Search Results (1,584)

Anaerobic biodegradation is the most affordable method for the degradation of N,N-dimethylformamide. However, the degradation efficiency depends on the concentration. To elucidate the responses of microbial community to N,N-dimethylformamide load, microbial diversity, composition and functional changes at different concentrations of 100, 2000, and 3500 mg/L were analyzed. Results showed that as the N,N-dimethylformamide influent concentration increased from 100 to 2000 mg/L, the removal rate stabilized at 90%, whereas it decreased to ~75% at concentrations over 2000 mg/L. Microbial community diversity increased, and specialists were enriched at 3500 mg/L. Patescibacteria (42.88% and 42.90%), Bacillota (18.52% and 18.54%), and Pseudomonadota (7.13% and 7.09%) were the dominant phyla at 100 mg/L and 2000 mg/L, respectively, and Patescibacteria (16.88%) and Pseudomonadota (15.34%) were the dominant phyla at 3500 mg/L. Methylotrophic methanogeneic (Methanolobus and Methanomassiliicoccus) and syntrophic electron-donating bacteria (Clostridiumand and Trichococcus) were significantly enriched. DMF-degrading genes (fdh, rfA/nrfH, and ATPase) and methylotrophic methanogenesis genes (mcr, mta, and mtm) were significantly upregulated. Therefore, the degradation of N,N-dimethylformamide was characterized by a parallel carbon flux distribution, “methylamine-driven methanogenesis + further oxidation/integration of single-carbon intermediates”, and the nitrogen flux tended to enter a reductive nitrogen cycle characterized by retention and reuse. Full article

Restoration of degraded shrublands is a major challenge for combating desertification in arid and semi-arid regions. Caragana korshinskii Kom., a dominant sand-fixing shrub widely planted in northern China, often shows growth decline and structural degradation as stand age increases. Stubble management is widely used to rejuvenate degraded shrublands; however, its influence on nutrient cycling and carbon-nitrogen-phosphorus (C-N-P) stoichiometric coupling within the leaf-soil system remains unclear. Here, we conducted a two-factor field experiment in a 30-year-old degraded C. korshinskii plantation in the Kubuqi Desert, northern China, manipulating stubble height and stubble density. Moderate stubble height (10 cm) significantly increased leaf N concentration (27.37 g kg⁻¹) and improved soil C and N availability, whereas higher stubble height (20 cm) led to elevated leaf N:P ratios (24.2), indicating stronger phosphorus limitation. In addition, all stubble density treatments significantly reduced leaf C:N, C:P, and N:P ratios. Among them, the two stubbled after one retained exhibited the most pronounced effect, with C:N and C:P decreasing to 14 and 273, respectively, and N:P to 20, suggesting an improved nutrient balance and allocation efficiency. Multivariate analyses showed that lower stubble heights combined with alternate-plant stubble patterns (H2D1 and H2D2) enhanced leaf-soil nutrient coupling and promoted coordinated recovery of C-N-P stoichiometry during regeneration. Overall, stubble management regulates shrub rejuvenation mainly by modifying leaf-soil nutrient coupling rather than single-element responses. It is recommended that, in the management of degraded C. korshinskii shrublands, a stubble height of approximately 10 cm combined with staggered cutting (alternate-plant or every two plants) be prioritized as an optimized management regime. Full article

Litter decomposition is a key regulator of soil carbon formation and nutrient cycling in the plant–soil continuum. However, the utility of structural chemical indicators for capturing the relationship between litter decomposition and environmental factors under nitrogen (N) enrichment remains unclear. We conducted a two-year in situ decomposition experiment with different N addition treatments in a pure Quercus variabilis forest on the Qinling Mountains, China. During the active six-month growing season, we investigated the stoichiometric ratios of typical organic acids in litter and soil layers and their responses to soil environments. The total relative content of the four organic acids showed the most pronounced nonlinear shift along the N addition gradient, peaking at N75 (7.5 g N m⁻²) then declining. The stoichiometric ratios of some typical organic acids varied analogously to soil physicochemical properties, microbial diversity and abundance. This inter-annual response was particularly pronounced in the warmer and wetter year of 2023. Structural chemical analysis revealed that steric hindrance and molecular symmetry are key factors regulating the decomposition efficiency of typical organic acids in litter. Notably, phenolic acid and butyric acid isomer ratios exhibited significant subgroup-specific responses to soil physicochemical factors, enzyme activities, and microbial abundances. Collectively, these ratios may indicate N addition impacts on litter decomposition, hold potential for predicting climatic variability responses, and provide conceptual support for an integrated framework linking N enrichment, litter chemistry, and soil carbon dynamics in temperate forests. Full article

The use of biodiesel blends in heavy-duty diesel engines changes the relationship between engine operating conditions, fuel properties, and exhaust emissions, which may limit the reliability of data-driven emission models trained under a single fuel condition. This study investigates the cross-fuel transferability of virtual emission sensors for a heavy-duty diesel engine operating on B7 and B20 fuel blends. The analysis was carried out for three target signals: nitrogen oxides concentration, hydrocarbon concentration, and dry carbon dioxide concentration, using data from the World Harmonized Transient Cycle (WHTC) and World Harmonized Stationary Cycle (WHSC) tests. A structured modelling workflow was developed, including signal time alignment, construction of baseline, dynamic, and memory-based features, feature selection, and separate evaluation scenarios: within-domain, cross-cycle, and cross-fuel transfer. Three tree-based regression algorithms were compared: Random Forest (RF), Histogram-Based Gradient Boosting (HGB), and Extreme Gradient Boosting (XGBoost). XGBoost achieved the best predictive performance in the source domain and was selected as the reference model. The results showed that a change in cycle characteristics led to a significant decrease in predictive performance, whereas the transition from B7/WHTC to B20/WHTC resulted in a clearly smaller drop in the evaluation metrics. The relationship between engine operating signals and emission response remained partially transferable across fuels. The highest stability was observed for carbon dioxide, intermediate stability for nitrogen oxides, and the lowest stability for hydrocarbons. The findings support the development of robust data-driven virtual sensing methods for emission monitoring and calibration of heavy-duty diesel engines operating with biodiesel blends. Full article

Understanding how long-term monoculture shapes soil microbial communities is crucial for sustainable management of tropical rubber plantations. Here, soils from a chronosequence of rubber plantations (5, 11, 18, and 36 years) in Danzhou, Hainan, China, were analyzed to assess changes in soil nutrients, enzyme activities, and bacterial communities. Soil organic matter, total phosphorus, and available phosphorus increased with stand age, whereas alkaline-hydrolyzable nitrogen (AN) and available potassium (AK) declined, indicating a decoupling between total and labile nutrients. Enzyme activities exhibited clear age-dependent patterns, with nitrogen-acquiring enzymes peaking in older stands and carbon-cycling enzymes peaking at intermediate stages, suggesting shifts in microbial resource acquisition strategies. Bacterial community composition shifted significantly with stand age, and this variation was primarily associated with AN, AK, and pH. Bacterial α-diversity exhibited a unimodal pattern, peaking at intermediate stages (11 years) and declined slightly in older plantations, and was primarily regulated by soil nutrient pools and microbial resource acquisition capacity. Overall, stand development restructures soil nutrient availability and enzyme-mediated processes, thereby reshaping the microbial community structure in unfertilized rubber plantations. These findings underscore that maintaining balanced nutrient supply is critical for sustaining soil microbial diversity and functional stability under long-term monoculture. Full article

Herein, we report the rational design of an A-SnO₂/Si@N-CNT nanocomposite, fabricated via facile ball milling followed by high-temperature annealing. In this design, surface-modified SnO₂ (A-SnO₂) serves as the primary active framework, silicon nanoparticles are introduced to enhance overall capacity, and nitrogen-doped carbon nanotubes (N-CNTs) provide a conductive and mechanically resilient network. The incorporation of silicon nanoparticles and N-CNTs into A-SnO₂ facilitated the formation of strong Si–C and Si–O–Sn bonds, thereby improving electrical conductivity and structural stability and reinforcing interfacial interactions between the active materials and the conductive CNT matrix, resulting in superior electrochemical performance. Morphological analysis confirmed that the composite maintained structural stability without severe cracking after 100 cycles at 100 mAh g⁻¹. The electrode delivered reversible capacities of 1002 and 622 mAh g⁻¹ at 0.1 and 0.5 A g⁻¹, with capacity retentions of 78.7% and 73.17%, respectively. Even at 1.0 A g⁻¹, a stable capacity of 441 mAh g⁻¹ with 80.96% retention was achieved. These findings demonstrate the effectiveness of coupling surface-modified SnO₂ with Si- and N-doped carbon frameworks for advanced lithium-ion battery anodes. Full article

Intensive agricultural production contributes significantly to greenhouse gas (GHG) emissions, accounting for between 10 and 12% of global anthropogenic emissions, at a time when the agricultural sector is facing increasing pressure to adapt to ever-stricter environmental regulations. This study develops and applies a multi-objective Goal Programming model to identify the optimal mix of crops and management practices that simultaneously minimize the carbon footprint and maximize productivity, at the level of a 300-hectare (ha) model agricultural system in Romania. The life cycle assessment (LCA) methodology, in accordance with ISO 14040/14044 standards and Ecoinvent 3.8 emission factors, was applied to nine crops distributed across three soil types, within four management scenarios, over an annual planning horizon. The unit of measurement used is a ton of CO₂ equivalent per agricultural system. The results show that the optimized configuration achieves near-zero total carbon emissions (0.33 t CO₂eq for the entire farm), reduces synthetic nitrogen inputs to 35.7% of the limit set by the EU Nitrates Directive, and generates water savings of 48%. However, these environmental gains entail a 52.9% production trade-off relative to the maximum target of 3000 tons, highlighting a Pareto-optimal structural conflict between climate and food security objectives. The sensitivity analysis identifies the nitrogen emission factor and crop yield as the most influential parameters. The results confirm the technical feasibility of the European Green Deal targets through systematic mathematical optimization, while also demonstrating that achieving economic parity requires policy support of 110–165 EUR/ha/year. Full article

As a typical mountain ecosystem in the western Tianshan Mountains, the Ili River Valley possesses abundant vegetation resources. Soil nematodes are effective biological indicators for evaluating soil micro-food webs. Nevertheless, the response mechanisms of nematode community structure to distinct vegetation types, especially native trees and forest-edge shrubs, remain poorly understood in this region. In this study, two dominant tree species (Picea schrenkiana and Malus sieversii) and two forest-edge shrub species (Berberis heteropoda and Berberis sibirica) were investigated. We analyzed the composition, diversity, and energy structure of rhizosphere soil nematodes and further compared their differences among plant species. The results indicated that tree rhizospheres had significantly higher amounts of nitrate nitrogen ($\mathrm{N}{\mathrm{O}}_3^{-}$-N and microbial biomass carbon (MBC), along with a lower amount of extractable organic carbon/extractable total nitrogen (EOC:ETN) than shrub rhizospheres (p < 0.05). Picea schrenkiana (PS) exhibited greater root carbon storage, higher root biomass, and a higher root carbon-to-nitrogen ratio (RC:RN) than Berberis heteropoda (BH) and Berberis sibirica (BS) (p < 0.05). The genus Chiloplacus dominated the nematode community across all four woody plants. The relative abundance of omnivore-predatory nematodes was markedly higher in shrubs (BH and BS) than in trees (PS and MS). The soil food webs of PS and MS were degraded, whereas shrub food webs were in a transitional state between structured and degraded habitats. Shrubs presented a higher maturity index, structural metabolic footprint, and energy flux of omnivore-predatory nematodes, but a lower energy flux of bacterivorous nematodes. Additionally, PS had the highest nematode carbon use efficiency (NCUE) and the lowest energy flux uniformity (U). $\mathrm{N}{\mathrm{O}}_3^{-}$-N extractable total nitrogen (ETN), soil organic carbon (SOC), and root traits were the primary factors driving variations in nematode communities and carbon indicators. Therefore, nematode carbon indicators closely associated with soil carbon and nitrogen cycling have the potential to serve as sensitive auxiliary biological metrics for evaluating material cycling and energy flow in pure forests and shrub ecosystems. This study provides empirical support for the assessment of regional ecosystem stability. Full article

Lodging is a major constraint on the stable production of high-quality japonica rice in the Yangtze River Delta. This study evaluated whether different concentrations of prohexadione calcium (Pro-Ca) could improve lodging resistance while maintaining grain yield in high-quality japonica rice. Field experiments were conducted in the 2024 and 2025 growing seasons, with TA 1 cultivated in 2024 and TA 1, SY 28, and HR 1212 cultivated in 2025. Pro-Ca was applied at the jointing stage at four concentrations: CK (water spray), P1 (15 mg L⁻¹), P2 (30 mg L⁻¹) and P3 (45 mg L⁻¹). Rice yield and its components, lodging parameters, culm morphological traits, and non-targeted metabolomic profiles were analyzed. Compared with CK, the P1 treatment significantly reduced the lodging index without a significant reduction in grain yield. In contrast, the P2 and P3 treatments further decreased the lodging index by 14.0–48.1% but decreased grain yield by 6.7–17.9%, mainly due to reductions in effective panicle number and spikelets per panicle. Pro-Ca treatment significantly increased internode diameter and culm wall thickness by 4.9–29.3% and 11.7–76.5%, respectively, and promoted the accumulation of lignin by 5.4–17.7% and cellulose by 3.0–8.6%, thereby enhancing the structural reinforcement of the rice stem. A metabolomic analysis showed that Pro-Ca treatment was associated with changes in carbon- and nitrogen-related metabolites, including metabolites linked to the tricarboxylic acid (TCA) cycle and amino acid biosynthesis. These changes were accompanied by increased accumulation of phenylpropanoid pathway intermediates and lignin-related precursors, including sinapyl alcohol and coniferyl aldehyde. Therefore, in our study, 15 mg L⁻¹ Pro-Ca showed the most favorable balance between lodging resistance and yield, indicating its potential for further evaluation; however, its agronomic and economic feasibility requires additional investigation before practical recommendation. Full article

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

Litter decomposition regulates the quantity and quality of plant-derived carbon (C) and nitrogen (N) inputs to soil and is closely associated with microbial community structure. However, how elevated ozone (O₃) and nitrogen (N) addition interactively affect residual litter inputs and their associations with soil microbial communities remains poorly understood, especially in agroforestry systems. Here, we conducted a 12-month in situ litter decomposition experiment using two poplar clones (107 and 546) under ambient or elevated O₃ with or without N addition (60 kg N ha⁻¹ yr⁻¹) at an O₃-FACE platform in northern China. Litter mass and chemical traits were measured during decomposition, and endpoint soil microbial community structure was characterized using phospholipid fatty acid (PLFA) profiling. Treatment effects and litter–microbe associations were evaluated using linear mixed-effects models, correlation analysis, and redundancy analysis (RDA). Endpoint litter mass remaining was significantly affected by O₃, clone identity, and their interactions with N addition, while endpoint litter chemical traits showed trait-specific responses. PLFA-derived microbial community indices also showed treatment- and clone-dependent responses, particularly in bacterial groups, AM fungi, and the fungal-to-bacterial ratio. Endpoint litter mass remaining showed the strongest statistical association with PLFA-derived microbial community structure, whereas individual nutrient concentrations showed weaker independent effects. These findings suggest that O₃- and N-induced changes in residual litter quantity and quality are associated with shifts in PLFA-derived microbial community structure. Because PLFA characterizes microbial community structure rather than process rates, these findings should be interpreted as evidence of structural microbial reorganization associated with altered residual litter inputs, rather than direct evidence of changes in C or N cycling rates. Full article

This study aimed to reveal the rhizosphere microbial community structure, carbon–nitrogen–phosphorus (C-N-P) nutrient cycling processes, and functional gene characteristics of Pinus massoniana and Schima superba in mixed forests. Furthermore, we sought to elucidate the microbial mechanisms by which mixed-species afforestation enhances soil quality improvement, providing a theoretical basis in soil microbiology for the cultivation of these mixed forests. The research subjects included pure P. massoniana plantations (CLPs), pure S. superba plantations (CLSs), and individual P. massoniana (HJP) and S. superba (HJS) trees within mixed plantations (HJLs). We collected rhizosphere and bulk soil samples to analyze their physicochemical properties and enzyme activities. Metagenomic sequencing was employed to profile the rhizosphere microbial communities and functional genes involved in C-N-P cycling. Furthermore, by integrating a functional gene co-occurrence network analysis with structural equation modeling (SEM), we systematically elucidated the coupling relationships among the stand types, soil properties, microbial communities, and nutrient cycling. Mixed planting significantly improved soil quality; compared to the CLP and CLS forests, the nitrate nitrogen (NO₃⁻-N) content in the mixed forest soils increased by 121.01% and 120.10% (p < 0.05), and the activity of urease (URE) also significantly increased by 123.99% and 49.56%, respectively. Mixing significantly altered the microbial community structure. In the bacterial community of the mixed forests, the abundance of nitrogen-fixing and potentially phosphorus-solubilizing bacteria from the genera Paraburkholderia and Burkholderia increased. In the fungal community, the arbuscular mycorrhizal fungus Rhizophagus, which possesses a nutrient absorption advantage, exhibited absolute dominance, with its relative abundance ranging from 14.84% to 88.81%. The abundances of genes associated with denitrification and phosphorus starvation regulation were significantly upregulated in the mixed forests; notably, the abundance of phosphorus starvation regulation genes in the HJSs was 18.84% higher than that in the CLSs. A co-occurrence network analysis demonstrated that the proportion of positive correlation edges in the HJP nitrogen cycling network reached as high as 75.0%, and the average degree of the HJS phosphorus cycling network (2.691) surpassed that of the CLSs. The structural equation modeling further revealed that the association strength between the fungi and phosphorus cycling genes in the mixed forests increased to R² = 0.915 (p < 0.01) from R² = 0.213 in the pure forests. This mixed planting practice transforms nutrient cycling from a resource-competitive mode to a microbially synergized mode, thereby forming an efficient endogenous nutrient cycling system. This synergistic rhizosphere microbial effect is a key internal mechanism for overcoming nutrient bottlenecks and should serve as a diagnostic indicator of soil recovery in the ecological restoration of degraded pine forests. Full article

Carbon-based supercapacitors are fundamentally limited by the tortuosity of conventional microporous architectures, which restricts ion transport kinetics and impedes the full utilization of active sites, particularly under high-rate conditions. Herein, we report a molten-salt-assisted topological transformation strategy to fabricate nitrogen-doped hierarchical porous carbon (A-ZC) featuring a distinctive open-windowed hollow architecture. This design effectively mitigates the tortuosity of conventional microporous networks, creating low-resistance pathways that facilitate rapid ion flux and deep electrolyte penetration. Consequently, the symmetric supercapacitor delivers a high energy density of 11 Wh kg⁻¹ at a power density of 250 W kg⁻¹. Moreover, it exhibits outstanding cycling stability, retaining 98.9% of its initial capacitance after 20,000 cycles. By elucidating the correlation between salt-induced microstructural evolution and electrochemical kinetics, this work offers a robust blueprint for overcoming the intrinsic limitations of traditional porous architectures in high-performance energy storage. Full article

Soil degradation, nutrient depletion, and persistent weed pressure represent critical challenges in the adoption of sustainable agriculture practices in subtropical organic farming systems. Reliance on conventional inputs threatens long-term soil health and ecosystem resilience, highlighting the need for regenerative alternatives. Cover crops are widely recognized as multifunctional agroecological tools with the capacity to enhance nutrient cycling, perform weed suppression, and improve soil organic matter. To evaluate their effectiveness in South Florida's subtropical climate and organic raised bed systems, a field experiment was conducted as a Randomized Block Design (RBD) at the Florida International University Organic Garden during the 2024 summer season. The six cover crops species that were tested include green gram (Vigna radiata), hibiscus (Hibiscus sabdariffa), sorghum (Sorghum bicolor), soybean (Glycine max), sunn hemp (Crotalaria juncea), and pearl millet (Pennisetum glaucum). Data collected includes plant establishment, biomass accumulation, weed suppression, soil physiochemical properties, and plant nutrient composition. Sorghum and sunn hemp produced the highest fresh and dry biomass, with sorghum achieving the most effective weed suppression with the lowest weed biomass and weed population. Sunn hemp contributed to enhanced nitrogen content in plant tissues, while hibiscus promoted the highest soil P and N concentrations. Pearl millet exhibited the highest total carbon and organic matter content, indicating potential for enhancing soil carbon content and soil fertility. Results show that each cover crop species can provide a specialized or generalized ecosystem service depending on management goals. Full article

To elucidate the mechanisms of nutrient cycling in rhizosphere soil and microbial metabolism during the prolonged continuous cropping of lavender, this study examined the rhizosphere soil of lavender with different continuous cropping years (1, 4, 7, 10, 15, and 20 years) in the Ili River Valley of Xinjiang, China, measuring physicochemical properties, microbial biomass C/N/P, and eight extracellular enzyme activities. Microbial carbon use efficiency (CUE) and nutrient limitation were quantified using vector analysis, threshold elemental ratios (TERs), and two derived indices (TER_EEA and TER_L). Soil properties exhibited distinct nonlinear patterns: SOC peaked at 4 years (p < 0.05), TN was highest at 20 years, and TP was lowest at 4–7 years. MBC and MBN peaked at 20 years, whereas MBP was significantly lower than in 1-, 4-, and 10-year fields (p < 0.05). EEC and EEN were highest at 20 years, while EEP was lowest at 4 years (p < 0.05). The activity of carbon-related acquisition enzymes increases from 134.81 μmol/g·h in the first year to 393.86 μmol/g·h in the 20th year, an increase of 192%; the activity of nitrogen acquisition enzymes increases from 686.11 μmol/g·h in the first year to 1430.58 μmol/g·h in the 20th year, an increase of 108%. This indicates that the decomposition of organic matter and the nutrient cycling capacity continue to enhance. Vector analysis showed a mean VA of 46° and VL of 0.25, with VA > 45° (P limitation) at 1–4 years shifting to VA < 45° (N limitation) at 20 years. Critically, TEREEA and TERL produced opposite dominant limitations due to differing normalization frameworks—TEREEA scales by microbial biomass stoichiometry—while TERL normalizes against enzyme-derived thresholds. CUET and CUEE ranged from 0.42 to 0.56, with the minimum at 10 years and relatively high values at 15–20 years (p < 0.05). RDA identified CBH (26.2%) and NO₃⁻–N (19.8%) as primary drivers, with extractable phosphorus exhibiting the strongest regulatory effect (pseudo-F = 26.0). These results demonstrate that multi-model stoichiometric assessment is essential, as single indices may yield contradictory diagnoses. These results demonstrate that multi-model stoichiometric assessment is essential, as single indices may yield contradictory diagnoses, and the observed nonlinear shifts in dominant limitation type provide a mechanistic basis for targeted nutrient management in sustainable lavender cultivation. Full article