Search Results (9,353)

Soil CO₂ emissions are critical for predicting terrestrial ecosystem feedbacks to climate change, yet significant knowledge gaps persist regarding carbon flux dynamics within the deep vadose zone and during freeze–thaw processes. In this study, the Mu Us Sandy Land, a representative seasonally frozen and semi-arid region in Northwestern China, was selected as the research site. Based on in situ observation data and the XGBoost algorithm, the spatiotemporal variations of soil carbon flux and its environmental drivers were investigated. Results revealed distinct depth-dependent patterns, where carbon release reached its maximum flux in the 100–200 cm layer and carbon sequestration dominated the soil layers below 200 cm. Soil temperature and moisture were the primary controlling factors, but their impacts exhibited significant depth and seasonal heterogeneity. Notably, in the 20–50 cm soil layer, soil water content provided the highest explanatory power, reaching 55.3% and 47.8% in winter and summer, respectively. Furthermore, carbon fluxes exhibited distinct response thresholds to environmental factors, and their spatiotemporal variations were fundamentally regulated by an atmosphere-driven coupled water–vapor–heat–carbon process. These findings elucidate the complex relationship between soil carbon fluxes and the environment at different depths, providing theoretical support for deepening the understanding of regional carbon cycling. Full article

Ecological restoration is increasingly applied as an effective strategy for mitigating environmental risks associated with tailings impoundments. However, plant establishment and ecological recovery in tailings substrates are often limited by unfavorable physicochemical properties and potential toxicity. This study investigated the changes in soil microbial community structure and diversity under the synergistic remediation of compound organic fertilizer and plants. Field plots subjected to combined organic fertilizer–plant remediation in a tailings impoundment in northern China were selected. The high-throughput sequencing of bacterial 16S rRNA genes and fungal ITS regions was performed alongside analyses of soil physicochemical properties. Compared to the untreated tailings soil, remediated soils showed pH values closer to neutrality, lower electrical conductivity, and significantly higher organic matter content, indicating an overall reduction in environmental stress and potential toxicity. The relative abundance of copiotrophic bacteria, such as Proteobacteria, increased, whereas that of stress-tolerant taxa adapted to extreme environments, such as Firmicutes , decreased. Although slight variations in dominant groups were observed among plots with different plant species, key microbial groups contributing to soil environmental improvement were largely consistent. These findings demonstrate that this combined remediation effectively improves the physicochemical properties and microbial community structure of tailings soil, providing a risk-oriented and ecologically sustainable strategy for the ecological restoration of similar sites. Full article

Background/Objectives: Antimicrobial agents have revolutionized disease management in humans and animals; however, their misuse and overuse have accelerated the emergence and spread of antimicrobial resistance (AMR) and antimicrobial resistance genes (ARGs). Dairy farms are recognized as potential hotspots for ARG dissemination, particularly through Escherichia coli, which acts as a reservoir and vector of ARGs, enabling their horizontal transfer via plasmids and other mobile genetic elements. This study aimed to characterize the genomic diversity, ARG profiles, plasmid content, and phylogenetic relationships of E. coli isolated from dairy farm environments and milk using whole-genome sequencing. Methods: A total of 31 E. coli isolates recovered from soil, effluent, cow dung, and milk samples underwent deoxyribonucleic acid extraction, library preparation, and sequencing on the Illumina MiSeq platform, followed by comprehensive bioinformatic analysis. Results: The E. coli isolates exhibited 20 distinct sequence types, including one novel sequence type. Plasmids were detected in 71% of the isolates, with the IncF plasmid family being the most predominant. Furthermore, 12 ARG groups were identified, with β-lactam resistance genes detected in 67.7% of isolates. Notably, blaCTX-M genes were identified in all phenotypically confirmed extended-spectrum β-lactamase-producing isolates. Additional ARGs, including those conferring resistance to tetracyclines (tet(A), tetX4), quinolones (qnrS1), aminoglycosides (aph, aad, ant), and folate pathway inhibitors (dfr and sul), were widely distributed throughout the samples. Phylogenetic analysis revealed clustering of isolates from different sample types, particularly among ST58 isolates, suggesting cross-environmental transmission. Conclusions: This study demonstrates that E. coli from dairy farm environments harbor diverse ARGs and plasmids, confirming their role as reservoirs of AMR. These findings underscore the importance of prudent antimicrobial use, routine genomic surveillance, and enhanced biosecurity measures to limit cross-environmental transmission. Full article

Drought is a major constraint on crop productivity, and microbial inoculants are increasingly explored to mitigate plant water stress. However, most inoculant discovery pipelines rely on trait-based screening performed outside the ecological context in which beneficial plant-microbe interactions naturally arise. In natural soils, drought-exposed plants can reshape the rhizosphere environment by altering carbon allocation and root exudation, thereby selectively recruiting microorganisms compatible with water-limited conditions and effectively performing an ecological pre-selection. Here, we captured this process during early seedling establishment and leveraged drought-driven rhizosphere recruitment as a nature-guided strategy to nominate bacterial inoculant candidates. Tomato seedlings were grown in natural agricultural soil microcosms under well-watered and drought-stressed regimes, and cultivable bacteria were comparatively isolated from rhizosphere and bulk soil fractions. Recruitment-prioritized isolates were subsequently characterized through biochemical assays and genome-informed analyses to provide functional and taxonomic context and were evaluated in early inoculation assays under water stress. Drought-recruited isolates displayed distinct plant-associated responses, and genome-scale taxonomy indicated that one drought-associated isolate represents a genomically distinct lineage within the genus Paracoccus. Together, these findings highlight drought-driven rhizosphere recruitment as an ecologically grounded framework for identifying stress-compatible bacterial candidates and uncovering previously undescribed rhizosphere diversity. Full article

In livestock-grazed pastures, urine patches are a major contributor of nitrous oxide (N₂O) emissions, and the use of nitrification inhibitors (NIs) has the potential to reduce N losses from urine patches using New Zealand (NZ)-devised Spikey^®—a ground-based machine that measures the change in soil conductivity from the deposited urine patches. Our ongoing research suggests that the efficacy of on-farm targeted NIs treatment requires suitable inhibitor concentrations within urine patches to be achieved to reduce N₂O emissions. This study evaluates the effect of varying NI rates and volumes on reducing N₂O emissions. The application rates for NIs were 1.6 g and 3.2 g dicyanamide (DCD) patch-1 and 0.96 g and 1.92 g of 3, 4-dimethylpyrazole phosphate (DMPP) patch⁻¹, using 100, 150, and 200 mL inhibitor solutions. These rates were higher than those used in previous studies to ensure an adequate supply of inhibitors above the threshold concentration within the urine patch and to enhance the inhibitor efficacy in reducing N₂O emissions. This study points to two important aspects: Determine the optimum inhibitor concentration required to eliminate, minimise/reduce N₂O emissions and ensure that at the optimised amounts of inhibitor application rates, inhibitor residues are below their maximum residue level (MRL) in the food chain and environment, and eliminate their potential harm to human health. Full article

Sustainable spatial development requires land-use allocation that aligns with reflects the environment’s biophysical capacity. However, rapid urbanization and agricultural expansion often result to spatial mismatches between land utilization and land capability, the reby increasing environmental degradation and disaster vulnerability. East Java Province, one of Indonesia’s most densely populated regions, has experienced significant land-use transformation driven by demographic pressure and economic development. This study aims to evaluate the environmental carrying capacity by assessing the spatial compatibility among land capability, existing land use, and the Provincial Spatial Plan (RTRWP) using a Geographic Information System (GIS)-based analytical approach. Land capability was determined based on key biophysical parameters, including slope gradient, soil texture, drainage conditions, erosion susceptibility, effective soil depth, and flood hazard. Spatial overlay analysis was employed to identify areas of conformity and mismatch between land capability and both current and planned land uses. The results indicate that only approximately 52% of the provincial area is utilised in accordance with its land capability. In comparison, the remaining 48% exhibits varying degrees of spatial mismatch. Erosion is identified as the dominant limiting factor, affecting more than 43% of the region, particularly in mountainous and hilly landscapes. Furthermore, over 60% of East Java falls within Land Capability Classes III–VII, indicating moderate to severe environmental constraints on limitations intensive land use. High levels of spatial mismatch are concentrated in the southern upland districts—such as Pacitan, Trenggalek, southern Malang, and Lumajang, which are highly susceptible to landslides, as well as in the northern lowland corridor, including the Surabaya–Gresik–Sidoarjo metropolitan region, which faces a significantly flood risk. These findings suggest that land-use practices exceeding environmental carrying capacity substantially amplify disaster risk. Therefore, integrating land capability assessment into spatial planning and zoning regulations is essential and for promoting ecosystem-based disaster risk reduction and achieving sustainable spatial development in East Java Province. Full article

Detection of brown spot needle blight (BSNB) disease caused by the fungal pathogen Lecanosticta acicola (Thum.) Syd. has increased significantly at commercial loblolly pine (Pinus taeda L.) plantations across the southeastern United States in recent years. Historically, it has been a serious problem in longleaf pine (Pinus palustris Mill) during the grass stage of seedlings, when the environment is more conducive to fungal infection. However, since 2016, confirmed cases of the disease on loblolly pines have increased in several states, including AL, AR, FL, GA, LA, MS, SC, TN, and TX. We investigated the distribution pattern of confirmed cases of BSNB on loblolly pine between 2016 and 2023, identified site-specific factors, and evaluated the historical standardized precipitation index (SPI) value record over the past four decades. Our results showed that extended periods of above-normal SPI values are associated with BSNB spatial distribution patterns, particularly where the disease has been widely reported in AL, AR, LA, and MS. We observed significant reduction in tree height and dbh in severely infected versus healthy trees at the six study sites evaluated in 2023. Excessive rainfall and prolonged water saturation associated with historical 5-Year SPI values suggest that vulnerable loblolly pine seedlings (depending on genetic family) are more likely to be predisposed to L. acicola infection due to persistent stress from reduced soil nutrient flux and other physiological processes of the host. Understanding the effect of precipitation patterns on cases of BSNB is an important step toward preventing or minimizing the future impact of the disease on commercial plantations in the Southeast. Full article

Urban green infrastructure plays a crucial role in enhancing environmental resilience in cities, particularly in arid regions characterized by water scarcity, soil salinity, and high climatic stress. However, arid coastal cities remain insufficiently studied with regard to spatially explicit assessments of the structure and dynamics of green infrastructure. This study evaluates the state and spatial organization of urban green infrastructure in Aktau, Kazakhstan, over the period 2015–2025, with the most recent satellite observations obtained in June 2025. Sentinel-2 satellite imagery was used to calculate seasonal Normalized Difference Vegetation Index (NDVI) and Soil-Adjusted Vegetation Index (SAVI) values, and zonal statistics were applied to assess intra-urban differentiation across functional zones. In addition, inventory-based indicators—Green Planting Density (GPD), Structural Composition of Greenery (SCG), and Protective Green Infrastructure (PGI)—were integrated to complement the remote sensing analysis. The results indicate a moderate overall increase in mean NDVI values (from 0.21 to 0.28), with the most significant growth observed in central and coastal areas (ΔNDVI = +0.12; ΔSAVI = +0.21), while industrial and newly developed zones exhibit only limited changes. Despite these localized improvements, the spatial configuration of green infrastructure remains fragmented, reflecting a persistent center–periphery asymmetry in urban greening. These results underline the importance of irrigation practices and spatially targeted greening strategies for improving vegetation conditions in arid urban environments. The proposed integrated approach combining satellite-derived vegetation indices and inventory-based indicators can serve as a useful tool for monitoring urban green infrastructure and supporting evidence-based planning in arid coastal cities. Full article

Returning organic amendments to saline–alkali soils constitutes a key strategy for soil amelioration, as it enhances crop productivity by modulating the rhizosphere microenvironment. In this study, straw, biochar, and peat were selected as representative organic amendments, and a two-year field experiment—employing a rotational cropping system of Sesbania and Triticale—was conducted to investigate their differential regulatory effects on rhizosphere properties and root development. Results demonstrated that all three amendments induced coordinated shifts in the rhizosphere “extract–microbiota–enzymes–nutrients” nexus, concomitant with significant stimulation of root growth. The hypothesized pathways through which different organic amendments improve the rhizosphere environment vary mechanistically: straw application appears to enhance alkaline phosphatase activity and enrich phosphorus-solubilizing microorganisms; it is hypothesized that this promotes root growth by facilitating the mineralization of organic phosphorus. In contrast, peat amendment induces the most pronounced increases in esterase content and sucrase activity, and its growth-promoting effect is likely attributable to accelerated carbon and phosphorus cycling. Biochar, meanwhile, is associated with elevated catalase activity, improved potassium retention, and enhanced organic carbon sequestration; its beneficial function is postulated to stem from mitigation of oxidative stress. Collectively, this study provides initial evidence that distinct organic amendments modulate rhizosphere processes via divergent biochemical and microbial mechanisms—offering a theoretical foundation for their rational selection and application in saline–alkali soil remediation. Full article

Lubricating oil (LO) is manufactured in various formulations for different applications. The inappropriate disposal of petroleum hydrocarbons can increase soil contamination, promoting deleterious environmental and human health impacts. More specifically, following prolonged exposure, LO contaminants are known to have carcinogenic and neurotoxic effects in humans. Bioremediation provides an effective and attractive strategy to expedite the clean-up processes of LO contaminants. We isolated and identified environmentally adapted strains of Pseudomonas aeruginosa, Pseudomonas putida, and Proteus vulgaris from Houston watershed bayou soils. Interestingly, all three exhibited increased resistance, vis-a-vis surrogate strains, to various antibiotic challenges (of chloramphenicol, tetracycline, kanamycin, penicillin, streptomycin, etc.) and increased biofilm formation ranging from 1.6 to 6.7-fold. In fact, all three environmental strains were significantly better at producing enhanced biofilm formation in the presence of spent LO rather than clean LO as well as outproducing biofilm made by the surrogate strains. Finally, the environmental isolates P. aeruginosa, P. putida, and P. vulgaris demonstrated an enhanced ability to sequester clean (2-, 2.5- and 1.14-fold) and spent (1.4-, 1.5, and 1.2-fold) LO when compared to their commercially acquired surrogate reference strains. Our three environmentally isolated organisms from Houston watershed soils appeared to be environmentally adapted to tolerate LO exposures. In the presence of LOs, all three environmentally isolated strains exhibited enhanced growth, enhanced biofilm production, and improved bioaccumulation of LOs relative to commercial reference strains. Taken together, environmentally adapted organisms can promote the bioremediation of contaminants threatening our environment and, potentially, human health. Full article

Secondary salinization in mulched drip-irrigated cotton fields of arid oasis–desert transition zones in Xinjiang imposes coupled root-zone constraints, including salt-induced aggregate structural degradation and ionic stress. However, field evidence remains limited on whether integrating a structure-oriented soil conditioner with humic acid can generate stable improvements across growing seasons. A two-year field experiment with a randomized block design (three replicates) was conducted to evaluate four treatments: control (CK), polyacrylamide (PAM, 30 kg ha⁻¹), humic acid (HA, 450 kg ha⁻¹), and PAM + HA. Soil physical and chemical properties and aggregate-size distribution were determined after harvest, while enzyme activities and root traits were assessed at the flowering–boll stage. Structural equation modeling (SEM) and random forest (RF) analysis were used to explore soil–root–yield linkages and identify key soil predictors associated with yield variation. Treatment effects were most evident in the 0–20 cm layer, with PAM + HA showing the greatest overall improvement. In the topsoil, PAM + HA lowered soil pH from 8.35 to 7.88 in 2024 (p < 0.05), increased soil organic carbon (SOC) to 4.29 g kg⁻¹ in 2025 (p < 0.01), and increased NO₃⁻–N to 25.51 and 30.27 mg kg⁻¹ in 2024 and 2025, respectively (both p < 0.05). PAM + HA also enhanced cellulase activity from 6.17 to 16.85 mg glucose g⁻¹ 72 h⁻¹ in 2024 and increased seed cotton yield to 6683.69 and 5996.89 kg ha⁻¹ in 2024 and 2025, with a 51.0% yield increase over CK in 2024. SEM showed that root development had the strongest direct positive effect on yield (β = 0.79, R² = 0.63; goodness of fit (GOF) = 0.74), while random forest identified alkaline phosphatase, cellulase, and NO₃⁻–N as the main yield predictors (out-of-bag R² (OOB R²) = 0.672, p = 0.01). This study elucidated the effects of the combined application of a structure-oriented soil conditioner and humic acid on the root-zone environment of mulched drip-irrigated cotton fields in arid regions, providing a theoretical basis for the coordinated regulation of soil structural improvement and nutrient activation in saline–sodic cotton fields. Full article

The widespread utilization of synthetic dyes within the textile industry, driven by their chemical recalcitrance and diverse chromatic spectra, constitutes a significant global environmental challenge. Improper discharge of these highly stable effluents into natural water bodies leads to severe ecological imbalances, affecting aquatic life and soil integrity while posing indirect risks to human health due to their mutagenic potential. Conventional physicochemical treatment methods are often hindered by prohibitive operational costs and the frequent generation of hazardous secondary pollutants. Consequently, there is an urgent demand for sustainable biotechnological alternatives to mitigate these industrial impacts. Bioremediation, specifically using white-rot fungi, represents a robust and eco-friendly strategy for the degradation of complex aromatic structures. Species such as Trametes versicolor, Pleurotus ostreatus, and Phanerochaete chrysosporium utilize a specialized extracellular enzymatic complex to mineralize toxic compounds effectively. Here we review the ligninolytic capacity of white-rot fungi and their specialized enzymatic systems for environmental sustainability. The primary points are: (i) the biochemical mechanisms of the ligninolytic system of laccases and peroxidases during dye degradation; (ii) the influence of operational parameters such as pH, temperature, and nutrient availability on fungal metabolic efficiency; (iii) the diverse environmental applications of these microorganisms in treating real textile effluents; (iv) the current biotechnological challenges, including maintaining enzymatic stability in non-sterile industrial environments; and (v) the future perspectives for scaling up fungal treatment systems from laboratory research to large-scale industrial implementation. Full article

Soil degradation poses a serious threat to the sustainability of global agricultural development, endangering the foundation and environment of human survival. Therefore, elucidating the effects of different agricultural production patterns on the quality and health of paddy soils is of great significance. To investigate the impact of the integrated rice-red swamp crayfish farming on paddy soil health, this paper systematically analyzed the differences in 19 soil physicochemical indicators and bacterial and eukaryotic microbial communities between the traditional rice monoculture (TRM) and integrated rice-red swamp crayfish (Procambarus clarkii) farming (IRPF), and it features a comprehensive quantitative assessment of paddy soil health status through Principal Component Analysis based on a minimum dataset. The experimental results showed that IRPF significantly increased the soil aggregate mean weight diameter, total phosphorus, available potassium, cation exchange capacity, pH, available zinc, and available silicon contents. Meanwhile, IRPF exerted marked effects on the beta diversity and composition of both bacterial and eukaryotic microbial communities, markedly enhancing the relative abundances of Bacillariophyta and Chlorophyta in the paddy soil. The integrated analysis of 19 soil physicochemical indicators along with bacterial and eukaryotic microbial community parameters revealed that the Soil Health Index under IRPF was obviously higher than that under the rice monoculture. In conclusion, the integrated rice-red swamp crayfish farming system markedly impacted the soil fertility, effectively improved soil aggregate structure and enhanced the overall paddy soil health status, representing a promising and sustainable agricultural production pattern within a single production cycle. Full article

The management of Culex pipiens (Diptera: Culicidae), key vectors of arboviruses like West Nile virus, necessitates sustainable alternatives to chemical insecticides. This study screened indigenous entomopathogenic fungi (EPF) from forest soils in Achaia, Greece, for their larvicidal efficacy against Cx. pipiens biotype molestus. Fifteen fungal isolates were obtained via insect baiting and identified as Beauveria and Metarhizium species. A comprehensive bioassay at 1 × 10⁸ conidia mL⁻¹ revealed significant variation in pathogenicity after 72 h. Two isolates, Beauveria bassiana (BB) (Hypocreales: Cordycipitaceae) and Metarhizium anisopliae (K3(1)) (Hypocreales: Clavicipitaceae), exhibited the highest virulence among the tested isolates, each causing 60% mortality with a rapid median lethal time (LT₅₀) of ~18.5 h. Survival analysis, Cox modeling, and non-linear kinetic modeling (Gompertz/Richards) classified three distinct virulence clusters: high/rapid, moderate/consistent, and low/delayed. A pathogenicity network analysis and a composite virulence index further validated BB and K3(1) as the most effective candidates. These results demonstrate the high isolate specificity of fungal efficacy and underscore the importance of screening local fungal diversity. The identified high-virulence isolates represent promising, environmentally sound candidates for the development of targeted biopesticides. Future research should focus on formulation for aquatic environments and integration into resistance-resilient integrated vector management programs. Full article

The increasing accumulation of microplastics (MPs) in soils necessitates a better understanding of their effects on soil chemistry and trace element behavior. This study examined the influence of three MPs—low-density poly(ethylene) (LDPE), polypropylene (PP), and poly(ethylene terephthalate) (PET)—on cadmium (Cd) and copper (Cu) mobility in four clayey–sandy soils with similar organic matter content but differing pH, representing acidic and alkaline terrestrial matrices. Soils were incubated with 1% (w/w) MPs at 60% water-holding capacity for 30 and 90 days. Total Cd and Cu concentrations remained largely unaffected; however, time-dependent changes in metal availability and distribution were observed. Extractability (CaCl₂ and DTPA), sequential BCR fractionation, and environmental risk indices (CF, Igeo, RAC, MF, and PLI) indicated slight increases in Cd availability after 30 days, which became more pronounced after 90 days, particularly in acidic soils (pH 5.5). The magnitude of the MP effect followed the trend PET > PP > LDPE in all cases. Among the two target metals, Cd exhibited substantially higher mobility than Cu, as reflected by RAC and MF values. Specifically, Cd RAC (6–35%) and Cd MF (28–63%) values were considerably higher than those of Cu (1.1–3.8% and 15–28%, respectively). Overall, although the general pollution indices remained relatively stable, MPs altered the extractability and geochemical partitioning of the examined heavy metals—particularly Cd—indicating their potential role as vectors in soil environments. These results demonstrate that incubation time, polymer type, and soil pH jointly regulate MP-induced change in Cd and Cu mobility, with important implications for soil ecosystem risk. Full article