Soil Heterogeneity Research Articles

Effect of colloidal particle size on physicochemical properties and aggregation behaviors of two alkaline soils

Abstract. Colloidal particles are the most active soil components, and they vary in elemental composition and environmental behaviors with the particle size due to the heterogeneous nature of natural soils. The purposes of the present study are to clarify how particle size affects the physicochemical properties and aggregation kinetics of soil colloids and to further reveal the underlying mechanisms. Soil colloidal fractions, from two alkaline soils – Anthrosol and Calcisol – were subdivided into three ranges: d<2 µm, d<1 µm and d<100 nm. The organic and inorganic carbon contents, clay mineralogy and surface electrochemical properties, including surface functional groups and zeta potentials, were characterized. Through a time-resolved light scattering technique, the aggregation kinetics of soil colloidal fractions were investigated, and their critical coagulation concentrations (CCCs) were determined. With decreasing colloidal particle diameter, the total carbon content, organic carbon, organic functional groups' content and illite content all increased. The zeta potential became less negative, and the charge variability decreased with decreasing particle diameter. The CCC values of Anthrosol and Calcisol colloids followed the descending order of d<100 nm, d<1 µm and d<2 µm. Compared with the course factions (d<1 and d<2 µm), soil nanoparticles were more abundant in organic carbon and more stable clay minerals (d<100 nm); thus they exhibited strongest colloidal suspension stability. The differences in organic matter contents and clay mineralogy are the fundamental reasons for the differences in colloidal suspension stability behind the size effects of Anthrosol and Calcisol colloids. The present study revealed the size effects of two alkaline soil colloids on carbon content, clay minerals, surface properties and suspension stability, emphasizing that soil nanoparticles are prone to be more stably dispersed instead of being aggregated. These findings can provide references for in-depth understanding of the environmental behaviors of the heterogeneous soil organic–mineral complexes.

Geological and geophysical evaluation of the subsurface conditions for establishing new dwelling area East New Cairo City

ABSTRACT An integrated geological and geophysical study utilising electrical resistivity tomography (ERT) and seismic refraction tomography (SRT) was carried out in a new residential area located northeast of New Cairo City and south of the Suez-Cairo Road. The purpose was to characterise the subsurface layer distribution, lithology, and geometry of faults . Initial surface geological mapping identified traces of some faults. Stratigraphically, the study area comprises sedimentary rocks and local basaltic flow outcrops ranging in age from the Middle Eocene (Mokattam Formation) to the Upper Miocene (Hagul Formation). ERT and SRT data were acquired along 15 closely spaced profiles oriented to intersect the expected surface fault zones. ERT delineated electrical conductive zones situated at different depths and composed of shale and altered basalt. Meanwhile, three layers were detected based on velocity values obtained from SRT data analysis. The ERT and SRT results successfully elucidated the fault configuration and its locations, providing crucial information for construction planning. Major structures were concealed and only outlined by the integrated ERT/SRT surveys. This study shows heterogeneous soil conditions and fault damage zones, which may impact some parts of the study area. The study’s findings , offering vital information for safe and effective construction planning.

An analytical solution of the one-dimensional steady-state advection-dispersion equation of a compressible fluid for a heterogeneous soil

An analytical solution of the one-dimensional steady-state advection-dispersion equation of a compressible fluid for a heterogeneous soil

Suffusion characteristics of a heterogeneous dam foundation with a cut-off wall of stochastic defects

Natural alluvial foundations are inherently heterogeneous. To enhance seepage safety, a cut-off wall is commonly embedded in a dam foundation. However, walls can also have stochastic defects. The dual uncertainties arising from soil heterogeneity and wall defects pose significant challenges for seepage safety evaluation. In this study, systematic numerical simulations were conducted on an internally unstable dam foundation based on a four-constituent mixture framework. Soil heterogeneity was characterized by stochastic initial hydraulic conductivity and initial fines content. An erosion model, specifically incorporating the influence of overburden pressure, was employed to quantify suffusion. A probabilistic assessment utilizing Monte Carlo simulations revealed that suffusion in heterogeneous fields could be more severe than that in homogeneous fields. Various combinations of stochastic soil properties and defect locations can result in substantial disparities in seepage and erosion fields. The mean values of the total flux and the fines eroded ratio are insensitive to the spatial variation length, while their deviations increase with increasing spatial variation length, leading to larger uncertainties in the leakage channel morphology. For highly heterogeneous alluvial foundations with large spatial variations, conventional seepage and suffusion analyses that rely on homogeneous assumptions may considerably underestimate the internal erosion risk.

Tracing recent large herbivore influence on soil carbon in permafrost and seasonally frozen Arctic ground using lipid biomarkers: a pilot study

This study investigates the impact of large herbivores on soil organic matter (OM) stability in Arctic permafrost and seasonally frozen ground ecosystems, focusing on the potential preservation effect of grazing. Soil samples were collected from Siberian and Finnish permafrost and nonpermafrost areas and organic carbon content, carbon-to-nitrogen ratio, stable carbon isotopes as well as the content of n-alkanes and n-alcohols were analysed to assess OM stability. The results suggest that grazing activity, particularly in permafrost environments, preserves soil OM by reducing decomposition. Permafrost soils exhibit higher functionalized to nonfunctionalized biomarker ratios, indicating in general better preservation under frozen conditions. While differences in grazing intensities had minor effects, the data also showed variability due to soil heterogeneity, especially in seasonally frozen ground ecosystems. Nevertheless, there are slight trends toward enhanced OM preservation with increasing grazing intensity, especially in permafrost, emphasising the potential role of grazing in locally preserving Arctic soil OM. This pilot study offers initial insights into the impact of large herbivores on OM stability in cold-region ecosystems, suggesting that significant effects may require prolonged, intensive grazing pressure.

Nitrogen enrichment drives accelerative effect of soil heterogeneity on the flowering phenology of a dominant grass

Nitrogen enrichment drives accelerative effect of soil heterogeneity on the flowering phenology of a dominant grass

Spatial heterogeneity of soil factors enhances intraspecific variation in plant functional traits in a desert ecosystem.

Functional traits of desert plants exhibit remarkable responsiveness, adaptability and plasticity to environmental heterogeneity. In this study, we measured six crucial plant functional traits (leaf carbon, leaf nitrogen, leaf phosphorus, leaf thickness, chlorophyll concentration, and plant height) and employed exemplar analysis to elucidate the effects of soil environmental heterogeneity on intraspecific traits variation in the high-moisture-salinity and low-moisture-salinity habitats of the Ebinur LakeWetland National Nature Reserve. The results showed that (1) The soil moisture and electrical conductivity heterogeneity showed significant differences between the two moisture-salinity habitats. Moreover, soil nutrient in high moisture-salinity habitat exhibited higher heterogeneity than in low moisture-salinity habitat. The order of intraspecific trait variation among different life forms was herbs > shrubs > trees in both the soil moisture-salinity habitats. (2) At the community level, intraspecific variation of leaf carbon, nitrogen, plant height and chlorophyll content in high moisture-salinity habitat was higher than that in low moisture-salinity habitat, while the opposite was true for leaf thickness and leaf phosphorus content. (3) Our findings revealed a positive impact of soil heterogeneity on intraspecific traits variation. In high moisture-salinity habitat, the heterogeneity of soil organic carbon had the highest explanatory power for intraspecific traits variation, reaching up to 20.22%, followed by soil total nitrogen (9.55%) and soil total phosphorus (3.49%). By comparison, in low-moisture-salinity habitat, the heterogeneity of soil moisture alone contributes the highest explanatory power for intraspecific traits variation in community-level, reaching up to 13.89%, followed by the heterogeneity of soil total nitrogen (3.76%). This study emphasizes the differences in soil heterogeneity and intraspecific trait variation among plant life forms under various soil moisture-salinity habitats and confirms the significant promoting effect of soil heterogeneity on intraspecific trait variation of desert plant. Our findings provide valuable theoretical basis and reference for predicting plant adaptation strategies under environmental change scenarios.

Dynamics of Soil N and P Nutrient Heterogeneity in Mixed Forest of Populus × Euramercana ‘Neva’ and Robinia pseucdoacacia in Coastal Saline–Alkali Land

The mixing of poplar and robinia in coastal saline land is a useful attempt at difficult site afforestation. Investigating the long–term mixing effects of nitrogen–fixing and non–nitrogen–fixing tree species on the spatial heterogeneity of N and P nutrients and their ecological stoichiometric characteristics in the coastal saline–alkali soil can provide a scientific basis for soil improvement and plantation management in the coastal saline–alkali soil. By replacing time with space, poplar and robinia mixed forests and corresponding pure forests with the ages of 3, 7 and 18 years were selected, and soil profiles of 0–20 cm, 20–40 cm and 40–60 cm were dug up to determine the contents of total nitrogen, hydrolyzed nitrogen, total phosphorus and available phosphorus, the activities of soil urease and phosphatase and the number of soil bacteria, fungi and actinomycetes in rhizosphere soil. The mixture of poplar and robinia and the increase in planting years led to the heterogeneity of soil N and P in a coastal saline–alkali forest, which could significantly increase the contents of soil total nitrogen, hydrolyzed nitrogen, total phosphorus and available phosphorus between soil layers. Compared with the pure forest of poplar and robinia at the same age, the soil urease activity in the 0–20 cm soil layer of an 18a poplar and robinia mixed forest increased by 94.75% and 73.36%, and the soil phosphatase activity increased by 30.36% and 70.27%. The mix of poplar and robinia significantly increased the abundance of soil microorganisms in saline–alkali soil. The number of bacteria, fungi and actinomycetes in the 0–20 cm soil layer of the 18a poplar and robinia mixed forest was the highest, which were 703,200, 31,297 and 1903, respectively. Redundancy analysis showed that there was a significant positive correlation between soil N and P nutrient contents, soil enzyme activities and microbial abundance. The soil depth of N and P nutrient decomposition and transformation in the mixed poplar and robinia plantation was expanded. The soil N and P nutrient contents, enzyme activities and microbial abundance in the 40–60 cm soil layer of the mixed forest were higher than those of the pure forest. With the increase in plantation years, the depth of soil that can be used in the forest land is increasing. The mixture of poplar and robinia plantation is an excellent choice for the construction of coastal saline–alkali land plantation, which has a significant mixed gain for the decomposition and transformation of N and P nutrients and increases the depth of the available soil layer in the forest land in coastal saline–alkali land. However, the coastal saline–alkali land soil N/P is < 14 and is still restricted by nitrogen, so the application of nitrogen fertilizer can be increased during the afforestation process.

A Comparative Account of the Sugarcane Bagasse and Rice Husk Biochar on the Physicochemical and Biological Properties of Soils from Heterogeneous Agroecosystems

ABSTRACT Biochar optimal use reduces agricultural waste and promotes sustainability in farming systems. Its production and characterization are crucial for carbon sequestration in agroecosystems. The present study elucidated the properties of Sugarcane Bagasse Biochar (SBB) and Rice Husk Biochar (RHB), synthesized under varying experimental conditions, and revealed that a pyrolytic temperature of 400°C and a duration of 90 min was optimum for the production of both biochars in terms of pH, electrical conductivity, total dissolved solids, total organic carbon, cation exchange capacity, and water holding capacity. The effect of varying concentrations of SBB and RHB (0.5%, 1%, and 1.5%) in response to control on the physicochemical and biological properties of soils revealed that 1.5% SBB had a significant increase in the soil pH and conductivity. Application of SBB increased the soil organic carbon due to its higher carbon content (64.24%) than RHB (46.04%). Also, the water-holding capacity of heterogeneous soil samples was higher with the SBB application of 1.5%. The THB was positively and significantly correlated with pH (r = 0.50, p < .05), EC (r = 0.60, p < .01), TDS (r = 0.48, p < .05), SOM (r = 0.55, p < .01), moisture content (r = 0.63, p < .01) and WHC (r = 0.90, p < .01) but negatively correlated with THF (r = -0.84, p < .01). At the same pyrolytic temperature, SBB had the highest surface area (266.51 m2/g) and pore volume (0.195 cm3/g) than RHB (39.06 m2/g and 0.095 cm3/g respectively). It is concluded that the application of SBB at 1.5% level can successfully improve the soil properties, thereby aiding in carbon sequestration.

Evolution of Forest Humipedon Following a Severe Windstorm in the Italian Alps: A Focus on Organic Horizon Dynamics

This study investigates the effects of the 2018 Vaia windstorm on the evolution of humus profiles in forest soils of the north-eastern Italian Alps five years after the disturbance. The humipedon in five soil conditions was compared: intact forest (IF) and permanent meadow (M) for undisturbed soils, and soil under herbaceous cover (G), under dead wood (W), and bare soil (B) for windthrow-affected areas. No difference in pH and soil organic matter content (SOM) emerged within the same soil horizon between IF and windthrow-affected soils. When compared to IF, however, in G and B, a thinning of all O horizons (OL, OF, and OH) was detected, resulting in SOM loss and an increase in pH in the top 15 cm of the humipedon, conditions approaching the values found in M. Amphi was the most frequently occurring humus system in IF, with a shift towards a Mull system observed in all windthrow-affected soils—a shift more marked in G and B, approaching M conditions, but less marked in W, where the O horizon remained thicker. This study underscores the importance of considering soil heterogeneity and humus dynamics when assessing forest recovery and resilience after a severe disturbance.

Temperature Sensitivity of Soil Nitrous Oxide Emissions in Tea Plantations at Different Elevations

To solve the problems that the response of nitrous oxide （N2O） emissions to warming may be different in different biological communities and the uncertainty of its response to warming may be aggravated by the high heterogeneity of tea plantation soils, an incubation experiment at five elevations of tea plantation soils [537 m（E1）, 433 m（E2）, 350 m（E3）, 308 m（E4）, and 238 m（E5）] and three temperatures （15, 25, and 30 ℃） was conducted for 35 days to explore the temperature sensitivity of N2O in different tea plantation soils and the driving factors. The results showed that elevated temperature could promote soil N2O emissions at different elevations, but the effect was inconsistent at different elevations. Specifically, elevated temperature decreased the cumulative N2O emissions in the E1 treatment, but the difference was not significant. At the same time, the cumulative N2O emissions in the E2-E5 treatments were increased, especially in the E3-E5 treatments. The Q10 values of N2O in the tea plantation soils at different elevations were significantly different, ranging from 0.90 to 4.98, with E4 &gt; E5 &gt; E3 &gt; E2 &gt; E1. The multiple regression model analysis showed that 97.4% of the variation in N2O temperature sensitivity was explained by soil physicochemistry and microorganisms, and N2O temperature sensitivity was significantly positively correlated with bacterial beta diversity PCoA1. In conclusion, increasing temperature can promote the N2O emissions in tea plantation soils at different elevations, but there is no consistent change rule between elevation and N2O temperature sensitivity, and N2O temperature sensitivity is mainly affected by the bacterial beta diversity.

A new mathematical solution of convection‐dispersion equation to describe solute transport in heterogeneous soils

AbstractThere was a long‐time debate about the validation of the convection‐dispersion equation (CDE) and its replacement with the well‐known convective lognormal transfer function model (CLT) to describe solute transport in a heterogeneous soil with uniformity at the longitudinal water flow direction and nonuniformity at the transverse direction. The objective of this study is to prove that the CDE is valid and almost identical to the CLT. Gamma probability density function (pdf) was initially assumed in this study to describe the distribution of pore‐water velocity across capillary tubes in a heterogeneous soil. The capillary bundle model was used to describe solute transport without transverse solute mixing between adjacent tubes. The inverse‐gamma function, a new mathematical solution of the CDE differential equation with scale‐dependent dispersivity, was initially derived from the capillary bundle model and the gamma pdf. The only difference between the inverse‐gamma function and the CLT is that lognormal pdf of pore‐water velocity is assumed in the CLT while the two pdfs are close to each other. The inverse‐gamma function and the CLT were tested with the published data from the miscible displacement experiments on the two repacked soils with different aggregate sizes. Results show that both the inverse‐gamma function and the CLT fit the measured breakthrough curves in the miscible displacement experiments. The estimates of the squared coefficient of variation of the pore‐water velocity in the gamma pdf were 0.314 and 0.0582 for the two soils, and they were consistent with the lognormal pdf in the CLT.

Assessing the Effectiveness of Satellite and UAV-Based Remote Sensing for Delineating Alfalfa Management Zones Under Heterogeneous Rootzone Soil Salinity

Site-specific application of agricultural inputs is crucial for optimizing resource utilization in alfalfa (Medicago sativa L.) production and addressing challenges such as soil salinity. The main objective of this study was to assess the effectiveness of PlanetScope and UAV-based NDVI imagery for delineating alfalfa management zones under heterogeneous rootzone soil salinity. The research was conducted in the alfalfa field located in Imperial Valley, CA. The extent of rootzone soil salinity was assessed using Electromagnetic induction (EMI) technology and deep soil sampling. Reference management zones were then defined using the soil salinity (ECe) map derived from apparent electrical conductivity (ECa) data. Additionally, a time series of NDVI images from PlanetScope imagery and an NDVI image captured using an unmanned aerial vehicle were used to delineate remote sensing-based management zones. Laboratory analysis of disturbed soil samples collected at various depths provided soil physicochemical property data. Soil salinity of the samples ranged from 2.2 to 13.4 dS m−1 with a moderate level of variability (CV = 37.7%). ECe-based management zones accounted for approximately 83% of the field's variability and exhibited substantial differentiation among delineated zones concerning diverse soil properties, including ECa, ECe, gravimetric water content, Mg2+, boron, Ca2+, Na+, and Cl−. Notably, NDVI images effectively captured field variability on par with ECe-based zoning. Moreover, NDVI images recommended the same optimal number of zones (i.e., three) to address the field's variability, aligning with the ECe-based zoning approach. Our findings highlight that heterogeneity of soil salinity in the root zone primarily impacts the variability of alfalfa NDVI early in the growing season. Consequently, this early stage emerges as the most opportune timeframe for NDVI-based zoning for rapid assessment of rootzone soil salinity concerns.

Theoretical Investigation of Dynamic Pile–Soil Interaction in Torsion Considering Continuity of Heterogeneous Soil

Theoretical Investigation of Dynamic Pile–Soil Interaction in Torsion Considering Continuity of Heterogeneous Soil

Analysis of Microbial Community Heterogeneity and Carbon Fixation Capabilities in Oil-Contaminated Soils in Chinese Onshore Oilfields.

This study selected 27 soil samples from four representative horizontally distributed onshore oilfields in China to explore the diversity of soil microbial communities and their carbon fixation capacity, with a focus on the potential interaction between pollution and carbon fixation under oil pollution stress. The analysis of the soil physicochemical properties and microbial community structures from these oilfield samples confirmed a clear biogeographic isolation effect, indicating spatial heterogeneity in the microbial communities. Additionally, the key factors influencing microbial community composition differed across regions. The dominant bacterial phyla of soil microorganisms under soil pollution stress were Proteobacteria, Actinobacteriota, Chloroflexi, Acidobacteriota, Firmicutes, Bacteroidota, and Gemmatimonadota. A correlation network analysis identified Immundisolibacter, Acinetobacter, Blastococcus, Truepera, and Kocuria as key players in the microbial network, with most showing positive correlations. The results of the KEGG database functional annotation showed that degradation and carbon fixation metabolic pathways coexist in soil samples and maintain a balanced relative abundance. These metabolic pathways highlight the functional diversity of microorganisms. Among them, prokaryotic and eukaryotic carbon fixation pathways, along with benzoate degradation pathways, are predominant. These findings establish a theoretical basis for further exploration of the synergistic mechanisms underlying pollution reduction and carbon sequestration by microorganisms in petroleum-contaminated soils.

Soil-associated fungal and prokaryotic diversity influenced by stoniness, depth and vintage in a high-altitude vineyard

Soil microbes are increasingly recognised as key contributors to wine terroir, playing crucial roles in soil health and nutrient cycling. Fungi and prokaryotes interact with soils, influencing physical and chemical properties and mediating nutrient availability for roots. These microorganisms also impact vine performance and wine quality. Viticulture is expanding to higher elevations due to their cooler temperatures; Mendoza's mountainous regions are of particular interest being, characterised by vineyards with heterogenous soil stoniness. However, the effect of this variability on soil-associated microbial communities remains unclear. This study explores microbial populations (alpha and beta diversity, taxonomical composition, and their relationship with soil physicochemical properties) in soils of contrasting stoniness, at different depths, vintages and sample types. A Malbec vineyard with heterogenous soil stoniness was selected, with two experimental sites 30 m apart containing stony soil (SS; 77 % stoniness) and non-stony soil (NS; 0 % stoniness), respectively, and which were managed identically. Samples were collected from two depths (0.3 m and 0.6 m) during two vintages (2017 and 2018), from bulk and rhizosphere. Amplicon sequencing targeted the V3-V4 region of the 16S rRNA gene (prokaryotes) and the ITS1 region (fungi). Results showed that soil type significantly influences fungal populations, with less effect on prokaryotes. Vintage, reflecting annual changes in weather and viticultural practices, was the most significant factor affecting microbial communities. Depth was particularly important for fungi, while the sampling type (bulk or rhizosphere) had no significant impact on the microbiome within the same soil profile. Certain soil components were found to influence microbial communities: pH affected prokaryotes, while calcareous content specifically influenced the Proteobacteria phylum. Additionally, five fungal orders were more abundant in the stony soils, though some remained unidentified. These findings provide a baseline for understanding microorganisms in contrasting soils types of a high-elevation vineyard, and they highlight the role of microbial diversity in supporting unique soil-plant-environment interactions.

Mobilization of poly- and perfluoroalkyl substances (PFAS) from heterogeneous soils: Desorption by ethanol/xanthan gum mixture

Remediating soils contaminated by per- and polyfluoroalkyl substances (PFAS) is a challenging task due to the unique properties of these compounds, such as variable solubility and resistance to degradation. In-situ soil flushing with solvents has been considered as a remediation technique for PFAS-contaminated soils. The use of non-Newtonian fluids, displaying variable viscosity depending on the applied shear rate, can offer certain advantages in improving the efficiency of the process, particularly in heterogeneous porous media. In this work, the efficacy of ethanol/xanthan mixture (XE) in the recovery of a mixture of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS), and perfluorobutane sulfonate (PFBS) from soil has been tested at lab-scale. XE’s non-Newtonian behavior was examined through rheological measurements, confirming that ethanol did not affect xanthan gum’s (XG) shear-thinning behavior. The recovery of PFAS in batch-desorption exceeded 95 % in ethanol, and 99 % in XE, except for PFBS which reached 94 %. 1D-column experiments revealed overshoots in PFAS breakthrough curves during ethanol and XE injection, due to over-solubilization. XE, (XG 0.05 % w/w) could recover 99 % PFOA, 98 % PFBS, 97 % PFHxS, and 92 % PFOS. Numerical modeling successfully reproduces breakthrough curves for PFOA, PFHxS, and PFBS with the convection-dispersion-sorption equation and Langmuir sorption isotherm.

Automated identification of soil functional components based on NanoSIMS data

NanoSIMS technique allows to investigate the micro-spatial organization in complex structures in multiple scientific fields such as material science, cosmochemistry, and biogeochemistry. In soil biogeochemistry applications, NanoSIMS-based approaches aim to disentangle the interactions of organic matter (OM) and mineral phases in the heterogeneous soil microstructure. Investigating the spatial arrangement of distinct organic and mineral functional components is necessary to understand how these components interact and contribute to biogeochemical processes in soil systems. Identifying soil functional components within NanoSIMS measurements necessitates advanced and efficient data processing tools capable of accessibility and automation. We have developed a pre-processing tool to streamline NanoSIMS data preparation and handling. The tool is provided as an open-source software toolbox (NanoT). In addition, a two-step unsupervised segmentation method was developed to identify soil functional components based on NanoSIMS analyses. To illustrate the segmentation method, here we describe its application to two exemplary NanoSIMS measurements. This allows to distinguish mineral- and OM-dominated regions, as well as different mineral phases. To improve the detection of iron oxides and aluminosilicates, the 56Fe16O− channel was separately processed. The presented NanoSIMS-based processing workflow helps to disentangle functional components within a biogeochemically-diverse microstructure in soils and further warrants applications to a wide range of complex environmental samples.

Formulation and Implicit Numerical Integration of a Kinematic Hardening Model for Unsaturated Soils

ABSTRACTCurrently, our understanding of material‐scale deterioration resulting from meteorologically induced variations in pore water pressure and its significant impact on infrastructure slopes is limited. To bridge this knowledge gap, we have developed an extended kinematic hardening constitutive model for unsaturated soils that refines our understanding of weather‐driven deterioration mechanisms in heterogeneous clay soils. This model has the capability of predicting the irrecoverable degradation of strength and stiffness that has been shown to occur when soils undergo wetting and drying cycles. The model is equipped with a fully coupled and hysteretic water retention curve and a hysteretic loading–collapse curve and has the capability to predict the irrecoverable degradation of strength and stiffness that occurs during cyclic loading of soils. Here, we employ a fully implicit stress integration technique and give particular emphasis to deriving a consistent tangent operator, which includes the linearisation of the retention curve. The proposed algorithm is evaluated for efficiency and performance by simulating various stress and strain‐driven triaxial paths, and the accuracy of the integration technique is evaluated through the use of convergence curves.

Land Use Legacy Landforms at the UNESCO Heritage Site Tarnowskie Góry, Upper Silesia, Poland—Stratigraphy, Soils and Age

ABSTRACTMetallurgy in Upper Silesia (Poland) has a long tradition of international significance, which was emphasized in 2017 when the historic silver mine in Tarnowskie Góry was inscribed as a UNESCO World Heritage site. The area consists of various anthropogenic landforms, the stratigraphy of which has hardly been studied so far. In this study, we describe five main morphological units: Unit I (RCH) and Unit II (RCH pit), resulting from charcoal production; Unit III (shaft) and Unit IV (shaft heap), resulting from mining; and Unit V (reference forest soil). The first four units are a variation of a Technosol with inherently different properties from the reference forest soil. Unit I exhibits typical properties of a relict charcoal hearth (RCH), whereas Unit II resembles a pit. Unit III consists of a mostly infilled mining shaft remain (MSR), characterized by relocated subsoil. Unit IV consists of material from the adjacent Unit III that has been dumped directly aside. The studied RCH was used no earlier than during the second half of the 17th century, probably between 1725 and 1813. The studied MSR was used most likely between the 3rd and 5th centuries, which is much older than described so far. Together, the units reflect the characteristic heterogeneity of soils in shaft mining and RCH areas.