From biowastes to risks? Impact of biosolids treatment and dose on antibiotic resistance in agricultural soils - A mesocosm study.

Decoding channel widening dynamics: Linking hydraulic forcing and soil resistance through time-continuous prediction

Cement-stabilized soil is a widely utilized material in infrastructure construction. However, prolonged exposure to freeze–thaw cycles induces surface spalling, cracking, and strength degradation, ultimately compromising the safety and service life of infrastructure. This paper systematically reviews the impacts of freeze–thaw cycles on the physical and mechanical properties of cement-stabilized soils, encompassing stress–strain behavior, unconfined compressive strength, mass loss ratio, hydraulic conductivity, shear strength, elastic modulus, modulus of deformation and resilience, and volume change ratio. It further elucidates the mechanisms through which material composition, freezing/thawing temperatures and durations, specimen moisture content, natural soil grain gradation, and testing methodologies influence these properties. The investigation extends to the mechanisms of freeze–thaw damage and the evolution of associated theoretical frameworks. A comprehensive analysis is presented regarding international freeze–thaw testing standards established by various nations, accompanied by critical evaluations of conventional performance indicators and their inherent limitations. Context-specific metrics are recommended for various environmental conditions. The study synthesizes principal enhancement strategies for improving freeze–thaw resistance, evaluating their performance, construction feasibility, and cost-effectiveness. Future research priorities are identified to advance this field. By providing theoretical foundations and technical guidelines, this work aims to optimize the freeze–thaw resistance of cement-stabilized soils and promote their application in cold-region infrastructure development. These findings offer novel perspectives and methodologies for enhancing the freeze–thaw resistance of cement-stabilized soils and their sustainable utilization in frigid environments.

Machinery traffic–induced compaction has detrimental effects on soil structure and physical properties, leading to the degradation of soil physical functionality. However, the potential of cover crops to mitigate the deleterious effects of cotton harvester traffic in sandy soils remains poorly investigated. This study aimed to evaluate how different cover crops grown either as sole crops or in mixtures can mitigate the adverse effects of cotton harvester traffic on the physical quality of a tropical sandy loam Oxisol in southeastern Brazil. The experiment was established in 2015 using a randomised complete block design with five cover crop treatments: Ruzigrass ( Urochloa ruziziensis ); Millet ( Pennisetum glaucum ) + Ruzigrass; Millet + Sunn hemp ( Crotalaria juncea ); Mixture (Ruzigrass + millet + radish ( Raphanus sativus ) + sunn hemp); and a control treatment (Fallow - weed). The harvester passed only once over each experimental plot, which were subdivided into trafficked and non-trafficked zones. Undisturbed soil samples were collected from the 0.00–0.10 and 0.10–0.20 m soil layers. Soil bulk density and degree of compaction, total porosity, mesoporosity and macroporosity, plant-available water, saturated and unsaturated soil hydraulic conductivity, matrix and relative soil aeration capacity, soil water storage capacity, and an index of soil resistance to compaction were determined for both soil layers. The results showed that the first harvester traffic substantially degraded soil physical quality, particularly in the 0.00–0.10 m layer, with increases in soil bulk density of up to 49% and reductions of 35% in saturated soil hydraulic conductivity, 28% in mesoporosity, 44% in macroporosity and 55% in relative soil aeration capacity, compared with non-trafficked soil, irrespective of the cover crop. The soil resistance to compaction index indicated that 96% of the increase in the degree of compaction occurred after the first machine pass, with the treatment Fallow exhibiting a 97% increase. The Millet + Ruzigrass treatment exhibited the lowest soil bulk density (1.57 Mg m⁻³) and degree of compaction (84%), as well as the highest values of total porosity (0.41 m³ m⁻³), saturated soil hydraulic conductivity (8.58 cm h⁻¹) and plant-available water (0.20 m³ m⁻³) following harvester traffic. The Mixture treatment showed the highest unsaturated soil hydraulic conductivity at a matric potential of −100 hPa (0.149 cm day⁻¹). Overall, the results suggest that the adoption of cover crops, particularly the Millet + Ruzigrass and Mixture, represents an agronomically efficient strategy to mitigate the negative impacts of harvester traffic on the soil physical quality. Improvements in soil physical attributes promoted by cover crops are essential for maintaining soil physical functionality, ensuring greater soil water and air availability. • Cover crops reduced soil compaction caused by harvester traffic. • Increased soil compaction enhanced water storage capacity but impaired soil aeration. • Increased soil bulk density markedly decreased macroporosity and saturated hydraulic conductivity. • Soil bulk density increase due to harvester traffic in the 0.10–0.20 m corresponded to 50% of that observed in the 0-0.10 m.

Nanoplastics (NPs) pose greater soil ecological risks than microplastics due to their surface charge-dependent uptake, transport, and accumulation in plants. However, how differently charged NPs affect maize growth and microbial functional resistance in rhizosphere hotspots remains unclear. Here, we investigated the effect of positively (PS-NH2) and negatively (PS-SO3H) charged NPs on maize growth, enzyme activities and gene abundance, microbial resistance, and functional properties in acidic soil using soil zymography, 16S rRNA sequencing, and metagenomics. PS-NH2 showed stronger inhibitory effects on maize growth than PS-SO3H, mainly through reducing microbial diversity and weakening N and P cycling-related enzyme activities and resistance. Conversely, PS-SO3H maintained higher microbial resistance. Functional hotspots microbial species (particularly in Actinobacteria) alleviated NPs toxicity by accelerating N and P cycling to meet the demand for nutrients limiting maize growth. This study provides a mechanistic basis for assessing soil NPs risk with implications for agricultural sustainability and food safety.

Humic substances with different molecular weights independently increased antibiotic resistance in agricultural soils contaminated with sulfamethazine.

Dynamic loads induced by environmental forces and seismic events significantly influence the performance of foundation systems throughout their lifespan. However, the dynamic resistance of soil is usually estimated from a limited number of laboratory tests, introducing uncertainty into design parameters. For example, the uncertainty can hinder the definition of reliable safety margins and lead to errors inherent in numerical simulations and constitutive models. To quantify the uncertainty and to evaluate the potential risks in design, a series of cyclic direct simple shear (CDSS) tests was performed on a sandy soil. Eight combinations of consolidation stress, relative density, and cyclic stress ratio are examined, with each combination being tested 30 times under stress-controlled, constant volume (equivalent undrained) conditions. The resulting data set provides robust statistical insight into the uncertainty and variability characteristics of the cyclic resistance of the soil. Clear distinctions in strain accumulation behavior and hysteresis response are observed between loose and dense samples. Variability analyses of (apparent) excess pore pressure, shear modulus, and damping ratio are performed. The variability of excess pore pressure increased with its magnitude, while the trend of pore pressure development remains relatively stable. The variability in shear modulus is observed to be sensitive to consolidation stress, while the damping ratio remains stable in all testing conditions. The number of cycles to reach a 5% strain threshold follows an approximately normal distribution, with a standard deviation around 20% of the mean. Applications based on probabilistic cyclic resistance are presented according to the results. This statistical feature enables a probabilistic framework for cyclic design, including confidence-based correction of design parameters. The findings improve understanding of test repeatability, highlight the degree of uncertainty in CDSS data, and support more reliable application of CDSS results in geotechnical design.

Carbon metabolic homogenization is linked to microbial competition and antimicrobial resistance in soils under forest-to-cropland conversion.

As marine resource exploitation advances into deep sea, existing mooring anchors require optimized design to achieve higher bearing capacity, more convenient installation method, and more precise positioning to meet engineering requirements. This study proposes a novel folding-plate anchor (FPA). An FPA consists of two folding plates attached to a mounting block via hinges. The plates remain folded during installation to reduce soil resistance, and then deploy after the keying process to provide maximum load capacity. In shallow water, the FPA can be installed using static press-in methods, whereas in deep water, it can be dynamically installed under their own gravity. However, the depth loss during the keying process can significantly affect its bearing performance. This study employed validated coupled Eulerian-Lagrangian modeling to systematically evaluate the pretension characteristics of the novel FPA. Depth loss during the pretension process was assessed, and the strain characteristics of the folding plates during rotational unfolding and the soil mobilization mechanism were revealed. It is found that the depth loss during pretension ranges from 1.0 to 1.4 times the plate length. An annular flow zone gradually forms around the folding plate during unfolding. Total soil resistance mobilized during pretension accounts for approximately one-third of the ultimate capacity under service conditions. These findings provide valuable reference for the design and application of novel FPAs. • Propose a novel folding-plate anchor (FPA) with plates folded during installation and deployed after keying. • Adopt a large-deformation model to simulate the FPA keying process and evaluate penetration depth loss. • Investigate the effects of key factors on depth loss, including undrained shear strength, folding-plate geometry, and deployment angle.

Multi-metal contamination shapes abundance, co-occurrence, and mobility potential of resistance and virulence genes in mining-impacted soils

Engineering Seismic Microzonation Based on Shear Wave Velocity for Soil Resistance and Ground Amplification in the Ketahun Segment of the Sumatra Fault

Traditional cement-based grouting, widely used to restore soil resistance around piles, poses serious environmental concerns due to its high CO2 emissions. To address this issue, this study introduces natural gum biopolymers as sustainable alternatives for pile grouting. For the first time, Persian and Arabic gums, both hydrocolloid biopolymers, were applied to improve the performance of tapered helical piles installed in poorly graded sand. Direct shear tests were conducted using a Taguchi experimental design, varying gum type, content, and curing time. The analysis revealed that Persian gum provided superior improvements in cohesion and internal friction angle compared to Arabic gum. Based on these results, Persian gum was selected for pile load tests. Axial loading experiments were then performed in the Frustum Confining Vessel (FCV) on tapered helical piles with different helix-to-diameter ratios. The results showed that gum injection increased both the ultimate bearing capacity and initial stiffness of tapered helical piles. Among the investigated configurations, the pile with closer helix spacing (λ = 1.5) exhibited the highest load-bearing performance due to enhanced interaction between adjacent helices and the surrounding soil. SEM observations confirmed that gums improved soil microstructure by forming hydrocolloid bridges between sand particles and increasing interparticle friction. Overall, the study demonstrates that natural gums can serve as effective, eco-friendly substitutes for cement, significantly enhancing pile performance.

ABSTRACT This study examines the uplift load-carrying capacity of vertical piles embedded in granular soils, focusing on developing and validating analytical models using the horizontal slice limit equilibrium approach. Experimental pile tests were employed to empirically determine the inclination angle of the failure surface, which was then incorporated into the model to enhance its accuracy. The research investigates how soil parameters and pile geometry influence shaft resistance and the position of the failure surface. Results reveal that the inclination angle of the failure plane increases with the angle of shearing resistance in sand, leading to steeper, more vertical failure surfaces under uplift loading in stronger soils. The analytical predictions showed consistent agreement with experimental and published data, confirming the reliability of the proposed models. These findings underscore the importance of jointly considering soil strength, pile geometry, and failure surface orientation when predicting uplift shaft resistance in granular soils.

Background/Objectives: Glyphosate-based formulations are globally pervasive pollutants increasingly recognized as potential contributors to antimicrobial resistance (AMR) in environmental microbiomes. Although glyphosate is designed to inhibit plant 5-enolpyruvylshikimate-3-phosphate synthase, it also affects microbial metabolism, stress response, and genetic exchange. This review synthesizes the pathways through which glyphosate, its metabolite aminomethylphosphonic acid (AMPA), and commercial mixtures influence resistance-associated phenotypes and the dissemination of antibiotic resistance (ABR). Methods: A critical synthesis of the literature was conducted to evaluate the mechanistic and ecological interactions between glyphosate exposure and bacterial resistance in soil, aquatic, and host-associated microbiomes. Results: Experimental evidence showed that sublethal glyphosate exposure induced oxidative stress, altered membrane permeability, activated multidrug efflux pumps, and promoted tolerance phenotypes that could modify antibiotic susceptibility. It also enhances mutation rates and horizontal gene transfer processes associated with the emergence of resistance under controlled conditions. At the community level, glyphosate exposure is associated with microbiome restructuring and enrichment of resistance determinants, often without major shifts in overall diversity of the microbiome. These effects have been reported at environmentally relevant concentrations, although the evidence remains largely derived from laboratory and mesocosm studies. Conclusions: Glyphosate acts as both a biochemical modulator of resistance-related phenotypes and an environmental selective pressure that shapes microbial communities. Its widespread use and environmental persistence position it as a context-dependent contributor to the emergence and dissemination of AMR through interacting mechanistic and ecological pathways. Integrating AMR endpoints into pesticide risk assessments and surveillance frameworks is warranted, in addition to expanded field-based validation.

ABSTRACT In southern Bahia, Brazil, cocoa trees (Theobroma cacao L.) are grown in soils with varied physical properties. As many orchards in the region have surpassed their productive lifespan, renewal is crucial for increasing productivity. However, there is limited understanding of how soil physical properties affect the productivity of renovated cocoa orchards. This study aimed to assess the relationship between soil physical properties and cocoa productivity in no-till renovated orchards. The research was conducted across 15 field trials on cocoa farms in southern Bahia. Cocoa yield was monitored from 2019 to 2022 (4th to 7th year post-establishment), while soil physical properties—granulometry, porosity, bulk density, soil penetration resistance, and volumetric water content (at field capacity, permanent wilting point, and available water)—were measured in 2019 as baseline in three soil layers: 0.00–0.10, 0.10–0.20, and 0.20–0.40 m. Data were subjected to univariate and multivariate statistical analyses. In all layers, yield was significantly correlated (p<0.05) with silt content (r = −0.29 to −0.31), silt/clay ratio (r = −0.23 to −0.27), field capacity (r = 0.24 to 0.34), permanent wilting point (r = 0.23 to 0.26), and available water (r = 0.22 to 0.24). Principal Component Analysis showed that yield was positively associated with field capacity and permanent wilting point, and negatively related to soil resistance to penetration and bulk density in the surface layers. Hierarchical cluster analysis grouped the 90 plots into four productivity classes: G1 (74 %, 2,758 kg ha -1 ), G2 (58 %, 1,878 kg ha -1 ), G3 (37 %, 1,557 kg ha -1 ), and G4 (17 %, 792 kg ha -1 ). Tukey’s HSD test (p<0.05) revealed that the higher-yielding groups (G1 and G2) had significantly lower silt content and silt/clay ratios compared to the lowest-yielding group (G4). Overall, cocoa yield was constrained by excessive soil penetration resistance in surface layers and by high silt content and silt/clay ratios across all layers, while balanced sandy-clay textures with improved aeration and water retention favored higher productivity. These results corroborate previous studies recommending cocoa cultivation in soils with lower silt content, due to its association with compaction, drainage limitations, and reduced water retention. The findings highlight the importance of considering soil physical properties, particularly granulometry, as a criterion for selecting priority areas for orchard renewal, thereby contributing to high-yielding and climate-resilient crops.

Abstract Burning reduced Actinobacteriota and Firmicutes but increased Proteobacteria. Rhizosphere networks were denser, but burning reduced their overall connectivity. Burnt straw increased specialist and generalist taxa, especially in the rhizosphere. Straw management significantly influences soil microbial dynamics, shaping biodiversity and resistance in agroecosystems. This study investigated how distinct straw management practices affect bacterial communities and their ecological interactions in bulk soil and the sugarcane rhizosphere. The study was conducted in an Oxisol using a split-plot design with two straw management treatments (burnt and unburnt) and two soil compartments (bulk soil and rhizosphere). Bacterial communities were characterized using 16S rRNA gene sequencing, followed by analyses of diversity, co-occurrence networks, and niche occupancy. The rhizosphere consistently exhibited higher bacterial richness and diversity, regardless of straw management. Burnt straw reduced the relative abundance of Actinobacteriota (∼52%) and Firmicutes (∼53%) but increased Proteobacteria (∼65%) in bulk soil, whereas the rhizosphere bacterial community remained stable. Network analysis revealed higher connectivity and modularity in the rhizosphere, while burnt straw increased negative correlations and reduced microbial complexity in bulk soil. Niche occupancy analysis showed a higher proportion of specialist taxa in the rhizosphere, particularly under burnt straw. Overall, the sugarcane rhizosphere exhibited high microbial resistance to straw burning. These findings highlight the importance of sustainable straw management for preserving soil biodiversity and maintaining ecological stability in tropical cropping systems.

ABSTRACT This study addresses challenges in predicting bearing capacity of super-long loess piles due to complex pile-soil interactions. A theoretical framework combining load transfer principles with multi-stage constitutive models is proposed. The soil-pile system is divided into two layers, employing four interaction models derived from tri-linear softening/hardening combinations: 1) Double Hardening (DH), 2) Upper Hardening-Lower Softening (UH-LS), 3) Upper Softening-Lower Hardening (US-LH), and 4) Double Softening (DS). Differential equations governing pile displacement were established for three soil states (elastic, plastic, slip). The DH model demonstrated superior accuracy (98.3%) alignment with field tests) by effectively simulating stress redistribution along the pile shaft. UH-LS and US-LH models showed 8–12% deviations due to inconsistent hardening/softening transitions. DS model underestimated capacity by 15–18% from excessive interface weakening. Numerical simulations confirmed the theoretical displacement patterns, particularly the DH model’s ability to capture progressive soil resistance development. Field data comparisons showed less than 5% variance in DH predictions versus 10–20% errors in conventional methods. This systematic verification highlights the critical role of appropriate interface modelling in super-long pile design, providing a practical methodology for loess foundation engineering. The DH model’s effectiveness stems from its realistic representation of layered soil hardening behaviour under sustained loading conditions.

With the rapid expansion of livestock farming, antibiotic resistance genes (ARGs) in the environment have become an increasing concern. However, studies on the vertical distribution of ARGs in soils surrounding livestock farms remain limited. This study investigates the distribution of antibiotics, potentially toxic elements (PTEs), and physicochemical properties in soils from three livestock farm types (pig, cattle, and layer) in Henan Province, China, and evaluates their effects on ARG prevalence. Antibiotic concentrations were highest in soils from layer farms, followed by those from pig and cattle farms, and decreased significantly with soil depth. Heavy metal concentrations varied across different soil layers. Soil organic matter decreased with depth, while water content increased. The soil pH remained relatively stable. Bacterial diversity analysis revealed Proteobacteria, Actinobacteria, Nitrospirae, and Acidobacteria as the dominant phyla across all farm types, with notable differences in bacterial genera abundance among farm types. qPCR detected six types of ARGs and two mobile genetic elements (MGEs) in soils, with sulfonamide resistance genes (SRGs) being the most abundant and quinolone resistance genes the least. Redundancy analysis indicated that environmental factors explained 82.20, 74.30, and 78.44% of the variation in soil ARGs and MGEs in pig, cattle, and layer farms, respectively, this highlights the critical role of environmental conditions in ARG transfer. Spearman correlation and network analysis identified potential hosts of ARGs across different farm types. These insights provide a scientific basis for developing more effective strategies to control the spread of antibiotic resistance in soils surrounding diverse livestock operations.

ABSTRACT The real-time assessment of the foundation safety margin for jack-up rig under extreme environmental loads is critical for preventing catastrophic failures. However, direct in-situ measurement of the resultant bearing resistance of the soil-structure system remains a significant challenge. This study develops a novel self-sensing spudcan by embedding Fiber Bragg Grating (FBG) sensors into the spudcan structure, enabling real-time monitoring of its structural strain. Laboratory tests demonstrated a synchronous evolution between the circumferential strain of the spudcan and the mobilised soil resistance. A key finding is that the normalised circumferential strain rate of the spudcan exhibits a strong positive correlation with the foundation safety margin and approaches zero as the foundation reaches its ultimate limit state. Leveraging this correlation, a predictive model that quantifies the safety margin using the measured real-time strain rate was established through numerical analyses, accounting for various loading paths, vertical loads, and soil-structure modulus ratios. The model predictions show less than 13% error compared to experimental data. This work presents a complete solution from smart hardware to an assessment algorithm, providing a robust approach for the real-time safety assessment of spudcan foundations.

Roots are essential for the survival and functioning of plants, serving as anchors in the soil and drawing in vital nutrients and water. Roots also engage in diverse microbial interactions, including pathogenic interactions that cause plant disease and non-pathogenic interactions, such as symbiotic and commensal relationships. Mechanical resistance in compacted soil is one of the biggest challenges for root exploration. Soil compaction hampers plant growth by restricting root elongation, reducing root proliferation, and limiting access to water, nutrients, and oxygen. These restrictions interfere with root-microbe interactions and also impair aboveground growth, leading to decreased shoot biomass, stunted development, and lower overall productivity. Legume roots form symbiotic relationships with soil-dwelling Rhizobium, resulting in root nodules that convert atmospheric nitrogen (N) into ammonia, thereby promoting plant growth. However, the impact of soil compaction on legume roots remains poorly studied. In this review, we examine key adaptive strategies used by legume roots to counteract soil compaction, focusing on the underlying molecular pathways. A complex signalling network regulates molecular processes that control root development and nodulation in legumes. We also explore the genetic and environmental factors that influence morphological, anatomical, and biochemical traits under mechanical stress, providing insights for improving stress resilience in legumes.