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Stone column technology is a method used to reduce liquefaction in saturated sediments. By using materials with greater permeability than the surrounding soil, stone columns can help drain excess pore water pressure and mitigate liquefaction potential during seismic loading. In this study, analytical solutions are proposed to address the liquefaction problem in saturated soils during earthquakes, taking into account the influence of stone columns and the surrounding soil. These solutions consider the excess pore water pressure at the boundary of the zones and analyze the vertical and horizontal drainages. The study also includes centrifuge tests on sandy soils improved with stone columns, calculating the total seepage flow and converting it into settlement based on the relationship between drainage flow rate and volumetric changes in the soil. The calculated settlement aligns well with the measured value in the centrifuge test, confirming the accuracy of the analytical formula for calculating settlement in stone column foundations. The study also evaluates the combined effects of radial and vertical drainages in stone column foundations using the derived analytical solutions. [ABSTRACT FROM AUTHOR]

Accurate prediction of excess pore water pressure (EPWP) generation in saturated sandy soils remains one of the most challenging issues in sandy site responses to strong earthquakes and extreme marine environments. This paper presents experimental results of undrained and drained multidirectional cyclic hollow cylinder (MCHC) tests on saturated coral sandy soils under various cyclic loadings. The results show that threshold generalized shear strain γga,th , below which EPWP and volumetric strain can be neglected, is an inherent property depending only on the soil type and initial state. Furthermore, there exists a virtually unique form of relationships between the generalized shear strain amplitude (γga) and the cumulative dissipated energy per unit volume of soil (Wc) at different relative density (Dr), irrespective of drainage conditions and cyclic loading conditions. These findings highlight the fundamental mechanism for cyclic deformation behavior and the uniqueness of correlations among rup (peak EPWP ratio), εvp (peak volumetric strain), and γga of saturated sandy soil at the similar Dr , regardless of cyclic loading conditions. Based on these findings, a novel unified model of γga -based cyclic shear–volume coupling and EPWP generation is established, which is independent of cyclic loading conditions over a wide loading frequency range. Then the applicability of the proposed model is validated by the experimental data of the same tested coral sandy soil and siliceous Ottawa sand, as well as the data of siliceous fine sands in previous work. It is found that the proposed model surpasses the existing strain- and stress-based models in accurately predicting EPWP generation under complex cyclic loadings, which can offer new insights into the mechanisms of the EPWP generation in saturated sandy soils. [ABSTRACT FROM AUTHOR]

Seasonal freeze–thaw (F–T) cycles significantly affect the mechanical properties of soils and the behavior of pile foundations in soils subjected to F–T cycles under different loading conditions. Soils exposed to F–T cycles can impact the performance of pile foundations. Consequently, the effects of F–T cycles should be taken into account when designing piles, particularly in cold regions such as Canada. In recent years, climatic conditions in Canada have changed due to global warming, increasing the number of F–T cycles in many regions each year. This study aimed to investigate the influence of different numbers of F–T cycles on the behavior of piles in sandy soils. Laboratory experiments were conducted on physical models of piles subjected to axial (uplift) and lateral loads combined with F–T cycles. The model was scaled using standard scaling principles, and the test apparatus was equipped with various sensors to measure temperatures, forces, and displacements. The results showed that as the number of F–T cycles increased, the lateral capacities of the piles under individual and combined loads increased steadily. The lateral load capacity increased from 350 to 430 N after five F–T cycles under individual loading and from 225 to 455 N after five F–T cycles under combined loading. However, the pile's uplift load capacity remained constant under individual and combined loads and there was no change due to F–T cycles. The results of this experimental study will be useful for understanding the behavior of piles subjected to seasonal F–T cycles and for improving the design of pile foundations in cold regions. [ABSTRACT FROM AUTHOR]

Owing to the scarcity of land resources, the rational development and use of frozen soil resources and solutions to frozen soil disasters are essential. In this study, an indoor one-dimensional soil column simulation test was conducted under unidirectional freezing conditions. The temperature, water content, and conductivity of the sand were monitored using a time-domain reflectometer (TDR), and a mathematical model to analyze the relationships among solute concentration, temperature, and conductivity was established, to convert the conductivity into soil solute concentration. Then, the sodium chloride solute redistribution in soil under different soil densities (1.23 and 1.40 g/cm3), initial water contents (10% and 13%), freezing temperatures (−20°C and −35°C), and salt concentrations (0.2 and 0.3 mol/L) was analyzed. The results show that solute concentration and temperature are the two factors that affect conductivity. The relationship between conductivity and solute concentration can be used to quantitatively analyze the solute changes in soil. The soil density, initial water content, freezing temperature, and solute concentration affect solute migration under unidirectional freezing conditions. The solute migration efficiency decreases with increasing soil density and initial water content and increases with decreasing freezing temperature and increasing solute concentration. In this study, the aim was to further understand the mechanism through which solute migration occurs in frozen soil, to provide theoretical support for the rational exploitation and use of resources, the prevention and control of soil pollution, and the promotion of agricultural development in cold regions. These results provide theoretical support for soil water and salt simulations, pollution control, and agricultural development in cold regions. [ABSTRACT FROM AUTHOR]

Volcanic eruption is known as multi-hazards to the surrounding environment and society causing the formation of lahar as the frequent hazards that shortly occurred due to airborne tephra after an eruption. Erosion triggered by rainfall on unconsolidated tephra material, such as volcanic ash, is the primary lahar initiation mechanism. The time and scale of lahars vary based on eruptions and watershed conditions. The variability of the erosion process is driven by a set of local factors including the grain size and spatial distribution of volcanic ash thickness, slope, and rainfall intensity. Laboratory simulation experiments were conducted in a 3.00 m long, 0.75 m wide, and 0.50 m deep flume to study the relationship of volcanic ash erosion rate to three driven parameters, namely slope, rainfall intensity, and volcanic ash thickness. Three slope gradients were selected to represent gentle (14.1%), mild (26.8%), and steep (46.6%) slopes. Meanwhile, the rainfall intensity ranged from 0.65 to 1.85 mm.min-1, and the variations of volcanic ash layer thickness were 1.00 cm; 2.50 cm; and 5.00 cm. The erosion rate model was generated from a dimensional analysis accommodating slope, rainfall intensity, flow discharge, and the ratio of critical and applied boundary shear stress as independent variables. The variable coefficients were obtained by parameter optimization of experiment data through nonlinear regression analysis. The erosion rate model performance was tested using the Nash-Sutcliffe model Efficiency (NSE), Index of Agreement (IOA), and Root Mean Square Error (RMSE). The performance of the volcanic ash erosion rate model was proven to be satisfactory with the NSE>0.75, IOA>0.95, and RMSE values ranging from 0.005 to 0.009. This model has proven applicable better for volcanic ash erosion than other erosion models which are sandy soil material-based experiments because of the specific characteristics of volcanic material itself. The volcanic ash erosion model in this study can be implemented to predict the sediment yield of tephra as part of volcanic disaster mitigation. [ABSTRACT FROM AUTHOR]

Violation of nomadic forms of pasture use leads to vegetation degradation, periodic large-scale outbreaks of deflation and desertification, and transformation of the physicochemical properties of sandy soils in the arid zone. Practice has shown that an effective means of restoring their production potential is the creation of multi-tiered vegetation cover—forest and pasture lands. The purpose of this study is to assess the current state, feed productivity, attractiveness, and sustainability of forest pastures and to develop proposals for their optimization. This research was carried out through a comprehensive study of natural objects on temporary trial plots using standard methods of agroforestry, geobotanical and soil research, and statistical data processing. It has been established that on the thick blown sands of the Nogai steppe in forest pastures with a tree layer of Robiniapseudoacacia and Ulmuspumila, the forage yield increases to 2–3 t/ha (in terms of hay) and, depending on the seasons of the year, is 1.5–3.5 times higher than that on natural pastures. On the fine sands of the Black Lands, there are forest pastures formed by plantings of Krascheninnikovia ceratoides and Calligonum aphyllum. At the age of 30–40 years, they produce 1.5–3 t/ha of dry food, which is 1.4–2 times higher than in the surrounding steppe. On weakly and unwinnowed sands of the Astrakhan Trans-Volga region, in 20- to 60-year-old forest–pastures with protective fodder plantings of Haloxylon aphyllum, C. aphyllum, and K. ceratoides, the consumed mass of shrubs is 0.1–4 t/ha, while the grass stand is 0.3–1 t/ha, which is 20% more than in the open steppe. Pastures with tree and shrub layers attract animals and are more resistant to deflation. The functional durability of silvopastures depends on the technology of their creation, maintenance, and operation regime. The most important measures are fire protection and rationing of the pasture load. [ABSTRACT FROM AUTHOR]

The present study evaluates the amelioration of fat clay by blending it with cohesive non-swelling soil (CNS) and cohesionless silty sandy soil (Kassu). The fat clay sample with a liquid limit (LL) of 50 and a plasticity index (PI) of 26 was collected from Narowal, while CNS and Kassu samples were procured from Lahore's outskirts. Geotechnical tests on the virgin soil indicated its unsuitability for construction. Laboratory tests, including modified Proctor compaction, unconfined compression, California bearing ratio (CBR), and one-dimensional consolidation, were performed on samples blended with 0–35% CNS or Kassu in 5% intervals. The LL and PI of fat clay decreased significantly with the addition of 35% CNS (LL: 50–32%, PI: 24 to 13) and Kassu (LL: 50–29%, PI: 24–12). The CBR value increased from 4 to 7%, making the blended soil suitable for subgrade use. Unconfined compression tests showed a strength increase from 102 to 185 kPa with 35% CNS and up to 140 kPa with 25% Kassu. Compaction tests revealed improved maximum dry unit weight and reduced optimum moisture content. Swell potential decreased from 4 to 1.2 and 0.26% with CNS and Kassu additions. Regression models predict swell pressure and ultimate swell potential. The study concludes that blending fat clay with CNS and Kassu significantly improves its geotechnical properties, with CNS being more effective in controlling swell characteristics. [ABSTRACT FROM AUTHOR]

Adding organic soil amendments can improve the physical and hydrological properties of soil, subsequently enhancing fertility for better crop production. In this study, spent Arabica and Columbian coffee wastes and their respective biochars were evaluated as soil amendments to improve the physical and hydrological properties of loamy sand soil and enhance maize (Zea mays L.) crop growth. Spent Arabica coffee (AC) and Columbian coffee (CC) wastes were collected and transformed into biochar through pyrolysis process at 550 °C with a residence time of 3 h and pyrolysis rate of 5 °C per minute. The AC and CC derived biochar were termed as ABC and CBC, respectively. The produced soil amendments were applied to soil at 0% (control), 1%, 3%, and 5% in a column setup. The moisture characteristics, including water infiltration, evaporation, and water retention, were investigated. Thereafter, the prepared amendments were applied to loamy sand soils at 0% (control), 1%, 3%, and 5% (w/w) application rates. Maize growth was then observed for a period of 30 days under greenhouse conditions. Results of the column trials showed that ABC and CBC applied at 5% reduced the cumulative water evaporation by 57%–66% and cumulative infiltration by 124%–181% compared to control. Likewise, 5% application of ABC and CBC resulted in 101 to 130% higher water retention in loamy sand soil. Results of the greenhouse experiment showed that 5% application of ABC and CBC amendments resulted in root biomass of 2.12 and 2.38 g, respectively, as compared to 0.51 g in control treatment. Similar treatments resulted in shoot biomass of 9.70 and 9.93 g respectively, as compared to 7.37 g in control. Likewise, 5% application of CBC and ABC increase plant height from 15.71 to 30.94 cm in ABC and 33.23 cm in CBC. Overall, 5% application of coffee waste-derived biochars significantly reduced water evaporation and infiltration, while increasing soil water retention and maize plant height, root biomass, and shoot biomass. Therefore, spent coffee waste-derived biochar could effectively be employed to improve physical and hydrological properties of loamy sand soils for better crop productivity. [ABSTRACT FROM AUTHOR]

Aeolian sandy soil and loess soil of the Mu Us Sandy Land are used as the research material in this study to investigate the effect of soil compounding on the improvement of aeolian sandy soil and to provide a feasible approach for sand prevention and sand control. In particular, loess soils were compounded at 0%, 20%, 40%, 60%, 80%, and 100% by volume percentage of the compounded soils. The improvement benefits of compounded soils on their textural properties, water-holding capacity, and fertilizer-retention capacity at different blending ratios were evaluated. The results showed that following the compounding of aeolian sandy and loess soils, with the increase of the loess proportion, the texture type of the compounded soil transforms from sandy soil to loamy sandy soil to sandy loam to loamy soil to powdery loam. Moreover, granular gradation was observed, the bulk density gradually decreased, the capillary porosity gradually increased, and the performance of water- and fertilizer-holding properties gradually increased and strengthened. The spatial variability of compounded soil bulk density, capillary porosity, and the water-holding and fertilizer-retention properties was almost entirely controlled by the proportion of loess soil. A theoretical basis is provided in this study for aeolian sandy soil improvement in the Mu Us Sandy Land that can be extended to similar areas, providing a feasible sand management approach. [ABSTRACT FROM AUTHOR]

The issue of water and wind erosion of soil remains critically important. Polymeric materials offer a promising solution to this problem. In this study, we prepared and applied an interpolyelectrolyte complex (IPEC) composed of the biopolymers chitosan and sodium carboxymethyl cellulose (Na-CMC) for the structuring of forest sandy soils and the enhancement of the pre-sowing treatment of Scots pine (Pinus sylvestris L.) seeds. A nonstoichiometric IPEC [Chitosan]:[Na-CMC] = [3:7] was synthesized, and its composition was determined using gravimetry, turbidimetry, and rheoviscosimetry methods. Soil surface treatment with IPEC involved the sequential application of a chitosan polycation (0.006% w/w) and Na-CMC polyanion (0.02% w/w) relative to the air-dry soil weight. The prepared IPEC increased soil moisture by 77%, extended water retention time by sixfold, doubled the content of agronomically valuable soil fractions > 0.25 mm, enhanced soil resistance to water erosion by 64% and wind erosion by 81%, and improved the mechanical strength of the soil-polymer crust by 17.5 times. Additionally, IPEC application resulted in slight increases in the content of humus, mobile potassium, mobile phosphorus, ammonium nitrogen, and mineral salts in the soil while maintaining soil solution pH stability and significantly increasing nitrate nitrogen levels. The novel application technologies of biopolymers and IPEC led to a 16–25% improvement in Scots pine seed germination and seedling growth metrics. [ABSTRACT FROM AUTHOR]

The aim of this work is to reveal correlation between the spectral characteristics of the open soil surface on the Pleiades image (April 25, 2020) and soils of a key site with a complex soil cover pattern in the south of the Volga Upland (Volga–Don irrigation system, Volgograd oblast). The study area is specified by the lithological heterogeneity: Paleogene and Neogene sands and loams are overlain by a mantle of Quaternary brown loams of variable thickness from 1–2 m to complete thinning out. The soil cover is represented by light chestnut solonetzic complexes complicated by a mosaic of lithological variants and erosion–accumulative combinations. Eight soil groups have been specified, and a map of their distribution has been developed for the key site of 343 ha with the use of digital methods of processing the spectral characteristics of the satellite image and ground-based soil information. Soil groups differ in general features of the soil surface due to differences in the contents of gravel and stones, texture of the surface horizon (from sand to silt loam), occurrence of brightened crusts, and surface effervescence depending on the thickness of the upper lithological layer. Soils with different horizonation of the profile—agrochestnut soils, agrozems, and agrosolonetzes—fall within the same groups of surface spectral characteristics; vice versa, soils of the same genetic type and, sometimes, subtype fall into different groups. This is explained by the incomplete correspondence of the properties of the soil surface affecting the spectral characteristics to the internal structure of the soil profile as a whole. [ABSTRACT FROM AUTHOR]

The effect of land use on sandy soils of southern Botswana was carried out by comparing the composition and properties of soil organic matter. Non-disturbed and disturbed soils were sampled from savanna ecosystems (Central District and Kweneng District). The biodegradability of organic matter was evaluated by incubation in the laboratory. Humic fractions were quantified and humic acids were analyzed by visible and infrared spectroscopy. The results indicate that continued disturbance, whether due to grazing or subsistence farming, has resulted in small yet significant changes in the concentration of available nutrients and organic matter in the soil. Nevertheless, substantial changes could be established in the soil C/N ratio, in the humic acid/fulvic acid ratio, and in the biodegradability of soil organic matter and the structural characteristics of humic acids. The increased aromaticity of humic acid (visible and IR spectroscopies) following disturbance suggests increased biogeochemical activity and/or the impact of abiotic processes (such as periodic fires) selectively removing aliphatic constituents. The overall results indicate low potential soil fertility, the sustainable preservation of which depends more on features related to quality than on the total amount of the soil organic matter, which shows aromatization parallel to its degree of association with the mineral fraction. [ABSTRACT FROM AUTHOR]

Coix lacryma-jobi L., an annual or perennial plant belonging to the Poaceae family, has long been cultivated as a food and medicine plant in China. In recent years, coix cultivation for high yields and good quality has become a research hotspot in Southwest China. Soil optimization is essential for improving crop growth. To ensure the robust establishment of coix plants, eight soil substrates, prepared from three typical soils, i.e., red clay soil, peat soil, and sandy soil, were used to cultivate two local coix varieties (Pu coix from Fujian Province, China; Qi coix from Hebei Province, China), and the plant growth and root coixol content of the two coix varieties were investigated. It was found that coix plants could maintain growth when cultivated with peat soil or sandy soil, but red clay soil was unfavorable for coix growth. The mixtures of sandy soils and peat soils resulted in synergistic benefits for coix growth and root coixol levels over the effects of sandy soil or peat soil alone. In conclusion, the mixtures of sandy soils and peat soils with appropriate proportions (sandy soils/peat soils = 2:1) were suggested as an ideal soil substrate for coix cultivation. The results provide valuable guidance for the establishment of coix plants, which could contribute to high yields and good quality in coix cultivation. [ABSTRACT FROM AUTHOR]

This research initiative, developed in response to the need for enhanced mechanization efficiency within solar greenhouses, particularly under yellow sand cultivation conditions, introduces an integrated ditching and film-covering machine. A novel spiral staggered throw-cut combined ditching knife was specifically engineered and optimized to meet the exacting agronomic requirements of embedded substrate cultivation. Extensive analyses of soil interactions and the formulation of dynamic equations for soil particles facilitated the determination of key operational parameters: a tangent height of 650 mm for the ditching knife, a soil-throwing width of 300 mm, a piece width of 120 mm, and an inclination angle of 30°. Performance simulations of the ditching knife, conducted using the discrete element method (DEM), revealed superior soil disturbance control and improved soil return compared to conventional designs. Critical operational variables such as forward speed, knife shaft speed, and ditching depth were rigorously tested, with trench depth quality and power consumption as primary evaluation metrics. The results demonstrated that knife shaft speed profoundly influences performance, with optimal operating parameters established through detailed field testing: a speed of 0.5 m/s, a blade shaft speed of 200 rpm, and a ditching depth of 300 mm. Under these optimized conditions, the machine achieved power consumption of 0.668 kW, trench depth stability of 86.7%, a surface width of 413 mm, a bottom width of 304 mm, and an average ditching depth of 310 mm, achieving a qualification rate of 87.1%. The post-ditching soil crushing rate was 92.4%. Both simulation and field evaluations validated that the innovative ditching knife markedly enhances ditching and soil-throwing quality in sandy soil, fulfills agronomic requirements for tomato sowing, and provides an essential reference for the mechanized planting of crops in the yellow sand matrix cultivation mode of solar greenhouses. [ABSTRACT FROM AUTHOR]

Bentonite-sand mixture is considered to be a potential liner material for landfill facilities owing to its excellent sorption potential and swelling characteristics. Such liner materials are expected to perform satisfactorily if the hydraulic conductivity is maintained less than 10−7 cm/s and thereby inhibiting the migration of the generated leachate. However, the performance assessment of these liners in the presence of highly concentrated organic fluids and under the overburden stresses that is usually expected in landfill conditions is scarce. Therefore, in the present work, the hydraulic performance of the bentonite-sand mixtures in the presence of the organic compounds commonly encountered in the landfill leachate is studied, which is a need of the hour. Flow tests were performed to evaluate the hydraulic conductivity of different bentonite-sand mixtures in unhydrated conditions and permeated with varied proportions of methanol-water and ethanol-water mixtures. The study reveals that the proportions of the organic pore fluids significantly influence the hydraulic conductivity of the bentonite-sand mixtures. A very good linear relationship was observed between the pore fluids' dielectric constants and the hydraulic conductivity of the bentonite-sand mixtures. The chemo-mechanical behavior suggests that the conventional bentonite-sand mixtures perform poorly in terms of the hydraulic and swelling characteristics with the change in the dielectric constant of the organic fluids. The microstructural analysis also supports the experimental findings that as the dielectric constant of the fluid are reduced, the effective flow path through the soil increases considerably resulting in higher hydraulic conductivity. [ABSTRACT FROM AUTHOR]

Background and aims: Olive trees are one of the most important crops in the Mediterranean, especially in Morocco, and they are vulnerable to various soil-borne pathogens that can cause significant yield losses and economic damage. This study aimed to investigate the diversity, abundance, and community composition of phytopathogenic nematodes in Moroccan olive agroecosystems, and to evaluate the impact of agroecological patterns on their abundance. Methods: Soil and root samples were collected from 13 olive-growing localities across 7 Moroccan regions (43 nurseries/22 orchards), and nematodes were ecologically assessed through the calculation of several diversity indices (e.g., Shannon Index, Evenness, and Plant Parasitic Index). In addition, the main nematode genera were evaluated in terms of soil types, irrigation regimes, and landscape complexity. Results: The obtained results revealed the presence of a diverse and complex community of phytopathogenic nematodes represented by 25 genera, including Meloidogyne, Pratylenchus, and Helicotylenchus among others. The abundance and diversity of nematodes varied significantly between the different regions and agroecological patterns, with higher densities observed in simple landscapes and higher irrigation regimes. Moreover, the community of dominant nematodes was influenced by soil types. Root-knot nematodes were the most prevalent in sandy soils, while root-lesion nematodes were significantly present in the clayish setting. The occurrence and severity of nematode damage were also correlated with the overall taxonomic richness shaped in different olive landscape modes. Conclusion: This study provides updated information and prospects into nematode sustainable monitoring and management in North African olive agroecosystems. [ABSTRACT FROM AUTHOR]

Microbial-induced calcium carbonate precipitation (MICP) is an emerging in situ grouting technology for sand ground improvement, slope stability, and subgrade reinforcement, featuring rapid implementation and low energy consumption. The precipitated calcium carbonate crystals can rapidly fill and cement sand particles so as to form a new soil structure that effectively reduces liquefaction sensitivity and dynamic damage. The centrifuge shake table test is an effective method for simulating liquefaction of sandy soil layers under shear wave excitation. Many studies have been conducted on this topic in recent years. However, the study on dynamic response, especially the liquefaction resistance of MICP-cemented sands by centrifuge shake table tests, is rare. In order to investigate the cementation effect of microbial treatment, centrifuge shake table tests were performed on two models, i.e., untreated and MICP cemented sand model. The test results indicated that, compared with untreated sand model, the liquefaction resistance of the MICP model was significantly improved in terms of acceleration response, shear stiffness, stress–strain relationship, and ground surface settlement. This study contributes to a better understanding of the mechanical law in the liquefaction process and enriches the engineering application of microbial grouting treatment of sand foundation prone to liquefaction. [ABSTRACT FROM AUTHOR]

After a wildfire event, ash is a newly formed surficial soil layer with microscale properties such as roughness, morphology, and chemical composition that may impact how ashes form fabrics in situ and so affect the overall hydrological conditions of a burned area (infiltration capacity, permeability, etc.). To examine the effects of ash microscale properties on macroscale behavior, eight wildfire ash samples from California were characterized physically (specific gravity, specific surface area, particle size, etc.), chemically (elemental composition, organic and inorganic carbon content, etc.), and geotechnically (strength, compaction, saturated hydraulic conductivity, etc.). The tested ashes were found to contain predominantly organic unburned carbons and carbonates derived from the combustion of calcium-oxalate rich fuels in temperatures likely ranging from 300°C to 500°C. Ashes had high specific surface areas because morphologically, particles had highly texturized and porous surfaces. Additional water was necessary to coat the particle surfaces, which led to high liquid limits and compaction optimum moisture contents. Hydraulic conductivity values were within range for silty sands (10−5–10−3 cm/s), and specimens had friction angles near 30°. However, tested ashes consistently demonstrated high void ratios and low bulk densities during testing for strength, hydraulic conductivity, and compaction. These anomalies were attributed to unusual carbonate morphologies; the high interparticle friction of these phases allowed ashes to form looser fabrics than a typical silty sand and contributed to the measured high void ratios, low maximum dry unit weights, and high friction angles. Overall, we hypothesize that the relative amounts of inorganic versus organic constituents in our wildfire ash samples affected how the ashes formed fabrics and so affected their geotechnical properties. Practical Applications: The role of wildfire ash in the postfire hydrological response of a catchment is not perfectly understood. Ash is a very heterogenous material whose properties are directly related to its formation environment (fuel type and accessibility, fire duration, and fire temperature, to name a few). This newly formed surface soil layer has unusual properties compared to natural soils, including low bulk densities and high porosities (sometimes up to 70% or more) in situ, but there is currently not enough information on ash properties in the literature to fully explain why. This study addresses this gap by providing physical, chemical, and geotechnical information about wildfire ashes. This is one of the first studies to specifically test wildfire ash maximum density, Atterberg limits, and shear strength. It provides geotechnical data to the community as well as information about ash chemical and physical properties. We hope that this study not only supplements the current literature on postwildfire landscapes but also informs researchers, engineers, and policy makers about how the formation environment of ash can influence its engineering behavior, such as strength, compressibility, and permeability. [ABSTRACT FROM AUTHOR]

Pipe-soil interactions are a crucial consideration in the realization of shallow-embedded pipelines' in situ stability, and the choice of pipe-soil interaction model is correlated with the distinction between "light" and "heavy" pipe motion patterns. Based on the difference in the motion pattern of a shallow-embedded pipeline in sandy soil after a breakout, a numerical model of pipe-soil interaction is constructed. The influencing factors of different motion patterns are studied, while taking into account the shear expansion or shrinkage characteristics of sand. Accordingly, a method of discriminating pipeline motion patterns is proposed. The results show that the motion pattern of a shallow-embedded pipeline in sandy soil depends on the relative weight of the pipe and soil bearing capacity, that the smaller the embedment, the easier the "heavy pipe" motion pattern appears, and that the critical pipe weight required for "heavy pipe" motion increases with initial sand density and pipeline embedment depth. This paper outlines the different motion patterns of pipelines during breakout stage in sandy soil. A numerical model that can consider the mechanical response of sand in pipe-soil interaction is established, and the factors influencing the light and heavy pipe motion patterns of submarine pipelines are analysed. Based on the numerical results, the empirical and theoretical formulas for assessing the critical pipe weight in sand are proposed. These formulas offer a basis for distinguishing between the "light pipe" and "heavy pipe" motion patterns of shallow-embedded pipes in sand. [ABSTRACT FROM AUTHOR]

Vegetation restoration has an important effect on soil carbon (C) pool dynamics. Highly stable iron (Fe)‐associated C is an important component of the soil C pool and it plays a crucial role in the soil C cycle. However, a knowledge gap remains regarding the existence of Fe‐associated C variation during vegetation restoration. Herein, 0–60 cm soil samples of cropland, grassland, shrubland and forestland from three soil types (loam, loess and sandy soils) were collected to explore the response of Fe‐associated C to vegetation restoration. The results showed that soil Fe‐associated C proportion in the study area ranged from 2.2% to 26.3%. Surface soil (0–20 cm) Fe‐associated C content in loess and sandy soils increased following vegetation restoration, but decreased in loam soil. The accumulation efficiency of soil Fe‐associated C during vegetation restoration was higher in coarser soils. Moreover, the Fe‐associated C content and proportion of forestland with a higher soil organic matter (SOM) pool were the highest among the land use types. Vegetation restoration affects soil Fe‐associated C in two different ways: (1) increasing the SOM and dissolved organic C and improving the efficiency of C and Fe binding to promote the accumulation of Fe‐associated C; (2) decreasing the total soil Fe content, reducing the trivalent iron (Fe(III)) to bivalent iron (Fe(II)) and breaking the binding of C and Fe to decrease soil Fe‐associated C content, and these two different ways were found in all three soil types. Additionally, higher SOM accumulation efficiency and less root destruction caused by vegetation restoration in coarse soils resulted in a higher Fe‐associated C accumulation efficiency. Synthesis and applications. Vegetation and soil type strongly regulated the effects of vegetation restoration on soil Fe‐associated C. Forestlands may be the optimum vegetation type to provide soil C sequestration benefits, effectively increasing soil C pool and maximising Fe‐associated C content. This study has addressed the knowledge gap regarding the effects of vegetation restoration on soil Fe‐associated C and provides scientific basis for a better understanding of the soil C cycle and developing scientific vegetation restoration measures. [ABSTRACT FROM AUTHOR]

This paper presents the results of studying changes in the main parameters and properties of soils in larch and pine forests growing on sandy soils of the Lena-Vilyui interfluve of Central Yakutia, where catastrophic forest fires occurred in 2021. According to the remote monitoring information system of Rosleskhoz, in 2021, almost 8.5 million hectares of forests burned in Yakutia, which is considered as one of the largest forest fires in Russia and in the world in that year. After the fire passes through the forest floor, the content of organic matter decreases as a result of combustion processes. The acidity of the soil changes towards its alkalization due to the entry of combustion products. Changes in soil profiles occur; turbation processes begin more intensively, which in turn change the natural distribution of soil indicator values such as the organic carbon content, the pH, and the number of exchangeable bases. Due to the sharp increase in heat supply after a fire, the depth of seasonal thawing in the soils of burnt larch forests increases by a quarter and by twofold in pine forests. With the beginning of the thawing of the seasonally frozen layer, all the soils experience waterlogging, and ground water occurs above the permafrost. [ABSTRACT FROM AUTHOR]

Terfezia boudieri Chatin (T. boudieri), which belongs to the Terfeziaceae family, is a desert truffle growing naturally from mycorrhizal relationships with plants that inhabit the slightly moist sandy soils of some desert or semi-desert regions. The chemical examination of the methanolic extract of T. boudieri led to the isolation of a new ketone and the known compound mannitol. The structures of the 2 isolated compounds were resolved using spectroscopic analysis including 1D and 2D Nuclear Magnetic Resonance (NMR), Infrared (IR) spectroscopy and were supported by literature data. The GC-MS analysis of the Fatty Acids (FAs) of T. boudieri oils showed high Unsaturated FA (UFA) profile (78.72%). The major FAs were linoleic acid (62.36%) and oleic acid (14.7%). Comparing the extracts obtained, the methanolic extract revealed the highest levels of Total Phenolic Content (TPC) of 185.56 mg GAE/100 g of truffle, thus the same extract showed the best results for antioxidant activity. [ABSTRACT FROM AUTHOR]

Most field corn in the United States receives a neonicotinoid seed treatment for the management of early-season, soil-dwelling insect pests. Grubs of Maladera formosae (Brenske) (Coleoptera: Scarabaeidae) have been reported feeding on young field corn with both low and high rates of clothianidin seed treatments in Indiana, Michigan, and Ohio. Anecdotally, these infestations are restricted to sandy soils in the region. The purpose of this study was to (1) evaluate whether grub populations in corn are restricted to sandy soils, (2) assess whether soil type influences M. formosae survival, and (3) determine whether soil type affects clothianidin uptake by the plant, possibly explaining the observed differences in M. formosae abundance by soil type. We observed nearly 10-times more grubs in sand (>80% sand content) than loam (<80% sand content) soil within a single corn field. Grub survival to adult was not influenced by soil type. We then compared the concentrations of clothianidin seed treatment in the roots and shoots of corn seedlings grown in either sand or loam soil over time. Similar amounts of the active ingredient were found in the roots and shoots of corn grown in both soil types. Within 2 week, the clothianidin concentrations in both soil types had significantly declined in roots and shoots and were no different from the no-insecticide control. These findings suggest that factors other than insecticide exposure contribute to the higher abundance of M. formosae larvae in sand relative to loam soils, even within the same field. [ABSTRACT FROM AUTHOR]

Crop rotation increases crop yield, improves soil health, and reduces plant disease. However, few studies were conducted on the use of intensive cropping patterns to improve the microenvironment of saline soils. The present study thoroughly evaluated the impact of a three-year maize–peanut–millet crop rotation pattern on the crop yield. The rhizosphere soil of the crop was collected at maturity to assess the effects of crop rotation on the composition and function of microbial communities in different tillage layers (0–20 cm and 20–40 cm) of sandy saline–alkaline soils. After three years of crop rotation, the maize yield and economic benefits rose by an average of 32.07% and 22.25%, respectively, while output/input grew by 10.26%. The pH of the 0–40 cm tillage layer of saline–alkaline soils decreased by 2.36%, organic matter rose by 13.44%–15.84%, and soil-available nutrients of the 0–20 cm tillage layer increased by 11.94%–69.14%. As compared to continuous cropping, crop rotation boosted soil nitrogen and phosphorus metabolism capacity by 8.61%–88.65%. Enrichment of Actinobacteria and Basidiomycota increased crop yield. Crop rotation increases microbial community richness while decreasing diversity. The increase in abundance can diminish competitive relationships between species, boost synergistic capabilities, alter bacterial and fungal community structure, and enhance microbial community function, all of which elevate crop yields. The obtained insights can contribute to achieving optimal management of intensive cultivation patterns and green sustainable development. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of applying arbuscular mycorrhizal fungi (AMF) on maize root growth and yield formation under different soil conditions. This study was conducted under sandy soil (S) and saline–alkali soil (Y), with treatments of AMF application (AM) and no AMF application (CK). The root characteristics, yield, and quality of maize were measured. High-throughput sequencing technology was employed to assess the impact of AMF on the soil microbial community structure, and the correlation between soil microbes and soil physicochemical properties was elucidated. The results show that under both sandy and saline–alkali soil conditions, AMF application significantly enhanced maize root growth, yield, grain quality, and soil available nitrogen (AN), available phosphorus (AP), and available potassium (AK) contents compared to the CK treatment. Soil microbial Alpha diversity analysis indicated that AMF application effectively increased soil microbial diversity and richness. Principal coordinate analysis (PCoA) and microbial community structure analysis revealed significant differences in bacterial communities between AM treatment in sandy soil (SAM) and CK in sandy soil (SCK), and significant differences in both bacterial and fungal communities between AM treatment in saline–alkali soil (YAM) and CK in saline–alkali soil (YCK). Furthermore, significant correlations between microbial communities and soil physicochemical properties were found, such as AN, AP, AK, soil salinity (SS), and organic matter (OM) content. AMF application had a greater impact on bacterial communities than on fungal communities. This study demonstrated that the use of AMF as a bio-fungal fertilizer was effective in improving spring maize yields, especially in terms of yield increase and quality stability in sandy and saline soils, thereby contributing to safe and sustainable cropping practices. [ABSTRACT FROM AUTHOR]

Purpose: Identify soil properties involved in the adsorption of the bacteriophages (phages) ΦITL-1 and ΦRSP, analyzing different soils and substrates used for greenhouse tomato crops. Methods: Soil samples were collected from greenhouses in Mexico Central, and soil properties were obtained using the NOM-021-RECNAT-2000. For phage adsorption, soil or substrate was mixed with a phage solution, using three different Water Retention Capacity (WRC) levels, incubated under shaking to room temperature, and finally, the plaque-forming units were counted for each phage by titration. Results: The phage elution counts showed that the amount of aqueous solution in the mixture is inversely related to the number of viral particles adsorbed on the soil. Furthermore, the soils with a sandy texture had lower adsorption of phages in comparison with the rest of the soils analyzed, which have clay, clay loam, and sandy loam textures. A correlation analysis showed that soil pH and texture are the properties that most influenced phage adsorption. Finally, a principal component analysis showed that Cation Exchange Capacity (CEC) has a direct relationship with phage adsorption. Conclusion: In the present study, we demonstrated that soil texture, pH, CEC, and WRC are determinant variables that affect the adsorption of R. solanacearum phages ΦITL-1 and ΦRSP. Furthermore, we propose that the responsible mechanism may be due to the richness of cations in the soil, which could imply an electrostatic interaction with some exposed phage proteins. These results highlight the influence of soil properties on biocontrol strategies based on phages, which try to reduce the impact of soil-borne bacterial phytopathogens. [ABSTRACT FROM AUTHOR]

The temperature sensitivity (Q10) of soil respiration (Rs) plays a crucial role in evaluating the carbon budget of terrestrial ecosystems under global warming. However, the variability in Q10 along soil moisture gradients remains a subject of debate, and the associated underlying causes are poorly understood. This study aims to investigate the characteristics of Q10 changes along soil moisture gradients throughout the whole growing season and to assess the factors influencing Q10 variability. Changes in soil respiration (measured by the dynamic chamber method) and soil properties were analyzed in a poplar plantation located in the suburban area of Beijing, China. The results were as follows: (1) Q10 increased with the increasing soil water content up to a certain threshold, and then decreased, (2) the threshold was 75% to 80% of the field capacity (i.e., the moisture content at capillary rupture) rather than the field water-holding capacity, and (3) the dominant influence shifted from soil solid-phase properties to microbes with increasing soil moisture. Our results are important for understanding the relationship between the temperature sensitivity of soil respiration and soil moisture in sandy soil, and for the refinement of the modeling of carbon cycling in terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

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Helicoverpa zea Boddie (Lepidoptera: Noctuidae) is an important pest in many crops in the southern United States. Upon reaching the final larval instar, H. zea quests for a pupation site in the soil. Pupae are vulnerable to mortality since their movement is limited. Soil type and moisture can influence H. zea emergence, but the interaction of these factors has not been demonstrated. We compared sandy and clay soils in greenhouse and laboratory experiments. In the first experiment, we evaluated the preference of larvae to choose either sandy or clay soil for pupation. In a second experiment, we set the sandy soils at different moisture levels and observed prepupae pupation preference in a choice scenario. In a third experiment, we observed prepupae pupation in different moisture levels in a no-choice scenario. In a 4th experiment, we evaluated adult emergence following pupation when we increased moisture or kept it constant. In a final experiment, we evaluated pupation behavior in sandy or clay soils with a webcam and a glass arena. We found that larvae preferred to pupate in sandy soils over clay soils and that pupal success was highest at intermediate moisture levels. In addition, elevated soil moisture levels did not impact the emergence of H. zea between sandy or clay soil. Finally, H. zea did not take longer to burrow in either sandy or clay soil, but the tunnels of the pupal burrow were larger in sandy soil compared to clay soil. Our results clarify H. zea behavior across soil moisture and soil type. [ABSTRACT FROM AUTHOR]

Potassium (K) is the primary limiting nutrient for cassava, being essential to achieve sustainably satisfactory cassava yields in low K reserve sandy soils that require proper K fertilization to avoid depleting the soil K reserve. Soil K dynamics, the growth, and yield responses of cassava were investigated using varying K fertilizer rates (0, 25, 50, 75, 100, and 125 kg K2O/ha). Four on-farm experiments were conducted in major cassava-producing areas, Northeast Thailand during 2019–2021 year. Cassava responded positively to K, producing yield increases up to 132%, with the highest tuber yield obtained being in the range 100–125 kg K2O/ha. Mineral K was the main K source for cassava grown without K fertilization, which resulted in the poorest growth and yield quantities. Potassium fertilization significantly promoted the uptake of K by cassava, especially in the tuber, causing a negative K balance due to the large removal from the soil, even when the K fertilizer compensated to some degree. Potassium use efficiency of cassava was low, particularly with K fertilization at the highest rate, which reflected intense leaching of the soil. The critical level of soil-available K, identified using a linear-plateau model, was 40.55 mg/kg for 90% relative yield, suggesting the potential to increase K use efficiency through better fertilization guidelines. Our findings suggested that K fertilization of cassava annually is advisable for better yields and to avoid progressive depletion of the soil K capital, even though the residual K from K fertilizer contributed to available K in soils. [ABSTRACT FROM AUTHOR]

In the context of COVID-19 rampant worldwide since 2019, the stock of disposable single-use face masks (SUFMs) has climbed steadily, which results in an urgent worldwide environmental problem. This study aims to propose a potential method for processing and utilizing SUFMs in soil reinforcement to address the significant volume of discarded masks, thereby contributing to geotechnical engineering construction. Hence, in this study, SUFMs were prepared into three geosynthetic forms considered potential candidate options: fibers, geotextiles, and geocells. The performance of geosynthetics-reinforced sand was assessed by the static triaxial tests by considering the fibers reinforcement with the content of 0.25% and 1.0%, single-layer and three-layer geotextiles reinforcement, and geocells reinforcement. A series of numerical simulations were also conducted to investigate the failure mechanisms of various reinforced forms. The experimental results show that the three geosynthetic types can improve the sandy soil's shear strength and apparent cohesion. The SUFMs fibers reduce the elastic modulus due to the higher compressibility of the SUFMs, while the elastic modulus of geotextile and geocell-reinforced soil samples is elevated. The numerical analysis results indicate that the SUFMs fibers and geotextiles can limit the lateral deformation and spread the shear stress over a wider area through the interface friction between geosynthetics and soil. On the other hand, the vertical walls of geocells can provide direct lateral restraint, and the reinforcement effect is more direct and better. [ABSTRACT FROM AUTHOR]

Conservation management practices often produced positive but limited desirable outcomes in US Southeast sandy soils, likely due to their intrinsically low clay contents that constrain the soil's capacity to preserve organic carbon (C) and nutrients. In the field, we tested the effectiveness of a novel approach, that is, clay soil amendment, to improve sandy soils. In October 2017, clay‐rich soils (25% clay) were spread at 25 metric tons ha−1 and tilled onto a sandy soil (1.9% clay) in the field, which was further mixed by light tillage at 0‐ to 15‐cm depth, followed by planting winter cover crop mixtures (cereal rye, crimson clover, and winter pea). The crop rotation was cotton and corn with cover crop mixtures planted in the winter fallow season. Soils (0–15 cm) were collected in August 2021 and subjected to physio‐biochemical analyses. Clay amendment increased soil clay content to 3.4%, which improved nitrogen (N) availability by 51% but inhibited the activities of C (β‐d‐cellubiosidase [CB]; β‐xylosidase [BX]; N‐acetyl‐β‐glucosaminidase [NAG]) and N (leucine aminopeptidase [LAP]) cycling enzymes, resulting in up to 78% reduction in microbial respiration. A follow‐up kinetic study on BG and LAP enzymes suggested that clay addition can have different impacts on enzymes with diverse biological origins through distinct mechanisms. Clay addition can potentially improve sandy soils by stabilizing the organic inputs in soils. However, more research is required to understand its long‐term impacts making this approach practical. [ABSTRACT FROM AUTHOR]

The three-dimensional (3D) stability problem of triple-step slopes is important due to their unique profiles under natural rainfall conditions. In this paper, an innovative approach was proposed for rapidly evaluating the stability of triple-step slopes, which considers the effects of diverse hydraulic hysteresis paths caused by rainfall and drought alternation. Considering diverse hydraulic hysteresis paths, a 3D upper-bound analysis (UBA) mechanical model was developed. On this basis, a new analytical solution for the stability number (N S) of 3D slopes under the influence of hydraulic hysteresis was derived through the work and energy equation. The comparisons showed that the new analytical solution and proposed method are correct. Then, ranges of the controlling parameters of triple-step slopes were designed for practical use in slope engineering. Comprehensive discussions were presented, considering four distinct hydraulic hysteresis cases within the context of two typical scenarios involving silty and sandy soils. The results could provide a reference for the design and construction of triple-step slopes where rainy and drought conditions frequently alternate. [ABSTRACT FROM AUTHOR]

The soil–water characteristic curve (SWCC) is an important parameter of unsaturated soil, and almost all the engineering characteristics of unsaturated soil are more or less related to the SWCC. The SWCC contains important information for geotechnical engineering, water engineering, hydrogeology modelling and climate modelling. It is noted that the experimental measurement of SWCC is costly and time consuming, which limits the implementation of principles of unsaturated soil mechanics in practical engineering. The indirect method, which estimates the SWCC from the index properties of soil, can provide the SWCC with the errors which are within tolerance in practical engineering. In addition, the indirect method can determine SWCC very fast and almost with no cost. In this paper, the domestic sandy soils are selected and the index properties of those sands are used to correlate the SWCC fitting parameters. Consequently, mathematical equations are proposed to estimate SWCC from index properties of domestic sands. The proposed models are trained from 44 sets of experimental data and verified with another independent 8 sets of experimental data from published literature. It is observed that the results from the proposed model agree well with the experimental data from literature. [ABSTRACT FROM AUTHOR]

Despite the high sand content of Yellow River water in arid Northwest China, locals in the region opt to use muddy water to meet the demand for agricultural irrigation. Muddy water irrigation is a complex process and is still poorly understood. In this study, six sets of saturated soil column infiltration tests were designed, considering soil texture (silt loam, sandy loam, and sand) and muddy water sand content (3%, 6%, 9%, and 12%) as the influencing factors, with two sets of validation tests. Change in hydraulic conductivity (Kh), the average change rate of hydraulic conductivity (ΔK), and cumulative infiltration volume (I) were experimentally studied in the context of muddy water infiltration to respectively establish the separate functional models and developed to fit their relationship with time. The study results indicated that the hydraulic conductivity (Kh) decreased with increasing muddy water infiltration time. For silt loam and sandy loam, Kh stabilized at 0.0030 and 0.0109 cm/min, respectively, after 70 min of infiltration. In contrast, Kh in the saturated sandy soil column significantly declined throughout the muddy water infiltration, showing a 90.84% reduction after 90 min compared to the saturated hydraulic conductivity of the sandy soil. As the sand content of the muddy water increased from 3% to 12%, Kh decreased by 83.99%, 90.90%, 91.92%, and 92.21% for 3%, 6%, 9%, and 12% sand content, respectively, in the saturated sandy soil columns at the end of the infiltration period. The I values were 21.20, 9.29, 7.90, and 6.25 cm for 3%, 6%, 9%, and 12% sand content, respectively. The ΔK values were 0.0037, 0.0041, 0.0043, and 0.0044 cm/min2 for the respective sand contents, at an infiltration time of 80 min. The validation test demonstrated that the segmented function model accurately emulated the changes in hydraulic conductivity of sandy soil textures throughout the infiltration period. Results from this study provide a significant basis for understanding the mechanisms to hinder muddy water infiltration and to efficiently utilize muddy water for irrigation. [ABSTRACT FROM AUTHOR]

Ammonium sulfate (AS) has been utilized in agriculture; however, there is a dearth of research on its application in maize cultivation subsequent to the implementation of nitrification inhibitors or coating treatments. This study aimed to analyze the impacts of various combinations of AS fertilizers on soil nutrients, plant nutrient uptake, yield, and fertilizer utilization efficiency in maize cultivation to establish an optimal and stabilized disposal method for AS. A completely randomized design was employed with five treatments (AU, the control using urea; AS, treatment using ammonium sulfate; ASN, treatment using ammonium sulfate with a nitrification inhibitor; ASG, treatment using oil-coated ammonium sulfate; and ASD, treatment using oil–humic acid-coated ammonium sulfate). The results show the following: (1) Compared with AU and AS, ASN, ASG, and ASD decreased the leaching rates of total nitrogen (TN), ammonium nitrogen (NH4+-N), and nitrate nitrogen (NO3−-N), and more residual N had accumulated in the soil. The first-order kinetic equation Nt = N0(1 − e−kt) could better fit the process of N accumulation and release, and the N-release rate constant was in the order of AU > CK > AS > ASG > ASN > ASD. (2) Compared with the AU and AS treatments, the plant dry weight, grain dry weight, spike width, spike length, and yields of maize increased by 8.85–11.08%, 12.98–14.15%, 2.95–3.52%, 5.50–5.65%, and 43.21–51.10%, respectively, under the ASG treatment. A path analysis revealed the main decision coefficient of the effective spike number on the maize yield. Furthermore, the accumulation levels of N, P, and K within above-ground plants significantly increased under the ASG treatment compared with those under the AU and AS treatments. N, P, and K partial factor productivity under the ASG treatment increased by 47.12%, 47.15%, and 73.40% on average, while grain N, P, and K balance increased by 50.45%, 47.10%, 55.61% on average, compared with the AU and AS treatments. Therefore, the ASG treatment exhibited the optimal slow-release effect on nutrients and achieved excellent performance in enhancing the production and efficiency of maize. [ABSTRACT FROM AUTHOR]

The problem of poor water and fertilizer retention in sandy soils can lead to physiological growth restriction and yield and quality decline in apples. Sodium carboxymethyl cellulose (CMC) formula can improve the soil structure and increase the water- and fertilizer-holding capacity of the soil, and Biogenic Stimulant (BS) can improve the drought stress resistance of crops and promote the physiological growth of crops. Considering that CMC and BS may improve the physiological characteristics of sandy soil apples, in this study, CMC was coupled with BS in sandy apples, and the effects on the physiological characteristics, yield, and quality of apples were systematically investigated. The results showed that CMC and BS could increase leaf N, P, and K content, with the greatest increases seen in the Y2C2 treatment (9.28, 0.61, and 0.56 g kg−1, respectively) compared with the CK treatment. The SPAD values of leaves following the coupled CMC and BS treatment compared to the CK treatment were elevated in the range of 4.47–24.29% at the flowering and fruiting stage, 2.84–26.50% at fruit expansion stage, and 6.64–19.41% at maturation stage. In the light response data of different treatments, the maximum net photosynthetic rate occurred in the Y2C2 treatment, and the net photosynthetic rate, transpiration rate, and stomatal conductance were all the highest in the Y2C2 treatment during the fruit expansion stage, with the net photosynthetic rate being higher than that of the CK treatment by 5.09 µmol m−2 s−1. The combination treatments of CMC and BS increased apple yield by 10.69 to 27.62% as compared to the CK treatment, and also increased soluble reducing sugar, soluble solids, and VC and reduced the titratable acid content. There was no correlation between the SPAD value during fruit expansion (p > 0.05) and the other physiological indexes (p < 0.05). Through the established functional relationship between the application rate of CMC and BS and apple yield, the recommended BS application rate of 27 kg ha−1 and CMC application rate of 20.625 kg ha−1 could yield up to 43,357.8 kg ha−1. [ABSTRACT FROM AUTHOR]

Bacterial leaf streak caused by Xanthomonas vasicola pv. vasculorum (Xvv) is an emerging disease in several corn-producing regions around the world. In Brazil, there is a lack of information on the survival of this bacterium in soil and crop residues. Thus, the objective of this study was to determine the survival of Xvv in soil and also in infected corn crop residues under the humid subtropical climate of southern Brazil. The survival of Xvv in soil was initially investigated in sandy and clayey soils maintained at 20, 25 and 30 °C under controlled conditions. The survival of the bacterium under field conditions was studied in artificially infested clayey soil. The survival of Xvv in corn crop residues was investigated in infected residues maintained on the soil surface or buried in the soil at 20 cm deep. Under controlled conditions, regardless of the type of soil, the bacterium survived longer at 20 °C than at higher temperatures. The bacterium survived for 40 days in clayey soil kept at 20 °C and four days in sandy soil maintained at 30 °C. Under field conditions, the survival of Xvv in the soil was only for 48 h and in infected corn crop residues for up to 15 days in the samples maintained on the soil surface. In samples of infected corn residues buried in the soil, the bacterium was only detected at the time the experiment was set up. In general, the results obtained in this study revealed that Xvv survives for a short period of time in soil and in infected corn crop residues under humid subtropical conditions. Therefore, soil and corn residues may not be highly important sources of primary inoculum for the development of bacterial leaf streak on corn crops under these conditions. [ABSTRACT FROM AUTHOR]

In regions with sandy soft soil strata, the subway foundation commonly undergoes freeze–thaw cycles during construction. This study focuses on analyzing the microstructural and fractal characteristics of frozen–thawed sandy soft soil to improve our understanding of its strength behavior and stability. Pore size distribution curves before and after freeze–thaw cycles were examined using nuclear magnetic resonance technology. Additionally, fractal theory was applied to illustrate the soil's fractal properties. The strength properties of frozen remolded clay under varying freezing temperatures and sand contents were investigated through uniaxial compression tests, indicating that soil strength is significantly influenced by fractal dimensions. The findings suggest that lower freezing temperatures lead to a more dispersed soil skeleton, resulting in a higher fractal dimension for the frozen–thawed soil. Likewise, an increase in sand content enlarges the soil pores and the fractal dimension of the frozen–thawed soil. Furthermore, an increase in fractal dimension caused by freezing temperatures results in increased soil strength, while an increase in fractal dimension due to changes in sand content leads to a decrease in soil strength. [ABSTRACT FROM AUTHOR]

Sweet basil is very important in the culinary and pharmaceutical sectors because it contains volatile oils that have a variety of biological functions. Considering the economical costs and adverse effects of chemical fertilizers, attention has been turned to the use of ecofriendly and cost effective alternatives. In this regard, eggshells could be used as a natural calcium source for nutring the medicinal and aromatic plants. Therefore, the aim of this trial was to assess the productivity of sweet basil in response to different application methods of eggshells on sandy soil. In this study, eggshells were added to the soil at rates of 1, 2, and 3 g/pot, to foliage at rates of 0.5, 1, and 1.5 g/L, and to irrigation water at rates of 1, 2, and 3 g/L; a rate of 0.5 g/pot of calcium carbonate also used as a reference. Plants exposed to eggshells at 1.5 g/L foliar spray gave the maximum values of fresh and dry weights herb (172.11 and 23.48 g/plant), carbohydrates (36.74%), crude protein (16.56%), inhibition of free radical scavenging (47.61%), total phenols (15.03 mg/g), total flavonoids (2.87 mg/g), and essential oil contents (1.18% or 27.71 g/100 plants). On the other hand, plants subjected to eggshells at 0.5 g/L foliar spray produce the highest amounts of linalool (76.34%) and oxygenated monoterpenes (83.37%). It may be concluded that the morphological and physiological characteristics of sweet basil plant may be enhanced by eggshells. [ABSTRACT FROM AUTHOR]

In this paper, a series of true triaxial tests with different intermediate principal stress ratios are conducted on both the lunar soil simulant and the sandy soils on earth using the discrete element method. An advanced discrete element servomechanism based on polyhedral specimen configuration is implemented such that true triaxial loading paths can be implemented under low confining pressure without introducing severe stress concentration. The high frictional angle and apparent cohesion of the lunar simulant are captured by employing a highly efficient contact model that fuses rolling resistance and van der Waals forces. The employed micro-scale parameters are calibrated based on the triaxial test results of the CSU-LRS-1 lunar soil simulant. The simulation results show that the lunar soil simulant exhibits lower shear strength with an increasing intermediate principal stress ratio. Generally, although the lunar soil simulant has a greater void ratio than that of sandy soils, the former exhibits significantly stronger shear-induced dilatancy and higher shear strength. The evolution of the load-bearing structure is quantified through a contact-normal-based fabric tensor. The interplay between internal structure evolution and external loadings can well explain the difference in mechanical behavior between lunar soil simulant and sandy soils on earth. [ABSTRACT FROM AUTHOR]

Fertiliser amendment is the most direct method for improving soil properties of ecologically vulnerable areas (e.g. desertification soil area), and then, understanding the response of microbial community activities and growth to different fertilisation treatments is of great significance in sandy soil restoration. Here, a field experiment with different fertiliser treatments in typical alkaline–sandy soil was conducted. In this study, the difference of physicochemical property, microbial communities and functions in different treatments of no fertiliser (CK), (ii) fly ash chemical fertilisers (CF), (iii) humic straw organic fertiliser (OF), (iv) functional microbial fertiliser (FMF), (v) sulphate-reducing bacterial (SRB) fertiliser (MF) and (vi) humic straw organic fertiliser + functional microbial fertiliser + SRB fertiliser (CMF) were evaluated. The result showed that the contents of soil total organic carbon, NO3-N, P and K in the FMF were highest. The abundance of keystone taxa (Gemmatimonadetes and Thaumarchaeota) increased significantly in the treatments of microbial fertiliser. Microbial fertiliser boosted genes for aerobic nitrite oxidation, nitrogen fixation, ammonia oxidation and aromatic compound degradation. The number of methylotrophy and dark sulphur oxidation genes was reduced. The bbove results indicated that the treatments with the inoculation of functional microbes are better than the others for the restoration of alkaline–sandy soil. [ABSTRACT FROM AUTHOR]

In some offshore implementations, such as the foundation structures for offshore wind turbines, pile foundations are crucial to withstand enormous lateral loads in combination with the imposed vertical reactions. Due to the low soil strength and stress level near to the seabed, the lateral reaction is weak and compliant close to the pile head. Enlarging the pile close to the pile head and adding fins can boost the lateral bearing capacity. With the extra benefit of providing a reduction in necessary pile length, this cross-sectional expansion improves the overall resistance from the soil. The goal of this inquiry is to showcase the shaft pile technique with fins installed in dry sand. This study examines the observed behaviour of forty-five model experimental test results from combined torsional and lateral capabilities of shaft piles installed in dry sand with and without expansion at the pile head. The impact of these fins, which are positioned at the top of the shaft and have varying widths, was examined. The test results demonstrated that enhancing the fin efficiency of combined torsional and lateral fin pile capabilities required raising both the fin width/pile diameter ratio (Wf/Dp) and sand relative density. At application points of arm length/pile diameter ratio, (E/Dp), of (1.9, 3.8, and 7.6) correspondingly, it was discovered that the fin efficiency, ηT values were around (7.2, 7.52, and 7.62) times the case of conventional pile without fins for dense sand condition. The increase in section modulus is due to the presence of fins which act as a reinforcement to the shaft. The fins enhance the surface area of the shaft, which boosts how the soil, pile, and fins interact with one another. Another advantage of augmenting the fin width of a shaft is that it ameliorates the frictional resistance of the shaft. This is so that the bigger surface area of the shaft creates a greater contact area for the sand strata, resulting in increased friction. This increased frictional resistance helps to restrain the pile from lateral movement, resulting in greater stability. This contributes to an enhancement in the combined torsional and lateral capacities of fin piles. However, the lateral resistance is appreciably diminished in the shafts during the simultaneous employing of torsional and lateral load, as limiting angular rotation is reached before limiting lateral displacement. Reduction in lateral resistance continues linearly with an increase the application point of arm length/pile diameter ratio, (E/Dp). Therefore, this investigation recommends that reduced lateral load resistance be utilized during foundation design. [ABSTRACT FROM AUTHOR]

Secant pile walls (SPWs) are frequently employed as temporary excavation support systems in urban areas; thus, they are useless once permanent foundations and basements have been constructed. Recently, attempts have been made to employ these walls to bear axial loads and lateral earth pressure, which may have significant potential benefits. Unfortunately, the shortage of research that recognizes them as bearing elements, especially numerical studies, has prevented this approach from reaching the final design and implementation stage. Thus, the primary objective of this research was to calibrate a finite element model to depict the performance of axially loaded SPW and extend the finite element analysis by including key factors and additional trials that may impact the performance of the axially loaded SPW. This research investigated various aspects to describe SPW behavior, including the maximum axial capacity of the SPW (Pmax), normalized horizontal deflection (δh/Ht%), normalized ground settlement (δvg/Ht%), the normalized vertical deflection of the SPW (δvw/Ht%), the normalized pivot point location (ε′/He) and settlement influence zone (Do). Several parameters, such as normalized penetration depth (He/Hc), sand relative density (Dr), surcharge load density (Wsur), and wall rigidity (Ht/Dp), were studied and examined in relation to these aspects. Additionally, 224 axially loaded SPW trails were performed as part of a parametric study. The findings demonstrated that the proposed FEM could depict the performance of the experimental model with fair accuracy under the effect of the axial and lateral loads. The effects of the investigated aspects on the Pmax were also discussed in detail. Also, using linear and non-linear regression analysis, the data from the parametric analysis was utilized to create rational relations between the various parameters. The best-achieved mathematical models for predicting the Pmax were also represented in graphical forms. Moreover, these graphs can be a useful and fast tool for civil and geotechnical engineers to predict the maximum axial capacity of an SPW according to the different variables. [ABSTRACT FROM AUTHOR]

Piles supporting large structures are often subjected to cyclic lateral loads due to natural phenomena, including earthquakes, winds, and waves. Such loads are main causes of progressive deterioration in the stiffness and reduce the lateral capacity of piles. However, the effects of unsaturated soil conditions on the lateral cyclic response of piles are not yet fully understood, and the p–y curves used in engineering practice are merely based on the assumption of full saturation or complete dry conditions. This study is aimed to investigate the pile performance under unsaturated soil conditions by performing monotonic, cyclic, and post-cyclic loading tests on piles installed in sand with a varying water table. A loading system was designed and constructed to carry out different types of cyclic loadings. It was observed that the lateral capacity of the pile is influenced by the average suction stress along the pile which increases with the depth of the water table. During the cyclic loading, gap formation is noticed around the pile head for tests conducted in unsaturated conditions, which results in significant stiffness degradation compared to the saturated state. However, post-cyclic loading tests showed that the ultimate lateral capacity of the pile is not affected by the cyclic loading history. Finally, a modified p–y curve is proposed for the piles embedded in unsaturated sandy soils, and a comparison of its performance with the observed results is promising. [ABSTRACT FROM AUTHOR]

Gypseous soil covers approximately 30% of Iraqi lands and is widely used in geotechnical and construction engineering as it is. The demand for residential complexes has increased, so one of the significant challenges in studying gypsum soil due to its unique behavior is understanding its interaction with foundations, such as strip and square footing. This is because there is a lack of experiments that provide total displacement diagrams or failure envelopes, which are wellconsidered for non-problematic soil. The aim is to address a comprehensive understanding of the micromechanical properties of dry, saturated, and treated gypseous sandy soils and to analyze the interaction of strip base with this type of soil using particle image velocimetry (PIV) measurement and Plaxis 3D simulation. The results showed that highresolution digital cameras captured soil deformation using PIV, displacement fields, and velocity vectors were generated, which helped identify different sand movement zones. Further, PIV showed punching and general shear failure in uncontaminated and soaked contaminated gypsum soils, respectively. Moreover, the Plaxis results corresponded well with the PIV, as material behavior models are essentially simplified representations of the actual behavior of footing and soil. Understanding soil deformation behavior is crucial for accurate engineering calculations and designs, making these findings valuable for geotechnical and construction engineering applications. [ABSTRACT FROM AUTHOR]

Many scholars have used samples of drying soil to observe the amount of soil condensation water, which may have exaggerated the amount of regional condensation water, as the soil water content in the natural state was not considered. To analyze the effect of soil moisture content on soil condensation in the natural state, the soil condensation volume in loess and sandy soil under different gravimetric moisture content conditions was measured in the autumn of 2022 and spring of 2023 using micro-lysimeters combined with the weighing method at the groundwater and environment site of Chang'an University, Guanzhong Basin, China. The results showed that the average daily condensation of loess under 0%, 3%, 7%, 11%, and 15% moisture content conditions was 0.34, 0.09, 0.01, −0.05, and −0.07 mm with the condensation days of 54, 40, 24, 21, and 16, respectively, and that of sandy soil was 0.21, −0.02, −0.28, −0.82, and −1.35 mm with condensation days of 54, 24, 2, 3, and 1, respectively. Under the same moisture content conditions, loess had more condensation and condensation days than sandy soil. Soil condensation water occurred mainly when the water content was less than 7%, and it was negatively correlated with soil water content. The quantity of soil condensation water was positively correlated with relative humidity and negatively correlated with air temperature–dew point differences. Relative humidity exceeding 60% and air temperature–dew point differences below 8 °C were more favorable for the formation of soil condensation water. This study provides a reference for the assessment of soil condensation in the natural state. [ABSTRACT FROM AUTHOR]

Accurate information about soil water retention curves (SWRCs) of sands is essential for evaluating groundwater recharge and vulnerability to contamination in many shallow sandy aquifers which are widespread on post glacial areas in Northern Europe and North America. Pedotransfer functions (PTFs) allow to estimate SWRC from basic physical characteristics of soils, such as textural composition. However, in the case of clean sands which are dominated by a single textural fraction, PTFs should be based on more detailed information given by the particle size distribution. In this study we evaluated three parametric PTFs, which estimate parameters of the van Genuchten SWRC based on empirical correlations to the parameters of soil particle size distribution, and five semi‐physical PTFs, which derive the pore size distribution from particle size distribution. PTFs were compared to SWRCs fitted to the results of drainage experiments on sandy soil samples from six locations in Gdańsk region (northern Poland). Although in all samples the content of silt and clay fractions was low (<3.5%), the differences in actual content of fines strongly influenced the shape of SWRC. In contrast, the amount of gravel fraction (varying from 1% to 35%) did not have significant effect on SWRC. Semi‐physical PTFs were found to be more accurate than parametric PTFs. The best overall performance was shown by the semi‐physical Chang and Cheng PTF. Among the parametric PTFs the best accuracy was obtained with the Schaap and Bouten method. However, all considered functions showed limited accuracy in higher suction range. Additionally, infiltration experiments were performed on four sites. SWRCs were obtained from ring infiltrometer tests using the Beerkan estimation of soil transfer parameters (BEST) method and from the tension infiltrometer (TI) tests using numerical solution of the inverse problem based on the Richards equation. In almost all cases the wetting SWRCs were characterized by higher values of the pressure scaling parameter α compared to SWRCs measured in drainage experiments, which is consistent with the well‐known phenomenon of hysteresis in soils. However, the BEST method resulted in significantly higher α and hydraulic conductivity Ks than TI, probably due to activation of the largest soil pores during ponded infiltration. Core Ideas: Semi‐physical pedotransfer functions were more accurate than parametric pedotransfer functions.Comparison of water retention curves from drainage and infiltration experiments showed significant hysteresis.Ring infiltrometer tests provided higher values of the van Genuchten parameter α and the saturated hydraulic conductivity than tension infiltrometer tests. [ABSTRACT FROM AUTHOR]

Understanding specific air–water interfacial area (SAWIA) is essential for characterizing and modeling various phenomena in vadose zone hydrology, such as virus and colloid transport, contaminant dissolution, evaporation, and the hydro‐mechanical behavior of unsaturated soils. Traditional measurement methods, including X‐ray imaging and tracer techniques, often encounter challenges, leading to a scarcity of studies that provide a reliable relationship for SAWIA. Currently, no pedotransfer function in the literature links SAWIA with saturation and suction using readily measurable soil properties such as median grain size and porosity. In this study, we initially developed a pore network model capable of predicting SAWIA by calibrating it with corresponding soil‐water retention curves (SWRCs). We then used these models to compile a comprehensive database of SAWIA for six sandy soils, for which experimental SWRCs were available, covering a range of median grain sizes and porosities. Utilizing this database, we established a pedotransfer function through multigene genetic programming. The accuracy of this function was validated against experimental data not previously used in its training and testing. Our parametric study indicated that increases in either porosity or median particle size led to a decrease in the regions exhibiting higher SAWIA in terms of saturation and suction. Core Ideas: Estimating the specific air–water interfacial area in different hydraulic branches using a pore network approach.Compiling a specific interfacial area database for soils with different values of porosity and median grain size.Using multigene‐genetic programming to extract a pedotransfer function for specific interfacial area.The proposed specific interfacial area pedotransfer function requires only soil median grain size and porosity. [ABSTRACT FROM AUTHOR]

As the world struggles with climate change and energy crises, understanding the role of soil in the food–water–energy nexus becomes increasingly critical. Accurately estimating the soil thermal conductivity drying curve is essential for assessing the impacts of temperature on soil biota and crop growth, environmental changes due to forest fires and global warming, and for designing geo‐energy extraction techniques such as geothermal energy piles. Existing empirical models often fail to accurately estimate the soil thermal conductivity (TC), particularly in pendular soil moisture regimes where they do not capture sharp changes in TC. This study introduces a novel approach using a pore unit cell network model to more accurately describe the dynamics of TC in variably saturated soils. A quadratic parallel scheme within each soil pore unit cell links the TCs of solid, water, and air to the overall effective conductivity. By modeling air invasion in the pore network model and employing the proposed equation, we determined the unsaturated soil TC based on varying local conductivities. The model effectively captures the significant decrease in conductivity in the pendular saturation regime, associated with the shrinkage of the spanning‐wetting cluster. Quantitative analyses showed a substantial improvement in prediction accuracy compared to existing models, especially under varying moisture conditions. Our findings have significant implications for better characterizing soil thermal and hydraulic properties, which are crucial for resource management in a changing climate and advancing geo‐energy technologies. Core Ideas: Spanning‐wetting cluster shrinkage in the pendular regime significantly decreases soil thermal conductivity.Soil thermal conductivity is influenced by both the distribution and specific values of local pore saturation.Pore unit cell network modeling leads to more accurate estimates of the unsaturated thermal conductivity. [ABSTRACT FROM AUTHOR]