Soil Conditions Research Articles

Metabolic Profile Evolution of Citrus sinensis ‘Navelina’ Under Different Cultivation Techniques and Water-Saving Strategies

Citrus trees, particularly oranges, are a highly significant plant genus due to their consumption as fresh produce and the multiple compounds derived from them, which are extensively used in the food, cosmetic, and pharmaceutical industries. Despite recent advancements, the understanding of metabolic processes in the Citrus genus remains limited, especially in the context of variable agricultural practices. This study aimed to investigate the metabolomic evolution in leaves of sweet orange (Citrus sinensis) cultivated under different conditions over two key developmental periods: pre-winter (t1) and spring sprouting and flowering (t2). Using proton nuclear magnetic resonance (H-NMR) spectroscopy, this research identified 27 key metabolites across five distinct cultivation treatments (T0, T1, T2, T3, T4), including amino acids, organic acids, and sugars, and their variation over time. T0 represents the traditional crop of the control plot, while T1, T2, T3, and T4 incorporate different strategies aimed at water-saving, such as the use of weed control mesh and subsurface drainage systems, all designed to improve profitability and crop efficiency under the same soil and climatic conditions. The treatments were evaluated for their impact on plant growth parameters such as height, trunk diameter, and flower production, with a focus on reducing water usage without compromising crop performance. The results indicate that the use of weed control mesh significantly improves plant growth, increases flower production, and stabilizes key metabolite levels, contributing to a concept termed “plant metabolomic homeostasis.” These findings are particularly relevant in regions like southeastern Spain, where water scarcity is a major concern. The study provides compelling evidence that the implementation of weed control mesh in orange cultivation can enhance water efficiency, promote healthier plant development, and maintain metabolic stability under variable growing conditions. These results suggest that such agricultural practices could be recommended for broader commercial application in citrus cultivation to improve sustainability and crop profitability.

Biodegradable Polyurethane Foams Based on Polyols Obtained from Cellulose and Its Hydroxypropyl Derivative

Three methods of cellulose-derived polyol synthesis were elaborated. The suitable substrates were (hydroxypropyl)cellulose or cellulose, which were hydroxyalkylated in reactions with glycidol and ethylene carbonate in triethylene glycol or in water. The products were characterized by IR, 1H NMR, and MALDI ToF spectroscopies. For all polyols, IR spectra showed strong bands at 1060 cm−1 from the ether group formed upon the ring opening of GL and EC. The polyol obtained from (hydroxypropyl)cellulose in the triethylene glycol solvent was accompanied by oligomeric products of glycol hydroxyalkylation and oligomeric glycidol. The polyol obtained by the hydroxyalkylation of cellulose with glycidol and ethylene carbonate in the water contained units of hydroxyalkylated cellulose and products of hydroxyalkylation of water. The physical properties of the obtained polyols, like density, viscosity, and surface tension, were determined. The polyols were then used to obtain rigid polyurethane foams. The foams have apparent density, water uptake, and polymerization shrinkage similar to classic rigid PUFs. The foams showed advantageous thermal resistance in comparison with classic ones. After thermal exposure, their compressive strength improved. The biodegradation of the obtained materials was tested by a respirometric method in standard soil conditions by the measurement of biological oxygen demand and also using the cellulases or the enzymes responsible for cellulose degradation. It has been found that polyols are totally biodegradable within one month of exposure, while the foams obtained thereof are at least 50% biodegraded in the same conditions. The enzymatic biodegradation of the PUFs by the action of microbial cellulase was confirmed.

Soil Bacteria in Archaeology: What Could Rank Abundance Functions Tell Us About Ancient Human Impacts on Microbial Communities?

Metagenomic analysis of soil bacterial communities based on 16S rRNA reflects a typical community composition containing a low number of high-abundance types and a very high number of low-abundance types. Here, the formation of characteristic rank order functions of bacterial abundance is investigated by modelling the dynamics of soil bacterial communities, assuming a succession of different bacterial populations that grow rapidly and decay more slowly. We found that the characteristic shape of typical rank order functions is well reflected by simulations. In addition, our model allowed us to investigate strong disturbances in the soil, which could be expected in cases of strongly changing local environmental conditions in soil, e.g., after translocation and covering of soil material. Such events could lead to the formation of shoulders in the rank order functions. Abundance rank orders observed in cases of some archaeological soil samples do indeed show such a shoulder and could be well interpreted by simulated rank order functions. As a result, it can be concluded that the investigations herein support our hypothesis that abundance rank orders contain information about the temporal order of developing bacterial types in changing communities and thus store information about local environmental conditions in the past, including ancient humans’ impact on soil. This information can be used for interpretation of archeological findings and for reconstruction of different former human activities, as well as knowledge on the translocation of soil material in the past.

An Investigation to Evaluate the Performance of Connected and Disconnected Piled Raft Systems Under Varying Soil Conditions

An Investigation to Evaluate the Performance of Connected and Disconnected Piled Raft Systems Under Varying Soil Conditions

Habitat Associated with Ramps/Wild Leeks (Allium tricoccum Ait.) in Pennsylvania, USA: Guidance for Forest Farming Site Selection

Ramps or wild leeks (Allium tricoccum) are a popular foraged non-timber forest product in North America consumed for their edible bulbs and leaves. The agroforestry practice of forest farming is a possible solution to conservation challenges surrounding the wild exploitation of this species, but it requires proper site selection to be successful. In this study, maximum entropy (Maxent) modeling using 163 occurrence points and field data collected at 30 wild populations were combined to determine the characteristics of the ramp habitat in Pennsylvania. Both Maxent modeling and field measurements highlighted moist, lower slope positions with base-rich bedrock types as suitable for ramps. Sites shared 50% of their floristic associates on average, with 252 species documented in total. Forest communities associated with ramps included many species indicative of base-rich mesic soil conditions, but the relative abundance of some indicator species differed by region. The confirmation of model variables by field measurements and forest community types points to the usefulness of these characteristics in identifying suitable forest farming sites. When used in tandem, these results can help to guide site selection for forest farming and other conservation strategies.

Autoinducer-2 relieves soil stress-induced dormancy of Bacillus velezensis by modulating sporulation signaling

The collective behavior of bacteria is regulated by quorum sensing (QS). Autoinducer-2 (AI-2) is a common QS signal that regulates the behavior of both Gram-positive and Gram-negative bacteria. Despite the plethora of processes described to be influenced by AI-2 in diverse Gram-negative bacteria, the AI-2-regulated processes in Bacilli are relatively unexplored. Here, we describe a novel function for AI-2 in Bacillus velezensis SQR9 related to the sporulation. AI-2 inhibited the initiation of sporulation through the phosphatase RapC and the DNA binding regulator ComA. Using biochemistry experiments, we demonstrated that AI-2 interacts with RapC to stimulate its binding to ComA, which leads to an inactive ComA and subsequently a sporulation inhibition. The AI-2 molecule could be shared across species for inhibiting Bacillus sporulation and it also plays the same role in different soil conditions. Our study revealed a novel function and regulatory mechanism of AI-2 in inhibiting sporulation in Bacilli.

Soil-climatic conditions of the vineyard and biochemical characteristics of the red dry wine ‘Kara-Koysu’ (Republic of Dagestan, Russian Federation)

ABSTRACT The article provides additional information that emphasizes the growing international interest in the impact of climate (temperature, humidity, precipitation, solar activity) on grape yields and the quality of terroir wine. The study deals with the climate gradient of the terroir of the Derbent region of the Republic of Dagestan (Russia), located on the terraced accumulative-coastal plain of the Caspian lowland, stretching for 160 km from north to south in a narrow strip between the coast of the Caspian Sea and the foothills. The influence of soil and climatic conditions on the biochemical characteristics of red dry wines ‘Kara-Koysu’ from Cabernet Sauvignon wingrapes of the 2019–2021 harvest was studied. The growing season occurred in dry, moderately humid conditions in 2019; hot, with a lot of precipitation in 2020 and more extreme conditions in 2021. The conditions of recent years have contributed to the change of almost all the studied indicators of tested wines. Studies have found that the climatic conditions of 2020–2021 were more favorable for obtaining a rich harvest, high-quality wines due to more UV light exposure and precipitation.

Impact of Salinity Stress on Morpho-physiology of Four Rice (Oryza sativa L.) Varieties

Abiotic stress, especially salinity, is one of the major restraints for attaining self-sufficiency in the food grain production. The saline soils affect the crop growth both directly and indirectly by interfering with plant metabolism resulting in reduction in yield potential of various crops. Rice (Oryza sativa L.), the staple food of much of the world’s population, is categorized as a salt-susceptible crop. Improving the salt tolerance of rice would increase the potential of saline-alkali land and ensure food security. To investigate the effect of different levels of salinity on morpho-physiological characters and yield of four rice variety viz. Pokkali, Narendra Ushar Dhan 3, IR 28 and IR 29. A pot experiment was conducted during Kharif 2011 and 2012 at the Department of Crop Physiology, Narendra Deva University of Agriculture and Technology, Kumarganj, Faizabad (U.P.) under normal soil and saline conditions with EC 6.0 and EC 10.0 dS/m. Gradual increase on plant height as well as biomass with the advancement in the age of crop up to dough grain in all the varities under both normal and salinity treatment. Maximum grain yield recorded in tolerant varieties Narendra Usar Dhan 3 followed by Pokkali, whereas minimum in IR 28. Under saline conditions regarding sink potential, the tolerant varieties recorded less reduction in yield attributes like length of panicle (cm), number of panicle per plant, number grain panicle-1 and grain yield plant-1 as compared to normal condition. The salinity tolerance capacity of tolerance varieties was associated with increased the activity of catalase and superoxide dismutase enzyme batter accumulation of proline and total carbohydrate as compared to normal condition.

Peat-based amendment of soils reduces the complexity of the volatile profile in cultivated black truffles.

Truffle cultivation is evolving rapidly and new agronomic practices such as 'truffle nests' (localized peat amendments of the orchard soil) are being developed. Truffle nests improve the shape of truffles and their depth in the soil and reduce the occurrence of insect damage but have also raised concerns about their impact on the ripeness and maturity of the harvested truffles. In this study, the effect of the nests on the volatile organic compounds profile and the aromatic profile of black truffles was evaluated, as well as the existence of perceptible sensorial differences in truffles. For this, truffles growing in nests were compared with truffles growing in the bulk soil of the same host tree. Gas chromatography showed that nest truffles had a less complex volatile organic compound profile than bulk-soil truffles. Olfactometry indicated that nest truffles were associated with higher modified frequency values of odorants corresponding to sulfur-containing compounds. Despite this, sensory evaluation with consumers could not clearly show that nest truffles can be distinguished sensorially from bulk-soil truffles. The results prove that soil conditions can influence the aromatic profile of truffles and thus suggest the possibility of managing truffle aroma using agronomic practices. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Vibration Analysis of the Bow Bridge With and Without the Soil Foundation

Abstract. Earthquakes can impart the phenomenon of resonance, where the frequencies of seismic waves align with a bridge's natural frequency, causing amplification of vibrations that can lead to structural failures. Aiming to accurately predict potential vulnerabilities posed to the bridge when subjected to earthquakes, this research presents a vibration analysis of the Bow Bridge. Two models, which simulate the Bow Bridge with and without soil foundation, are conducted to investigate the bridges natural frequencies and mode shapes under soilless and soiled conditions. The research result shows that the average vibration frequency in a soiled environment is much lower than that in a non-soil environment, intuitively proving the mitigation of soil environment to bridges vibration frequencies. Based on the agreeable data output, this research demonstrates the feasibility of modeling in the prediction of practical construction.

Pecan-medicinal crops intercropping improved soil fertility and promoted interactions between soil microorganisms and metabolites

BackgroundPecan [Carya illinoinensis (Wangenh.) Koch] is a widely cultivated dried fruit and woody oil tree with high economic value. Continuous sole planting of pecan caused some land to lie idle and deterioration of soil conditions. Tree and medicinal crops intercropping represents an environmental-friendly and economically feasible solution to these issues. Thus, we aimed to explore the underlying mechanism by which intercropping improved soil condition by regulating the interactions of the soil microbiome and metabolome. In this study, pecans were intercropped with medicinal crops caper spurge and honeysuckle on a tree farm in China. A combined analysis of soil microbiomes and metabolomes was performed to discover the effects of intercropping on bulk and rhizosphere soils.ResultsThe results showed that intercropping improved the edaphic properties of bulk soil and promoted the growth of pecan and caper spurge. Intercropping also significantly altered the structures of both bacterial and fungal communities in bulk soil, stabilised the enrichment of nitrogen-cyclic bacteria, for instance, Bacillus, and decreased the relative abundances of plant–pathogenic fungi, for instance, Fusarium. In addition, the result of metabolomic analysis showed that intercropping promoted the synthesis of functional compounds, such as trehalose and ethanolamine, which enhanced plant disease resistance in bulk soils. Moreover, the co-occurrence networks of microbiomes and metabolomes of bulk soils revealed that Bacillus was significantly correlated with Fusarium, Alternaria, and trehalose under intercropping patterns. Furthermore, analysis of microbiomes and metabolomes in the rhizosphere soil of caper spurge and honeysuckle revealed that Penicillium and Rhizomicrobium were significantly increased by intercropping and showed more dynamic connections with other genera and metabolites compared with single planting.ConclusionsOverall, intercropping pecans with caper spurge and honeysuckle can improve soil conditions and promote plant growth through microbiological and metabolomics integrated analyses. This study provides valuable information and theoretical basis for optimizing land resource utilisation and improving soil conditions in tree fields like pecan fields via intercropping, thereby reducing production losses and ensuring economic benefits.Graphical

Calibration and implementation of a design tool for drag anchors in clay

Abstract Drag anchors are considered as one of the most applicable anchor solutions for floating offshore wind as they can be used for a wide range of soil conditions. For feasibility studies of floating offshore wind farms different anchor concepts needs to be compared in order to select the most proper anchor solution. To do so, the level of details in the analysis for the various anchor types must be similar. Currently design charts are adopted as a simple design method for drag anchors. However, design charts are developed for specific soil conditions, and do not account for site specific soil conditions. To have similar precision, as analytical solutions for suction anchors, a simple design methodology that can account for site specific soil conditions for drag anchors must be adopted. This paper presents an example for how a simple analytical solution can be calibrated against design charts, which makes it possible to account for site specific soil conditions, resulting in a better basis for comparing early stage drag anchor design to other anchor solutions.

Automatic cleaning suggestion adapting to real-time soiling status of solar farms

Solar farms are subject to various environmental factors that can affect their performance and output. One of the major factors is soiling. Consequently, it is essential to monitor and mitigate the effects of soiling on solar panels to ensure optimal performance and maximum profitability of a solar farm. In this paper, we present a novel cleaning intervention strategy that adapts to the present solar panel performance status to detect cleaning requirements for maximizing profit. This algorithm works with onsite insolation and panel data to give live feedback on cleaning requirements. Moreover, unlike other models in the literature, this method does not require historical or a priori insolation, weather, or soiling data. We have comprehensively tested the algorithm through experiment and simulation under various conditions (i.e., seasonal rain, few annual rainfall or sandstorms, unpredictable dust accumulation). The results show that the adaptive cleaning algorithm, even with no historical insolation or soiling information, outperforms optimal periodic cleaning strategies in terms of net revenue. The adaptive cleaning suggestion system shows significant advantages especially in locations with high variability in weather and soiling conditions. The algorithm is also suitable for practical deployment in solar farms near industrial or construction zones where sudden dust accumulation can occur. Our adaptive model will maximize profit in such unpredictable soiling scenarios, while in comparison, it is not even possible to utilize historical information-based cleaning cycle model in such cases.

Atributos microbiológicos em Latossolo Vermelho cultivado com cana-de-açúcar na região de cerrado do Brasil Central

ABSTRACT The contribution of plant residues throughout the sugarcane cycles favors the increase of organic matter and the activity of microorganisms in the soil, especially in the surface layers. Soil texture also has an important effect on ecological processes and soil quality. In this context, the objective of this study was to evaluate soil biological attributes in different sugarcane cultivation cycles under mechanized harvesting in an Oxisol in the Savanna region of Central Brazil. The study was conducted in commercial areas under sugarcane cultivation during the 2018/2019 season, which were considered homogeneous in terms of soil and climatic conditions, with the source of variation among the areas being the cultivation cycles (C1: one cultivation cycle; C3: three cultivation cycles; C7: seven cultivation cycles) and a savanna vegetation area selected as a reference. Microbiological variables were determined in two layers, 0-0.1 and 0.1-0.2 m. The variables related to microbial biomass and texture were subjected to principal component analysis. Areas with longer sugarcane cultivation cycles show higher proportion of microbial biomass carbon in the total organic carbon in subsurface layers (microbial quotient). The performance of the soil microbial community, as expressed by total organic carbon and microbial biomass nitrogen indicators, was associated with higher presence of clay and silt, i.e., soil particles smaller than 0.02 mm.

An evaluation of soil carbon models and their role on finding ways to net-zero carbon in agricultural systems

The estimation of changes in soil organic carbon (SOC) is a key issue for national green-house gasses (GHG) inventories, climate change mitigation programs and the estimation of carbon footprint of farm products in life cycle assessments. Any strategy related to net-zero carbon in agricultural systems needs to quantify the SOC balance. In this way, SOC models help decision makers involved in agriculture to understand the dynamics of the SOC and the interaction between all variables related to soil, climate, land use, and management, to design the best solution to reduce emissions or enable carbon sequestration. Likewise, it is important to identify suitable models for the region. This study aims to address three main subjects: a) a discussion on the importance of SOC estimation for GHG inventories and the carbon footprint of crops, using the Intergovernmental Panel on Climate Change (IPCC) Tier 1 method and AMG model; b) an evaluation and brief description of the IPCC “Steady State Method” (SSM), using experimental data from two sites in Argentina, comparing these results to AMG and RothC models (both previously validated at those sites); and c) a brief discussion about the potential use of SOC models for what-if management scenarios, their real limitations and future research needs. The three models were consistent in predicting the impact of tillage and the long-term trends in changes in SOC stocks under different management practices. The SSM model was evaluated for the first time in Argentina and performed even better than the other two models. It was consistent with the observed values, when predicting the effect of tillage system under different crop rotations, including pasture systems. Regarding efficiencies of the models, they showed acceptable Nash-Sutcliffe Efficiency (NSE) values, and the root mean square error (RMSE) was also acceptable between 3 % and 7 %, within a range of 4–5 Mg C.ha−1. Therefore, the SSM model proved to be a valuable tool to estimate SOC trends for crop and pasture rotations under different management scenarios (i.e., tillage systems and fertilization), to identify best practices that allow for a zero or positive SOC balance, in two different soil and climate conditions of the Pampean Region of Argentina. In our study, the SSM did have a better fit to the data and, furthermore, this Tier 2 method is simpler than the Tier 3 models, and, therefore, is advantageous for conducting regional assessments and GHG inventories.

Vegetation community recovery on restored bottomland hardwood forests in northeast Indiana, USA.

Vegetation communities in restored bottomland hardwood forests in northeast Indiana were studied 6-21 years after restoration to assess progress toward restoration objectives. The study focused on four sites that were restored to compensate for resource injuries after contaminant releases. The restored sites were compared with four reference-site conditions, including crops (prerestoration condition), old field communities representing a no-management alternative, locally sampled second-growth mature forests, and forest community types described by the US National Vegetation Classification (USNVC), which represent ideal or defining conditions of recognized vegetation communities. Fixed-area plots provided data on field-sampled environmental variables, vegetation, soil, and hydrological conditions for crops, old fields, restored areas, and mature forests. The USNVC database provided quantitative data for three historically and geographically relevant reference forest community types for comparison with the sampled communities. Results of nonmetric multidimensional scaling based on species cover revealed clear gradients relating to site age and canopy development. Along those gradients, restored areas demonstrated increasing similarity to mature forest reference communities in terms of floristic composition. Specifically, the floristic quality of restored areas was significantly greater than that of crops and old fields. Furthermore, soil health measurements of physical, chemical, and hydrological conditions indicated significant improvements in restored site soils compared with prerestoration conditions represented by cropland soils. Descriptions and data from the USNVC provided ecological context for restoration target conditions and facilitated the assessment of restoration recovery along a trajectory from starting conditions to those target conditions. Descriptions by USNVC also helped identify deviations from the intended restoration objectives (e.g., invasive species recruitment) and potential adaptive management actions to return sites to their intended trajectories. Integr Environ Assess Manag 2024;20:1917-1938. Published 2024. This article is a U.S. Government work and is in the public domain in the USA. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Influence of environmental conditions on the growth of Pleurotus ostreatus in sand

Pleurotus ostreatus, a saprotrophic fungus, has been proposed for the remediation of organic contaminants in soils and more recently for modifying the hydraulic and mechanical behaviour of granular soils. The in situ performance of fungal-based biotechnologies will be controlled by the fungal growth and associated biochemical activity that can be achieved in soil. In this study, the influence of environmental conditions (temperature, degree of saturation), substrate type (lignocellulose and spent coffee grounds) and concentration on the mycelium growth of P. ostreatus in sand are investigated. Furthermore, the evolution of growth/survival indicators (respiration, ergosterol concentration) and enzymatic activity (laccase, manganese peroxidase) are investigated. Temperature was shown to have a strong influence on the growth of P.ostreatus in sand: growth was observed to be delayed at low temperatures (e.g. 5 °C), whereas growth was prevented at high temperatures (e.g. 35 °C). No growth was observed at very low degrees of saturation (Sr=0% and 1.2%), indicating there is a critical water content required to support P.ostreatus growth. Within the mid-range of water contents tested radially, growth of P.ostreatus was similar. However, growth under saturated soil conditions was restricted to the air-water atmosphere due to the requirement for oxygen availability. Low substrate concentrations (1%–5%) resulted in high radial growth of P.ostreatus, whereas increasing substrate content further acted to reduce radial growth, but visual observations indicated that fungal biomass density increased. These results are important for understanding the feasibility of P.ostreatus growth under specific site conditions and for the design of successful treatment strategies.

Effects of soil physical ameliorants on the growth and root morphology of Prunus yedoensis and Ginkgo biloba seedlings in compacted soils

ABSTRACT Soil compaction is prevalent in forest ecosystems, it alters the physical structure of the soil and impedes tree growth. Although ameliorants are known to enhance soil properties and positively influence tree growth, studies remain limited on the effects of potential factors on root development in compacted soils after amelioration. This study aimed to examine the effects of the physical ameliorant treatments BIOC (compaction + biochar) and ORGF (compaction + organic fertilizer) on the soil properties, growth, and root development of Prunus yedoensis and Ginkgo biloba seedlings in compacted soils. We found that ameliorant treatments improved physicochemical soil conditions, such as bulk density, porosity, permeability, pH, total carbon, and total nitrogen, which in turn influence seedling growth. Specifically, in P. yedoensis, the relative growth rate of height was significantly higher in BIOC (46.19 ± 3.47%) compared to the control (29.58 ± 3.22%). The ameliorants did not significantly affect root morphological traits; however, we found that the total fine root length was positively correlated with shoot biomass in G. biloba (R = 0.97), but not in P. yedoensis. Root length tended to increase in BIOC, with measurements of 288.12 ± 68.97 m for P. yedoensis and 65.96 ± 25.08 m for G. biloba, while the mean fine root diameter tended to decrease in ORGF (1.25 ± 0.04 mm) and BIOC (1.37 ± 0.08 mm) for G. biloba. We conclude that biochar and organic fertilizer positively affect both soil properties and plant growth, highlighting that enhanced root development through ameliorants can improve plant growth in compacted soil.

Changes in the Water Deficit Characteristics of Rangeland Dominant Species at Different Grazing Intensities in Gypseous and Sandy Soil Conditions

Changes in the Water Deficit Characteristics of Rangeland Dominant Species at Different Grazing Intensities in Gypseous and Sandy Soil Conditions

Modified Complex Electrical Resistivity Technique: Applications to Saturated and Unsaturated Soils

Abstract Direct current (DC) electrical resistivity is a common laboratory soil characterization method to support geotechnical infrastructure design and to supplement site investigations. The complex electrical resistivity method has the potential to provide additional electrical soil properties to enhance electrical soil characterization. Both methods are conventionally performed under fully saturated soil conditions; however, many environments exist where soil is not fully saturated, such as ballast structure supporting railways. In this study, a new experimental setup featuring a current enhancing agent (agar) for complex electrical resistivity testing is evaluated by testing five different soil specimens reconstituted at saturated and unsaturated conditions. Results showed that the new experimental setup is valid and can be used to obtain repeat measurements, particularly for specimens reconstituted in the unsaturated conditions where the traditional DC electrical resistivity setup yields results that are unreliable. This is one of the very few studies where tolerances for triplicate specimens are reported to establish differences in measurements from sample preparation versus discernable variability between different geomaterials. Additionally, all results are supported by a Cole-Cole model. The results show that the additional data collected in a complex electrical resistivity test can be used to differentiate different soil types that are ambiguous with the DC electrical resistivity method. The additional data have the potential to more fully characterize the electrical properties of saturated and unsaturated soils, as well as to help distinguish unique geophysical signatures of various geomaterials to enhance a geophysical site investigation for identifying soil variability in the subsurface.