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Many high earth rockfill dams are currently being constructed in the alpine region of Southwest China. Since the effective working time is reduced by the cold climate, it is necessary to solve the problem of intermittent filling of the core wall at low temperature. However, freeze–thaw (FT) cycles in the filling process will change the deformation behavior of gravelly soil. For 300 m-high earth core rockfill dams, the deformation of gravelly soil is a crucial factor in predicting the long-term deformation and settlement after dam construction. To investigate the influence of FT cycles on the deformation characteristics, the deformation of the gravelly soil under different amounts of FT cycles was tested using an MTS-810 test system. The deformation characteristics were discussed, and a modified Burgers model was used to describe the deformation characteristics. The results show that the freeze–thaw action makes the coarse particles break, resulting in an increase in the fine content. The FT cycles can make the creep characteristics of gravelly soil more obvious. The creep strain has a large contribution to the total strain with the increasing in the FT cycles. It is thus suggested that the coverage of thermal insulation material would effectively prevent freezing of the gravelly soil and control the deformation.

Wind erosion and associated dust emissions play a fundamental role in many ecological processes and provide important biogeochemical connectivity at scales ranging from individual plants up to the entire globe. Yet, most ecological studies do not explicitly consider dust-driven processes, perhaps because most relevant research on aeolian (wind-driven) processes has been presented in a geosciences rather than an ecological context. To bridge this disciplinary gap, we provide a general overview of the ecological importance of dust, examine complex interactions between wind erosion and ecosystem dynamics from the scale of plants and surrounding space to regional and global scales, and highlight specific examples of how disturbance affects these interactions and their consequences. It is likely that changes in climate and intensification of land use will lead to increased dust production from many drylands. To address these issues, environmental scientists, land managers, and policy makers need to consider wind erosion and dust emissions more explicitly in resource management decisions.

Aims All components of the soil-plant-atmosphere (s-p-a) continuum are known to control berry quality in grapevine (Vitis vinifera L.) via ecophysiological interactions between water uptake by roots and water loss by leaves. The scope of the present work was to explore how the main hydraulic components of grapevine influence fruit quality through changes in liquid- and gas-phase hydraulic conductance. Methods To reach our objectives, determinations of shoot growth, berry size and sugar content, leaf gas exchange, predawn leaf water potential (as a proxy of soil water potential), midday stem water potential and leaf water potential were performed in conjunction with anatomical measurements of shoot xylem. All measurements were conducted in two different cultivars (Cabernet franc and Merlot) and on three different soil types (clayey, gravelly, and sandy). Results Shoot xylem morphometric characteristics and whole-plant hydraulic conductance were influenced by cultivar and soil type. Differences in leaf gas exchange parameters and water potentials were determined by soil type significantly more than by cultivar. Between the two extremes (gravelly soil imposing drought conditions and sandy soil with easily accessible water) the clayey soil expressed an intermediate plant water consumption and highest sugar accumulation in berry. Conclusions Hydraulic and non hydraulic limitations to vine/berry interactions supported the conclusion that water availability in the soil overrides differences due to cultivar in determining the productive potential of the vineyard. Non hydraulic stomatal control was expected to be an important component on plants grown on the clayey soil, which experienced a moderate water stress. Possible links between hydraulic traits and berry development and quality are discussed.

The presence of overlarge gravel particles poses significant challenges for laboratory testing on prototype gravelly soils due to sample size limitations. To address this issue, replacement techniques, such as substituting overlarge particles with finer materials, offer practical solutions. However, the impact of these techniques on the mechanical behavior of gravelly soils, particularly shear strength and stiffness, remains poorly understood. This study aims to bridge this knowledge gap by investigating the particle size effect on the shear behaviors of binary mixtures using a series of Discrete Element Method (DEM) simulations. Updated scaling relations, based on Iai’s generalized scaling relations, were proposed to correct for particle size effects. DEM simulations, including drained triaxial tests and shear modulus measurements, were performed to validate the proposed law. The results indicate that the gravel replacement technique has a minor effect on peak shear strength but significantly reduces soil stiffness, especially at high gravel contents. The scaling relations effectively correct for the particle size effect, enabling the accurate prediction of shear behaviors of the prototype gravelly soils from those of the model gravelly soils. These validations demonstrate that for addressing the soil deformation problem instead of the stability problem in ultimate state, the developed scaling relations are highly effective for correcting the particle size effect. Based on the developed scaling relations, engineers can predict prototype-scale shear behaviors of gravelly soils with overlarge particles using scaled laboratory models, reducing reliance on costly large-scale equipment. Additionally, future studies, through both DEM simulations and laboratory experiments, are recommended to further validate and refine the proposed method across diverse soil conditions and loading scenarios, such as cyclic loadings.

Because of its angularity, crushability, and high void ratio, calcareous gravelly soil has peculiar geotechnical properties. A series of large-scale direct laboratory shear tests was conducted on calcareous gravelly soil taken from coral reefs in the South China Sea. This study aimed to investigate the shear characteristics of calcareous gravelly soil under conditions of varying gradation, water content, density, and mineral composition. The experimental results revealed the extremely different mechanical properties of calcareous gravelly soil compared to common non-cohesive soil: calcareous gravelly soil has greater apparent cohesion, larger friction angle, and lower softening value than quartz sand. The friction angle increases with dry density, while the apparent cohesion increases with the median particle size ( D 50 ) of the soil. After shear failure, the apparent cohesion decreases significantly from the peak value, but friction angle decreased slightly. Grouting can be employed to reinforce foundations and enhance slopes consisting of calcareous gravelly soil at the early stage of shear failure. This study intends to provide reference information for engineering constructions on coral reefs and report new findings on coarse-grained soil.

Cultivation of soybean and off-season corn is advancing in areas under restricted edaphoclimatic conditions, such as petric plinthosols, which have significant proportions of gravel and are deficiency in micro-nutrients such as copper (Cu) and zinc (Zn). The effects of Cu and Zn concentrations on soybean nutrition cultivated in petric plinthosol are unclear, and it is unknown whether the levels considered adequate for other soils are sufficient for gravely soils, or even if higher Cu and Zn rates can cause a toxic effect in soybean. The objective was to compare the response of soybean grown in petric plinthosol and ferralsol to Cu and Zn doses for identifying the changes induced by gravel soils and to evaluate the residual effect on off-season corn grown in ferralsol. Four experiments were carried out with Cu and Zn doses applied to soil with the soybean crop in ferralsol and plinthosol. The leaf tissues of soybean crops in the two soils showed the same rate of increase in Zn concentrations, for each kg·ha-1 of Zn applied, the increase in Zn was 0.7 mg·kg-1, suggesting no difference in the effect of Zn fertilization between soils with and without gravel. The dosages of Zn and Cu Oxysulfate applied to soil did not cause residual effects in the off-season corn. The highest doses of Cu and Zn did not have any toxic effects on the plants. The main criteria for interpreting Cu and Zn in soil analysis are thus also applicable to soybean crops grown in petric plinthosol. RESUMO: O cultivo de soja e milho safrinha avança em condições edafoclimáticas restritivas, como nos PLINTOSSOLOS PÈTRICOS, que apresentam proporções consideráveis de cascalho no seu perfil e são deficientes em cobre (Cu) e zinco (Zn). Não se sabe os efeitos de doses de Cu e Zn na nutrição da soja cultivada em PLINTOSSOLO PÉTRICO, nem se os níveis considerados adequados para outros solos são suficientes para solos cascalhentos, ou ainda, se altas doses de Cu e Zn podem causar toxidez nas plantas de soja. O objetivo foi comparar a resposta a doses de Cu e Zn em soja cultivada em PLINTOSSOLO PÉTRICO e em LATOSSOLO, a fim de identificar alterações provocadas pelo solo com cascalho, e adicionalmente, avaliar o efeito residual da adubação feita na soja para o milho safrinha cultivado no LATOSSOLO. Quatro experimentos foram desenvolvidos com doses de Cu e Zn aplicadas via solo na cultura da soja em LATOSSOLO e em PLINTOSSOLO PÉTRICO. Houve a mesma taxa de incremento na concentração de Zn no tecido foliar da soja nos dois solos estudados, para cada kg ha-1 de Zn aplicado, o incremento foi de 0,7 mg·kg-1 demonstrando que não há diferença de um solo com ou sem cascalho para os efeitos da adubação. As doses de oxissulfato de Zn e Cu aplicadas via solo não causaram efeito residual no milho safrinha. As maiores doses de Cu e Zn não causaram efeito tóxico nas plantas. Os principais critérios de interpretação de Cu e Zn em análise do solo se aplicam para soja cultivada em PLINTOSSOLO PÉTRICO.

The essence of plant ecological stoichiometry is to study the relationships between species and their environment, including nutrient absorption, utilization and cycling processes as well as the nutrient limitation of plants. Plants can regulate nutrient elements and adapt to environmental changes. To understand the adaptation mechanism, it is important to take plants as a whole and quantify the correlation between the chemometrics of different organs. Ammopiptanthus mongolicus is within the second-class group of rare–endangered plants in China and is the only evergreen broad-leaved shrub in desert areas. We analyzed the ecological stoichiometric characteristics of leaves, stems, roots, flowers and seeds of A. mongolicus in five habitats, namely fixed sandy land, semi-fixed sandy land, stony–sandy land, alluvial gravel slope and saline–alkali land. We found that (1) the nutrient contents of N, P and K were in the order of seed > flower > leaf > root > stem. The enrichment of the N, P and K in the reproductive organs promoted the transition from vegetative growth to reproductive growth. Additionally, (2) the contents of C, N, P and K and their stoichiometric ratios in different organs varied among different habitat types. The storage capacity of C, N and P was higher in sandy soil (fixed and semi-fixed sandy land), whereas the content of K was higher in gravelly soil (stony–sandy land and alluvial gravel slope), and the C:N, C:P and N:P were significantly higher in gravelly soil than those in sandy soil. A. mongolicus had higher nutrient use efficiency in stony–sandy land and alluvial gravel slope. Furthermore, (3) the C:N and N:P ratios in each organ were relatively stable among different habitats, whereas the K:P ratio varied greatly. The N:P ratios of leaves were all greater than 16 in different habitats, indicating that the growth was mainly limited by P. Moreover, (4) except for the P element, the content of each element and its stoichiometric ratio were affected by the interaction between organs and habitat. Habitat had a greater impact on C content, whereas organs had a greater influence on N, P and K content and C:N, C:P, C:K and N:P.

Wave erosion on soil bank slopes has become severe with the long-term operation of the Three Gorges Reservoir; however, the progression of soil bank slope erosion varies in different regions. The influence of the physical parameters of the soil mass on the wave erosion bank slope was investigated using a self-designed and manufactured wave erosion bank slope model test device. Physical model tests were conducted on wave erosion bank slopes comprising six groups with different dry densities and gravel contents to obtain the erosion process of the bank slope under wave action. The results show that the higher the dry density of the soil, the stronger the erosion resistance of the bank slope, and the longer the time required for the bank slope to reach a final steady state; the higher the gravel content, the stronger the erosion resistance of the bank slope. Owing to the protective effect of gravel, the time required for bank slope erosion stability was also shortened. Increasing the dry density or gravel content increased the stable slope angle after bank slope erosion. The wave erosion rate of the bank slope was high at the early stage of the test, and the bank slope erosion of each group was effectively completed within 240 min of the start of the test. The erosion rate of each bank slope under wave action decreased exponentially. Based on this, an empirical equation between the wave frequency and bank slope erosion rate was derived, which can be used to determine the erosion process of a bank slope. This research provides technical support for the prevention and control of erosion on soil bank slopes in the Three Gorges Reservoir area.

Liquefaction, which can be defined as a loss of strength and stiffness in soils, is one of the major causes of damage to buildings and infrastructure during an earthquake. To overcome a lack of comprehensive analyses of seismically induced liquefaction, this study reviews the characteristics of liquefaction and its related damage to soils and foundations during earthquakes in the first part of the twenty-first century. Based on seismic data analysis, macroscopic phenomena of liquefaction (e.g., sand boiling, ground cracking, and lateral spread) are summarized, and several new phenomena related to earthquakes from the twenty-first century are highlighted, including liquefaction in areas with moderate seismic intensity, liquefaction of gravelly soils, liquefaction of deep-level sandy soils, re-liquefaction in aftershocks, liquid-like behavior of unsaturated sandy soils. Additionally, phenomena related to damage in soils and foundations induced by liquefaction are investigated and discussed.

Gravelly soil is a typical heterogeneous porous medium with a multiscale structure and hydraulic conductivity that is challenging to quantify. The aim of this study is to examine the structure of an eluvial-colluvial gravelly soil at different scales and link the structural characteristics to the hydraulic conductivity. To this end, large gravelly soil samples and small fines-sand mixture samples were prepared and then characterized by X-ray computed tomography (CT) and optical microscopy, respectively. Through image analyses, the pore structural characteristics at the gravel scale (≥ 1.0 mm) and sand scale (0.01–1.0 mm) were identified. Constant-head tests were performed on the large gravelly soil samples to measure the saturated coefficients of permeability (k). The results show a relatively small gravel-scale porosity and a large sand-scale porosity in compacted gravelly soils. The dominant sizes of gravel-scale pores and sand-scale pores are several millimeters and approximately 0.06 mm, respectively. An evaluation of ten existing permeability equations indicates that most of the previous empirical equations proposed for sand and gravel are not applicable to well-graded gravelly soils. For this reason, the existing permeability equations were improved. In addition, novel empirical equations for estimating the k value of gravelly soils were proposed based on the structural parameters of pores, as well as the concepts of the effective porosity and the effective grain size.