Search Results (441)

A fungal strain with comparably high chitosan yield was isolated from the Shivaganga hills and identified as Aspergillus versicolor AD07 through molecular characterization. Later, the strain was cultivated on Sabouraud Dextrose Broth (SDB) and wild jackfruit-based media to evaluate its potential for chitosan production. Among the various media formulations, the highest chitosan yield (178.40 ± 1.76 mg/L) was obtained from the jackfruit extract medium with added peptone and dextrose. The extracted chitosan was characterized through FTIR, XRD (reported a crystallinity index of 55%), TGA/DTG, and DSC analysis, confirming the presence of key functional groups and high thermal resistance. The extracted chitosan was fabricated into a sheet incorporated with 1% lemongrass oil; the sheet exhibited strong antibacterial activity against Escherichia coli (30 mm) and Bacillus megaterium (48 mm). The biodegradation studies reported a weight loss of 38.93 ± 0.51% after 50 days of soil burial. Further, the chitosan film was tested as a packaging material for paneer, demonstrating better preservation by maintaining nutritional quality and reducing microbial load over a 14-day storage period. These findings highlight the potential of A. versicolor AD07-derived chitosan, cultivated on a waste substrate medium, as a sustainable biopolymer for food packaging applications. Full article

Leveraging the sensitivity of long-period fiber grating (LPFG) to changes in the environmental refractive index, an LPFG-based seawater concentration monitoring sensor is proposed. Considering the highly saltine and alkali characteristics of the sensor’s operating environment, the proposed sensor is packaged by basalt fiber-reinforced polymer (BFRP), and the sensor’s sensitivities were studied by sodium chloride and calcium chloride solution concentration experiments and one real-time sodium chloride solution concentration monitoring experiment. The test results show the wavelength of LPFG, a 3 dB bandwidth and a peak loss of LPFG’s spectrogram change with changes in the concentration of sodium chloride or calcium chloride solutions, but only the wavelength has a good linear relationship with the change in solution concentration, and the sensing coefficient is −0.160 nm/% in the sodium chloride solution and −0.225 nm/% in the calcium chloride solution. The real-time monitoring test further verified the sensor’s sensing performance, with an absolute measurement error of less than 1.8%. The BFRP packaged sensor has good corrosion resistance and a simple structure, and it has a certain application value in the monitoring of salinity in the marine environment and coastal soil. Full article

The accurate estimation of evapotranspiration ($ET$) and its components are vital for water resource management and irrigation planning. This study models tree transpiration ($T$) and $ET$ for grapefruit, litchi, and mango orchards using light gradient-boosting machine (LightGBM) optimized using the Bayesian hyperparameter optimization. Grounds $T$ and $ET$ for these crops were measured using the heat ratio method of monitoring sap flow and the eddy covariance technique for quantifying $ET$. The Sentinel 2 satellite was used to compute field leaf area index ($LAI$). The modelled data were used to partition the orchard $ET$ into beneficial ($T$) and non-beneficial water uses (orchard floor evaporation—$E_s$). We adopted the 10-fold cross-validation to test the model robustness and an independent validation to test performance on unseen data. The 10-fold cross-validation and independent validation on $ET$ and $T$ models produced high accuracy with coefficient of determination ($R^2$) $\ge$ 0.88, Kling–Gupta efficiency ($KGE$) $\ge$ 0.91, root mean square error ($RMSE$) $\le$ 0.04 mm/h, and mean absolute error ($MAE$) $\le$ 0.03 mm/h for all the crops. The study demonstrates that LightGBM can accurately model the transpiration and evapotranspiration for subtropical tree crops using Sentinel 2 data. The study found that $E_s$ which combined soil evaporation and understorey vegetation transpiration contributed 35, 32, and 31% to the grapefruit, litchi and mango orchard evapotranspiration, respectively. We conclude that improvements on orchard floor management practices can be utilized to minimize non-beneficial water losses while promoting the productive water use ($T$). Full article

Intercropping legumes offers a sustainable approach to enhance resource efficiency and yields, yet the effects of different legume densities and nitrogen addition levels on soil quality within such systems remain unclear. We conducted a comparative analysis of crop yield, nitrogen use efficiency, and soil quality between intercropping and monoculture systems, and further examined the effects of four planting densities (D1: 210 kg ha⁻¹, six rows; D2: 280 kg ha⁻¹, eight rows; D3: 350 kg ha⁻¹, ten rows) and four nitrogen application levels (N0: 0 kg ha⁻¹; N1: 80 kg ha⁻¹; N2: 160 kg ha⁻¹; N3: 240 kg ha⁻¹) within a jujube–alfalfa (Ziziphus jujuba Mill. and Medicago sativa L. respectively) intercropping system. The results showed that intercropping significantly enhanced land productivity within the agricultural system, with the highest yields (alfalfa: 13790 kg ha⁻¹; jujube: 3825 kg ha⁻¹) achieved at an alfalfa planting density of 280 kg ha⁻¹. While the intercropping systems generally improved productivity, an alfalfa planting density of 350 kg ha⁻¹ resulted in an actual yield loss due to excessive nutrient competition at higher densities. As the planting density of alfalfa increased, its competitive ratio declined, whereas the competitive ratio of jujube trees increased. Compared to monocropping systems, intercropping systems demonstrated a clear trend of enhanced nitrogen utilization efficiency and improved soil quality, particularly at an alfalfa planting density of 280 kg ha⁻¹. At an alfalfa density of 280 kg ha⁻¹, the intercropping system exhibited increases of 15.13% in nitrogen use efficiency (NUE), 46.60% in nitrogen partial factor productivity (NPFP), and 32.74% in nitrogen nutrition index (NNI), as well as improvements in soil quality of 19.53% at a depth of 0–20 cm and 15.59% at a depth of 20–40 cm, compared to the monoculture system. Further analysis revealed that nitrogen utilization efficiency initially increased and then decreased with a rising competitive ratio of alfalfa. Accordingly, soil quality was improved along with the enhanced nitrogen utilization efficiency. Thus, at an alfalfa planting density of 280 kg ha⁻¹, resource use efficiency and soil quality were maximized as a result of optimal interspecific competitiveness and the highest nitrogen use efficiency, with minimal influence from the application of nitrogen fertilizer. Full article

As a critical ecologicalbarrier in the semi-arid to semi-humid transition zone of northern China, the interaction between afforestation and climatic stressors in the Yellow River Basin constitutes a pivotal scientific challenge for regional sustainable development. However, the synthesis effects of afforestation and climate on primary productivity require further investigation. Integrating multi-source remote sensing data (2000–2020), meteorological observations with the Standardized Precipitation Evapotranspiration Index (SPEI) and an improved CASA model, this study systematically investigates spatiotemporal patterns of vegetation net primary productivity (NPP) responses to extreme drought events while quantifying vegetation coverage’s regulatory effects on ecosystem drought sensitivity. Among drought events identified using a three-dimensional clustering algorithm, high-intensity droughts caused an average NPP loss of 23.2 gC·m⁻² across the basin. Notably, artificial irrigation practices in the Hetao irrigation district significantly mitigated NPP reduction to −9.03 gC·m⁻². Large-scale afforestation projects increased the NDVI at a rate of 3.45 × 10⁻⁴ month⁻¹, with a contribution rate of 78%, but soil moisture competition from high-density vegetation reduced carbon-sink benefits. However, mixed forest structural optimization in the Three-North Shelterbelt Forest Program core area achieved local carbon-sink gains, demonstrating that vegetation configuration alleviates water competition pressure. Drought amplified the suppressive effect of afforestation through stomatal conductance-photosynthesis coupling mechanisms, causing additional NPP losses of 7.45–31.00 gC·m⁻², yet the April–July 2008 event exhibited reversed suppression effects due to immature artificial communities during the 2000–2004 baseline period. Our work elucidates nonlinear vegetation-climate interactions affecting carbon sequestration in semi-arid ecosystems, providing critical insights for optimizing ecological restoration strategies and climate-adaptive management in the Yellow River Basin. Full article

The increasing demand for reliable food preservation strategies has driven the development of active biopolymer-based films as alternatives to conventional packaging. This study evaluates Nisin/Na-EDTA-enriched alginate and gelatin films for preserving Dosidicus gigas (jumbo squid) during refrigerated storage. Films were formulated using alginate, gelatin 220/280 Bloom, and glycerol, and characterized in terms of their mechanical, optical, and biodegradation properties. Their effectiveness for the preservation of squid fillets was tested, focusing on weight loss and color stability during refrigerated storage. The incorporation of Nisin/Na-EDTA significantly modified the film’s properties: elongation at break increased from 4.95% (alginate control) to 65.13% (gelatin 280 active), while tensile strength decreased from 8.86 MPa to 0.798 MPa (alginate). Transparency was reduced by up to 2.5 times in active agent-incorporated alginate films. All films degraded within 14 days under soil exposure, with polysaccharide-based films degrading faster. In refrigerated storage, squid fillets coated with gelatin–alginate films containing Nisin showed reduced weight loss (24.05%) compared with uncoated controls (66.36%), particularly in skin-on samples. Color parameters and whiteness index were better preserved with gelatin-based coatings. These results demonstrate the potential of gelatin–alginate films with Nisin/Na-EDTA as biodegradable, active packaging to extend the shelf life of high-protein seafood. Full article

Over the past several decades, extensive research has advanced the understanding of liquefaction in clean sands and sand–silt mixtures under seismic loading. However, the influence of plastic (i.e., clayey) fines on the liquefaction behavior of sandy soils remains less well understood. This study investigates how the quantity and plasticity of fines affect both the susceptibility to liquefaction and the resulting failure mode. A series of stress-controlled cyclic triaxial tests were conducted on sand specimens containing varying proportions of non-plastic silt, kaolinite, and bentonite. Specimens were prepared at a constant relative density with fines content ranging from 0% to 37%. Two liquefaction modes were examined: flow liquefaction, characterized by sudden and large strains under undrained conditions, and cyclic mobility, which involves gradual strain accumulation without complete strength loss. The results revealed a clear relationship between soil plasticity and liquefaction mode. Specimens containing non-plastic fines or fines with a liquid limit (LL) below 20% and a plasticity index (PI) of 0 exhibited flow liquefaction. In contrast, specimens with LL > 20% and PI ≥ 7% consistently displayed cyclic mobility behavior. These findings help reconcile the apparent contradiction between laboratory studies, which often show increased liquefaction susceptibility with plastic fines, and field observations, where clayey soils frequently appear non-liquefiable. The study emphasizes the critical role of plasticity in determining liquefaction type, providing essential insight for seismic risk assessments and design practices involving fine-containing sandy soils. Full article

Context: Planting forests is an important strategy to combat biodiversity loss and ecosystem service degradation, but its effects on biodiversity and ecosystem services remain uncertain. Objectives: This study aimed to investigate the restoration of plants along successional and environmental gradients in planted forests by examining how understory plant diversity (species richness, composition, functional diversity), functional diversity—the range of species’ traits influencing ecosystem functions and services and their environmental drivers—evolve in temperate plantations over time. Methods: We examined a total of 36 plots with different stand ages in Chongli District, China, and compared the differences in species richness, biodiversity, composition, and functional diversity across different successional stages and over time. We also analyzed the response mechanisms of species richness and functional diversity to environmental factors at both the local and landscape scales. Results and Discussion: Our results showed species diversity, species richness, and functional diversity tended to increase with time in most plots and stabilized after 45 years. Although species richness was lower in mature plots (>100 years), functional diversity was higher, and species composition was significantly differentiated. This trade-off reflects environmental filtering selecting for competitively dominant species with distinct functional traits, while continuous species turnover prevents compositional convergence. The increase in functional diversity was not directly related to the rise in species richness, but it depended on the relative dominance of several species with different functional characteristics in the ecosystem. Simulation analysis confirmed this pattern aligns with a Simpson’s index-driven trait complementarity mechanism. At the local scale, stand age was the most significant positive factor influencing species richness and functional diversity. Soil total nitrogen and organic matter only negatively affected species richness in interactions. At the landscape scale, landscape heterogeneity plays an important role in restoring functional diversity. Historical afforestation since the 1950s restricted comparisons to secondary forests, lacking primary forest baselines. Conclusions: The results suggest that the effects of the successional stage and multiscale environmental factors should be comprehensively considered in the restoration strategy of restored forests. Full article

Agroforestry (AF) effectively enhances ecological restoration and soil–water conservation (SWC), yet the relationship among soil and water conservation agroforestry (SWCAF) in karst soil, water loss (SWL) and rural eco-revitalization (RER) remains unclear, which may hinder the ecological restoration process around the world. This study aims to reveal whether SWCAF in karst areas improves RER through SWC benefits, ecosystem service (ES) enhancement and rural ecological environment quality (REEQ) improvement. We take Guizhou Province, the core area of the South China Karst (SCK), as the study area and 2010–2020 as the study period. By using the equivalent factor method, the remote sensing ecological index (RSEI) model, bivariate spatial autocorrelation and the panel vector autoregressive (PVAR) model, the study reveals SWCAF’s ecological benefits and its interaction mechanism with RER. Key findings reveal the following: (1) SWCAF reduced the area of SWL by 14.93% by converting cropland into forests. (2) The AF ecosystem service value (AFESV) increased by CNY 9.181 billion, and the forest-related AFESV increases represented 184% of the total AFESV, while REEQ showed an overall positive trend in the western SWC area. (3) The AFESV has an obvious synergistic effect with REEQ (r = 0.60) and obvious positive synergy with SWL (r = 0.69), and its spatial correlation increases over time. (4) The PVAR model verified that there is a bidirectional Granger causal relationship between the AFESV and RER, showing dynamic positive and negative alternating influences. This research study reveals that SWCAF drives RER through the dual path of SWL control and value-added ecological services, among which the forest ecosystem plays a core role. In the future, it is necessary to optimize the diversity of AF structures to avoid ecological service trade-offs. This research study provides a scientific basis for decision making and the ecological management of SWC in karst soils globally. Full article

Flood hazards caused by intense short-term precipitation have led to significant social and economic losses and pose serious threats to human life and property. Accurate disaster risk assessment plays a critical role in verifying disaster statistics and supporting disaster recovery and reconstruction processes. In this study, a novel Large-Scale Flood Risk Assessment Model (LS-FRAM) is proposed, incorporating the dimensions of hazard, exposure, vulnerability, and coping capacity. Multi-source heterogeneous data are utilized for evaluating the flood risks. Soil erosion modeling is incorporated into the assessment framework to better understand the interactions between flood intensity and land surface degradation. An index system comprising 12 secondary indicators is constructed and screened using Pearson correlation analysis to minimize redundancy. Subsequently, the Analytic Hierarchy Process (AHP) is utilized to determine the weights of the primary-level indicators, while the entropy weight method, Fuzzy Analytic Hierarchy Process (FAHP), and an integrated weighting approach are combined to calculate the weights of the secondary-level indicators. This model addresses the complexity of large-scale flood risk assessment and management by incorporating multiple perspectives and leveraging diverse data sources. The experimental results demonstrate that the flood risk assessment model, utilizing multi-source data, achieves an overall accuracy of 88.49%. Specifically, the proportions of areas classified as high and very high flood risk are 54.11% in Henan, 31.74% in Shaanxi, and 18.2% in Shanxi. These results provide valuable scientific support for enhancing flood control, disaster relief capabilities, and risk management in the middle and lower reaches of the Yellow River. Furthermore, they can furnish the necessary data support for post-disaster reconstruction efforts in impacted areas. Full article

Water scarcity in arid regions poses a severe threat to agricultural sustainability, necessitating optimized irrigation strategies. This study investigates the cumulative impacts of long-term irrigation deficits on soil quality, microbial diversity, and maize yield in the arid maize fields of Xinjiang, China, where consistent irrigation patterns have been maintained over multiple years. Seven sites were monitored from April 2023 to March 2024, with a single end-of-cycle sampling in March 2024. Using the Irrigation Water Deficit Index (IWDI), the sites were classified into low (LD, 16.37–22.30%), moderate (MD, 30.54–38.10%), and high drought (HD, 47.49–50.00%) categories. The findings reveal that long-term consistent irrigation deficits exacerbate soil salinization, compaction, and nutrient loss, with organic matter declining significantly under HD conditions. Bacterial richness increased by ~6% under HD, driven by stress-tolerant taxa, while fungal diversity decreased by 14–50%, impairing nutrient cycling functions critical for soil health. The Soil Quality Index (SQI) and maize yield declined with drought severity (LD > MD by 26.18% and 21.05%; LD > HD by 45.02% and 13.13%), highlighting the pivotal role of sustained irrigation patterns in maintaining productivity. These results underscore the need for tailored irrigation management in arid regions, such as precision drip irrigation, to mitigate soil degradation and sustain maize yields, providing a scientific foundation for optimizing water use efficiency in water-scarce agroecosystems under long-term irrigation regimes. Full article

Film mulching and gravel mulching are effective methods for increasing crop yields in Northwest China but exacerbate soil organic carbon (SOC) mineralisation. Manure amendment is a viable method for offsetting carbon (C) losses from mulching. SOC stability is a key factor in determining the nutrient supply capacity of soils, as it affects the C sources available to microorganisms. However, the synergistic effects of film mulching and manure amendment on SOC stability and crop nutrient uptake are still unclear. Therefore, four treatments—no mulching (CK), gravel mulching (GM), film mulching (FM), and film mulching with manure amendment (FCM)—were established on the Loess Plateau. Experiments were conducted to measure plant and grain nitrogen (N), phosphorus (P), potassium (K) uptake, SOC, labile organic C fractions (LOCFs), stability-based organic C fractions (SOCFs), and the C management index (CMI) in 2019 and 2020. The results showed that the FM and FCM treatments significantly improved crop dry matter accumulation in both years compared to the control. The FCM treatment significantly increased the two-year NPK averages of plants to 44.9%, 50.7%, and 54.5% and significantly increased those of grains to 46.7%, 58.2%, and 30.4%. The FCM treatment significantly increased all LOCFs, water solution C (WSC), hot-water-extractable C (HWC), permanganate oxidisable C (POXC), and particulate organic C (POC) in the topsoil (0–20 cm) in both years. The fractions of the active C pool (AP) in the SOCFs, namely, very labile C (C_VL) and labile C (C_L), were significantly increased, suggesting that the FCM treatment significantly decreased C stability in the topsoil. The sensitivity index showed that, among all SOC fractions, POC (21.5–72.9%) and less labile C (C_LL) (20.8–483.8%) were the most sensitive fractions of LOCFs and SOCFs compared to SOC (1.93–35.8%). A random forest analysis showed that most labile C fractions and the CMI significantly contributed to crop N, P, and K uptake, especially POXC to crop N uptake, the CMI to crop P uptake, and the AP to crop K uptake. It was concluded that the FCM treatment synergistically enhanced SOC lability, crop NPK uptake, and labile C fractions, especially POXC, the AP, and the CMI, which serve as robust indicators for guiding precision nutrient management in semi-arid croplands. Full article

This study investigates the impact of climate variability on wheat production in Algeria’s semi-arid interior plains from 2014 to 2024, aiming to curb the challenges of rainfed wheat cultivation, optimize irrigation, and improve water productivity. The Soil–Water–Atmosphere–Plant (SWAP) model-driven approach refined irrigation scheduling to mitigate climate-induced losses and improve resource efficiency. Using historical climate data, soil properties, and wheat growth observations from the experimental farm of the Technical Institute for Field Crops, the SWAP model was calibrated and validated using one-factor-at-a-time sensitivity analysis, achieving a coefficient of determination (R²) of 0.93 and a Normalized Root Mean Squared Error (NRMSE) of 17.75. Two drought-based irrigation indices, Soil Moisture Drought Index (SMDI) and Crop Water Stress Index (CWSI), guided adaptive irrigation strategies, showing a significant reduction in crop failure during drought periods. Results revealed a strong link between rainfall variability and wheat yield. Adopting a 9-day irrigation interval could increase water productivity to 18.91 kg ha⁻¹ mm⁻¹, enhancing yield stability under varying climatic conditions. The SMDI approach maintained soil moisture during extreme drought, while CWSI optimized water use in normal and wet years. This study integrates SMDI and CWSI into a validated irrigation framework, offering data-driven strategies to enhance wheat production resilience. Findings support sustainable water management and provide practical insights for policymakers and farmers to refine irrigation planning and climate adaptation, contributing to long-term agricultural sustainability. Full article

Ginger is an important spice crop in the north-eastern region of India. Rhizome rot, also called soft rot, is one of the most devastating diseases found in ginger that causes yield losses of up to 100% under favourable conditions. Initially, the disease symptoms appear as a light yellowing of the leaf tips that gradually spreads down to the leaf blade of lower leaves and the leaf sheath along the margin. Under favourable environmental conditions, the disease spreads rapidly, potentially causing significant crop damage. The pathogen can infect at any stage of crop growth, and under favourable environmental conditions, the disease spreads rapidly, failing the crop. Current research emphasises mitigating the losses caused by the devastating disease by using management strategies and biocontrol agents (BCAs). Results revealed that the average highest percent rhizome germination, lowest mean disease incidence, lowest mean disease severity index, lowest coefficient of disease index value, highest rhizome yield and benefit–cost ratio were recorded with Trichoderma harzianum (10 g/kg of rhizomes) + soil application of T. harzianum-enriched well-decomposed farm yard manure (3 kg of T. harzianum mixed with 100 kg FYM at 10–15 days before sowing) + soil drenching with T. harzianum at the rate 10 kg/ha, compared to the untreated control. Furthermore, soil chemical properties such as pH, electrical conductivity, soil organic carbon, total available nitrogen, total available phosphorus, and total available potassium play critical roles in rhizome rot disease severity. BCAs can suppress the phytopathogenic fungi and modulate different functions in plants. Full article

This study systematically evaluated the residual behavior of fluxapyroxad (FXP) and mefentrifluconazole (MFZ) in rice–soil systems, alongside their soil and metabolic impacts. Analytical methods validated via linear regression (0.0001–0.05 mg/L) complied with EU guidelines, demonstrating recoveries of 71.97–114.96%, RSDs ≤ 12.12%, and effective mitigation of matrix effects (−85.08% to −76.97%) using matrix-matched calibration. Residual dissipation followed first-order kinetics, with half-lives (T_1/2) spanning 10.83–21.00 d (FXP) and 23.10–57.76 d (MFZ). Notably, MFZ exhibited prolonged persistence in brown rice (T_1/2 = 57.76 d), though final residues (0.031 ± 0.001 μg/g FXP; 0.011 ± 0.0003 μg/g MFZ) remained below regulatory limits (China: 1 mg/kg; CAC: 5 mg/kg). Microbial analysis revealed transient diversity loss in rhizosphere communities (Chao1 index, p < 0.05), recovering by 21 d, while endophytes displayed resilience linked to plant metabolites. Enrichment of degraders (e.g., Sphingomonas) contrasted with suppression of nitrogen-fixing Bradyrhizobium, indicating functional trade-offs. Metabolomic profiling identified 3512 metabolites, with 332 and 173 differentially expressed metabolites at 7 d (S) and 21 d (T), dominated by lipids, benzenoids, and phenylpropanoids. Key metabolic shifts included a 2.11-fold increase in coumarin and elevated L-aspartic acid, highlighting adaptive responses via phenylalanine and TCA cycle pathways. Correlation analyses linked stress-tolerant endophytes (Azorhizobium) to defense-related metabolites (e.g., coumarin), suggesting microbial modulation of plant resilience. These findings emphasize the need for integrated strategies combining residue monitoring, microbial management, and metabolic insights to mitigate agrochemical risks in sustainable agriculture. Full article