Search Results (184)

Soil salinity severely constrains strawberry production by disrupting ion homeostasis and provoking oxidative injury. This study investigated whether soluble silicon (Si) and activated carbon (AC) act to enhance salt tolerance in strawberry (Fragaria × ananassa). Under NaCl stress, plants showed pronounced growth inhibition, increased Na⁺ accumulation and a deteriorated K⁺/Na⁺ balance, accompanied by elevated reactive oxygen species (ROS) and lipid peroxidation. In contrast, combined AC + Si treatment consistently provided the strongest protection, improving seedling vigor and survival. Relative to NaCl alone, AC + Si increased shoot and root fresh weight by 67.5% and 78.5%, reduced shoot Na⁺ by 59.1%, and lowered shoot H₂O₂ and MDA by 62.6% and 66.5%, respectively, indicating marked improvement in ion–redox homeostasis. Beyond plant responses, AC-containing treatments alleviated salt-induced increases in soil electrical conductivity, coinciding with a clear restructuring of the rhizosphere bacterial community and enrichment of putatively beneficial taxa. Transcriptome profiling further supported coordinated reprogramming of ion transport, redox control and stress-responsive signaling pathways under the AC + Si regime. Collectively, the results indicated that Si and AC co-application enhances strawberry salt tolerance through an integrated soil–plant–microbiome mechanism that stabilizes ion homeostasis and reinforces redox homeostasis. Full article

Silicate rocks represent alternative K sources when finely ground, reducing production costs and dependence on imported fertilizers. Therefore, this study aimed to evaluate the effects of potassium (K) dose, application timing, and fertilizer sources on the concentrations and accumulation of K, silicon (Si), and sodium (Na) in maize diagnostic leaves, straw, and grains under a no-tillage system in Savanna. The soil was classified as Typic Haplustox (Oxisol). The experiment followed a randomized block design in a 2 × 4 × 3 factorial scheme, with two application times (30 days before sowing soybean and at sowing soybean), four K₂O rates (0, 40, 80, and 120 kg ha⁻¹), and three sources (KCl, Potasil, and Ekosil). K fertilization was applied by broadcasting without incorporation, before the preceding crop. Potasil provided a higher foliar Si concentration, and Si accumulation in grain and straw increased with the increment of K fertilization using the Potasil. Early fertilization promoted greater K accumulation in maize straw. For grain K accumulation, moderate K₂O doses favor greater accumulation, with Ekosil and Potasil showing superior results compared to KCl. There was less sodium accumulation in the grains with Ekosil compared to KCl. Agronomic efficiency is maximized at 40 kg ha⁻¹ of K₂O, with Ekosil showing the best performance for maize crop. These findings indicate that alternative K sources, applied at optimized rates, improve crop nutrition and promote sustainability in soybean–maize crop rotation. Full article

Deep brines represent important sources of strategic resources such as lithium and potassium, characterized by low exploration costs and high utilization rates. The Triassic strata in the Sichuan Basin contain abundant lithium- and potassium-rich brines, and understanding their origin is essential for exploring similar deposits. This study integrated field sampling and published data to systematically analyze the brines through hydrochemical testing, statistical methods, and water–rock reaction experiments, providing a comprehensive genetic interpretation based on hydrochemical features, element correlations, and characteristic coefficients. The results indicated that the brines are of the Cl–Na type, and both the sodium–chloride and chloride–bromide coefficients are consistent with a marine origin. Evapo-concentration was identified as the main controlling factor for ion enrichment, with subordinate influence from atmospheric precipitation. The common source of Ca²⁺ and Mg²⁺ likely includes the widespread marine carbonate rocks and/or the alteration of Ca–Mg-bearing silicate minerals (e.g., in green bean rocks or detrital layers) during brine–rock interaction. The desulfation coefficient indicated that lithium enrichment depends on a closed reducing environment, while potassium enrichment shows minimal correlation with brine confinement. Leaching experiments confirmed that green bean rocks serve as a key effective source rock for lithium and potassium, with elemental leaching efficiency positively correlated with fluid salinity. Based on these findings, a “dual-recharge” genetic model is proposed: paleo-marine brines undergoing deep circulation and meteoric water infiltrating along tectonic fractures collectively leached lithium and potassium from the green bean rocks, providing abundant lithium and potassium to the deep brines. This study refines the metallogenic mechanism of lithium- and potassium-rich brines in the Triassic Sichuan Basin and provides guidance for regional brine mineral exploration. Full article

In reclaimed and poorly drained soils, combined salinity–waterlogging stress markedly inhibits the early vegetative growth of maize. In this study, maize seedlings at 12 days after sowing (DAS) were subjected to combined stress by immersing the entire root system in 200 mM NaCl for 7 d (stress; ST), then transferred to recovery conditions and supplied potassium at equivalent activity (5 mM K⁺; soil drench) as KH₂PO₄ (ST + K + P), K₂SO₄ (ST + K + S), and potassium silicate (ST + K + Si) at 0 and 5 days after treatment (DAT). Morphological traits, chlorophyll fluorescence, and gas-exchange parameters were measured at PreTR (immediately after stress termination), 5 DAT, and 10 DAT. Phytohormone, mineral nutrient profiles, oxidative stress markers and redox status, osmotic and metabolic parameters, and the expression patterns of key ion transport and stress-responsive genes were quantified at 0 and 10 DAT. The effects of K supplementation were evident across the growth- and photosynthesis-related indicators. Treatment groups (ST + K + Si, ST + K + S, and ST + K + P) exhibited significantly higher carbon fixation capacity than ST at 10 DAT. The Na/K ratio was also notably reduced in all K-supplemented groups, indicating that ionic homeostasis was restored with K supplementation through improvements in various stress response indicators such as phytohormones, osmotic adjustment, and antioxidant responses. The potassium- and silicon-treated group showed the greatest recovery effect, which may reflect the physiological characteristics of cereal species. Overall, these findings provide foundational data for the development of cultivation technology to expand the cultivation area of maize. Full article

Brines in playas and salt lakes provide crucial raw materials for potassium and lithium products in fertilizers and the energy sector. In this contribution, elemental and multiple H, O, Sr, B, and Li isotopic constraints were employed to determine the sources and origin of brines in the Bieletan Section (BLT) of Qarhan Salt Lake, northwestern China. The δD-δ¹⁸O results demonstrate that the brines of BLT mainly originated from river waters. The correlations of [Li] vs. [B], δ⁷Li vs. [Li] and δ¹¹B vs. [B]/[Cl] suggest that the original provenance and silicate weathering played important roles in the elemental and isotopic signatures of B and Li in these river waters, which had been obscured by evaporation and concentration of brines and the related precipitation and redissolution of salt minerals during the evolution of brines in the salt lake. Strontium isotopes rule out the recharge of CaCl₂ fluids from the northern fault zones for brines in BLT. Finally, the combination of elemental composition and Li, Sr, and B isotopes suggests that the current brine in BLT is mainly sourced from the Wutumeiren River and has experienced constant and intense evaporation to form the highly concentrated brine. By contrast, the contribution of the Golmud River/Tuolahai River and the CaCl₂ spring water from the north fault zone to the brines in BLT is negligible. Our results highlight that integrated elemental and multiple isotope analyses are more effective for achieving a precise and comprehensive understanding of the source-to-sink process in the river–salt lake system. Full article

Mixed-anion silicate–phosphate oxysulfide glasses have attracted increasing interest due to their tunable thermal stability, electrical response, and potential use in functional glass and glass–ceramic materials. In this work, silicate–phosphate oxysulfide glasses in the SiO₂-P₂O₅-K₂O-MgO-SO₃-ZnO system were examined to determine how partial substitution of MgO with ZnO influenced their thermal and electrical properties under reducing conditions. Melting in a strongly reducing atmosphere predominantly converted sulfur to reduced sulfur species, producing mixed oxygen–sulfur glass networks. Differential scanning calorimetry (DSC) shows that ZnO substitution reduces the configurational heat capacity at the glass transition (ΔC_p) by up to ~40%, suppresses crystallization exotherms, and shifts crystallization onset temperatures by more than 100 °C toward higher values, indicating enhanced network rigidity. Potassium and magnesium K-edge X-ray absorption spectroscopy (XAS) revealed increased short-range ordering around Mg²⁺ in Zn-free glasses after heat treatment, whereas Zn-containing glasses remain more structurally disordered. Impedance spectroscopy demonstrated that ZnO-substituted glasses exhibit higher activation energies for electrical transport (≈0.9–1.0 eV) and lower AC conductivity compared to Zn-free compositions, reflecting restricted alkali-ion mobility. These results demonstrate that partial substitution of MgO with ZnO significantly enhances the thermal stability and electrical insulating behavior of reduced silicate–phosphate oxysulfide glasses, providing valuable structure–property insights for the design of thermally stable functional glasses and glass–ceramics. Full article

Banded iron formations (BIFs) are marine chemical sedimentary rocks comprised of alternating siliceous- and iron-rich bands and deposited from Eoarchean to early Paleoproterozoic. Due to their geological antiquity, BIFs normally have been overprinted by postdepositional tectono-thermal events, leading to large uncertainties with respect to their depositional age and field occurrence. The studied Gongyiming BIF-type iron deposit, which is a typical example of its metamorphosed Archean counterparts, is preserved within the Guyang Greenstone Belt, the North China Craton (NCC). The formation age of this BIF and effects of postdepositional tectono-thermal events on this BIF have not yet been well determined, limiting our understanding of its geological implication and the current occurrence of its orebodies. In this study, we provided new geological and zircon U-Pb geochronological evidence for the Gongyiming BIF that supports a possibly early Neoarchean depositional age (>2.66 Ga). This finding not only helps to fill the early Neoarchean age gap in BIF records in China, but also supports the previously documented multi-stage crustal growth model for the NCC. Furthermore, a metamorphic age of ~2.50 Ga is recorded by the BIF-bearing plagioclase amphibolite and monzogranitic gneiss that intruded into the plagioclase amphibolite. This metamorphic age is consistent with the time for an extensively identified late Neoarchean tectonic event in the NCC. The identification of a 1.90 Ga old potassium feldspar granite within this BIF indicates the plausible influence of the regional late Paleoproterozoic tectono-thermal event. This event is likely to have caused the development of a large-scale scale dextral shearing in the Gongyiming mining area, which ultimately shaped the field occurrence of its No. 2 and No. 3 ore bodies. Collectively, a structurally controlled exploration model was established for the Gongyiming BIF-type iron deposit, which facilitates the understanding of its ore body reworking processes and guides further regional iron deposit exploration and prospecting efforts. Full article

Refractory geopolymers derived from aluminosilicate sources and alkaline activation are a promising alternative to traditional fired bricks, particularly when low-cost, waste-derived raw materials are used. This study improves the workability of a refractory brick formulated with clays (Kaolin and Tepozan–Bauwer), seashell waste, sodium silicate, potassium hydroxide, and water by incorporating sodium lignosulfonate (LS) and polycarboxylate (PC) plasticizers. Clays from Comonfort, Guanajuato, Mexico, and seashells were ground and sieved to pass a 100 Tyler mesh. A base mixture was prepared and evaluated using the Mini Slump Test, varying plasticizer content from 0 to 2% relative to the solid fraction. Based on workability, 0.5% LS and 1% PC (by solids) increased the slump, and a blended plasticizer formulation (1.5% by solids, 80%PC+20%LS) produced the highest workability. These additives act through different mechanisms, with LS primarily promoting electrostatic repulsion and PC steric repulsion. Bricks with and without plasticizers exhibited thermal resistance up to 1200 °C. After four calcination cycles, compressive strength values were 354.74 kg_f/cm² for the brick without plasticizer, 597.25 kg_f/cm² for 1% PC, 433.63 kg_f/cm² for 0.5% LS, and 519.05 kg_f/cm² for 1.5% of the 80%PC+20%LS blend. Strength was consistent with changes in porosity and apparent density, and 1% PC provided a favorable combination of high workability and high compressive strength after cycling. Because the cost of clays and seashells is negligible, formulation selection was based on plasticizer cost per brick. Although 1% PC and the 1.5% of 80%PC+20%LS blend showed statistically comparable strength after cycling, 1% PC was selected as the preferred option due to its lower additive cost ($0.0449 per brick) compared with the blend ($0.0633 per brick). Stereoscopic microscopy indicated pore closure after calcination with no visible cracking, and SEM–EDS identified O, Si, and Al as the significant elements, with traces of S and K. Overall, the study provides an integrated assessment of workability, multi-cycle calcination, microstructure, and performance for refractory bricks produced from readily available clays and seashell waste. Full article

Silicon (Si) plays a critical role in regulating plant physiological processes, particularly through its influence on non-enzymatic antioxidant systems and amino acid metabolism. This study aims to assess soybean performance in response to both soil and foliar Si applications under well-watered and drought conditions, with the goal of enhancing Si accumulation in plant tissues and potentially strengthening the crop’s physiological responses to water deficit stress. This is especially pertinent given that the mechanisms underlying Si fertilization and its contribution to drought tolerance in soybean remain poorly understood. Greenhouse experiments were conducted using a 3 × 2 factorial design. The factors were: (i) three foliar Si treatments: control (no Si), potassium silicate (SiK; 128 g L⁻¹ Si, 126.5 g L⁻¹ K₂O, pH 12.0), and sorbitol-stabilized potassium silicate (SiKe; 107 g L⁻¹ Si, 28.4 g L⁻¹ K₂O, 100 mL L⁻¹ sorbitol, pH 11.8); and (ii) two soil water levels: well-watered (80% field capacity) and water-restricted (40% field capacity), the latter simulating tropical dry spells. Silicon was applied to the soil via irrigation and to the leaves via foliar spraying prior to the onset water restriction. All Si solutions were adjusted to pH 7.0 with 1 M HCl immediately before application. Potassium (K) levels were standardized across treatments through supplementary applications of KCl to both soil and foliage. Biometric and physiological parameters were subsequently measured. Sorbitol-stabilized Si enhanced Si accumulation in soybean tissues and improved plant resilience under both well-watered and drought conditions by promoting key physiological traits, including increased levels of daidzein and ascorbic acid levels, along with reduced amino acid concentrations. It also improved biometric parameters such as leaf area, root development, and number of pods per plant. These findings further support the role of Si as a beneficial element in enhancing stress tolerance and contributing to sustainable agricultural practices. Full article

Water stress is among the most important abiotic constraints affecting forest ecosystem functioning and regeneration, a phenomenon expected to intensify with climate change. It impacts photosynthesis, growth, and seedling survival, therefore threatening biodiversity and accelerating forest degradation. The use of silicon-based biostimulants has emerged as a way of mitigating the effects of water stress by improving water status and stimulating mechanical and biochemical defense. However, its effectiveness on forest tree species remains poorly explored. This study examines how potassium silicate (PS) alleviates the effects of drought on Canarium madagascariense, with the aim of improving our understanding of the resilience mechanisms of tropical forest species. To do this, an experiment with 135 two-year-old C. madagascariense saplings has been conducted, testing three irrigation levels in combination with the addition of potassium silicate (PS) at concentrations of 5 and 10 mM, via foliar spraying and soil application. Morphometric and physiological parameters were monitored, followed by the biochemical profiling of the induced responses. Linear mixed models were computed to assess the effects of the different factors on the different growth performance, physiological functioning parameters over time, and ANOVA was used for evaluating the punctual data on the biochemical compounds. Drought had a significant impact on the morphological and physiological behaviour of the seedlings. However, the application of PS modified the drought-induced changes, even at a low concentration of 5 mM. Biochemical defenses were also improved further with PS application. Hormone profiling revealed a predominance of auxins, while abscisic acid was lower in the water stress treatments under drought. Therefore, using PS could support the production of robust seedlings that are more tolerant of, and adaptive to, the challenges of climate change, making restoration more efficient. Full article

This study investigates the optimization of sol–silicate façade coatings modified with colloidal silica and a silane-based hydrophobizing additive to enhance hydrophobicity while maintaining a high water-vapor transmission rate (V). The effects of the binder ratio between potassium water glass (WG) and colloidal silica (CS), the type of colloidal silica (unmodified or epoxy-silanized), and the concentration of the hydrophobizing additive (HA) were systematically evaluated. Water-vapor transmission was determined according to EN ISO 7783, and surface wettability was measured before and after accelerated UV-A aging. Dynamic viscosity was monitored for two years to assess long-term storage stability. The optimized formulation contained 7 wt % potassium water glass, 15 wt % colloidal silica, and 1 wt % hydrophobizing additive. It exhibited stable viscosity over time (≈19,000 mPa·s after six months), high water-vapor transmission (V > 6700 g·m⁻²·d⁻¹, class V1), and an initial contact angle of 118°, which decreased only moderately after UV-A exposure. Coatings containing epoxy-silanized colloidal silica showed slightly lower transmission but still remained within the high V range suitable for vapor-open façade systems. The results confirm that balanced sol–silicate systems can combine durable hydrophobicity with long-term rheological and functional stability. Full article

Cabbage is an important vegetable crop worldwide. In Taiwan, during cabbage production, bacterial soft rot caused by Pectobacterium carotovorum subsp. carotovorum often leads to significant yield losses. Aligning with the Sustainable Development Goals, there is a high demand for sustainable disease control strategies. Silicates are considered to be effective elicitors in activating plant defense responses and are reported to improve resistance to certain plant diseases. Bacillus amyloliquefaciens PMB05 fermentation liquid has been shown to enhance plant immunity and control many bacterial diseases. The supplementation of silicates to the PMB05 fermentation liquid may further improve its efficacy to control bacterial soft rot in cabbage. This study evaluated the effects of sodium metasilicate and potassium silicate on PMB05-mediated plant immune responses and disease control. Initial assays confirmed that treatment with B. amyloliquefaciens PMB05 suspension significantly increased HrpN-triggered reactive oxygen species (ROS) generation and callose deposition; moreover, PMB05 treatment alone reduced bacterial soft rot severity by 39.7%. When combined with B. amyloliquefaceins PMB05 fermentation liquid, sodium metasilicate at 2000 μM further enhanced ROS generation and callose deposition by 100% and 133%, respectively, compared to the treatment of PMB05 alone (p < 0.05). In contrast, potassium silicate exhibited inconsistent effects on ROS production, with both 500 and 1000 µM concentrations significantly reducing ROS generation by 26% and 38%, respectively, while none of the tested concentrations affected callose deposition (p < 0.05). Lastly, disease severity assessments in cabbage inoculated with P. carotovorum subsp. carotovorum PCCSB1 revealed that B. amyloliquefaciens PMB05 fermentation liquid was able to reduce bacterial soft rot symptoms by 60.3%. Supplementation with 1500 and 2000 µM sodium metasilicate further decreased disease severity by 77.9% and 76.4%, respectively (p < 0.05). Although the supplementation of potassium silicate also significantly reduced disease severity compared to P. carotovorum subsp. carotovorum PCCSB1 alone, it was less effective than PMB05 fermentation alone. Overall, these results demonstrate that sodium metasilicate enhances the biocontrol activity of B. amyloliquefaciens PMB05 by further intensifying plant immune responses. This approach may broaden the large-scale use of B. amyloliquefaciens PMB05 fermentation liquid for sustainable soft rot management in cabbage, although the stability and cost-effectiveness of sodium metasilicate under field conditions still require validation. Full article

In this research article, a silicon carbide (SiC) nanocluster has been designed and characterized as an anode electrode for lithium (Li), sodium (Na), potassium (K), beryllium (Be), magnesium (Mg), boron (B), aluminum (Al) and gallium (Ga)-ion batteries through the formation of SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC nanoclusters. A vast study on energy-saving by SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC complexes was probed using computational approaches accompanying density state analysis of charge density differences (CDDs), total density of states (TDOS) and molecular electrostatic potential (ESP) for hybrid clusters of SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC. The functionalization of Li, Na, K, Be, Mg, B, Al and Ga metal/metalloid elements can raise the negative charge distribution of carbon elements as electron acceptors in SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC nanoclusters. Higher Si/C content can increase battery capacity through SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC nanoclusters for energy storage processes and to improve the rate performance by enhancing electrical conductivity. Full article

This study develops a sustainable welding approach by incorporating 35–50% blast furnace slag (BFS), a byproduct of the steel industry, into rutile-type electrode coatings. To fabricate the electrodes, BFS was dry-mixed with fluxes, followed by the addition of potassium silicate binder to create a paste. This mixture was then pressed onto 3.25 mm core wires at 150 bar and heat-treated at 150 °C for two hours. Weld quality and performance were evaluated through visual inspections, microstructure and XRD analyses, hardness, tensile, and impact tests. Visual inspections confirmed weld quality comparable to commercial standards, with stable arc and minimal spatter. Microstructure analysis revealed a ferrite-dominated weld metal with TiO₂ and FeTiO₃ phases in the slag layer, enhancing strength and toughness. Electrodes with 35–40% BFS achieved yield strength of 477–482 MPa, tensile strength of 570–573 MPa, and impact energy of 58–59 J at 0 °C, complying with ISO 2560:2020. BFS integration reduced CO₂ emissions by 0.28–0.4 kg per kg of coating and diverted 200–600 kg of slag per ton of steel from landfills. Coating and raw material costs decreased by 33–48% and 15–25%, respectively, aligning with the EU Green Deal’s circular economy goals and enhancing weld quality and sustainability. Full article

This study investigates the adsorption efficiency of thermally activated natural opoka, a siliceous–calcareous sedimentary rock, as a low-cost adsorbent for removing phosphorus from aqueous solutions. Comprehensive characterization using XRF, XRD, and STA revealed that raw opoka is primarily composed of quartz, tridymite, and calcite, with a CaO/SiO₂ molar ratio of approximately 0.45. After calcination at 850 °C, calcite decomposes and reacts with silica to form wollastonite, enhancing surface reactivity. Adsorption experiments conducted at phosphorus concentrations of 0.2, 2.6, and 5.0 g of P/L demonstrated that the material’s removal efficiency for phosphorus was highest at low concentrations (25.7% at 0.2 g/L) and decreased with an increase in concentration (20.8% at 2.6 g/L and 18.6% at 5.0 g/L). The adsorption process followed pseudo-second-order kinetics (R² > 0.999), indicating that chemisorption is the dominant mechanism. It is assumed that amorphous calcium phosphate forms at low phosphorus concentrations and an alkaline pH, whereas brushite is more prevalent at higher concentrations under acidic conditions. Potassium adsorption was negligible and reversible in all cases. The findings demonstrate that calcined opoka has promising applications as a reactive calcium silicate material for sustainable phosphorus management in decentralized water treatment systems. Full article