Soil Testing Laboratories Research Articles

Settlement control investigation of high fill subgrade in karst section with tunnel slag filling

In this paper, based on the Kaihua section of the G205 (China) national highway reconstruction project, the construction area of the K4+550-K4+940 section was chosen to conduct settlement control research on the high-fill roadbed of the karst section within the construction area. The viability of using clayey gravel and tunnel slag as roadbed fill was evaluated through laboratory soil tests. The construction technology of grouting is used to manage the substructure of the karst section. After installing pre-stress anchors on the top of the foundation, a “layered” filling scheme was utilized to fill the tunnel slag and clayey gravel. The FLAC3D simulation software contrasted the deformation curves of key nodes on unanchored and anchored roadbeds. The test results indicate that the California Bearing Ratio test (CBR) test satisfies the requirements of the specification and that the uniaxial compression strength of the tunnel slag satisfies the requirements of the specification when the clayey gravel is near the optimal moisture content and dry density, and when the compaction is controlled to within 94%. The use of pre-stress anchors can strengthen the foundation’s rock and soil layers, and reduce the plastic zone’s distribution. This article provides a corresponding engineering experience for the treatment of high-fill roadbeds in karst areas.

Evaluation of Post Tension Runway Plate as Retrofitting Simulated with Compression In-Plane Force in Numerical Approach

The swelling of soil can result from fluctuations in its moisture content, causing it to expand and contract. To mitigate this, structures in direct contact with the soil may require retrofitting. Post-tensioning is one such method that can enhance the stiffness of the structure without altering its properties, thereby helping to prevent damage from expansive soil. This research presents a novel methodology for the design of retrofitting runway pavements using post-tension plates, employing a numerical approach that considers various influencing factors. The methodology integrates the use of differential and Kerr foundation equations, employing the Levy method to ascertain the deflection of the plate structure. Soil parameters are derived from soil sampling and laboratory tests, while loads are determined based on prior research findings and governmental regulations. The findings of the study indicate that the thickness of the plate structure influences its deflection, as greater thickness results in increased stiffness within the structure. Increasing the thickness of the plate enhances stiffness and diminishes deflection. Regarding the direction of post-tensioning, employing tension in both directions proves most effective, resulting in a reduction of deflection by 22.11%. However, this model demands higher costs compared to others due to the increased requirement for tendon post-tensioning. As an alternative, aligning the direction of post-tensioning with the direction of load movement can lead to a reduction of 15.14% in plate deflection, while incurring lower costs compared to applying post-tensioning in both directions.

Estimation of Soil Nutrients and Fertilizer Dosage Using Ion-Selective Electrodes for Efficient Soil Management

ABSTRACT The recent advancements in precision agriculture have led to a high demand for a portable and intelligent device capable of accurately measuring soil nutrients with reduced use of chemicals. Instead of relying on chemical-based laboratory tests, a smart portable device has been developed. The device measures soil nutrients, such as ammonium, calcium, potassium, nitrate, and chloride, and provides fertilizer dose recommendations. The device uses ion-selective electrodes, a microcontroller, multiplexer, operational amplifier, data logger, and input/output units. It reports soil health status to farmers or users via WhatsApp and e-mail. The measured soil nutrient values are uploaded to a database, which generates soil health cards and fertilizer dose recommendations. The device’s performance was compared to standard methods, with a correlation coefficient of 0.9906 for ammonium, 0.9949 for calcium, 0.9852 for potassium, 0.9716 for nitrate, and 0.9716 for calcium. The sensor-based soil nutrient analyzer demonstrated similar performance to other established standard methods when tested on 250 soil samples of agricultural fields. Consequently, this device holds great potential for utilization in soil testing laboratories as well as for on-site soil monitoring in agricultural fields, specifically for the purpose of precision farming.

Soil monitoring infrastructure in response to war

ABSTRACT Soil degradation is not the least impact of the Russian aggression. War degradation of soils includes compaction, erosion, biodiversity loss, contamination, physical destruction of soils etc. Explosions release harmful chemicals and metals that can persist in the environment affecting the quality of both soil and water resources; and fires at the site of burning military equipment impact soil. Assessment of soil to support soil management requires a well-functioning soil monitoring infrastructure which we describe in terms of: 1) legislative support, 2) soil testing laboratories, 3) a soil information system, and 4) finance. Gaps in Ukrainian legislation make effective soil monitoring impossible; there is need for decree to officially recognise military soil degradation and establish an effective monitoring. The main body of soil sampling and analysis can be carried out within the network of the State Institute “Institute of Soil Protection of Ukraine” but a publicly accessible soil database is needed to hold and transmit the updated information. Novadays funding is hard to come by; we would seek it firstly through cooperation with international donors. If these the times, visiting scientists who participate in the survey and assessment of battlefields will gain experience that finds widespread international application.

Experimental and Numerical Study of Soil Strata for Underground Transportation System: A Case Study

In the current capital of Yemen, Sana’a, a time-efficient and economical transportation system is one of the greatest challenges to overcome the increasing urbanization for many years. Rapid transport systems use tunnel structures to reach the city's most inaccessible areas. Given the Gulf's geopolitical unrest, these structures could also serve as emergency shelters. Consequently, this research conducted an experimental soil exploration investigation in Sana'a, Yemen, to identify potential tunneling sites for the city's rapid transit system. The field exploration, in-situ, and laboratory soil testing at the four locations were performed with the collaboration of the Ministry of Public Works & Highways, Yemen. Further, to calculate the geotechnical parameters for tunnel design, numerical analysis has been carried out using the finite element package ABAQUS, and two-dimensional plane-strain numerical models of underground tunnel structure have been developed to conduct the parametric study in different soil types and boundary conditions under static loading. The material behavior of soil strata has been incorporated into the well-known Mohr-Coulomb constitutive model. The field investigation found that the geotechnical properties of the soil strata in Sana’a have a lot of variation. The numerical study shows that the maximum deformation in the concrete liner of the tunnel was observed at the crown of the tunnel. The ovalling effect in tunnel concrete liner was also seen in all the tunnel models, and the maximum ground settlement at sites 1, 2, 3, and 4 was estimated to be approximately 4, 25, 17, and 11 mm, respectively. Doi: 10.28991/CEJ-2024-010-01-03 Full Text: PDF

The edaphic niche of ploidy-different grasses in the light of the coarse-grained data modeling and direct soil sampling

In the framework of polyploidization, a widely discussed issue is the possibility of niche shift. Numerous studies have investigated niche differentiation among cytotypes, with some confirming distinct differences, while others finding them to be similar. Within this research project, we focus on the case of the cytotypes (2x and 4x) of Festuca amethystina L. and the closely related F. tatrae (Czakó) Degen (2x). We hypothesize that a significant change in the edaphic niche of tetraploids could be a factor that enabled them to occupy new lowland areas inaccessible to diploids which are characteristic of mountain habitats.The edaphic niche differentiation between Festuca amethystina cytotypes was determined by studying the niches’ breadths using PCA-based modeling and separate analyses of particular soil features. The modeling was based on SoilGridsTMdata, and the conclusions were compared with the results of the direct soil studies. Such a research model makes it possible to determine to what extent the data coming from the mentioned database allows for the indication of niche differentiation.Coarse-grained modeling based on SoilGridsTM data indicated a significant change in the edaphic requirements of the tetraploids, as well as pointed to the niche shift towards a higher content of sand, lower carbon and nitrogen content, and lower pH. The direct soil sampling and laboratory tests confirmed these trends and provided a more detailed understanding of the cytotypes requirements. However, no statistically significant differences were observed between cytotypes concerning soil pH, the majority of base cations, available forms of phosphorus and potassium, and the results of CHN elemental analysis. While the direct soil sampling did not reveal significant differences, the analyses based on the niche modeling, considering a wide background area in Central Europe (using SoilGrids data), captured significant variations. This comprehensive approach allowed us to uncover a highly logical pattern of niche shift, which indicates that tetraploids are predisposed to extend their geographical range to post-glacial lowland areas.Additionally, Festuca amethystina tetraploids display a wider edaphic niche breadth than their closely related and hypothetical ancestor Festuca tatrae. The decision to include the latter reduced the probability that the obtained result of the significant increase of the tetraploid edaphic niche was a simple result of hybridization.

Assessing the Nutrient Status and Soil Fertility Using Nutrient Indexed of Farmer’s Fields in Chikkaballapura District, Karnataka

The soil samples were collected by farmers in their own cultivable land analysed at soil testing laboratory at KVK, Chikkaballapura. From last decade (2012 to 2022), the samples were analysed following standard procedures. Nutrient status and nutrient Index was estimated to know the fertility status of the soils. The pH of soils of Chikkaballapura district was found be neutral (65.15 %) followed by alkaline (24.33%) and acidic (10.52 %) and low (68.09%) to medium (31.65%) range in EC values. Organic carbon content was found lower (89.64%) in majority of the soils and medium range in 10.02 % soils. Likewise OC values, available N status was in lower limits (63.63 kg ha-1) and 36.37 % soils are in medium range. Available P2O5 status was recorded lower in 91.63 % and medium range in 8.19 % of the soils. Majority of the soils of the Chikkaballapura district is in medium range of available K2O according to critical limits. With respect to Nutrient Index (NI) values for OC, available N, P2O5 and K2O more than 90% soil samples found in lower category with exception to Chikkaballapura taluk for N and K2O. In this study, it was found that most of the examined soils are in low in important parameters such as OC, N, P2O5 and K2O. In this context, the adoption of appropriate soil management strategies would be helpful to improve the low and medium soil nutrient index of the soil.

Identification of calculated parameters of the Hardening Soil model based on laboratory soil tests

The modern soil model Hardening Soil, which is used in many software complexes intended for solving geotechnical problems, is considered. The model makes it possible to take into account changes in deformation parameters of soils depending on the level of applied stresses and to describe the deformation processes of cohesive soils under complex loading/unloading trajectories.
 The paper also presents tables and graphs obtained during laboratory studies of semi-hard clay "Kyiv marl" in a triaxial system and an oedometer. Based on these data, the soil strength parameters с' and φ', as well as the stiffens modules , ,  were determined.
 To correlate the results of numerical simulation with the real behavior of clay soil in the Plaxis software complex, using the SoilTest virtual laboratory, a test in a triaxial compression device was simulated and soil parameters were identified. This approach makes it possible to increase the accuracy and quality of calculation results.
 During identification, the parameters that most affect it were analyzed, which made it possible to better understand which parameters and in which ranges to vary in order to achieve the desired result.
 It was determined that the most sensitive parameters are the section modulus of rigidity and the coefficient of destruction Rf. Their percentage sensitivity is 65.9% and 32%, respectively.
 By varying the c' and φ' characteristics during the tests in the virtual laboratory, the destruction of the sample was simulated in accordance with real soil studies. Therefore, it is very important to correctly determine these parameters, because this can lead to an underestimation or, on the contrary, an overestimation of the strength of the soil base.

A parameter design model for EPB shield soil conditioning in gravel stratum based on machine learning

The utilization of soil conditioners plays a vital role in preserving excavation safety during the construction of an earth pressure balanced (EPB) shield, as they enhance the reliability of the cutting chamber. The kinds and amounts of soil conditioner that ought to be pumped into the EPB system, however, lack theoretical direction. This study aims to develop predictive and design models to investigate the reciprocal relationship between soil conditioners and soil characteristics. The soil conditioner parameters were designed with the targeted characteristics of the soil using the intelligent hybrid design model, which combined the prediction model and the design model. The study's conclusions showed that the Gradient Boosting Regression (GBR) model, which was developed, had improved generalization and accuracy abilities when used to forecast the properties of upgraded soils. The current Artificial Neural Network (ANN) design model provided a variety of available options, but its accuracy was poor, and it could not be used directly. A hybrid GBR-ANN model created by the researchers showed a difference between the goal value and the experimental value acquired from laboratory soil testing of less than 10%. A solution that was required was the model's time-consuming explosion of the marginal value design. As a result, it is determined that using the Hybrid GBR-ANN model is adequate for figuring out the necessary amount and composition of soil conditioner, making it a workable method for soil property-oriented design.

Nutrient Analysis of Different Media Used for Nursery Production

An experiment was conducted in the Soil testing laboratory PLANTICA – Indian Academy of Rural Development, Dehradun during January – July 2023, which focused on the nutrient analysis of various growing media for nursery development. Growing media is a crucial component of nursery cultivation as it aids in the growth and development of plants. Different types of growing media are used, and one of them is soil-based media, which is a mixture of different materials with soil being the primary component. In this trial, a mixture of soil, sand, vermicompost, and cocopeat was used to create growing media with different ratios. In this experiment completely randomized design (CRD) was used, in which soil and sand were mixed together to form one treatment, while cocopeat and vermicompost were mixed with soil and sand in different ratios, resulting in a total of 13 treatments with 4 replications each. The treatments for this experiment were, as follows: T1 - soil, T2 - soil + sand (1:1), T3 - soil + sand + cocopeat (1:1:1), T4 - soil + sand + cocopeat (1:1:2), T5 - soil + sand + cocopeat (1:1:3), T6 - soil + sand + vermicompost (1:1:1), T7 - soil + sand + vermicompost (1:1:2), T8 - soil + sand + vermicompost (1:1:3), T9 - soil + sand + cocopeat + vermicompost (1:1:1:1), T10 - soil + sand + cocopeat  + vermicompost (1:1:1:3), T11 - soil + sand + cocopeat + vermicompost (1:1:2:1), and T12 - soil + sand + cocopeat + vermicompost (1:1:3:1). To analyse the nutritive value of the growing media, NPK (nitrogen, phosphorus, potassium), organic carbon, electrical conductivity (EC), pH, and water holding capacity were measured. The most suitable treatments for nursery n cultivation were found to be T9 (soil, sand, cocopeat, and vermicompost with a ratio of 1:1:1:1) and T11 (soil, sand, cocopeat, and vermicompost with a ratio of 1:1:1:3). These treatments had the perfect balance of soil, sand, vermicompost, and cocopeat, providing all the necessary nutrients required by the plants. T9 was particularly suitable for nursery beds due to its high phosphorus content, which is beneficial for root development. On the other hand, T11 was the best choice for growing media after transplanting the saplings as it contained a high nitrogen content, which promotes foliage development.

History and Methods of the Everglades Soil Testing Laboratory

This publication provides a history of the University of Florida Everglades Soil Testing Laboratory (EvSTL), current analytical methods, and information about fertilizer recommendations made by the laboratory. Written by J. Mabry McCray and Ronald W. Rice, and published by the UF/IFAS Agronomy Department, October 2023.

Starch-Grafted Sodium Alginate-Modified Clay Composites as Environmentally Controlled-Release Materials for NPK Fertilizer

In an effort to mitigate the harm caused by the irregular use of agrochemicals, a safer release system using biopolymers is promising due to their availability, biodegradability, and eco-friendliness. Herein, controlled-release materials for NPK fertilizer were formulated using clay-based graft biopolymer composites. The clay soil sample was collected and classified through Skempton’s laboratory tests for soils and used as filler in starch-grafted sodium alginate (ST-g-SAG) with different percentages of clay. The clay-based graft biopolymer composites were synthesized via a microwave-assisted method. The biopolymer composites were characterized by FTIR, SEM, and EDS. The materials were loaded with NPK fertilizer, and a leaching test was conducted via a conductometric method to ascertain their release capacities. Biodegradation studies and the effect of humidity on the release of the NPK fertilizer were studied. Results of classification studies of the clay show Ca-montmorillonite (Ca-MMT) type. The average percent graft yield of starch-grafted sodium alginate/Ca-MMT (ST-g-SAG/Ca-MMT) was 83%. The results from FTIR and EDS showed that OH-, COO-, and CONH2 were responsible for the absorption of water. The release profile of the active NPK in the biocomposites ranged from 1% to 103%. Biodegradation results also showed a significant breakdown in biopolymer structure and mass loss. The release of active NPK from the material was humidity-responsive.

Tree root-soil interaction: field study of the effect of trees on soil moisture and ground movement in an urban environment

Abstract Aims Little research has been conducted to quantify the atmosphere-plant-soil interaction in urban environments due to a lack of understanding of plant water use characteristics and the limited availability of high-quality field data. This research aims to quantify the drying effect of root systems of two Australian native tree species on soil water dynamics and ground movement using high-quality field measurement data. Methods A long-term field monitoring on soil moisture variation and ground movement close to C. maculata and M. styphelioides, was conducted for up to 45 months in Melbourne, Australia. The water requirement of each tree was monitored using sap flow sensors. Laboratory soil testing was conducted to obtain soil properties and develop profiles of soil suction and water content. The intercorrelation between soil water dynamics and tree soil water use was established. Results Tree roots could no longer extract water from the soil when total soil suction exceeded a wilting point of approximately 1000 kPa. The soil profile differences between the two sites were a significant factor causing substantial differences in tree water consumption. Conclusions At the C. maculata site, tree-induced soil desiccation occurred to a depth of 1.1 m, while at the M. styphelioides site, it extended down to 2.2 m depth. The tree root-soil interaction analysis shows that water uptake of 10.64 kL by tree roots partially contributes to a 5% decline in soil water content and a 270 kPa rise in soil suction, resulting in a continuous soil settlement of 22 mm.

EVALUATION OF THE STRENGTH CHARACTERISTIC OF SOIL STABILIZED WITH FLY ASH

High domestic consumption of coal, especially in energy sector, has raised concerns on several environmental issues in Indonesia. Large amount of coal combustion product in the form of solid waste, such as fly ash resulting from coal power plant production causes problems in its disposal since its necessity of land occupancy. Over the last decade, many researchers have put effort to solve this disposal concerns by utilizing these materials for various purposes, such as construction materials as part of circular economy. This paper presents the utilization of fly ash for soil stabilization in Surabaya. Firstly, the index properties of soil samples were determined through a series of laboratory soil test including specific gravity, unit weight, moisture content, sieve analysis and Atterberg’s limit tests. Subsequently, standard proctor test was conducted to obtain the maximum dry density and optimum moisture content of the soil samples. Using those parameters, four types of soil stabilized with fly ash samples were prepared with fly ash content based on weight of soil as follows: 0%, 5%, 10%, and 15%. Finally, unconfined compression tests were performed with cylindrical soil samples to assess the unconfined compressive strength of those samples. The results indicate that soil with fly ash content of 10% showing the highest unconfined compressive strength compared to the other variations of 0.90 kg/cm2.

Assessment of Soil Fertility Status in Rupani Rural Municipality, Saptari, Nepal

As soil fertility is one of the most important factors for soil productivity, soil fertility management is important for sustainable soil management. This study was conducted to determine the soil fertility status of Rupani Rural Municipality, Saptari, Nepal. A total of 60 soil samples were collected randomly from 0-30 cm depth. The exact location of the samples was recorded using a handheld GPS device. All collected samples were analyzed at a regional soil testing laboratory in Saptari to determine their pH, soil texture, nitrogen, phosphorus, potassium, and organic matter status. In addition, fertility status maps were prepared using ArcGIS 10.8 software. The study area consists mainly of 51.66% clay and 18.33% sandy loam soils. The soil pH ranged from highly acidic to slightly alkaline, with pH values ranging from 4.5 to 8.0. Soil organic matter (0.42-3.21%), nitrogen (0.02-0.16%), available phosphorus (40.1-282.35 kg P2O5/ha) and exchangeable potassium (64.8-729.6 kg K2O/ha) are present in the soil with the status of low to high in the study area. In order to improve crop potential and maintain soil nutrient status through the use of site-specific fertilizers, a reduction in the use of chemical fertilizers and various sustainable soil management practices were adopted. This research provides valuable information to policymakers, farmers, and agricultural stakeholders, facilitating evidence-based decision-making for agricultural development and food security in Rupani Rural Municipality, Saptari, Nepal.

Water Quality Management in Improving Freshwater Aquaculture: Interventions of KVK-Khordha

Adoption of Scientific Management Practices (SMPs) is imperative for increasing production and productivity in fish farming. From pond preparation to harvesting fish, the Research and Development Institutions have disseminated technologies and techniques for the benefit of farmers and it is understood that adoption varies from farmer to farmer based on their capacity, willingness and the robustness of the practice. Among the different SMPs in fish farming, water quality management is one of the key practices that determine the success of fish farming. This study was conducted with the objective of assessing the advisory role of Krishi Vigyan Kendra (KVK)-Khordha in promoting water quality management practices through its soil and water testing laboratory. Twenty beneficiaries of the KVK from three districts of Odisha were selected for the study. The results indicated that majority of the farmers have never tested water samples before and tested for the first time at KVK. Further, the sources of information for testing water were found to be limited. The study also concluded that the major reason for testing water was towards understanding the manuring and fertilization schedule. Most of the farmers tested their water before stocking and also fully adopted the recommendations provided by KVK. The study suggests more intensive efforts by development agencies to organize different campaigns and use of the other extension methods to sensitize the adoption of water quality management practices with a larger impact.

Common Mistakes in Execution of Plane Load Test

Shallow foundation is the preferred foundation whenever possible, as it is economically more feasible compared to deep foundation. The design method for shallow foundation has long been established by Terzaghi. The Terzaghi’s bearing capacity equation requires soil strength parameters for its calculation. To obtain accurate results, undisturbed sample for laboratory testing is necessary. However, depending on the accuracy of soil sampling and laboratory testing, the results can have large inaccuracy. The in-situ determination of shallow foundation can be carried out by plate loading test. It is a well-established test which was standardized by British Standards in 1990 and American Society for Testing and Materials in 1994. The testing method is simple, and the standards provide flexibility in the execution of the test. Unfortunately, this flexibility can cause mistakes in the execution of the test, as practitioners can be selective in choosing the test procedure to minimize the test duration and/or cost. These mistakes can cause the plate load test results to be unusable or lead to erroneous results. This paper aims to address common mistakes in execution of plate load test.

Nutrient Management Recommendations Based on Mehlich-3 Extractant for Calcareous Soils in Miami-Dade County

This factsheet provides information about the history of soil testing calibrations and justification for recommending extraction of soil nutrients using Mehlich-3 for calcareous soils in Miami-Dade County. The dominant soils from this County have an extraordinarily high concentration of calcium resulting in high pH. This document also includes UF/IFAS approved Mehlich-3 extractant-based testing interpretations and recommendations for these soils. The purpose of this publication is to elucidate an appropriate approach for analyzing the unique calcareous soils from Miami-Dade County for plant available nutrients. The target audiences are Extension agents, agronomists at soil testing laboratories, crop advisors, growers, representatives of the state and local agencies, and others concerned about soil testing and plant analysis in Miami-Dade County.

Assessing the Scale Effect on Bearing Capacity of Undrained Subsoil: Implications for Seismic Resilience of Shallow Foundations.

This research investigates the influence of the scale effect on the bearing capacity of fine-grained subsoil under undrained conditions. The analyses were conducted based on laboratory tests of silty clay. Uniformly compacted samples were subjected to an unconfined compression test. The research was performed on cylindrical specimens. Three different variants of the diameter D (38 mm, 70 mm, 100 mm) and the corresponding height H = 2D were analyzed. Based on the tests results, the unconfined compression strength qu was determined, and from this, the undrained shear strength cu was calculated. The obtained results showed a clear decrease in cu with increasing sample size. However, in the existing reference documents, there are no specific guidelines for calculations of bearing capacity with consideration of sample size effect on the soil shear strength. Therefore, this study utilized the laboratory soil test data to calculate the bearing capacity of undrained subsoil, taking into account the seismic impacts, with a particular focus on spread foundations.

Vertical Farming using Smart Farming

Nutrient content (Nitrogen, Phosphorous, Potassium) monitoring in soils is essential for the proper use of fertilizers to minimize the environmental impact of wrong pattern fertilization practice. Collecting samples from different locations and laboratory testing takes longer and costs a lot. New-generation digital sensors are smart enough to replace chemical lab testing in real-time with minimum effort and with almost precise results. The Proposed system tends to implement various suggestions that would also help improve the quality of the work being done by the soil testing laboratories. By this, we can able to test our soil parameter in that condition quickly in our field for further processes and we will get the soil parameter report without any delay. And we can get information about the fertilizer and crop matches for that result and the number of fertilizers to be used. And to demonstrate soil humidity sensors and pH sensors to measure the NPK values which determine the fertility of the soil, which helps to improve cultivating system. The results obtained from our developed sensing system are almost accurate and very close to the laboratory test readings. Arduino plays a key role in processing data received from the sensor as input, the counters used here produce the respected output values for the parameters. There the values received by the Arduino are compared with the database and provide related information which is matched to the current calculated values. The output values provided by the Arduino and sensors will be displayed on the LCD. Here the output not only provides formation on fertility present in the soil but also suggests crops to be grown on that soil. Keywords—Vertical farming, smart farming, nutrient monitoring, digital sensors, soil fertility, crop suggestions.