scholarly journals Evaluation of sand-clay-anionic polyacrylamide blends for alternative compacted clay landfill liner design

2021 ◽  
Vol 337 ◽  
pp. 04002
Author(s):  
Mauro Codevilla ◽  
Camilo Casagrande ◽  
Marcos Montoro ◽  
Sandra Orlandi ◽  
Teresa Piqué ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Water Retention ◽  
Mechanical Performance ◽  
Clayey Soil ◽  
Swelling Behavior ◽  
Water Retention Capacity ◽  
Soil Water Retention ◽  
Retention Capacity ◽  
Unsaturated Hydraulic Conductivity ◽  
Anionic Polyacrylamide

In this project, an innovative low hydraulic conductivity material for landfill cover and liner construction was studied. The material is a blend of natural clayey soil from Comodoro Rivadavia city (Chubut province, Argentina) mixed with fine uniform sand and anionic polyacrylamide (APAM). The research emphasizes understanding the influence of APAM addition on the soil water retention capacity (SWRC), unsaturated hydraulic conductivity, and swelling behavior. APAM is a super absorbent polymer that swells when immersed in water. SWRC was evaluated through the filter paper method. The unsaturated hydraulic conductivity and swelling behavior were determined using two fluids: distilled water and brine (C = 2 M). Results showed that APAM addition reduced the blends' microporosity, increased the water retention capacity, and reduced the hydraulic conductivity of the system. These promising results encourage further research on these blends' behavior to determine the most efficient blend formulation to enhance its hydro-mechanical performance and its chemical compatibility with landfill leachates for cover and low hydraulic conductivity liner layer construction.

scholarly journals Use of Soil Water Retention Capacity and Hydraulic Conductivity Estimation in the Preparation of Soil Water Management Maps

2006 ◽  
Vol 55 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Brigitta Tóth ◽  
A. Makó ◽  
K. Rajkai ◽  
G. Sz. Kele ◽  
T. Hermann ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Water ◽  
Water Retention ◽  
Estimation Method ◽  
Mapping Method ◽  
Estimation Methods ◽  
Water Retention Capacity ◽  
Soil Water Retention ◽  
Retention Capacity ◽  
Estimation Efficiency

According to the Hungarian Soil Information and Monitoring System's (HSIMS) database a group estimation method was developed to predict the mean soil hydrophysical properties. The estimation efficiency of the worked out prediction procedures was controlled on a test database, and on a dataset of a study area. It can be established that the water retention and the hydraulic conductivity of soils are sufficiently predictable from the category data of soil maps. The 10-digit map codes of the PWW mapping method were created by different estimation methods, and as a result the PWW map was drawn. However, it is not always possible to estimate the necessary soil hydrophysical properties from the available map information for preparing the PWW map. Sometimes the knowledge gained from the field reports is needed as well. Further studies are planned for integrating these morphological information into our estimations.

scholarly journals A numerical study on the effect of salinity on stability of an unsaturated railway embankment under rainfall

2020 ◽  
Vol 195 ◽  
pp. 01004
Author(s):  
Ali Kolahdooz ◽  
Hamed Sadeghi ◽  
Mohammad Mehdi Ahmadi
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Water ◽  
Water Retention ◽  
Numerical Study ◽  
Water Retention Curve ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Unsaturated Hydraulic Conductivity ◽  
Influence Of Water ◽  
Dispersive Soils

Dispersive soils, as one of the main categories of problematic soils, can be found in some parts of the earth, such as the eastern-south of Iran, nearby the Gulf of Oman. One of the most important factors enhancing the dispersive potential is the existence of dissolved salts in the soil water. The main objective of this study is to explore the influence of water salinity on the instability of a railway embankment due to rainfall infiltration. In order to achieve this goal, the embankment resting on a dispersive stratum is numerically modeled and subjected to transient infiltration flow. The effect of dispersion is simplified through variations in the soil-water retention curve with salinity. The measured water retention curves revealed that by omitting the natural salinity in the soil-water, the retention capability of the soil decreases; therefore, the unsaturated hydraulic conductivity of the soil stratum will significantly decline. According to the extensive decrease in the hydraulic conductivity of the desalinated materials, the rainfall cannot infiltrate in the embankment and the rainfall mostly runs off. However, in the saline embankment, the infiltration decreases the soil suction; and consequently, the factor of safety of the railway embankment decreases.

scholarly journals Modeling the hydrophysical soil properties and comparative analysis for three systems of functions

2020 ◽  
Vol 175 ◽  
pp. 09016
Author(s):  
Vitaly Terleev ◽  
Roman Ginevsky ◽  
Viktor Lazarev ◽  
Aleksandr Nikonorov ◽  
Alexander Topaj ◽  
...  
Keyword(s):  
Porous Medium ◽  
Soil Moisture ◽  
Comparative Analysis ◽  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Water Retention ◽  
Field Measurements ◽  
Practical Significance ◽  
Water Retention Capacity ◽  
Retention Capacity

A functional description of the hydrophysical properties of the soil as a capillary-porous medium is presented. The described functions of water retention capacity and hydraulic conductivity of the soil have common parameters, which are interpreted within the framework of physical and statistical concepts. The practical significance of the proposed functions lies in the fact that the volume of labor-intensive field measurements necessary, for example, for modeling the dynamics of soil moisture, is significantly reduced. To identify the parameters of these functions, it is sufficient to use data only on the water retention capacity of the soil. The parameters identified in this way can be used to predict the ratio of the hydraulic conductivity of the soil to the moisture filtration coefficient. The presented system of the hydrophysical functions of the soil is compared with world analogues using literature data on soils of different texture.

scholarly journals Use of organic fertilization with irrigation in coffee production in brazilian cerrado

2020 ◽  
Vol 15 (5) ◽  
pp. 1
Author(s):  
André Luís Teixeira Fernandes ◽  
Eusímio Felisbino Fraga Júnior ◽  
Márcio José de Santana ◽  
Reginaldo De Oliveira Silva ◽  
Marcelo Moreira Dias
Keyword(s):  
Water Retention ◽  
Chicken Manure ◽  
Water Retention Capacity ◽  
Brazilian Cerrado ◽  
Soil Water Retention ◽  
Organic Fertilization ◽  
Retention Capacity ◽  
Yield And Quality ◽  
Productive Development

Coffee irrigation has increased in the main Brazilian coffee regions. However, in recent years, with climate change, years with water deficits greater than 150 mm have been observed, affecting the vegetative and productive development of the crop and also the replenishment of surface and underground springs. One practice that increases soil water retention capacity is organic fertilization. This work evaluated different combinations of irrigation and organic fertilization on the yield and quality of coffee produced in the Minas Gerais cerrado region. The treatments were: T1: total irrigation; T2: no irrigation; T3: total irrigation + organic fertilization (chicken manure, 10 ton ha-1); T4: no irrigation + organic fertilization (chicken manure, 10 ton ha-1); T5: 50% irrigation + organic fertilization (chicken manure, 10 ton ha-1). After 7 harvests, it was concluded that the treatment that combined organic fertilization with application of half of the necessary irrigation presented the best yield, superior to the treatment with total irrigation and exclusively mineral nutrition.

scholarly journals How and why does willow biochar increase a clay soil water retention capacity?

2018 ◽  
Vol 119 ◽  
pp. 346-353 ◽  
Author(s):  
Kimmo Rasa ◽  
Jaakko Heikkinen ◽  
Markus Hannula ◽  
Kai Arstila ◽  
Sampo Kulju ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Clay Soil ◽  
Water Retention Capacity ◽  
Soil Water Retention ◽  
Retention Capacity

Enhanced Mualem-Van Genuchten Approach for Estimating Relative Soil Hydraulic Conductivity

2015 ◽  
Vol 725-726 ◽  
pp. 355-360 ◽  
Author(s):  
Vitaly Terleev ◽  
Vladimir Badenko ◽  
Inna Guseva ◽  
Wilfried Mirschel
Keyword(s):  
Hydraulic Conductivity ◽  
Water Retention ◽  
Soil Characteristics ◽  
Water Volume ◽  
Water Retention Capacity ◽  
Moisture Capacity ◽  
Theoretical Justification ◽  
Retention Capacity ◽  
Relative Water ◽  
Relative Hydraulic Conductivity

New theoretical justification for the function of soil differential moisture capacity (dependence of the relative water volume content on the capillary pressure) and its antiderivative is presented. New method is based on the concept of capillarity and the lognormal distribution of the effective radii of pores. Relative hydraulic conductivity of soil is calculated with usage of these functions and Mualem's approach. Hydrophysical parameters have been interpreted and evaluated on the base of some physical and statistical soil characteristics. Also the approximation for functions of water-retention capacity and relative hydraulic conductivity of soil has been proposed.

scholarly journals Material Characteristics, Hydraulic Properties, and Water Travel Time through the Heterogeneous Vadose Zone of a Cenozoic Limestone Aquifer (Beauce, France)

2020 ◽  
Author(s):  
Arnaud Isch ◽  
Carlos Aldana ◽  
Yves Coquet ◽  
Mohamed Azaroual
Keyword(s):  
Hydraulic Conductivity ◽  
Water Flow ◽  
Vadose Zone ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Limestone Aquifer ◽  
Limestone Rock ◽  
Hydrus 1D

<p>Water retention and hydraulic conductivity are the most important properties governing water flow and solute transport in unsaturated porous media. However, transport processes in the vadose zone (VZ) are still not completely understood, in spite of their importance for the preservation and management of aquifers, especially in the geographic zones under intensive agriculture. This study has been carried out as part of the construction of the O-ZNS platform (Observatory of transfers in the vadose zone). This platform aims to integrate observations over a wide range of spatial and temporal scales thanks to a large access well (depth–20 m & diameter–4m) surrounded by several boreholes in order to combine broad characterization and focused monitoring techniques.</p><p>Three cored boreholes have been drilled in Spring 2017. Structural and mineralogical analyses were carried out for four types of materials sampled throughout the entire VZ profile (20 m depth) including soft sediments (soil, marl and sand) and fractured limestone rock. Hydraulic properties (q(h) and K(h)) were measured on representative core samples by means of a triaxial system used by applying the multistep outflow method. Simulations were then made using HYDRUS-1D to simulate water flow and bromide (conservative tracer) transport over 50 years using meteorological and water table level data.</p><p>The results brought valuable information about factors contributing to the heterogeneity of hydraulic properties within the VZ. For the applied matric heads (from 0 to -1000 cm), the water content and hydraulic conductivity of (i) the soft materials (9 samples) ranged from 0.173 to 0.485 cm<sup>3</sup>/cm<sup>3</sup> and from 1.26.10<sup>-5</sup> to 2.41 cm/d, respectively ; (ii) the hard materials (5 samples) ranged from 0.063 to 0.340 cm<sup>3</sup>/cm<sup>3</sup> and from 8.54.10<sup>-5</sup> to 1.82 cm/d, respectively. The shape of the water retention and hydraulic conductivity curves obtained for the soft sediments is strongly related to the physical properties of the material but also to the proportion and the nature of clay minerals. The soil material displayed the largest average water retention capacity due to the presence of smectite and kaolinite, indicating weathering and matrix transformation. The water retention capacity of the marl and sand materials was lower due to higher content in palygorskyte and calcite. The limestone rock materials displayed an important heterogeneity in their hydraulic properties. Mineralogical analysis helped understanding water flow pathways within the limestone aquifer. The non-altered matrix, that seemed impermeable at first sight, presented few thin microfractures where water probably accumulates. The altered matrix showed microfractures where water has circulated and calcite has been replaced by phyllosilicates, thus increasing the water retention capacity. Natura macrofractures observed at dm-scale showed the presence of iron oxides which highlighted an exposure to high water flow. Simulations made using HYDRUS-1D allowed a first estimation of water and solutes travel time through this highly heterogeneous vadose zone. The results highlighted transfer time of between 25 to 35 years for the bromide to reach water table. The differences observed between the three cored boreholes were mainly due to the heterogeneity of the marl materials located between 1 and 7 m deep.</p>

scholarly journals Effects of soil temperature and moisture on biological nitrogen fixation in soybean crop

2019 ◽  
pp. 1327-1334
Author(s):  
Evandro Ademir Deak ◽  
Thomas Newton Martin ◽  
Glauber Monçon Fipke ◽  
Jessica Deolinda Leivas Stecca ◽  
Luciane Almeri Tabaldi ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Root System ◽  
Azospirillum Brasilense ◽  
Water Retention ◽  
Nodule Formation ◽  
Water Retention Capacity ◽  
Soil Water Retention ◽  
Retention Capacity ◽  
Soybean Crop ◽  
Temperature And Humidity

Soil temperature and humidity are the chief determinants for good nodule formation at the time of sowing and emergence. The aim of this study was to estimate the soil temperature and humidity range, at which the Bradyrhizobium spp., and Azospirillum brasilense may have the highest effect on root enhancement and development of nodulation in soybean. Two experiments were conducted, the first of which was done in the seed laboratory performing the treatments listed as non-inoculated; inoculation with Bradyrhizobium; root enhancers; inoculation with Bradyrhizobium + root enhancers; co-inoculation with Bradyrhizobium + Azospirillum brasilense; co-inoculation with Bradyrhizobium + Azospirillum brasilense + root enhancers, and assessed at temperatures of 15, 20, 25, 30 and 35ºC. The experimental design was completely randomized with distribution in a factorial. The second experiment was executed in a greenhouse, employing the same treatments affected in the seed laboratory experiment, but with the addition of non-inoculated control with mineral nitrogen. Tests were done at the soil moisture levels of 25, 50, 75 and 100% water retention capacity, forming a factorial 7 x 4 (only second experiment). All co-inoculated treatments induced the soybean root system to improve, in terms of length, volume, surface area and root diameter, exhibiting superiority to the uninoculated control in the 20 to 30ºC temperature range. The co-inoculation raised nodulation in the soybean crop, when soil water retention capacity was at the range of 56 - 96%, achieving higher means compared to the standard inoculation. The root planter added no improvement to either the root system or nodulation in soybean.

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