High Clay Content Research Articles

Long-term transfer of 137Cs in sensitive agricultural environments after the Chornobyl fallout in Sweden.

In this study, the long-term transfer of 137Cs from soil to grass on Swedish farms and fields, heavily contaminated after the 1986 radioactive fallout, was investigated. The study spans over 8-14 years, beginning in June 1986, and covers various soil types and agricultural practices. The transfer of 137Cs from soil to grass was highly variable, with transfer factors ranging from 1.0×10-5 to 0.357m2kg-1. Higher values were observed on fields with sandy loam, loamy sand, and organic soils, and lower values on fields with a high clay content. The transfer of 137Cs to grass generally exhibited an exponential decline across the majority of fields over the years. The rate of decrease was most pronounced in clay loam and silty loam soils, while it was least evident in sandy loam, sandy soils, and peat soils. The soil properties and farming practices were more important for 137Cs uptake than the initial deposition density. The transfer factor had a negative correlation with soil pH, clay, and fine silt content. No significant relationships were found with other soil variables, such as soil organic matter content and plant available potassium concentration. The median effective half-life of 137Cs in the grass was 4.5 years, with a range of 2-18 years. The uptake of 137Cs by plants did not correlate with the potassium concentration in grass tissues; however, the activity concentration of 137Cs in grass correlated negatively with the potassium content in the plants grown on fields with high deposition levels.

Assessing the influence of land use change on soil quality across different ecosystems in Kolli hills, Eastern Ghats

Soil quality indices (SQIs) assess an ecosystem’s susceptibility to land-use change (LUC), highlighting the impacts on soil parameters. This study developed an SQI for six ecosystems in the Kolli Hills (KH), Eastern Ghats (EG), India: evergreen forest (EF), deciduous forest (DF), thorn forest (TF), agricultural system (AS), horticulture system (HS), and plantation system (PS). Soil samples were collected at two depths, surface (15 cm) and subsurface (30 cm), from 240 sites (40 samples per depth per ecosystem) and analyzed. LUC altered the soil physical and chemical properties. AS and HS had higher sand content (54.63%), bulk density (1.47 Mg m−3), and particle density (2.48 Mg m−3), whereas EF and DF had higher clay content (63.91%), porosity (52.03%), and available soil moisture (18.33%), all of which decreased with depth. The organic carbon and nutrient levels were greater in EF, DF, TF, and PS, with EF having the highest values (soil organic carbon: 60.70 g kg−1; nitrogen: 322.21 kg ha−1; phosphorus: 80.54 kg ha−1; potassium: 617.06 kg ha−1, iron—83.16 mg kg−1, manganese—60.16 mg kg−1, zinc—5.16 mg kg−1 and copper—5.35 mg kg−1) at 15 cm and decreasing with depth. In conclusion, the SQI for surface soil was the maximum in EF (2.50), followed by DF, TF, PS, HS, and AS, with a similar pattern in subsurface samples, suggesting an urgent need for land management strategies to improve soil quality in these ecosystems of the Eastern Ghats.

THE INFLUENCE OF CONSERVATION WORKS ON SOIL PHYSICAL AND CHEMICAL CHARACTERISTICS IN PADINA COMMUNE, MEHEDINȚI COUNTY

A study was carried out in the case of experiments on soil Works located at Padina, Mehedinti county (Romania), on a soil of reddish Preluvosol type with a texture on the depth of 5-10 cm, medium clay and clay loam on the sampling depths 25-30 cm and 45-50 cm). The apparent density was significantly affected by the soil works systems, with the lowest values for the conventional system on the depth of 5-10 cm, and on the depth of 25-30 cm, the highest values being recorded in minimum tillage. This difference is given by the higher clay content. The degree of susceptibility of reddish Preluvosol for the two systems of works is moderately susceptible for conventional and unsusceptible for conservative, due to the preservation of plant debris at the soil surface.

Acetamiprid retention in agricultural acid soils: Experimental data and prediction.

The overuse of pesticides in agriculture has led to widespread pollution of soils and water resources, becoming a problem of great concern. Nowadays, special attention is given to neonicotinoids, particularly acetamiprid, the only neonicotinoid insecticide allowed for outdoor use in the European Union. Once acetamiprid reaches the soil, adsorption/desorption is the main process determining its bioavailability and environmental fate. Therefore, in this work, the adsorption/desorption behaviour of acetamiprid in 60 agricultural soils was studied. The results indicate that acetamiprid has a low affinity for soil constituents, with values ranging from 0.2 to 4.28 L kg-1 for Kd(ads). At the same time, acetamiprid shows high desorption levels (up to 96.3%), indicating that it is poorly retained in soils, thus presenting high bioavailability and a potential risk for transport to other environmental compartments. Regarding the influence of soil properties on the adsorption/desorption process, soils with a high content of organic matter, clay, and exchangeable basic cations showed higher retention of acetamiprid, with greater adsorption and lower desorption. Finally, robust and universal models were successfully developed to predict the adsorption and desorption behaviour of acetamiprid in soil.

Microbial adaptation and genetic modifications for enhanced remediation in low-permeability soils.

Low-permeability soils, characterized by fine texture and high clay content, pose significant challenges to traditional soil remediation techniques due to limited hydraulic conductivity, restricted nutrient flow, and reduced oxygen availability. These unique properties enable low-permeability soils to function as natural barriers in environmental protection; however, they also trap contaminants, making traditional remediation efforts challenging. This review synthesizes current knowledge on microbial adaptation and genetic engineering approaches that enhance the effectiveness of bioremediation in such environments. Key microbial adaptations, including anaerobic metabolism, extracellular enzyme production, and stress response mechanisms, allow individual microbes to adapt in low-permeability soils. Additionally, community-level strategies like microhabitat creation, biofilm formation, and functional redundancy further support microbial resilience. Advancements in genetic engineering now enable the modification of microbial traits-such as soil adhesion, nutrient utilization, and stress tolerance-to enhance bioremediation efficacy. Synthetic biology techniques further allow for the design of tailored microbial consortia that work cooperatively to degrade contaminants in complex soil matrices. This review highlights the integration of microbial and genetic engineering strategies, offering a comprehensive overview that informs current practices and guides future research in low-permeability soil remediation.

Modeling of heteroaggregation driven buoyant microplastic settling: Interaction with multiple clay particles.

The ecological risk of microplastics (MPs) has received widespread attention, but understanding ecological risk starts with understanding environmental migration. Heteroaggregation is an important process that affects the vertical migration of MPs, and the mathematical model is a common tool used to project the migration behavior of MPs. However, the mathematical model based on the aggregation of MPs with one clay particle is not applicable to simulate the migration behavior of buoyant microplastic (BMP). Hence, this study developed a model for heteroaggregation of one BMP with multiple clay particles based on the Population Balance Equation, and the main factors affecting the sedimentation of BMP are clarified through parameter sensitivity analysis and scenario simulation. The results show that neglecting the interaction of one BMP with multiple clay particles in the mathematical model can underestimate the predicted settling concentration of BMP, especially in aqueous environments with higher clay concentration and salinity. The settling process of BMP is controlled by the heteroaggregation rate, which is sensitive to environmental conditions and insensitive to particle properties. This study emphasizes the importance of considering the interaction of one BMP with multiple clay particles in the future mathematical model, which will provide a more reliable prediction of the migration of MPs in aquatic environments.

Transport mechanisms of the anthropogenic contaminant sulfamethoxazole in volcanic ash soils at equilibrium pH evaluated using the HYDRUS-1D model.

The volcanic soils in Chile, where a significant portion of agricultural activities take place, are impacted by the presence of veterinary drugs, including sulfamethoxazole (SMX). The study examines how different soil types influence the movement and retention of sulfamethoxazole (SMX) across four regions of Chile, focusing on conditions at a neutral pH of 7.0. Collipulli's Ultisol soils (CLL), characterized by high clay and sand content but low organic matter (OM), promote low SMX adsorption and rapid transport. In contrast, the volcanic ash-derived Andisols from Frutillar (FRU), Nueva Braunau (NBR), and Osorno (OSR) have high OM and cation exchange capacity (CEC), which enhance their ability to retain SMX and reduce its mobility. Adsorption batch, kinetics, and column breakthrough curve (BTC) experiments were conducted alongside transport modelling. The adsorption kinetics of SMX in CLL soil followed a pseudo-first-order (PFO) model, while FRU, NBR, and OSR soils aligned with a pseudo-second-order (PSO) model. Freundlich isotherms effectively described SMX adsorption in CLL and OSR soils, indicating multilayer adsorption, while Langmuir isotherms fit the FRU and NBR soils, suggesting monolayer adsorption. Using HYDRUS-1D software, we simulated SMX transport in soil columns. BTCs were best modelled using a two-site sorption model with both equilibrium and kinetic adsorption. SMX was more mobile in CLL soil due to its lower organic matter (OM) content and adsorption capacity. In contrast, FRU, NBR, and OSR soils showed slower transport, reflecting higher OM content and greater adsorption capacity, reducing SMX leaching. These findings emphasize the importance of soil properties, such as OM content, in influencing SMX behavior, and are vital for assessing environmental impacts and developing mitigation strategies.

Investigating Environmental Determinants of Hookworm Transmission using GPS Tracking and Metagenomics Technologies.

To identify potential sources of hookworm infections in a Ghanaian community of endemicity that could be targeted to interrupt transmission, we tracked the movements of infected and noninfected persons to their most frequented locations. Fifty-nine participants (29 hookworm positives and 30 negatives) wore GPS trackers for 10 consecutive days. Their movement data were captured in real time and overlaid on a community grid map. Soil samples were collected and divided into two parts: one for determining the physical and chemical properties and the other for culture of helminth larvae. Soil parameters were determined using standard methods, and the number of larvae recovered from Baermann cultures (expressed as larvae per gram of soil) was recorded. We found no significant difference in the larval counts between sites of infected and noninfected participants (P = 0.59). Sandy-loam soil, pH, and effective cation exchange capacity were associated with high larval recovery counts (P <0.001), whereas nitrogen and clay content were associated with low counts (P <0.001). Genomic DNA was extracted from helminth larvae, and species were identified using metagenomic analysis of DNA sequences. The dominant helminth species identified were Panagrolaimus superbus, Parastrongyloides trichosuri, Trichuris trichiura (human whipworm), and Ancylostoma caninum (dog hookworm). Despite Necator americanus being the predominant species in the community, no larvae of this species were identified. This study, however, demonstrates the feasibility of applying molecular tools for identifying environmental factors and places associated with exposure to human and zoonotic helminths, including areas that may be targeted to break transmission in communities where infection is endemic.

Chemical EOR Formulation for a Clay-Rich Sandstone Reservoir with Reduced Surfactant Consumption.

Alkali-surfactant-polymer (ASP) flooding can reduce oil-water interfacial tension to ultralow values and mobilize oil in petroleum reservoirs. Surfactant is consumed by adsorption/retention which is significant in clay-rich reservoirs. Alkali can be added to surfactant-polymer formulations to minimize surfactant adsorption. The goal of this work is to study the effect of alkali and surfactant concentrations on surfactant-brine-oil phase behavior and minimize the amount of surfactant and alkali while mobilizing oil in a clay-rich sandstone reservoir (at a temperature of 75 °C). Many surfactants were studied for ASP formulations, and a mixture of two surfactants was identified that can produce ultralow IFT (∼0.001 mN/m) with the oil at low surfactant concentrations. Ten different ultralow IFT formulations were identified, but only two formulations were evaluated for oil recovery and surfactant retention in core floods. The optimal salinity decreased when the surfactant concentration was reduced. The cumulative oil recovery was high (>94%) for three types of cores (Berea sandstone, Leopard sandstone, and a reservoir core). The surfactant retention was in the range of 0.11-0.22 mg/g of rock for high clay content (>8%) cores due to the presence of alkali. Decreasing the surfactant concentration (while keeping the total amount of surfactant the same) did not change the surfactant adsorption or oil recovery but delayed the oil production.

Spontaneous imbibition characteristics and influencing factors of shale oil reservoir in Qintong depression

This study integrates one-dimensional and two-dimensional nuclear magnetic resonance (NMR) techniques to conduct spontaneous imbibition experiments on two distinct lithologies (laminated calcareous shale and bulk clay-rich shale) from the Qintong Depression using four different fluid types. Field emission scanning electron microscopy (FE-SEM) and computed tomography (CT) scanning were employed to observe and track the dynamic changes in shale microstructures at specific intervals allowing for a comprehensive analysis of induced microfractures and their propagation patterns. These methods enabled a deeper understanding of the underlying mechanisms, enriching the interpretation of the imbibition results. The study reveals that anionic surfactants demonstrate exceptional performance during the imbibition process, and the combination of surfactants further enhanced oil recovery. The imbibition process can be divided into three stages: the imbibition diffusion stage, the transition stage, and the equilibrium stage, with the diffusion stage serving as the primary contributor, driven predominantly by capillary pressure. The calcareous shale cores exhibited the highest imbibition rates in the early stages, approaching equilibrium in the middle stages. Conversely, the clay-rich shale cores maintained relatively high imbibition rates throughout the second stage, indicating different imbibition dynamics based on lithology. NMR, CT scanning, and SEM analysis highlighted significant lithology-dependent differences in the mechanisms driving induced microfracture development during the imbibition and hydration. In laminated calcareous shale, imbibition and hydration primarily proceeded through the dissolution of calcareous minerals, resulting in pore expansion and induced microfractures along pre-existing fractures. In contrast, clay-rich shale exhibited similar mineral dissolution but also experienced clay swelling due to its high clay content, leading to the formation of bedding-parallel fractures with distinct directional patterns along weak mineral-matrix bonds. The experimental results underscored the pivotal role of lithology in determining final imbibition efficiency, with high-clay-content shales demonstrating superior recovery rates under spontaneous imbibition conditions. This study provides critical experimental data and insights into the microscopic mechanisms governing spontaneous imbibition across varied lithologies and fluid types in the Qintong Depression. The results offer foundational knowledge for optimizing oilfield development strategies.

Seabed Liquefaction Risk Assessment Based on Wave Spectrum Characteristics: A Case Study of the Yellow River Subaqueous Delta, China

Seabed liquefaction induced by wave loading poses considerable risks to marine structures and requires careful consideration in marine engineering design and construction. Traditional methods relying on statistical wave parameters for analyzing random waves often underestimate the potential for seabed liquefaction. To address this underestimation, the present study employs field observations and numerical simulations to examine wave characteristics and liquefaction distribution across various wave return periods in the Chengdao Sea area of the Yellow River subaqueous delta. The research results indicated that the wave decay phase exhibited a higher liquefaction potential than the growth phase, primarily because of the prevalence of low-frequency swell waves. The China Hydrological Code Spectrum (CHC Spectrum) effectively captured the wave characteristics in the study area, with parameterization grounded in measured data. The poro-elastic wave–sediment interaction model further elucidated the liquefaction distribution under extreme wave conditions, revealing a maximum liquefaction depth exceeding 3 m and prominent liquefaction zones at water depths of 5–15 m. Notably, seabed properties emerged as a critical factor for liquefaction and overshadowed water depth, with non-liquefaction zones occurring at water depths of less than 15 m at high clay content, highlighting the general liquefaction risk of silty seabed. This study enhances understanding of the seabed liquefaction process and offers valuable insights into engineering safety.

Drivers of soil organic carbon recovery under forest restoration: a global meta-analysis

Forest restoration by planting tree seedlings is a crucial strategy to mitigate climate change and restore forest functions. The Intergovernmental Panel on Climate Change (IPCC) targets to remove around 70 Pg carbon (C) from the atmosphere via forest restoration. However, the impact of forest restoration on the recovery of soil organic carbon (SOC) and its driving factors remains unclear. Here, we conducted a global meta-analysis, based on 348 observations from 144 studies across 150 sites, to evaluate the recovery time of SOC and the driving factors of surface SOC recovery during forest restoration. We found that soil clay content and stand age were recognized as the dominant factors regulating SOC recovery during forest restoration. Overall, SOC recovery was lower in boreal and Mediterranean forests than that in tropical, subtropical, and temperate forests, lower in burned areas and mine sites than that in other sites, and lower in soils with 0%–20% clay contents than that in those with higher clay contents, and comparable among soils with different pH values. Across studies, surface SOC in restored forests with stand ages ranging from 1 to 200 years did not fully recover to the levels of reference forests. However, the SOC recovery rate was roughly twice as fast in tree polycultures (~ 10 years to plateau) as that in monocultures (~ 20 years). This global synthesis identifies critical drivers of SOC recovery during forest restoration and provides important insights into SOC management in forests.Graphical

Review of Analytical Studies on The Failure of Granular Anchor Piles in Expansive Soil

Abstract: Soft ground, characterized by a high content of clay, silt, peat, and loose sand, is generally unsuitable for constructing large structures due to insufficient stability. Ground improvement techniques, such as the use of stone columns (or granular piles), are often implemented in these areas to enhance load-bearing capacity and minimize settlement. The Granular Anchor Pile (GAP) is an advanced version of the stone column that includes an anchor to boost its tensile load-bearing or pullout capacity. In this study, formulations from various authors regarding the pullout capacity of anchors embedded in clayey soils are analyzed to assess the contributions of pile failure and anchor failure to overall GAP failure. The results indicate that GAP failure occurs due to two main factors: 50%–65% of the anchor length failing, and 35%–50% of the pile length failing. This breakdown helps in understanding the role of each component in the overall pullout capacity of GAP

Feldspathic sandstone as an emerging soil stabilizer for aeolian sand in the Mu Us Sandy Land: insights into particle size distribution.

Stabilization of aeolian sand is essential for achieving desertification control, soil and water conservation, and agricultural development in sandy lands. Feldspathic sandstone is a soft clay rock widely found in the Mu Us Sandy Land. The purpose of this study was to ascertain the mechanism for aeolian sand stabilization with feldspathic sandstone from the perspective of particle size distribution. Feldspathic sandstone was added to aeolian sand at different ratios (m f:m s = 1:0, 1:1, 1:2, 1:5, and 0:1, where m f is the mass of feldspathic sandstone and m s is the mass of aeolian sand). The results showed that the soil texture was modified upon addition of feldspathic sandstone. The content of particles <0.05 mm increased with increasing addition ratio of feldspathic sandstone, in contrast to the downward trend observed for particles >0.05 mm. Consequently, the soil texture changed from sand to sandy loam, then loam, and finally silty loam. The addition of feldspathic sandstone ameliorated aeolian sand, resulting in a broader particle size distribution and lower particle size uniformity. Continuously well-graded soil was obtained at m f:m s = 1:5 (coefficient of uniformity: 54.71; coefficient of curvature: 2.54) or 1:2 (coefficient of uniformity: 76.21; coefficient of curvature: 1.12). While the addition of feldspathic sandstone solved the problem of single particle size distribution in aeolian sand, the presence of aeolian sand prevented soil compaction caused by the high clay content of feldspathic sandstone. Findings of this study indicate that the addition of feldspathic sandstone to aeolian sand leads to the mixing of various sized particles and continuous gradation of the soil. Although a higher addition ratio of feldspathic sandstone is more favorable for soil texture improvement, m f:m s = 1:5 is recommended for practical application in terms of particle gradation and cost effectiveness.

Behavior of CBR value of laterite soil mixed with metakaolin

Laterite soil is a material widely used for civil engineering purposes in South Kalimantan. Most laterite soil has low bearing capacity due to high clay and plastic content, causing cracks and damage, especially when mixed with a fairly high volume of water. Therefore, this study aimed to improve the soil through stabilization using metakaolin. An experimental study was conducted using laterite soil from Mount Kupang, Cempaka Village, Banjarbaru. This soil wasmixed with metakaolin on various percentage variations of the mixture, namely 2%, 4%, 6%, 8%, and 10% of the weight. The incubation period of the sample commences from 3, 7, and 14 days. Some of the test conducted include soil consistency limits (Atterberg limit test), soaked laboratory, and unconfined compressive strength (UCT). The result showed an effect on the characteristics of laterite soil mixed with metakaolin. The Plasticity Index (PI) value of laterite soil experienced a constant decrease due to the influence of methakoline by 14.75%. The soaked CBR value increased in a mixture of 2 to 8% metakaolin, but there was a decrease in the case of 10% at a curing time of 3, 7, and 14 days. Furthermore, the maximum soaked CBR value in laterite soil samples was mixed with 10% metakaolin at a curing period of 14 days and experience a percentage increase of 43.47%. The maximum qu value also increased by 42.02% in a mixture of 8% metakaolin and decreased in a 10% metakaolin at a curing time of 14 days.

Comparative study of the stabilizing behavior of organoclays in Pickering emulsion

Pickering Emulsions are commonly applied in the pharmaceutical, food, and chemical industries. The use of natural particles as stabilizers provides access to surfactant-free dispersions with reduced toxicity and environmental impact. This work investigates the use of three commercial organoclays (C15A, C10A, and C30B) and hydrophilic sodium montmorillonite (Mt) as stabilizers for Pickering emulsions. Emulsion stability was evaluated through macroscopic and microscopic morphological observations and the emulsion microstructure was characterized by optical microscopy and DLS measurements to assess creaming and coalescence. The influence of different experimental parameters on emulsion stability was evaluated, including organoclay content, emulsification time, emulsification speed, and oil–water ratio. The results showed that emulsions based on C15A exhibit better stability against coalescence as compared to emulsions prepared with the other clays. This was attributed to the wettability of the particles and solution viscosity. Droplet size decreased as emulsification time and stabilizer content increased and reached a minimum value at 1 wt.% of C15A and for emulsification time of 5 min and oil–water ratio O/W (v/v: 50/50). The experimental parameters also impacted emulsion viscosity, increasing it for high clay content and as the stirring speed and emulsification time increased. The results of the heat and cold resistance stability tests indicated that 25 °C represents the optimal storage temperature for the prepared emulsions.

Investigation of the pore structure characteristics and fluid components of Quaternary mudstone biogas reservoirs: a case study of the Qaidam Basin in China

Quaternary mudstone biogas reservoirs in the Qaidam Basin have shown great potential. However, complex pore structures with high clay contents and high heterogeneity limit the understanding of the storage and migration principles of these reservoirs. In this paper, HPMI and nitrogen adsorption experiments, in combination with NMR experiments under water saturation, centrifugation, various drying temperatures and other conditions, were adopted to determine the pore structure characteristics. Specifically, the reservoir space types and pore radius distribution characteristics were clarified. The cutoff values for different types of pores were identified based on the water-saturated mudstone NMR T2 spectra for full aperture distribution scales jointly characterized by mercury injection and nitrogen adsorption experiments. Furthermore, the three pore components and the saturation of different fluids were obtained. The research results indicate that the mudstone biogas reservoir has developed various reservoir spaces, and the pore size is primarily in the micronanometer range. The average total porosity reaches 27.28%, but the proportion of movable water pores is only 9.23% with poor fluid mobility, and the fluids in the pores are mostly capillary-bound water and clay-bound water. Among the different lithologies, argillaceous sand is more likely to become a good production layer.

Study on combination of surfactant and acid for depressure and increasing injection oil displacement in heterogeneous sandstone reservoirs

This study addresses the challenges faced by unconventional tight sandstone reservoirs, including low porosity, permeability, high clay content, and complex wettability, which lead to increased flow resistance and injection pressures. The research aims to optimize depressure and increasing injection methods by investigating the effects of various two-phase and three-phase displacement systems, employing experimental treatments including acids, alkalis, and surfactants. Nuclear magnetic resonance, computed tomography, scanning electron microscopy, inductively coupled plasma, and wettability tests are utilized to investigate the mechanisms of these treatments. Key findings indicate that weak alkaline ethylenediaminetetraacetate tetrasodium and weak acids like hydroxyethylidene diphosphonic acid and acetic acid can cause significant pore blockage, while hydrochloric acid can dissolve pore minerals, achieves a high depressure rate of 89.42%. Although surfactants exhibit a negative effect in two-phase displacement systems, they demonstrate considerable potential in three-phase displacement. Surfactants can modify the wettability of rock surfaces, reduce oil saturation, and improve water phase permeability, resulting in a depressure rate of 11.68%. Notably, the combination of surfactants and HCl enhances the depressure rate to 60.82% and improves oil displacement efficiency from 26.12% to 57.96%. The optimal formulation identified is “0.5% unconventional agent (CNI-A) +3% HCl,” which improves oil displacement capacity and alleviates injection pressure, providing valuable insights for the management of heterogeneous sandstone reservoirs.

Assessing watershed vulnerability to erosion and sedimentation: Integrating DEM and LULC data in Guyana's diverse landscapes

This study assesses watershed vulnerability to erosion and sedimentation in Guyana using Digital Elevation Model (DEM) and Land Use/Land Cover (LULC) classification. It aims to assess erosion risk by examining rainfall erosivity, soil types, and spatial variability. The integration of DEM-derived slope data with LULC and rainfall erosivity shows a strong correlation between high rainfall (20,809.02–31,262.35 mm) and erosivity (21,433.29–32,200.22 MJ mm ha−1 h−1 yr−1), indicating increased erosion potential, particularly in southwestern regions. Soil analysis reveals Plinthic Acrisols, with high clay content, are more prone to erosion, whereas Orthic Ferralsols are less vulnerable. Slope analysis suggests flat terrain (89.16 %) has low erosion risk, but steeper slopes require interventions. Conservation strategies like reforestation, sustainable agriculture, contour plowing, and terracing are recommended to reduce erosion impacts. This integrated assessment provides insights for prioritizing soil conservation and adaptive management to address erosion risks in Guyana.

Particle size characteristics of sliding-zone soil and its role in landslide occurrence: a case study of the Lanniqing landslide in Southwest China

In landslide studies, particle size is a key quantitative indicator, reflecting the formation and development of the sliding zone. It plays a crucial role in understanding the mechanisms and evolutionary processes that lead to landslide occurrences. Precise measurement of particle size is crucial. This study centered on soil samples from the Lanniqing landslide in Southwest China. To begin, seven distinct methods were used to preprocess the soil samples. Next, the particle size frequency distribution was measured using the Mastersizer 2000 laser particle size analyzer. Key parameters, including median particle size, mean particle size, sorting coefficient, skewness, and kurtosis, were then compared and analyzed to determine the most appropriate preprocessing method for evaluating the characteristics of the soil samples. The mechanism of landslide occurrence was subsequently analyzed by examining the particle size characteristics, mechanical properties, and mineral composition of the soil samples. The results suggested that method C provides the most reliable analysis of particle size characteristics in soil samples. The observed coarsening of coarse particles, along with a significant increase in clay content within the sliding zone, indicates that the sliding surface has undergone multiple shear and compression events. The interplay of the upper traffic load and slope cutting at the front edge set the stage for the Lanniqing landslide, prompting the initial development of potential sliding surfaces. Rainfall acts as a catalyst for slope instability. The high clay content, combined with the formation of a low-permeability layer rich in clay minerals on the sliding surface, leads to excessive pore water pressure and mineral lubrication. These factors inherently trigger and accelerate the occurrence of the landslide.