Search Results (280)

Shallow groundwater in saline soils creates a self-reinforcing cycle where waterlogging-induced root hypoxia impairs the ATP-dependent sodium exclusion mechanisms that plants rely on for salt tolerance. We conducted a two-year field experiment to test whether subsurface drainage must precede root-zone aeration for oxygen delivery to be effective. The experimental site was located in Heyang County, Weinan City, on the Guanzhong Plain of Shaanxi Province, north-central China—a major alluvial agricultural region representative of shallow-groundwater-induced salinization. The site had saturated paste electrical conductivity of 6.0 dS m⁻¹ and groundwater depth fluctuating between 0.5 and 1.4 m. A randomized complete block design with 2 × 2 factorial arrangement compared four treatments: control (CK), subsurface drainage only (SD), root-zone aeration only (RA), and both interventions combined (SD + RA). Drainage increased air-filled porosity from 5.8% to 13.5%, crossing the 10.2% threshold (95% CI: 9.1–11.3%) where gas-phase continuity emerges according to segmented regression analysis. Without drainage, aeration achieved only 4.2 mg L⁻¹ dissolved oxygen with high spatial variability (CV 12.5%), while the combined treatment reached 6.8 mg L⁻¹ (CV 6.8%). Root ATP content increased by 89% in SD + RA compared to control, accompanied by 56% lower root Na⁺ and 185% higher K⁺/Na⁺ ratio. These physiological changes correlated with 31% higher grain yield (7580 vs. 5798 kg ha⁻¹). The synergy index of 1.40 (95% CI: 1.28–1.52) indicated that combined effects exceeded the sum of individual treatments by 40%. Methane emissions declined by 62%, and the system achieved a 2.9-year payback period with a benefit–cost ratio of 4.08. These results establish drainage as a physical prerequisite for effective oxygenation, providing a mechanistic explanation for the variable performance of aeration systems reported in previous studies. Full article

Groundwater sustains human activity in arid crystalline terrains where surface water is scarce and hydrogeological data are limited. However, most groundwater potential mapping approaches depend on deterministic weighting methods without quantifying model variability. This study describes an uncertainty-aware Remote Sensing and Geographic Information Systems (RS–GIS) framework to delineate groundwater potential zones in the Wadi Arab Watershed, Northeastern Sudan. Nine thematic factors—geology and lithology, rainfall, slope, drainage density, lineament density, soil, land use/land cover, topographic wetness index, and height above nearest drainage—were integrated using the Analytical Hierarchy Process (AHP), with acceptable consistency (Consistency Ratio (CR) < 0.1). To address subjectivity in weights, a Dirichlet-based Monte Carlo simulation (500 iterations) was implemented to perturb AHP weights whilst preserving compositional constraints. The resulting Groundwater Potential Index (GWPI) classified 32.69% of the watershed as high to very high potential, primarily associated with alluvial deposits and fractured crystalline rocks. Model validation using Receiver Operating Characteristic (ROC) analysis yielded an Area Under the Curve (AUC) of 0.704, indicating acceptable predictive performance. Uncertainty assessment showed low spatial variability (mean standard deviation (SD) = 0.215) and stable exceedance probabilities, verifying the robustness of predicted high-potential zones. The proposed probabilistic AHP framework augments decision reliability and provides a transferable, cost-effective tool for groundwater planning in data-limited arid basement environments. Full article

Sustainable water management in high Andean ecosystems involves identifying and protecting recharge areas, integrating both biophysical and social knowledge. The purpose of this study was to conduct a participatory analysis of the recharge zone in the Totorani micro-basin, with a total area of 61.39 km², located in Puno District, Peru, which supplies water to more than 21,000 people. A hierarchical multicriteria analysis in a GIS environment was used, considering five variables (vegetation cover, slope, soil type, geology, and land use), complemented by participatory workshops. The results indicate that moderate recharge predominates in 56.01% of the area, followed by high (39.91%) and very high (3.81%) recharge, associated with the high-altitude Andean wetlands and alluvial plains. Areas of low recharge comprised 0.28% and were found on slopes >30%, with thin soils and low infiltration. The participatory validation process confirmed the alignment between the maps and local knowledge, emphasizing the wetlands and springs as essential areas for water regulation. The stakeholder analysis identified three key groups as direct users: farmers and livestock breeders, public or educational institutions, and social organizations. The stakeholders highlighted threats, such as agricultural expansion, overgrazing, and climate variability, while also emphasizing the importance of traditional conservation practices. Water recharge in Totorani is both a biophysical and social process, requiring the integration of technical methodologies with community participation for effective management. These findings represent a strategic contribution to water governance and offer a replicable model for other high Andean micro-basins. Full article

Alluvial–proluvial parent-material soils are widely distributed in the Qinghai Lake Basin; however, their timing of development and associated climatic background remain poorly constrained. In this study, two representative alluvial–proluvial fan-covered soil profiles (QRZQ and YXC) from the Qinghai Lake Basin were investigated. Quartz optically stimulated luminescence (OSL) dating was combined with analyses of grain-size composition and soil organic carbon (SOC) to constrain the timing of soil development and its climatic background. The results show that the studied soil profiles are mainly characterized by Ah–As–C and Ah–A–C horizon configurations, with soil development spanning from 15.7 to 1.0 ka. The underlying alluvial–proluvial parent material of the QRZQ profile formed during the Last deglaciation, whereas the oldest OSL ages in the YXC profile occur within a weakly developed A horizon, indicating that this profile had already transitioned from a depositional environment to a pedogenic environment during the Last deglaciation. This contrast reflects staged differences between depositional and pedogenic processes within alluvial–proluvial settings. The soils were formed through upbuilding pedogenesis, in which sediment accumulation and top-down pedogenic modification proceeded concurrently. Grain-size composition and SOC characteristics further indicate that the depositional environment of the YXC profile was relatively stable. Integrating the obtained chronological results with regional climatic changes suggests that climate variability in the Qinghai Lake Basin exerted a primary control on the transformation between sedimentary processes and soil development. In particular, the Late Holocene (0–4 ka), characterized by a generally cold–dry climate accompanied by pronounced humidity fluctuations, represents an important pedogenic stage for alluvial–proluvial parent-material soils in the Qinghai Lake Basin. This study provides a robust chronological framework for further investigating the mechanisms of soil development in alluvial–proluvial environments from a climatic perspective. Full article

Earthfill dams located in seismic regions are highly vulnerable to earthquake-induced deformations, particularly when founded on soft alluvial soils. This study presents a comparative numerical investigation of earthfill dams with asphalt and clay cores subjected to seismic loading. A 20 m-high zoned embankment dam founded on soft alluvial deposits was modeled in PLAXIS2D and subjected to four earthquake records. The dynamic responses at the crest and downstream slope were evaluated in terms of acceleration, settlement, and lateral displacement. The results indicate that while lateral displacements are nearly identical for both core types, dams with clay cores experience significantly higher seismic settlements, reaching up to 35% more than those with asphalt cores under strong earthquake loading. Overall, the asphalt core demonstrated enhanced resilience, exhibiting reduced settlement due to its higher stiffness, viscoelastic behavior, and inherent capacity for self-healing following seismic loading. Full article

The 1964 M7.5 Niigata earthquake remains one of the most significant natural laboratories for understanding seismic–induced soil liquefaction and its dependence on geological setting. Among global field case histories, Niigata stands out for the exceptional documentation of liquefaction triggering, lateral spread displacements, and soil–structure interaction. This paper reexamines the event from an engineering–geologic perspective, emphasizing how Holocene coastal and fluvial depositional processes beneath the Echigo Plain controlled the spatial and stratigraphic distribution of liquefaction during the 1964 earthquake. The most severe ground deformations occurred in fluvially reworked sands derived from three major Holocene dune and barrier island systems (CSD1,2,3) formed along the paleo–shoreline of the Sea of Japan. The largest of these, a mid–Holocene transgressive barrier complex deposited to a thickness of 50–60 m of beach and aeolian sand between 8 and 5 ka B.P., now lies buried 5–8 km inland beneath fine–grained alluvial deposits. Tectonic downwarping and deltaic progradation by the Shinano and Agano rivers redistributed these sands into loose, saturated fluvial facies beneath modern Niigata city. Quantitative geotechnical analyses demonstrate that liquefaction occurs within these reworked Holocene units rather than anthropogenic fills. Full article

The geological complexity of Java Island, Indonesia, has resulted in the extensive distribution of very soft clay soils, posing significant challenges to geotechnical design and construction. A reliable estimation of the geotechnical properties of these soils is therefore essential to address these challenges and ensure the safety and sustainability of construction projects. The cone penetration test with pore pressure measurement (CPTu) is a reliable in situ test for soil characterization, providing a continuous shear strength profile. However, the determination of a representative cone bearing factor ($N_{kt}$) to estimate undrained shear strength ($S_u$) is critical for geotechnical design. Although several studies on CPTu have been conducted in Indonesia, there has been a lack of emphasis on establishing $N_{kt}$ values for local soft, high-plasticity clays in Indonesia. This study aims to fill this gap in the literature by proposing updated correlations for $N_{kt}$ specific to the soft, high-plasticity clays of Java, Indonesia, derived from the statistical analysis of combined field and laboratory data obtained from two representative sites in Western Java. These sites correspond to a coastal plain deposit in Central-North Jakarta and an alluvial deposit in Gedebage, Bandung. A comprehensive database was compiled, consisting of 20 CPTu boreholes, 84 depth points of vane shear test (VST), 29 samples of consolidated undrained (CU) triaxial tests, 26 samples of unconsolidated undrained (UU) triaxial tests, and 18 standard penetration test (SPT) boreholes. The results indicate that the representative $N_{kt}$ value for these soft, high-plasticity clays in the investigated sites in Western Java ranges from 14 to 16. A refined empirical correlation between $N_{kt}$ and the pore pressure ratio (B_q) is proposed, demonstrating consistent trends with recent data. Additionally, a reasonable correlation between the undrained modulus ($E_u$) and undrained shear strength of $E_u$ = 276–323 $S_u$ was identified, enabling the derivation of a continuous profile of the undrained modulus from CPTu data. This study also further highlighted the absence of significant relationships between $N_{kt}$ and other parameters such as OCR, PI, and NSPT. These findings provide practical insight and a regionally calibrated reference that can be useful for engineers working in similar soft, high-plasticity clay environments with characteristics comparable to the investigated sites in Western Java. Full article

Integrated Electrical Resistivity Imaging (ERI) and Induced Polarization (IP) studies were performed to identify potential tin (Sn) mineralization prospects in the Eastern Tin Belt of Peninsular Malaysia. A total of 23 profiles were obtained utilizing a Schlumberger configuration, generating resistivity and chargeability sections employed to delineate weathering structures, lithological connections, and structurally regulated anomalies. ERI models consistently delineate a three-tier subsurface structure consisting of conductive soil/alluvial deposits (5–300 Ωm), weathered bedrock (300–1500 Ωm), and resistive fresh bedrock (>1500 Ωm), featuring undulating basement relief beneath floodplain layers. IP data indicate localized, often pronounced chargeability anomalies (~5–40 ms; locally reaching ~50 ms), interpreted as corridors influenced by fractures and veins, especially when they align with significant resistivity contrasts at metamorphic–granitic boundaries and intrusive contacts. The integration of fence diagrams in the alluvial-over-granite zone reveals laterally consistent chargeability peaks at the alluvial–bedrock interface, suggesting enduring subsurface conduits. XRF examination of quartz-vein samples verifies Sn enrichment (599–717 ppm), corroborating a granite-related vein/alteration hypothesis and indicating possible isolated greisenized zones within the weathered granite. The integrated ERI–IP analysis identifies priority targets for subsequent trenching and borehole drilling to verify an anomaly’s origins and evaluate Sn grade and continuity. Full article

Priority habitat 91E0* (alluvial forests with Alnus glutinosa and Fraxinus excelsior) constitutes a key riparian biodiversity hotspot, yet it is increasingly threatened by woody invasions that alter the community composition and reduce the habitat’s heterogeneity. Ten permanent plots (15 m radius) were surveyed in the Nestos River delta (NE Greece) in 2019 and 2023, following a manual control campaign conducted in 2021, targeting Amorpha fruticosa and Acer negundo. Because systematic plot-level vegetation data were collected only in 2019 and 2023, the study evaluates before–after changes rather than continuous annual dynamics. Woody species composition and diversity, community turnover (Bray–Curtis dissimilarites/PCoA; PERMANOVA), invasive dynamics (negative binomial GLMs), and community-weighted Ellenberg-type indicator values and their relationships with the soil properties (0–30 cm) were assessed. Across the surveys, 18 woody taxa were recorded, dominated by native riparian trees and shrubs, together with four established alien species. The total alien abundance declined from 943 to 385 individuals between 2019 and 2023, driven by A. negundo (−68%) and A. fruticosa (−39%). The woody community composition differed significantly between years (R² = 0.12; p = 0.013) and river banks, whereas plot-scale diversity indices changed modestly and evenness increased. The mean community-weighted moisture affinity increased (CWM_F: 6.28 → 7.07), nutrient affinity remained high, and reaction values declined slightly. The soil’s properties did not differ between the treated and control plots; nevertheless, Shannon diversity was positively correlated with organic C, total N, exchangeable Ca and K, and clay content. Permanent plot resurveys thatintegrate soil properties and indicator-based community metrics provide robust baselines to support Article 17 reporting under the EU Habitats Directive and to guide spatially targeted invasive-species management in Mediterranean alluvial forests (habitat 91E0) undergoing restoration actions. Full article

This study investigates the effects of terroir on the sensory expression of two major white grape varieties, Fetească albă and Sauvignon blanc. The experimental design included wines from eleven wineries distributed across the main Romanian wine-growing regions—Banat, Dobrogea, Moldova, Muntenia–Oltenia, and Transylvania—covering a wide range of altitudes (75–400 m), latitudes (21.6–28.4°), and contrasting soil types (chernozems, alluvial soils, luvaceous and clay-illuvial brown soils) over two climatically distinct vintages (2019 and 2021). Volatile profiling was performed by GC–MS, and aroma relevance was assessed using odor activity values (OAVs) and weighted aromatic scores, while sensory attributes were integrated through structured sensory evaluation. Esters and thiols emerged as the dominant contributors to varietal aroma expression. Sensory aggregation revealed clear winery-dependent differences, whereas vintage effects were moderate, with 2021 wines displaying a more pronounced fruity–floral profile compared to 2019. Linear Discriminant Analysis (LDA) identified grape variety as the strongest discriminant factor, surpassing vintage, and confirmed distinct regional sensory identities. The integrated OAV–sensory–LDA framework demonstrates the defining role of terroir in shaping aromatic structure, enabling robust varietal typicity assessment and regional differentiation across Romanian wine-growing areas. Full article

Arsenic (As) accumulation in rice (Oryza sativa L.) is considered a major environmental and food safety concern, particularly in flooded agroecosystems where reducing conditions mobilize As from soils. Portugal is one of Europe’s rice producers, especially in the Tejo, Almansor, and Sorraia valleys. As such, this study evaluates As pathways across 5000 ha of rice fields in the Tagus, Sorraia, and Almansor alluvial plains by combining soil, water, and plant analyses with a geostatistical approach. The soils exhibited consistently elevated As concentrations (mean of 18.9 mg/kg), exceeding national reference values for agricultural soils (11 mg/kg) and forming a marked east–west gradient with the highest levels in the Tagus alluvium. Geochemical analysis showed that As is strongly correlated with Fe (r = 0.686), indicating an influence of Fe-oxyhydroxides under oxidizing conditions. The irrigation waters showed low As (mean of 2.84 μg/L for surface water and 3.51 μg/L for groundwater) and predominantly low sodicity facies, suggesting that irrigation water is not the main contamination vector. In rice plants, As accumulation follows the characteristic organ hierarchy roots > stems/leaves > grains, with root concentrations reaching up to 518 mg/kg and accumulating progressively in the maturity phase. Arsenic content in harvested rice grains was 266 μg/kg (with a maximum of 413.9 μg/kg), being close to EU maximum limits when considering typical inorganic As proportions, assuming 60 to 90% inorganic fraction. Together, the findings highlight that a combined approach is essential, and identify soil geochemistry (and not irrigation water) as the primary source of As transfer in those agroecosystems, due to the flooded conditions that trigger the reductive dissolution of Fe oxides, releasing As. Additionally, the results also identified the need for targeted monitoring in areas of elevated As content in soils and support future mitigation through As speciation analysis, cultivar selection, improved fertilization strategies, and water-management practices such as Alternate Wetting and Drying (AWD), to ensure the long-term food safety. Full article

This study investigates 49 gold solidi issued between the 4th and 5th century AD to determine their chemical composition. The coins were first catalogued by recording mass, diameter, and thickness. All specimens underwent non-destructive µ-EDXRF analysis to identify main elements, followed by semi-quantitative fineness evaluation. To validate these results, six coins were randomly micro-sampled: material was dissolved in aqua regia and analysed by ICP-AES for gold quantification and ICP-MS for high precision trace element determination. The non-destructive analyses showed consistently high gold percentages, confirming authenticity and the extensive use of this noble metal during the studied period. Two distinct groups were identified based on the XRF Pt/Pd ratio, suggesting the use of gold from different sources. Comparison of μ-EDXRF and ICP-AES gold contents shows no statistically significant differences; however, this apparent agreement should be interpreted cautiously, as it mainly reflects the limited resolving power of ICP-AES at very high gold concentrations rather than definitive evidence for the absence of surface-related effects. Trace elements analysis detected low concentrations of Cu, Sn, and Pb suggesting the use of alluvial gold for minting. The presence and correlation of terrigenous elements (Al, Ca, Ti, Cr, Mn, Fe, Ni, Zn, Sr) indicate soil as the burial site. Full article

Potassium (K) is a vital macronutrient for plant growth and yield, yet most soil K occurs in insoluble mineral forms, limiting availability to crops. Reliance on chemical K fertilizers is unsustainable due to cost and environmental concerns. Microbial solubilization of mineral K, particularly by purple nonsulfur bacteria (PNSB), offers an eco-friendly alternative. This study focused on isolating mica-potassium-solubilizing purple nonsulfur bacteria (MK-PNSB) from in-dyke alluvial soil and assessing their effects on hybrid maize germination and seedling growth. Among the isolates, the results showed that strain M-Wa-19 released the highest amount of soluble K under microaerobic light conditions (27.4 mg∙L⁻¹). Under aerobic dark conditions, M-Wa-24 and M-Wa-26 released 20.1–21.0 mg∙L⁻¹ of soluble K. Strains M-Wa-21, M-Wa-25, and M-Sl-13 solubilized K in the range of 14.3–25.1 mg∙L⁻¹ and 12.9–24.4 mg∙L⁻¹ under both incubation conditions. The selected strains were identified by 16S rRNA as Rhodopseudomonas palustris strain M-Sl-13 (PX588604), Rhodoplanes pokkaliisoli strain M-Wa-19 (PX588605), Afifella marina strain M-Wa-21 (PX588606), Rhodocista pekingensis strain M-Wa-24 (PX588607), Rhodocista pekingensis strain M-Wa-25 (PX588608), and Rhodocista pekingensis strain M-Wa-26 (PX588609). None exhibited toxicity to maize seeds; instead, all enhanced seed vigor indices by up to 99.7% and improved plant height and root biomass by 19.0–26.2% and 14.4–22.9%, respectively, under static hydroponic conditions. At a 1:1000 (bacteria and distilled water) dilution rate, strains M-Wa-26, M-Wa-25, M-Sl-13, M-Wa-24, M-Wa-19, and M-Wa-21, along with the six-strain mixture, improved seed vigor index by 3.96–7.91%. These findings suggest that MK-PNSB, individually or in mixtures, hold promise as biofertilizer candidates for sustainable K management in crop production. Full article

Nitrogen deficiency is a major constraint on maize (Zea mays L.) productivity in Afghanistan, where poor soil fertility limits yields. This study investigated the effect of urea fertilizer on maize growth, physiology, and yield under semi-arid conditions in Balkh Province with a Calcisols soil type, focusing on maize cultivated for grain production. A field experiment was conducted in 2019 using a randomized complete block design with three replications and four nitrogen levels: 0 (control), 38.4, 76.8, and 115.2 kg ha⁻¹. The region consists of fertile alluvial plains suitable for crop cultivation, though maize productivity is constrained by soil nutrient limitations, especially nitrogen deficiency. The soil at the experimental site is silty loam in texture, moderately fertile with alkaline pH (8.1), low organic matter (0.5%), and limited available nitrogen (15 mg kg⁻¹). Growth traits (plant height, leaf number, leaf area, SPAD value), physiological parameters (leaf area index, crop growth rate, biomass), and yield components (cob length, cob diameter, seed number, 100-seed weight, biological yield, and Brix content) were recorded. Results showed that nitrogen application significantly improved all traits compared to the control. The highest values for plant height (260.2 cm), cob length (31.67 cm), biological yield (216.6 t ha⁻¹), and Brix content (8.6%) were observed at 115.2 kg ha⁻¹, although 76.8 kg ha⁻¹ produced nearly similar results. Correlation analysis revealed strong positive associations between SPAD values, vegetative traits, and yield. The findings indicate that 115.2 kg ha⁻¹ urea is an efficient and practical nitrogen rate for enhancing maize productivity under Afghan conditions. Full article

Identifying the dominant mechanisms of water and soil salinization in arid and semi-arid endorheic basins is fundamental for our understanding of basin-scale water–salt balance and supports water resources management. In many inland basins, mineral dissolution, evaporation, and transpiration govern salinization, but disentangling these processes remains difficult. Using the Barkol Basin in northwestern China as a representative endorheic system, we sampled waters and soils along a transect from the mountain front through alluvial fan springs and rivers to the terminal lake. We integrated δ¹⁸O–δ²H with hydrochemical analyses, employing deuterium excess (d-excess) to partition salinity sources and quantify contributions. The results showed that mineral dissolution predominated, contributing 65.8–81.8% of groundwater salinity in alluvial fan settings and ~99.7% in the terminal lake, whereas direct evapoconcentration was minor (springs and rivers ≤ 4%; lake ≤ 0.2%). Water chemistry types evolved from Ca-HCO₃ in mountainous runoff, to Ca·Na-HCO₃·SO₄ in groundwater and groundwater-fed rivers, and finally to Na-SO₄·Cl in the terminal lake. The soil profiles showed that groundwater flow and vadose-zone water–salt transport control spatial patterns: surface salinity rises from basin margins (<1 mg/g) to the lakeshore and is extremely high near the lake (23.85–244.77 mg/g). In spring discharge belts and downstream wetlands, the sustained evapotranspiration of groundwater-supported soil moisture drives surface salt accumulation, making lakeshores and wetlands into terminal sinks. The d-excess-based method can robustly separate the salinization processes despite its initial isotopic variability. Full article