Search Results (6,061)

Clarifying SOC sequestration via physical and microbial processes is key for improving farmland fertility, yet the relative contributions of agronomic practices to carbon fractions and aggregate sizes remain unclear. This study (2010–2019, rice–wheat rotation, Funiu Mountain eastern plain, central China) examined tillage and organic amendment effects on SOC dynamics and underlying mechanisms across aggregate sizes under six treatments (conventional/reduced tillage with no fertilizer, chemical fertilizer, or organic manure). SOC, particulate organic carbon (POC), and mineral-incorporated organic carbon (MOC) were measured in bulk soil and water-stable aggregates (>2000, 250–2000, 53–250, <53 μm), and physical fractionation and phospholipid fatty acid (PLFA) analysis were conducted to assess interactions among aggregates, carbon quality, and microbial communities. Results showed that, compared with conventional tillage without fertilization, both conventional tillage and reduced tillage with organic manure significantly increased bulk SOC by 92–122% and macroaggregate (>250 μm) mass by 15–110%. The combined application of organic manure and reduced tillage redirected SOC from micro- to macroaggregates. Moreover, POC and MOC were the primary contributors to bulk SOC, with POC showing a strong direct effect on SOC accumulation. Furthermore, a positive priming effect was detected exclusively in macroaggregates, identifying them as key sites for SOC turnover and confirming that optimized tillage with manure shifts aggregates to larger sizes and boosts SOC through physical protection. The micro-to-macro cascade offers a robust framework for SOC dynamics, and its persistence under diverse climates warrants future research for sustainable management. Full article

Land-cover-based ecosystem service valuation commonly assigns a uniform value coefficient to pixels within the same land-cover class, thereby overlooking ecological heterogeneity in mountainous protected areas. This study developed an improved remote sensing ecological index (IRSEI) and applied it as a spatial adjustment factor in the equivalent factor method to assess ecosystem service value (ESV) changes in the Qionglai Mountains section of Giant Panda National Park, China, between 2017 and 2022. IRSEI integrated the normalized difference vegetation index, wetness, normalized difference built-up and soil index, land surface temperature, and cumulative dynamic habitat index derived from the fraction of absorbed photosynthetically active radiation. DHI-cum was included as a proxy for annual cumulative vegetation productivity and habitat energy availability rather than a direct measure of biodiversity or giant panda habitat quality. Total ESV increased from 3.27 × 10⁸ CNY in 2017 to 4.25 × 10⁸ CNY in 2022, representing an increase of 9.79 × 10⁷ CNY, or 29.98%. Water bodies contributed the largest absolute increase, rising by 4.79 × 10⁷ CNY, or 42.45%, whereas farmland showed the highest relative increase of 45.35%. Woodland remained the dominant contributor to total ESV. Spatially, ESV was higher in the northern and southern parts and lower in the central region. All corrected sensitivity coefficients were below one, indicating that total ESV responded inelastically to ±50% perturbations of individual land-cover value coefficients. The framework improves within-class spatial differentiation of ESV and may support targeted management of mountainous protected areas, although field-based habitat and biodiversity data are needed for further validation. Full article

This study investigates the interrelationships between soil organic matter (SOM) quality characteristics and key mercury species in two sites in Czech Republic under historical Hg contamination. SOM properties derived from DRIFT spectral analysis including the aromaticity index (iAR), potential wettability index (PWI), decomposability index (DI), and organic matter quality index (OMQ) along with additional SOM quantity and quality indicators were evaluated against several key Hg fractions (Total Hg (HgT), potentially mobilizable Hg (HgPM), potentially mobilizable Hg ions (Hg²⁺), methylmercury (MeHg), and water-soluble Hg (HgWS)). Neural network analysis revealed that type of horizon (organic or mineral) as well as SOM quality characteristics play an important role in Hg mobility and methylation processes. The results show the difference in relevant SOM quality properties that affect Hg mobility and methylation that can also be opposite based on the soil horizon type for the same soil, potentially forcing different pathways for the mobilization and methylation, and indicating that the state of transformation of organic matter and its quality characteristics along with the environmental conditions are some of the key attributes influencing mobility and methylation processes of Hg in the soil. Full article

Film-mulched drip irrigation (FMDI) is used increasingly for cotton (Gossypium hirsutum L.) production in arid regions. However, salts often accumulate in the soil, eventually leading to soil salinization and crop failure when using FMDI with brackish water inappropriately. Evaluation of the leaching requirement (LR) for cotton under FMDI with brackish water that comprehensively considers cotton yield, water saving, soil conditions, and economic benefits needs to be investigated more completely. The present study compared the cotton growth for different leaching fractions (LF) under FMDI with brackish water and provides comprehensive analysis of LR for cotton and its relationships with soil conditions. A higher LF was related to a lower cotton yield when the LF was larger than 0.15. Moreover, a larger LF led to a lower ratio of reproductive growth and irrigation water productivity when the LF was larger than 0.2. A high soil water content (SWC) strip was observed in the 40–60 cm soil layers for all scenarios. Moreover, a higher SWC proportion in the deeper soil layers as for LF_0.15 or LF_0.2 may also be beneficial to cotton growth. Soil salinity decreased with decreases in irrigation water quantity when the LF was lower than 0.2, but increased when the LF was higher than 0.2. Either too much or too little irrigation water was not beneficial from an economic perspective. Our study indicated that the LR values between 0.05 and 0.15 were recommended for FMDI when the total dissolved solids for brackish water is within 1.61–3.21 g L⁻¹. Integrated strategies, including optimized irrigation-fertilizer management, groundwater depth monitoring, and halophyte intercropping, are required to sustain production while mitigating secondary salinization and groundwater pollution under FMDI with brackish water. Full article

Edible mushroom polysaccharides have attracted considerable attention because of their diverse biological activities, particularly their antioxidant potential. However, efficient extraction of these polysaccharides remains challenging due to the rigid chitin–β-glucan network of fungal cell walls. In this study, polysaccharides from Termitomyces albuminosus were extracted using hot water extraction (HWE), ultrasound-assisted extraction (UAE), and ultrasound-assisted aqueous two-phase extraction (UA-ATPE). Extraction conditions for each method were optimized using Box–Behnken response surface methodology, and the effects of different extraction strategies on polysaccharide yield, physicochemical properties, and antioxidant activity were systematically compared. Among the three methods, UAE produced the highest polysaccharide yield (110.32 ± 3.68 mg/g). The extraction strategy significantly influenced the molecular weight distribution and monosaccharide composition of the crude polysaccharides. The crude UAE extract was further purified by DEAE-52 anion-exchange chromatography, yielding the major antioxidant-active fraction eluted with 0.1 M NaCl (designated ATPs-0.1M), which was identified as an acidic heteropolysaccharide with an average molecular weight of 6.37 kDa and composed primarily of glucose, mannose, galactose, xylose, glucuronic acid, rhamnose, and fucose. In vitro antioxidant assays demonstrated that TAPs-0.1M exhibited stronger DPPH radical scavenging, hydroxyl radical scavenging, and ferric reducing activities than the other purified fractions under the tested conditions. The results indicate that different extraction strategies are associated with distinct physicochemical characteristics and antioxidant activities of T. albuminosus polysaccharides. These findings provide a practical basis for selecting appropriate extraction methods and support the further development of T. albuminosus polysaccharides as natural antioxidant ingredients. Full article

Accurately acquiring soil moisture content (SMC) and its spatial distribution is of great significance for water-saving irrigation and sustainable agricultural development in arid regions. However, the complex soil background noise and weak moisture absorption features in the Xinjiang region severely restrict the accuracy and reliability of remote sensing inversion for SMC. To address the challenges of difficult feature capture and low estimation accuracy in soil moisture monitoring, this study utilized GF-5 satellite hyperspectral data and ground-measured SMC data. First, the effects of Fractional-Order Differentiation (FOD) at orders 0–2 (with a 0.2 step size) on spectral moisture response were systematically evaluated. Next, 60 dual-band spectral indices (DBIs) were constructed from full-band combinations under the optimal differentiation orders, and highly correlated indices were selected as candidate features. Finally, three variable screening methods were coupled with three machine learning models to construct nine SMC inversion schemes, and the optimal model combination was employed to map the spatial distribution of SMC in the study area. Results showed that FOD at orders 0.8–1.2 effectively enhanced spectral responses at soil moisture absorption bands, the introduction of DBI concentrated high-correlation band combinations in moisture-sensitive regions, and the optimal scheme (BSS-PLSR) demonstrated good predictive performance and stability. These findings provide data support for precision irrigation decision-making and soil moisture management in arid farmlands. Full article

Problem statement: Contaminated mixed plastic waste—bearing metallic, paper, cardboard and organic residues—remains largely excluded from mechanical recycling because conventional routes require a costly, water- and energy-intensive washing–drying pretreatment. Research gap: No published study combines a fully dry, washing-free valorisation route for such waste with certified mechanical characterisation and a quantified CO₂ mass balance that explicitly credits elimination of the washing–drying stage. Methodology: This study presents DMP (Downcycled Mixed Plastic), a patented (OSIM, Romania) dry valorisation process based on continuous single-screw extrusion (D = 150 mm, L/D = 17.3), characterised through differential scanning calorimetry (DSC), certified mechanical/thermal testing at accredited Romanian laboratories, Weber-number dispersion analysis, and a process-parameter sensitivity study. Key findings: The composite exhibits certified mechanical properties (tensile strength 9.22 MPa, elongation at break 112.8%, compressive strength 14.5 MPa); composition–property analysis across four batches shows that increasing the PP weight fraction from 20 to 28 wt% raises tensile strength by 8.3% while reducing elongation by 5.2%; a computed Weber number (We = 166.7 ≫ We_crit) is consistent with fine PP-phase dispersion within the PE matrix; the sensitivity study confirms statistically robust structure–property relationships (R² = 0.93–0.98); and the CO₂ mass balance establishes a net avoidance of 3.150 t CO₂ eq per tonne of waste processed relative to conventional wet recycling. Significance: dry, washing-free processing is a technically promising pathway for valorising plastic waste streams currently considered non-recyclable, potentially reducing production cost by 60–70% relative to wet recycling, pending additional characterisation identified as priorities for future work. Full article

Located in the northeastern Tibetan Plateau, the Qaidam Basin hosts abundant strategic lithium (Li) and boron (B) salt lake resources crucial for national resource security. Existing studies focus on individual lakes, lacking systematic Li-B geochemical and source–transport–sink research across the geothermal–river–lake system. Based on 40 water samples from 16 lakes and multi-isotope and hydrochemical data, this study explores Li-B spatial distribution, isotopic evolution and enrichment rules. The results reveal prominent spatial heterogeneity of Li and B distributions. The contents of riverine Li and B are higher than the global average level, and terminal salt lakes show the highest enrichment degree. Specifically, southern lakes are Li-dominant, while northern lakes are B-dominant, with both reaching industrial exploitation grades. Significant Li and B isotopic fractionation occurs throughout the hydrological system, with geothermal fluids presenting depleted isotopic compositions and lake waters showing enriched features. H-O isotopic evidence and Gibbs diagram analysis indicate that surface waters in the basin are primarily recharged by atmospheric precipitation, and their hydrochemical compositions are jointly controlled by rock weathering and strong evaporative concentration, accompanied by distinct north–south hydrogeological zonation differences. Source analysis demonstrates that Li is mainly derived from high-temperature water–rock interactions of Li-rich volcanic and granitic rocks in the southern East Kunlun Mountains, whereas B originates from ultrahigh-pressure B-rich metamorphic rocks along the northern North Qaidam margin. The migration and accumulation sequence of Li and B follows the pathway: geothermal fluid emission → fluvial transportation → terminal lake enrichment. Evaporation and mineral precipitation are the dominant factors controlling elemental enrichment and isotopic fractionation. This basin-wide study supplements salt lake critical mineral metallogenic theories and guides efficient Li-B exploration and sustainable development. Full article

Water limitation during soybean (Glycine max (L.) Merr.) establishment restricts leaf expansion and root–shoot development, whereas microbial biostimulants may modify these responses only within particular moisture contexts. We tested whether a mixed-species suspension of Bacillus subtilis and Bacillus amyloliquefaciens produced water-regime-dependent dose responses in a controlled-environment tray-cell experiment. The seedlings received a single rhizosphere-directed application of 0, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.75 or 2.0 mL of undiluted inoculum per cell before exposure for 15 days to full irrigation (W100), 50% or 25% of the W100 replacement volume (W50 and W25), or no irrigation (W0). Each of the 44 treatment combinations comprised six independent biological replicates (264 cells). Two-way ANOVA detected significant water-regime, dose and interaction effects for most thermal, growth, biomass and allocation traits, with water regime as the dominant source of variation. Averaged across doses, relative to W100, W0 increased the leaf-surface temperature by 8.8% and reduced the root length by 44.3%, shoot length by 25.4%, stem diameter by 38.2%, leaf area by 72.3%, total dry mass by 20.1% and specific leaf area by 70.4% on average. The concurrent 17.3% increase in the leaf mass fraction indicated the retention of proportional leaf dry-matter investment despite strongly restricted surface expansion. The bacterial response was non-linear and water-regime-specific. Within W0, 0.05 mL increased root dry mass by 116.7% and total dry mass by 39.3% relative to the untreated W0 control. The highest integrated mean z-score occurred at 0.05 mL under W0, 0.2 mL under W25, 1.2 mL under W50 and 0.2 mL under W100. Correlation analysis identified coordinated trait covariation, whereas hierarchical clustering and principal component analysis separated a warm, low-expansion W0 phenotype from a cool, high-vigour W100 phenotype. These findings provide a quantitative experimental basis for selecting candidate pre-drought doses for seedling-stage screening. Validation across soils, application timings, formulation persistence and reproductive-stage yield are required before commercial recommendation. Full article

Accurate estimation of crop water requirements is essential to improve irrigation efficiency for forage maize production. This study compared satellite- and UAV-derived normalized difference vegetation index (NDVI) models for estimating crop coefficients (K_c) and evaluated their operational performance for irrigation scheduling. K_c–NDVI models were developed during the 2023 growing season and subsequently validated under field conditions during the 2024 season in two forage maize hybrids (N83N5 and Matador) under three irrigation strategies: conventional producer irrigation (ID1), satellite-based irrigation scheduling (ID2), and UAV-based irrigation scheduling (ID3). Both NDVI sources exhibited strong relationships with K_c, with higher calibration accuracy for the UAV model (R² = 0.9414) than for the satellite model (R² = 0.8278). The UAV-based model applied 23–30% less irrigation water, maintaining high water productivity but also reducing crop growth, forage yield, and nutritional quality. In contrast, satellite-based irrigation scheduling promoted greater crop growth and produced the highest forage yield, reaching 59.8 t ha⁻¹ in hybrid N83N5 while maintaining efficient water use. This treatment also improved forage quality by increasing dry matter and starch concentrations while reducing fiber fractions. The findings highlight the complementary potential of satellite and UAV imagery in precision irrigation and underscore the trade-offs between spatial detail, temporal resolution, and operational scalability. Furthermore, the results demonstrate that a stronger K_c–NDVI relationship does not necessarily translate into improved irrigation scheduling performance. Under the conditions evaluated, the satellite-based model provided the best balance between water use, forage yield, and nutritional quality. Full article

The sizing of rooftop solar energy systems is commonly based on the most visible load or on generic end-use allocations, leading to an inadequate distribution of the limited rooftop area between heat and electricity. This study formalizes the energy audit within a three-level deterministic framework that selects and sizes solar technologies by energy vector: demand is first decomposed by vector; the technology for the thermal vector is then selected through a levelized cost of heat selection ratio $\psi$, while the photovoltaic system of the electrical vector is sized for self-consumption; and the rooftop area is finally allocated among vectors according to marginal value per unit area. In a 75-bed university residence in Cienfuegos, Cuba, air conditioning is the dominant energy end-use in terms of installed power (accounting for $77\%$ of the connected load), whereas the thermal vector dominates annual energy consumption (domestic hot water: 127,440 versus 76,818 kWh/year for electricity; thermal-to-electric ratio $1.66$). Solar thermal technology has been selected for the thermal vector ($0.018$ versus $0.088$ USD/kWh_th; $\psi =0.21$, a robust value according to the sensitivity analysis), and the marginal value (≈111 versus ≈32 USD/(m²·year)) allocates 104 m² to solar thermal collectors and 134 m² to photovoltaic energy, thereby reversing the original design that prioritized photovoltaic energy. The resulting portfolio achieves an annual solar fraction close to $100\%$ in both vectors on an energy balance basis, avoids $86.5$ t of operational CO₂ emissions per year, and combines a simple payback of $1.1$ years (solar thermal) with a net present value of 55,327 USD and an internal rate of return of $28\%$ (photovoltaics). The sizing decision is shown to be robust to the choice of statistical design criterion (median, mean, P90, maximum), and none of the three framework decisions is reversed under $\pm 30\%$ parameter variations. By replacing the subjective weightings of multi-criteria methods with observable economic criteria, the framework provides a replicable and auditable design protocol. Full article

Photocatalytic CO₂-to-CH₄ conversion is usually assessed through catalyst activity, selectivity, and methane formation rate, although the practical usefulness of the resulting gas stream also depends on methane recovery from CO₂-rich mixtures. Here, a phenomenological Langmuir–Hinshelwood reactor model was used to evaluate batch gas-phase CO₂ photoreduction under different reactor thicknesses, water-availability conditions, photocatalyst activities, and idealized methane-selective extraction configurations. The model considered competitive adsorption, transient gas-phase balances, finite or buffered water supply, and a lumped selective CH₄ extraction term. Under finite vapor inventory, water depletion limited reaction progress, particularly in thin reactors. Buffered-water operation increased CO₂ conversion and methane formation, while reactor thickness produced a trade-off: thin reactors favored apparent conversion and methane enrichment, whereas thicker reactors provided a larger CO₂ reservoir and higher cumulative methane formation. At the baseline kinetic condition, methane extraction strongly decreased the in-reactor CH₄ fraction but only modestly increased methane formation. When photocatalyst activity was increased, the non-membrane thin reactor reached a product-accumulation-limited regime, and methane-selective extraction became kinetically relevant. These results indicate that methane-selective extraction concepts should be evaluated not only as separation devices, but as conditional reactor-intensification tools whose relevance depends on water availability, reactor geometry, catalyst productivity, and product dilution. Full article

Oxidative stress is known to disrupt intestinal barrier integrity, whereas certain polysaccharides have demonstrated protective effects on intestinal function. This study aimed to isolate a polysaccharide from processed Hippophae rhamnoides subsp. sinensis pomace (remaining after oil and juice extraction) and evaluate its protective effect against H₂O₂-induced intestinal barrier dysfunction in Caco-2 cell monolayers. A polysaccharide fraction, designated SPP-0.2b, with a weight-average molecular weight (Mw) of 42.405 kDa, was successfully isolated by hot water extraction and purified using DEAE-52 cellulose and Sephadex G-100 gel chromatography. Monosaccharide composition analysis revealed that SPP-0.2b was mainly composed of rhamnose, arabinose, galactose, mannose, and galacturonic acid. Compared with the H₂O₂-treated group, SPP-0.2b (500 μg/mL) increased the transepithelial electrical resistance (TEER) by 76.67% and reduced basolateral FITC-dextran fluorescence intensity by 34.63% in Caco-2 monolayers. In addition, SPP-0.2b significantly increased the protein expression levels of Occludin and Zonula Occludens-1 by 79.49% and 66.75%, respectively. SPP-0.2b also reduced intracellular reactive oxygen species and malondialdehyde levels while enhancing the activities of superoxide dismutase and glutathione peroxidase. Collectively, these findings suggest that the protective effect of SPP-0.2b against H₂O₂-induced intestinal barrier dysfunction is associated with the maintenance of tight junction proteins and attenuation of oxidative stress. This study provides experimental evidence supporting the further investigation of SPP-0.2b as a potential functional food ingredient for intestinal health. Full article

Stable drainage of coalbed methane wells is essential for reducing reservoir pressure and promoting methane desorption. However, coal fines carried by produced water tend to accumulate and deposit within the standing valves of drainage pumps. To address this common problem, this study investigates the transport characteristics of coal fines within the standing valve during the liquid-dominated water-pumping stage of the plunger upstroke, with the standing valve fully open. Theoretical calculations, numerical simulations, and settling experiments were conducted for three coal fines size fractions of 60–100, 100–200, and 200–400 mesh to validate the model’s predictive capability for coal fines motion. The results show that the RNG k–ε model has the lowest mean absolute relative error, at 14.50%. A solid–liquid two-phase flow model was employed to comparatively analyze five valve seat cone angles ranging from 105° to 165° and representative inlet velocities of 0.1–0.4 m/s. The results indicate that the mixture within the standing valve accelerates markedly while passing through the narrow clearance between the valve ball and the valve seat and then decelerates in the region above the valve ball. The region above the valve ball and the valve seat transition region are the primary locations of instantaneous coal fines enrichment. Increasing the inlet velocity generally enhances coal fines transport capacity and reduces the local maximum solid-phase volume fraction. Larger coal fines particles exhibit more pronounced inertial deviation and a higher degree of local enrichment, whereas smaller particles show stronger flow-following behavior and a more dispersed spatial distribution. The results further indicate that, within the investigated structural range, the 150° valve seat cone angle provides the best overall balance between coal fines transport capacity and hydraulic resistance. Ultimately, the findings provide a theoretical foundation and methodological reference for understanding the anti-clogging mechanisms of CBM pump standing valves, optimizing structural parameters, and guiding the blockage-resistant design of downhole flow components. Full article

In temperate coastal waters, phytoplankton communities often follow a classical seasonal pattern, with diatoms dominating in spring and dinoflagellates becoming more prominent during summer. However, spring-to-summer phytoplankton community reorganization in eutrophic Liaodong Bay remains poorly characterized. Here, we examined seasonal changes in phytoplankton communities and environmental conditions in Liaodong Bay in spring and summer 2025. The phytoplankton community underwent a marked spring-to-summer reorganization that differed from the classical seasonal pattern. In spring, dinoflagellates accounted for 63.51% of total community abundance, with the heterotrophic dinoflagellate N. scintillans comprising 99.56% of this fraction. By contrast, diatoms comprised 91.02% of the summer community, with Coscinodiscus granii, Skeletonema costatum, and other diatom taxa sharing dominance. This reorganization coincided with a seasonal shift in phosphorus regime and nutrient stoichiometry, from low dissolved inorganic phosphorus (DIP; 0.12 μmol P L⁻¹), dominance of dissolved organic phosphorus (DOP; 0.28 μmol P L⁻¹) and high N:P in spring to higher DIP (0.66 μmol P L⁻¹), lower DOP (0.18 μmol P L⁻¹), lower N:P, and higher Si:N in summer. Correlation and redundancy analyses indicated that the spring N. scintillans-dominated assemblage was broadly aligned with DOP-rich and high-N:P conditions, whereas summer-dominant diatoms were broadly aligned with DIP, dissolved silicate (DSi), and Si:N gradients, although not all bivariate relationships were significant. These patterns suggest that potential relative inorganic phosphorus deficiency in spring may have been less favorable for diatom dominance, whereas higher DIP, lower N:P, and higher Si:N in summer were consistent with a resource regime more favorable for multi-diatom expansion. Overall, the phytoplankton community in Liaodong Bay exhibited a non-classical seasonal reorganization from a spring N. scintillans-dominated assemblage, rather than a conventional autotrophic dinoflagellate-dominated stage, to summer multi-diatom co-dominance, coinciding with shifts in phosphorus regime and nutrient stoichiometry. Full article