Search Results (1,824)

Water-soil gushing caused by tunnel leakage can induce severe ground disturbance and threaten the safety of shield tunnels, yet rapid prediction remains difficult because high-fidelity numerical simulations are computationally expensive. This study develops an interpretable machine-learning framework for predicting gushing-induced ground disturbance around shield tunnels based on a validated two-phase Material Point Method database. Six governing variables are considered, including the tunnel depth ratio, gushing location, soil friction angle, Young’s modulus, intrinsic permeability, and soil gushing mass. Three representative response variables were selected, namely the maximum ground settlement, flow-zone width, and flow-zone centroid angle. Five algorithms, including MLP, RF, XGBoost, SVR, and Ridge, were established and compared, with hyperparameters optimised using Optuna. The results show that nonlinear models consistently outperform the linear baseline, among which MLP, RF, and XGBoost achieve the best overall accuracy and robustness. Error-distribution analysis further indicates that MLP and RF yield the highest proportion of low-error predictions. SHAP interpretation shows that SGM is the dominant factor governing maximum settlement and flow-zone width, whereas gushing location primarily controls the flow-zone centroid angle. The proposed framework provides an efficient and physically interpretable surrogate for rapid hazard assessment of gushing-induced ground disturbance in shield tunnelling. Full article

This paper introduces the research progress of path planning, trajectory tracking control, and multi-machine collaborative operation systems for agricultural robots. It summarizes the development laws of 3D terrain modeling and adaptive path planning algorithms for complex agricultural environments such as hills and mountains, and analyzes the dynamic disturbance characteristics of agricultural machinery under slip, sideslip, and dynamic load changes. Through comprehensive analysis, it is found that traditional kinematic control models have limitations in complex and unstructured environments. Combining soil mechanics mechanisms, variable load identification, and robust control strategies is key to improving trajectory tracking stability and operational quality. In terms of multi-machine collaboration, this paper discusses master–slave collaboration, distributed control, and task allocation modes. It further identifies that the stability of collaboration and interoperability standards between devices in weak network environments are currently the main bottlenecks limiting the large-scale application of this technology. Finally, this paper provides prospects for future research directions and suggests strengthening the closed-loop integration of perception, decision-making, and dynamic models, establishing industry unified standards, and enhancing the safety of the entire lifecycle of operations, providing suggestions for the unmanned application of agricultural robots. Full article

River ecological restoration in lowland plain basins is often constrained by fragmented river networks, degraded riparian zones, eutrophication risk, and intensive human disturbance. Conventional monitoring approaches rarely connect watershed-scale dynamics with responses from typical restoration units, limiting quantitative evaluation and the separation of direct project outcomes from broader environmental variability. To address this gap, this study developed a collaborative satellite–unmanned aerial vehicle (UAV)–unmanned surface vehicle (USV) monitoring framework and applied it to the Nihe River Basin, China, a lowland plain river undergoing systematic restoration under the Shan-shui Initiative. The framework combines Sentinel-2 time-series imagery, high-resolution Gaofen-1, Gaofen-2, and Jilin-1 imagery, UAV orthophotos, USV observations, and auxiliary environmental datasets. Unlike single-scale monitoring approaches, it links watershed-scale indicators, including water-body dynamics, chlorophyll-related eutrophication risk, riparian ecological background, and soil-water conservation capacity, with unit-scale diagnosis of riparian buffer and riverine wetland restoration. Results showed that river water-body area increased from 37.78 km² to 40.59 km² during 2021–2024, while normalized difference chlorophyll index (NDCI)-based eutrophication risk improved in 9.12% of the monitored river area and degraded in only 0.47%. Riparian vegetation cover remained high, whereas regional soil-water conservation capacity declined due to climatic factors, revealing asynchronous responses between local recovery and regional background conditions. At the unit scale, riparian buffer restoration enhanced buffer continuity and near-bank water quality, as reflected by decreased chemical oxygen demand (COD), increased dissolved oxygen (DO), and limited ammonia nitrogen (NH₃-N) improvement. Riverine wetland restoration promoted land-use adjustment and ecological spatial reorganization. This cross-scale evidence chain supports adaptive management of inland river and wetland restoration projects. Full article

This study examined the effect of east–west orientation of willow tree (Salix alba L.) rows on soil biological activity and weed dynamics in a temperate maize (Zea mays L.) intercropped agroforestry (AF) system in Eastern Hungary. The experiment evaluated how the year (2022, 2023), location (distance from the rows), and irrigation (IR) influenced spatial patterns of earthworm (EW) parameters and weed cover. The study aimed to assess how willow-based AF systems influence soil biological and weed community dynamics under varying IR and row spacing, in comparison with monoculture cropland (MC) systems, and to evaluate their potential role in climate change adaptation in arable farming. Both soil sampling for the EW survey and vegetation studies were conducted along perpendicular transects extending from the tree rows to measure EW abundance and biomass, as well as total weed cover. Experimental results revealed clear spatial gradients in EW distribution and weed abundance near the tree rows, driven by litter input, shading, moisture, and reduced disturbance. These effects were intensified under IR at narrower row spacings. No significant differences were observed between AF-South (shaded), AF-Center, and MC plots; however, significantly higher EW abundance and biomass were found on the AF-North (sunny) side. As for the location, significantly greater total EW abundance was found at AF-North (105.0 individual m⁻²) compared with the MC plots. AF systems enhance soil biological activity and shape weed dynamics through spatial ecological gradients influenced by tree row spacing and irrigation, supporting their role as sustainable land-use systems while emphasizing the need for site-specific management and further long-term optimization. Full article

Understanding how natural and anthropogenic factors jointly influence avian diversity is essential for biodiversity conservation and the sustainable management of large-scale wetland ecosystems, yet their combined effects remain insufficiently understood. This gap is particularly evident for land birds, as most studies focus on waterbirds. Using structural equation modeling, we quantified the effects of these drivers on habitat quality and avian richness in the Sanjiang Plain, separately for waterbirds and land birds. Our results show that: (1) habitat quality is primarily controlled by natural factors, particularly soil organic carbon (SOC), normalized difference vegetation index (NDVI), and topography, whereas human activities exert weak negative effects; (2) waterbirds are primarily associated with SOC- and temperature-driven pathways, whereas land birds respond more directly to climate and human disturbance; (3) natural drivers exert stronger effects than anthropogenic factors on both waterbird and land bird diversity; and (4) the effects of natural drivers differ between bird groups, with SOC and NDVI showing stronger effects on waterbirds, and precipitation and temperature being more influential for land birds. These findings highlight the need for group-specific conservation strategies, including conserving soil carbon and maintaining hydrological conditions for waterbirds, and enhancing vegetation and mitigating human disturbance for land birds. Full article

Deltas are highly susceptible to biological invasions because of strong hydrological connectivity, frequent disturbance, and intense human use. Here, we synthesise coordinated monitoring observations and literature evidence on invasive alien plant species (IAS) recorded in four Black Sea riparian protected areas located across five countries, surveyed under the IASON/IASON+ initiatives (Danube Delta, Nestos Delta and Lake Vistonida, Kızılırmak Delta, Chorokhi Delta and Kolkheti National Park). Across the study sites, 17 IAS were documented, mainly represented by taxa native to North America and characterised by high propagule production and/or strong vegetative regeneration. Woody riparian invaders (e.g., Amorpha fruticosa, Robinia pseudoacacia, Acer negundo, Gleditsia triacanthos and Ailanthus altissima) exploited nutrient-rich floodplain soils and disturbances. In contrast, annual weeds (e.g., Ambrosia artemisiifolia, Sicyos angulatus and Xanthium orientale) remained associated with disturbed habitat edges. Aquatic dominance was confined to the Danube Delta, where Elodea nuttallii and Elodea canadensis formed dense submerged stands. Species were assigned to broad range expansion categories (slowly, moderately and rapidly spreading species) based on project observations and supporting records. We discuss shared invasion syndromes linked to reproductive and dispersal traits and outline management implications for Black Sea deltas, emphasising pathway prevention, early detection and rapid response for localised taxa, and sustained control combined with restoration for dominant invaders. Full article

Nitrogen applied in excess of plant demand in intensive agricultural systems can be lost through runoff and leaching into surface and groundwater, with potentially negative effects on water quality. Zeolites, due to their high cation exchange capacity and internal porosity, can adsorb ammonium (${NH}_4^{+}$) and help mitigate excessive nitrate (${NO}_3^{-}$) leaching. Owing to such properties, zeolites can play an important role in reducing the potential negative impact associated with the extensive use of nitrogen-based fertilizers. In this study, we investigated the effects of two commercial natural zeolites on selected hydraulic properties, water storage, and solute transport parameters of three sandy-loam soils with different pedological characteristics. Laboratory experiments were conducted on disturbed soil columns. The leaching of ${NO}_3^{-}$ and ${NH}_4^{+}$ ions was monitored using ion-selective electrode analysis. The results indicate that zeolite application reduces the mobility of nitrate and ammonium. This effect can be attributed to changes in the original pore size distribution of the investigated soils, characterized by a reduction in macropore regions and a corresponding increase in meso- and micropore regions. In the case of ammonium, adsorption mechanisms are also involved, which further contribute to retarding its mobility. These effects were consistently observed across the investigated soils. For a given soil, the magnitude of the observed effects depended on both the type of zeolite used and the amount of zeolite mixed with the soil. Finally, ANOVA tests and multivariate analyses were applied to the full dataset to provide statistical support for the observed changes in the selected parameters. Full article

Islands have high ecological and tourism value; however, owing to their remoteness and limited accessibility, environmental radioactivity is often less systematically evaluated than in mainland regions. This study investigates the distribution, source partitioning, and radiological implications of multi-radionuclides (⁷Be, ¹³⁷Cs, ²¹⁰Pb, ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K) in surface soils of Zhoushan Island, a representative tourism-oriented island in the East China Sea. Activity concentrations of ⁷Be, ¹³⁷Cs, ²¹⁰Pb, ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K ranged from 3.4 to 585.5, below detection limit −5.7, 45–1490, 33.3–72.4, 32.3–58.9, 37.8–91.7, and 439.6–872.3 Bq/kg, respectively. Using multivariate statistics and geochemical interpretation, we classified radionuclides into three groups: (i) atmospheric deposition-driven nuclides (⁷Be, ²¹⁰Pb_ex), (ii) lithogenic background-controlled nuclides (²³⁸U−²²⁶Ra−²³²Th), and (iii) the alkali-metal-like behavior group (¹³⁷Cs−⁴⁰K). This shows that soil radionuclide patterns result from atmospheric inputs, geological inheritance, and land-use disturbance, rather than simple concentration variability. Spatial analysis revealed that agricultural disturbance enhances ¹³⁷Cs redistribution, low-lying terrains preferentially accumulate atmospheric fallout nuclides, and lithogenic radionuclides are higher in the northern island due to parent material and weathering. No significant ⁴⁰K enrichment was observed in cultivated soils, indicating limited fertilizer influence. Although radiological indices remain within international safety thresholds, several parameters exceed global background levels, indicating elevated natural radiation driven primarily by thorium-rich lithology. Importantly, we show that radiological risk assessments based solely on bulk activity may overestimate environmental significance without considering process controls. This study provides a process-informed radiological assessment for island systems, offering insights for environmental monitoring and risk evaluation in similar coastal and tourism-dominated regions. Full article

Greenhouse environments with restricted air exchange favor the accumulation of gaseous elemental mercury (GEM), posing potential exposure risks. However, the exact contribution of soil–air mercury fluxes to ambient greenhouse GEM, and the mechanisms by which organic manure application regulates this process, represent a critical knowledge gap. To address this, a 90-day simulated greenhouse incubation experiment (incorporating 0%, 1%, 2%, and 3% sheep manure fertilizer (SMF) amendments) and continuous 24 h micro-meteorological monitoring were conducted to evaluate GEM dynamics, soil Hg(0) fluxes, and mercury valence-state partitioning. Furthermore, macroscopic Hg(II) adsorption–desorption experiments were performed to elucidate the retention mechanisms. Our results demonstrated that while mechanical fertilization disturbances caused a transient short-term release of pre-existing Hg(0) on Day 0, both ambient GEM concentrations and soil Hg(0) emission fluxes generally declined over the long-term incubation period. Soil Hg(0) emission was identified as the predominant source process driving greenhouse GEM dynamics. Crucially, SMF addition consistently decreased operationally defined soil Hg(0) while relatively increasing the oxidized Hg(I) and Hg(II) fractions. Macroscopic batch experiments corroborated that SMF significantly enhanced Hg(II) retention and reduced its reactivation potential. Overall, under controlled experimental conditions, SMF exhibited a strong time-dependent suppressive effect on soil Hg(0) release and ambient GEM accumulation. These findings highlight the potential of organic manure in mitigating mercury risks in protected agriculture, though future molecular-level spectroscopic validations remain necessary to deduce the precise binding mechanisms. Full article

Agricultural land abandonment is widespread in high-latitude regions, yet its effects on soil microbial communities in permafrost ecosystems remain insufficiently understood. In this study, we used a 0–25 year chronosequence of abandoned soils in the Yamalo–Nenets Autonomous Okrug to analyze the succession of soil microbial communities and compared them with mature reference Podzols. Soil physicochemical properties, microbial community composition, and potential functional changes were systematically assessed using 16S rRNA gene sequencing, multivariate statistical analyses, and functional prediction. The results showed that, in mature soils, SOC was the key factor driving microbial community variation, whereas in agricultural and abandoned soils, available nutrients were the main factors influencing microbial community structure. The abandonment process also constrained soil microbial mineralization. The dominant microbial phyla mainly included Proteobacteria, Acidobacteriota, Verrucomicrobiota, Bacteroidota, and Actinobacteriota, while the relative abundances of other taxa differed markedly among land-use stages. Agricultural soils were dominated by copiotrophic microbial groups, whereas microbial communities in abandoned soils gradually shifted toward oligotrophic groups with increasing recovery time, and some taxa associated with the degradation of complex carbon substrates also increased in abundance. Functional analysis further indicated that carbon and phosphorus cycling functions in soil microbial communities exhibited a certain degree of functional redundancy, whereas nitrogen-cycling functions depended more strongly on specific microbial taxa. Land abandonment promoted an increase in the abundance of genes related to microbial carbon metabolism in soil. However, even after 25 years of abandonment, microbial community composition and functional potential had not fully recovered to the level of mature reference Podzols, indicating that agricultural disturbance exerts long-term legacy effects on soil microbiomes in permafrost-affected regions. Full article

Agricultural watersheds must simultaneously support multiple Ecosystem Services (ESs), yet the coordination between Ecosystem Service Value (ESV) growth and synergies of ESs remains poorly understood. Taking the Liaohe River mainstream Basin (LRMB), a typical agricultural watershed, as a case, this study investigates the spatiotemporal dynamics of ESV and trade-offs among ESs, along with their driving factors. Five key ESs—Food Production (FP), Water Conservation (WC), Water Purification (WP), Soil Conservation (SC), and Landscape Aesthetics (LA)—were selected. The InVEST model, Function-based Valuation Method, Root Mean Square Deviation (RMSD), and Coupling Coordination Degree (CCD) were comprehensively applied to assess the spatiotemporal variations in ESV, trade-off intensity, and their coupling coordination degree in the watershed from 2000 to 2023. Furthermore, the Optimal Parameters-based Geographical Detector (OPGD) and Multiscale Geographically Weighted Regression with Spatial Auto-correlation (MGWR-SAR) were employed to explore the driving mechanisms underlying changes in ESV and trade-off intensity, and to identify the major driving factors and their spatial heterogeneity. The results reveal the following: (1) From 2000 to 2023, total ESV in the LRMB increased by 69.5% from 77.66 to 131.59 billion yuan, with WC and FP accounting for 42.8% and 41.9% of this growth. Spatially, ESV shifted from a west-to-east increasing gradient to a U-shaped pattern, with high values concentrated in mountainous areas and low values along the mainstream. (2) Mean trade-off intensity remained stable at approximately 0.29, yet exhibited pronounced spatial polarisation. High trade-off zones shifted from the southwestern estuary toward the mainstream corridor, driven primarily by intensifying conflicts between FP and other ESs. (3) Despite a stable watershed-average CCD of 0.71–0.73, the CCD along the Liaohe River mainstream declined by over 15%, forming a corridor of coordination decay and revealing that ESV growth occurs at the expense of internal synergy. (4) Nonlinear interactions dominated ES dynamics, with the interaction of precipitation and human disturbance intensity exhibiting the highest explanatory power (q-values of 0.61 for ESV and 0.58 for RMSD). (5) Natural climatic factors (precipitation, temperature) predominantly enhanced synergy in mountainous areas, whereas human and landscape factors (human disturbance intensity, Shannon’s Diversity Index, PLAND of water) intensified trade-offs along the mainstream and central plains. This study establishes an integrated “ESV–trade-off–CCD” diagnostic framework and proposes a differentiated management strategy, offering a potentially transferable paradigm for sustainable governance in agricultural watersheds. Full article

Seismic damage has been observed not only in liquefiable sandy soil layers but also in thick deposits of soft clayey soils, which are characterized by the destruction of the soil structure, leading to strain softening. Previous studies conducted numerical simulations and defined this phenomenon as soil disturbance, which refers to the simultaneous reduction in stiffness and peak shear strength. To fill the research gap, this study systematically compares the post-cyclic degradation behavior of stiffness and peak shear strength of UDS and REC specimens derived from the same material. Based on the experimental results, the peak shear strength and rigidity of the UDS specimens simultaneously decrease, as the number of cycles increases. In contrast, the peak shear strength degradation effect is absent in the REC samples; both specimens exhibited loss in stiffness. The reduction in stiffness of UDS specimens was slower than that of REC specimens due to aging effects. Nevertheless, both effects on UDS and REC specimens are due to soil disturbance, which is defined in the numerical simulations of previous studies. Hence, the effects of soil disturbance can be summarized as (1) a reduction in the initial stiffness of soft clay and (2) a reduction in the mean effective stress during cyclic loading. Full article

Balancing wetland conservation with food security is a critical challenge for developing countries. This study compares land use change and its impacts on soil properties in two hydrologically distinct wetlands: the rain-fed Jinchuan Peatland in China and the flood-fed Kilombero Valley Floodplain (KVFP) in Tanzania. Using remote sensing data from 1990 to 2018 and soil physicochemical analysis, we found divergent reclamation trajectories. Wetland conversion has slowed in China but accelerated in Tanzania’s KVFP due to population pressure. Our results reveal a fundamental mechanism: rain-fed wetlands, lacking external nutrient replenishment, experience significantly greater soil degradation after conversion compared to flood-fed wetlands, which benefit from continued alluvial sediment inputs. Both sites showed post-conversion declines in soil moisture, total organic carbon (TOC), and total nitrogen (TN), alongside increased pH and bulk density. However, soil fertility loss was markedly more severe in Jinchuan than in KVFP. This disparity is attributed to the inability of rain-fed systems to replenish nutrients externally, whereas flood-fed KVFP benefits from continued alluvial sediment inputs. Our findings elucidate a key mechanism: flood-fed wetlands possess a natural resilience to agricultural disturbance through hydrological replenishment, making them potentially more suitable for sustainable utilization in food-insecure nations. Consequently, we propose that wetland management policies must be customized based on water source type and national development context, advocating for the targeted, science-based utilization of flood-fed wetlands as a strategic approach to reconcile food production with ecosystem preservation in regions like Tanzania. Full article

This study investigates the influence of various land use systems (LUSs) on soil physico-chemical properties, nutrient dynamics, and soil organic carbon (SOC) stocks in the Central Plain Zone of Uttar Pradesh, India. Soil samples were collected from six distinct LUSs, i.e., fallow, crop-based, horticulture-based, forest-based, vegetable-based, and barren land, and analyzed across three depth intervals (0–15 cm, 15–30 cm, and 30–60 cm). Soil pH increased steadily with depth, ranging from 7.43 to 8.58 at the surface layer to 7.55 to 10.32 in deeper layers. Horticulture-based LUSs recorded the lowest pH, while barren lands had the highest. Electrical conductivity (EC) also rose with depth, ranging from 0.12 to 3.63 dS m⁻¹, from the surface to subsoil layers, all below critical salinity thresholds. Soil organic carbon (SOC) content decreased with increasing soil depth across all land use systems. Among the studied systems, horticulture-based land use recorded the highest SOC content (0.77%), whereas barren land showed the lowest SOC content (0.21%). Due to greater organic matter inputs and reduced disturbances, horticultural systems also exhibited significantly higher levels of macronutrients (N: 17.98 kg ha⁻¹, P: 330.45 kg ha⁻¹, K: 374.81 kg ha⁻¹, S: 84.33 mg ha⁻¹) and micronutrients (Fe: 164.12 mg ha⁻¹, Mn: 60.89 mg ha⁻¹, Cu: 2.85 mg ha⁻¹, Zn: 1.80 mg ha⁻¹). Bulk density increased slightly with depth (1.46–1.63 Mg m⁻³), while soil moisture content remained relatively stable (43.43% to 42.31%), with moderate variability (CV: 24–27%). The mean total SOC stock was 10.77 t C ha⁻¹, ranging from 5.44 to 14.46 t C ha⁻¹. Microbial properties also varied among land uses: dehydrogenase activity (DEA), an indicator of microbial functionality, peaked in vegetable-based systems (30.54 µg TPF g⁻¹), whereas microbial biomass carbon (MBC) was highest in forest-based systems (184.83 µg g⁻¹). Correlation and regression analyses revealed a strong positive relationship between SOC and nutrient availability, with the highest correlation observed for Zn (R² = 0.99), followed by N (R² = 0.83) and K (R² = 0.75). Overall, barren lands showed the poorest soil quality indicators, while horticulture-based systems consistently demonstrated superior soil fertility and carbon sequestration potential. These findings emphasize the critical role of land use management in regulating soil fertility, SOC dynamics, and the long-term sustainability of agro-ecosystems in the region. Full article

Submarine landslides pose severe marine geological hazards. Their movement and deposition behaviors can seriously threaten marine engineering stability and coastal safety. The propagation characteristics of landslide-generated tsunamis are therefore critical for hazard assessment. Physical model experiments provide an effective approach for investigating the underlying mechanisms of tsunami generation and propagation. To investigate the complete process from landslide motion to wave generation and propagation, this study developed an underwater soil-movement physical model test system. The system integrates controllable landslide initiation, real-time monitoring of landslide motion, wave height measurements, and full-field image acquisition, enabling synchronous observation of landslide movement and water body response. By controlling the main variables influencing submarine landslide dynamics, a series of physical model experiments were conducted to investigate water surface waves generated under different test conditions. The study examines the complete process from the initial water disturbance caused by submerged landslide motion to tsunami generation and propagation. The effects of landslide volume, particle size, initial submergence depth, and slope angle on tsunami parameters, including wave height, wave velocity, and wave period, were evaluated. Using 21 experimental datasets for each landslide type, namely, cohesionless sandy slides and muddy debris flows, empirical formulas for maximum surge height were established through dimensional analysis, SPSS (v25)-based multiple nonlinear regression, and validation against experimental results. The validation results show strong agreement between the empirical predictions and the physical model test data. Full article