Search Results (1,568)

Alternate wetting and drying (AWD) is a crucial water-saving irrigation strategy in rice production, yet its regulatory mechanisms during drought–rewatering cycles remain unclear, particularly across recovery stages. Using a polyethylene glycol (PEG-6000) hydroponic system, we analyzed physiological, metabolomic, and transcriptomic responses of Oryza sativa L. ssp. japonica under control, continuous drought, and rewatering treatments. The net photosynthetic rate (P_n) recovered within one day after rewatering, and subsequently exceeded control levels, indicating a photosynthetic compensatory effect. In contrast, instantaneous water-use efficiency (WUE) showed only a transient increase before declining thereafter and remaining lower than under continuous drought, revealing an asynchronous recovery in which carbon assimilation precedes the recovery of transpiration. Metabolomic analysis indicated a shift from drought-induced accumulation to recovery-driven metabolic reprogramming, with coordinated up-regulation of central carbon metabolism and chlorophyll biosynthesis. Decreases in citrate, malate, and glutamate suggested their sustained utilization to support nitrogen assimilation and chlorophyll synthesis. Transcriptomic data further revealed large-scale reprogramming during late recovery, including up-regulation of nitrogen assimilation genes (e.g., NIA, NiR), linking carbon–nitrogen coordination with photosynthetic compensation. Overall, these results demonstrate that stage-specific integration of physiological recovery, metabolic restructuring, and transcriptional regulation underlies AWD-induced efficiency and identify early rewatering as a critical window for optimizing WUE. Full article

This study evaluated the effects of two silicon sources (silicic acid and Agrisil) and increasing Si concentrations on physiological responses, total polyphenol content, photochemical performance, nutrient uptake, and phenolic metabolism in sour passion fruit (Passiflora edulis Sims) grown under soilless culture conditions. The experiment was conducted in a greenhouse using increasing concentrations of Si applied through the nutrient solution. Gas exchange parameters, chlorophyll index (SPAD), chlorophyll fluorescence variables, leaf temperature, and the contents of Si, nitrogen, and total polyphenols in leaves and roots were evaluated. Moderate Si concentrations enhanced stomatal conductance and transpiration, improving intrinsic water use efficiency, and maintaining higher chlorophyll levels and photochemical performance. In contrast, higher Si concentrations increased Si deposition in leaf tissues, reduced stomatal regulation and transpiration, and increased leaf temperature. These changes were associated with reductions in chlorophyll index and photochemical performance index (PI), as well as increased F₀/Fm. Net CO₂ assimilation remained relatively stable. Silicon uptake differed between sources, with silicic acid showing faster absorption and Agrisil a more gradual release. Silicon fertilization also increased nitrogen uptake and stimulated the accumulation of phenolic compounds in roots. Overall, moderate silicon supplies enhanced physiological stability, whereas excessive accumulation imposed photochemical constraints. Full article

Tomato (Solanum lycopersicum) is a globally important high-value cash crop. However, long-term continuous cropping causes frequent soil-borne diseases and soil microecological imbalance, while overreliance on chemical pesticides leads to pesticide residues and water eutrophication. Plant growth-promoting rhizobacteria (PGPR) are key resources for addressing tomato cultivation challenges, with their functions partly depending on the rhizosphere microenvironment inherently shaped by seedling tray materials. Using rhizosphere soil and substrates of tomato at different growth stages under biomass (BM) and plastic (PM) seedling tray treatments, this study combined culture-independent and culture-dependent techniques to analyze microbial community characteristics and screen high-efficiency PGPR. Results showed that pH and available nitrogen drove microbial community assembly. BM significantly enriched beneficial taxa (e.g., Trichoderma and Bacillus) and enhanced culturable microbial abundance and genetic diversity, while PM enriched potential pathogens (e.g., Fusarium and Pyrenochaeta). The multifunctional strain S25095 from BM, with phosphate-solubilizing, potassium-solubilizing, and indole-3-acetic acid (IAA)-producing abilities, significantly promoted tomato shoot and root growth, outperforming single-functional strains and synthetic consortia. This study reveals the effects of growth stages and seedling tray treatments on tomato rhizosphere microorganisms, providing valuable PGPR resources for tomato cultivation. Full article

Nitrogen is a key determinant of both yield and quality in cereal crops; however, its efficiency is strongly influenced by environmental conditions and genotype. This study evaluated the impact of different sowing densities and nitrogen fertilization regimes on grain quality indices in four triticale (×Triticosecale Wittmack) varieties—Negoiu, Utrifun, Zvelt, and Tulnic—using a split-plot arrangement of the 4 × 3 × 3 type, under the climatic conditions of northwestern Romania. The experiment, conducted over two contrasting growing seasons (2021–2023), employed a split-plot design testing three sowing densities (450, 550, and 650 seeds/m²) and three fertilization levels: basic soil nitrogen fertilization, soil + foliar N-P-K application, and soil + foliar + biostimulant. The results indicated that climatic variability had a predominant effect on grain quality, followed by the genetic characteristics of the varieties and their response to water stress. In the drought-affected 2021–2022 season, the Zvelt variety recorded the highest protein content (14.2%), significantly outperforming the control (13.3%). Supplementary foliar fertilization and the use of biostimulants under drought conditions did not improve quality; in some cases, they led to significant decreases in protein content (from 14.36% to 13.69%) and thousand-kernel weight (TKW). Under optimal precipitation conditions in the 2022–2023 season, supplementary fertilization significantly improved hectoliter weight and TKW (reaching 46.7 g compared to 44.2 g in the soil-only treatments). Higher sowing densities (650 seeds/m²) generally led to decreases in hectoliter weight and TKW in favorable years. These results suggest that nitrogen fertilization can improve triticale quality. In this study, high yields, both quantitatively and qualitatively, appear to be mainly influenced by varieties and climatic conditions, especially water availability during critical growth stages. Full article

With the rapid development of software-defined radio (SDR) technology, a digital, software-reconfigurable, and flexible solution is provided for microwave radiometers, particularly suitable for atmospheric water vapor and oxygen detection with wideband, multi-channel requirements, significantly improving system efficiency. Meanwhile, digitization helps improve channel consistency and address nonlinearity issues, while the digital zero-balancing mechanism implemented through adaptive integration is more suitable for digital platforms. This paper proposes a digital Dicke-type radiometer system based on an SDR platform, using Xilinx RFSoC XCZU47DR (AMD, San Jose, CA, USA) as the core hardware to achieve single-chip integration of RF signal sampling, digital local oscillator generation, and signal processing. The system implements a 46-channel channelized receiver (23 channels each for K-band and V-band) on an FPGA using a polyphase filter bank. The prototype filters achieve 70 dB stopband attenuation and 0.5 dB passband ripple, with each polyphase branch requiring only 25 coefficients, significantly reducing hardware resource consumption. An adaptive integration method is proposed, where an adaptive switch controller dynamically adjusts the hot source injection time ratio by calculating the power difference between adjacent integration periods, enabling the Dicke zero-balancing mechanism to operate entirely in the digital domain. Furthermore, a complete hardware transfer model is established for three signal branches (antenna, hot source, and matched load), and full-chain calibration of all 46 channels is performed using a liquid nitrogen cold source, with calibration reliability verified through blackbody measurements. Experimental results demonstrate brightness temperature consistency better than 0.7 K, with a sensitivity of less than 0.15 K for the K-band and less than 0.21 K for the V-band at 1 s integration time. Full article

The benefits of legume-nitrogen-fixing bacteria symbioses are vital in agricultural systems globally. Cross-infectivity studies are important for identifying rhizobial strains with potential for use as inoculants. The native rhizobial isolates inoculated on different legume species are the first step to determining host range and ecological adaptive traits. This study reports on the water-use efficiency and mineral nutrition of diverse legume species cross-inoculated by native rhizobial isolates from Eswatini, Ghana and South Africa under glasshouse conditions. A portable infrared red gas analyzer was used for water use efficiency. Data from a gas exchange study shows that rhizobial strains can significantly influence the photosynthetic functioning of their host plants. As a result, photosynthetic rates differed depending on bacterial compatibility with the host plant, as well as its symbiotic efficacy. Isolate TUTGmGH2 induced greater accumulation of P, K, Mg, Zn, Cu and Mn in soybean and Winged bean, clearly suggesting that rhizobia do have an influence on the mineral nutrition of their host plants. Therefore, these findings further show that native rhizobial isolates can be manipulated to enhance mineral nutrient uptake, promote growth and development and also produce nutrient-dense food with a low environmental impact globally since rhizobia do have an influence on the mineral nutrition of their host plants. Full article

Helium-rich unconventional natural gas resources have attracted increasing attention from both academia and industry. A pronounced local enrichment of helium has recently been identified in coal-derived unconventional natural gas in the Sanjiaobei block on the eastern margin of the Ordos Basin. To clarify the main controls on helium enrichment in unconventional natural gas in this area and to guide the exploration of helium-rich resources, this study systematically examines the source of helium, its transport carrier, multiphase fractionation processes, and enrichment and accumulation pattern in natural gas. The analysis is based on conventional gas composition, helium volumetric content, carbon isotopes, and noble gas isotopes (He, Ne, and Ar) measured from wellhead gas samples collected from 11 production wells in the block, together with the regional deep structural evolution and hydrogeological conditions. The results show that: (1) the helium volumetric content of natural gas in the study area ranges from 0.0175% to 0.214%, with an average of 0.108%, and most wells fall within the high-helium grade category; (2) the helium isotope ratios ³He/⁴He (R/Ra) of the samples range from 0.0148 to 0.0824, indicating a typical crustal helium source; the good positive correlation between helium and nitrogen volumetric contents suggests that the two components share a highly consistent source affinity or common migration and accumulation behavior during fluid evolution; and the extremely high He/Ne ratios, on the order of 10⁴, together with excess Ar isotopes, indicate that the gases experienced little dilution by shallow atmospheric water or modern atmospheric fluids during migration and accumulation. The formation of helium-rich unconventional gas reservoirs on the eastern margin of the Ordos Basin is interpreted to be characterized by basement-derived helium supply, activation by tectonothermal events, groundwater transport, efficient fault-controlled migration, reservoir capture along migration pathways, and sealing by stagnant groundwater and lithologic barriers. On this basis, a helium enrichment model is established. This model depicts the geochemical evolution pathway of trace noble gases in a natural gas system and may provide a useful reference for helium resource evaluation in analogous areas. Full article

Population growth, climate change, and increasing pressure on water and nitrogen resources pose major challenges for sustainable maize production. Maize yield is highly sensitive to inter-annual weather variability, yet many prediction approaches still rely on simple linear relationships and rarely integrate SPAD (Soil Plant Analysis Development)-based crop diagnostics with machine learning in multi-year nitrogen × irrigation experiments. In a three-year field experiment (2018–2020) in Hungary, we evaluated how basal and top-dressing fertilization and supplemental irrigation under contrasting water supply conditions affected the chlorophyll status and grain yield of a maize hybrid. Relative chlorophyll content was monitored using SPAD measurements at key phenological stages (V6, V12, and R1), and a multilayer perceptron (MLP) model was developed to improve yield prediction and to identify informative combinations of input variables. Five alternative scenarios (SC1–SC5) were tested by combining SPAD values with the fertilization rate, irrigation status, and crop year in different configurations, and model performance was assessed using root mean square deviation (RMSD), mean absolute error (MAE), normalized root mean square error (NRMSE), correlation (r, r²), Nash–Sutcliffe efficiency (NSE), Kling–Gupta efficiency (KGE), Kendall’s tau, and the index of agreement (d). Overall, SC4 (SPAD + fertilization + crop year + irrigation) achieved the best agreement with observed yields across most indices (e.g., r ≈ 0.93, NSE ≈ 0.86, KGE ≈ 0.90), whereas SC2 (SPAD + fertilization) produced the lowest prediction error on the independent test subset, indicating the most robust generalization. Basal fertilization with 60 and 120 kg N ha⁻¹ significantly increased yield in 2019 and 2020, while irrigation generally enhanced yield except for the 30 kg N ha⁻¹ top dressing applied at the V6–V12 stages. These results demonstrate that coupling SPAD measurements with MLP modeling and multi-criteria performance evaluation can support more efficient, site-specific nitrogen and irrigation decisions and help stabilize maize yields under variable climatic conditions. Full article

A new type of bio-based adsorbents thiamine-functionalized maleated chitosan (CSMA@TA) was prepared and tested to help the effective removal of methylene blue (MB) in water systems. Successful functionalization was confirmed using structural and surface analysis by FTIR, SEM, XRD, TGA, BET and XPS that revealed a mesoporous structure with a surface area of 50.61 m²/g, pore volume of 0.062 cm³/g and an average pore diameter of 2.65 nm, as well as incorporation of active sites containing nitrogen and sulfur. The best fit of the Langmuir model (R² ≈ 0.986; RMSE less than 1.0) demonstrated that the adsorption capacity of CSMA@TA was highly dependent on operation parameters, with an optimum adsorption capacity of about 230 mg/g and a removal efficiency of more than 93.4% under an initial MB concentration of 25 mg/L. Kinetic studies followed the pseudo-second-order model (R² ≈ 0.986), indicating that the uptake was dominated by chemisorption. Analysis of intraparticle diffusion indicated that the adsorption process involved three stages: diffusion in the boundary layer (k1d = 17.95 mg/g·min^−1/2), which controlled the first stage; gradual diffusion in the pore diffusion; and stabilization of the equilibrium. The thermodynamic parameters indicated the presence of strong adsorbate-adsorbent interactions and interfacial structuring. ∆G° values ranged between −24.85 and −23.56 kJ/mol, ∆H° = −44.08 kJ/mol, and ∆S° = −64.65 J/molK indicated strong adsorbate-adsorbent interactions and interfacial structuring. The adsorbent also exhibited good reusability, retaining more than 90% of its initial efficiency after five cycles, making it stable. The enhanced performance of CSMA@TA is due to the synergistic effect of carboxyl groups and heteroaromatic thiamine moieties, which enable electrostatic attraction, hydrogen bonding, and π–π interactions. These findings support the claim that CSMA@TA is a high-efficiency, sustainable, and reusable adsorbent with strong potential for practical wastewater treatment applications. Full article

Wheat (Triticum aestivum L.) productivity in saline soils is often constrained by nutrient imbalance, water scarcity, and ionic stress, particularly in arid regions such as the Nile Delta of Egypt. This study evaluated the combined effects of biochar (2.4 t ha⁻¹) and 1% foliar seaweed extract under varying nitrogen application levels on soil chemical properties, wheat growth, yield, nutrient uptake, and N-use efficiency indices over two consecutive winter seasons (2023/2024 and 2024/2025). A factorial field experiment with three replicates was conducted using four nitrogen rates: 0%, 50%, 75%, and 100% of the recommended application (168 kg N ha⁻¹), combined with four treatments: control, seaweed extract, biochar, and their integration. Combined analysis showed that the highest grain yield was obtained under full nitrogen with biochar and seaweed extract (7085.75 kg ha⁻¹), although this was not significantly different from several integrated treatments, particularly those involving 75% nitrogen with amendments. The 75% N + biochar + seaweed extract treatment achieved comparable yield while significantly improving nitrogen-use efficiency indices, including recovery efficiency, agronomic efficiency, and partial factor productivity. Biochar and seaweed extract improved soil organic carbon, cation exchange capacity, and nutrient availability, while electrical conductivity was not significantly affected. These results indicate that nitrogen input can be reduced by up to 25% without yield loss when combined with these amendments, while enhancing nutrient-use efficiency. However, conclusions regarding salinity stress mitigation remain indirect due to the absence of physiological measurements. Overall, this integrated approach supports more sustainable wheat production in saline soils. Full article

Hydrogen (H₂) storage in subsurface formations has recently gained attention as a promising large-scale energy storage solution. Although previous studies have revealed distinct displacement behaviors between H₂ and other gases such as nitrogen (N₂) and carbon dioxide (CO₂) in high-permeability sandstones, the mechanisms governing H₂ migration in tight formations remain largely unexplored. To provide experimental observations that may help improve the understanding of H₂ migration in tight reservoirs, we conducted H₂ flooding experiments on a tight sandstone sample from the Ordos Basin under pore fluid pressures of 0.5, 1, and 2 MPa. Dynamic core flooding processes were monitored using a low-field nuclear magnetic resonance (NMR) analysis system. The capillary number (Nc) in this work ranged from 1.7 × 10⁻⁹ to 3.4 × 10⁻⁹, indicating a capillarity-dominated flow. H₂ saturation in the tight sandstone increased from 41.9% to 53.3% and then to 57.7% with increasing pore fluid pressure. Under a pore fluid pressure of 0.5 MPa, H₂ initially displaced water in small pores (T₂ < 10.5 ms), leading to prolonged fluctuations in water content over 136 min before significant displacement occurred in large pores (10.5 ms < T₂ < 6579.3 ms). In contrast, at a pore fluid pressure of 2 MPa, the water in large pores was more significantly impacted, with a marked decrease in water saturation observed after 8 min of flooding. These findings provide direct experimental evidence of pressure-dependent and pore-scale selective displacement patterns of H₂ in tight sandstone, offering new insights into the fluid dynamics that control hydrogen injectivity and storage efficiency in low-permeability reservoirs. Full article

The integration of multiple species has been proposed as a strategy to improve resource use efficiency in intensive aquaculture systems. This study evaluated the inclusion of a native fish species, yellowtail lambari (Astyanax bimaculatus), in a biofloc-based aquaponic system co-cultivating Nile tilapia (Oreochromis niloticus) and lettuce (Lactuca sativa var. capitata). The experiment was conducted over 35 days using eight experimental units with two treatments (with and without lambari) and four replicates. Water quality, zootechnical performance, lettuce growth, hematological parameters of tilapia, and nitrogen and phosphorus retention were assessed. The presence of lambari was associated with lower total ammonia nitrogen, toxic ammonia, and total suspended solids, particularly during the final stage of the experimental period (p < 0.05), as well as reduced pH and alkalinity, likely reflecting increased microbial activity. Lettuce cultivated in the lambari treatment showed higher final weight, leaf height, and total biomass (p < 0.05), resulting in increased system productivity. No significant differences were observed in growth performance or hematological parameters of Nile tilapia (p > 0.05). In addition, nitrogen and phosphorus retention at the system level were higher in the lambari treatment (p < 0.05), although no differences were detected when fish and plants were evaluated separately. These results indicate that the inclusion of a native fish species can influence nutrient retention and productivity in biofloc-based aquaponic systems without compromising the performance of the primary cultured species. Full article

To achieve synergistic, efficient degradation of volatile, harmful gases in asphalt and to scientifically quantify inhibitor dosage, this study proposes a dosage optimization method that integrates nonlinear regression with a multi-response satisfaction function. Focusing on a proprietary composite volatile gas suppressant, we systematically measured the concentration trends of ammonia, nitrogen oxides, sulfur dioxide, and hydrogen sulfide emitted from three asphalt systems: base asphalt, SBS modified asphalt (Styrene-Butadiene-Styrene modified asphalt), and rubber modified asphalt under different suppressant dosages (0%, 0.02%, 0.04%, 0.06%, 0.08%, and 0.10%). First, high-precision prediction models (R² > 0.95) were established using nonlinear regression to relate different inhibitor dosages to corresponding gas concentrations. Based on a satisfaction function, the multi-objective degradation effects were normalized into a comprehensive satisfaction index, and the optimal dosage was then determined. The results indicate: (1) the constructed models can accurately predict the concentrations of volatile harmful gases at various dosages; (2) the predicted optimal blending ratios vary by asphalt type, specifically 0.082% for base asphalt, 0.079% for SBS modified asphalt, and 0.080% for rubber modified asphalt; and (3) at the optimal blending ratios, all four gases achieve high and balanced degradation levels, resulting in the best overall degradation performance. At the same time, road performance tests confirmed that this blending ratio has no significant negative impact on the high-temperature and low-temperature stability or water stability of the asphalt mixture. Compared with traditional single-factor empirical methods, this approach represents a methodological upgrade from qualitative description to quantitative prediction, and from single-objective comparison to multi-objective synergistic optimization, providing data and theoretical support for the precise, efficient, and engineering-applicable use of asphalt volatile gas inhibitors. Full article

This study investigates the synthesis and kinetic behavior of a magnetic biochar derived from avocado seed biomass for the removal of hexavalent chromium (Cr(VI)) from aqueous solutions. Magnetite (Fe₃O₄) was synthesized through different routes, including nitrogen-assisted coprecipitation, redox-controlled coprecipitation, polyol, sol–gel, and sonochemical methods, to evaluate their structural properties and iron incorporation efficiency. Based on compositional and crystallographic analyses, the coprecipitation under an inert atmosphere exhibited improved phase purity and higher Fe₃O₄ content, which was selected for in situ incorporation onto biochar produced by pyrolysis at 450 °C. The resulting magnetic material and composite were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS), confirming the suitability of the synthesis method and the successful deposition of magnetite onto the porous carbon matrix while preserving its structural integrity. Batch adsorption experiments were conducted at pH 2.0 to evaluate the effect of adsorbent dose and initial Cr(VI) concentration. The adsorption process reached equilibrium within 120 min and was better described by the pseudo-second-order kinetic model (R² ≥ 0.98), suggesting that chemisorption governs the rate-controlling step, with diffusion phenomena contributing but not dominating the overall mechanism. The maximum adsorption capacity predicted by the kinetic model reached 42.49 mg g⁻¹ at an initial concentration of 100 mg L⁻¹. The results demonstrate that avocado-seed-derived magnetic biochar represents a sustainable and effective material for chromium-contaminated water treatment, integrating agro-industrial waste valorization with enhanced adsorption performance and magnetic separability. Full article

Drought and nitrogen deposition are major drivers of global change that can influence forest ecosystems and plant–microbe interactions, yet their combined effects on endophytic fungal communities and the roles of dark septate endophytes (DSE) remain unclear. In this study, we examined the diversity of culturable endophytic fungi in leaves and roots of Quercus dentata under different drought and nitrogen deposition treatments and evaluated the functional effects of representative DSE strains on host growth and physiology. A total of 1488 fungal isolates were obtained, revealing distinct organ-specific community patterns. Root-associated communities showed greater compositional stability across treatments, whereas leaf communities were more responsive to environmental variation. Severe drought reduced the dominance of several genera and promoted community restructuring, while nitrogen deposition had contrasting effects on α-diversity in leaves and roots. Beta diversity analyses indicated significant interaction effects between drought and nitrogen addition. Inoculation with four DSE strains produced strain-dependent effects on plant biomass, photosynthesis, water-use efficiency, physiological traits, and nutrient contents. These results indicate that drought and nitrogen deposition jointly influence endophytic fungal communities and that functional differences among DSE strains may affect host responses to combined stress. Full article