but the hydraulic conductivity functions derived from these expressions appeared to lead to a significant under-estimation, confirming the need of operational and simple device for the experimental determination of the hydraulic conductivity function.

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