Search Results (1,096)

Assessing fish biodiversity is essential for freshwater ecosystem conservation. This study compares environmental DNA (eDNA) metabarcoding and traditional morphological surveys to investigate fish communities in the Gaya River, China. A total of 42 fish species were identified, with 13 detected only by eDNA, 7 exclusively by morphology, and 11 by both methods. A comparative analysis of species composition, functional diversity, and phylogenetic diversity revealed significant differences between the two approaches. Notably, eDNA data indicated higher phylogenetic diversity (PD), while morphological surveys captured greater functional evenness (FEve). Multivariate analyses indicated that total phosphorus (TP), total suspended solids (TSS), electrical conductivity (EC), temperature (T), and pH significantly influenced fish community composition, while dissolved oxygen (DO) was a key driver of species richness (SR), functional richness (FRic), and PD. These findings highlight the methodological differences and complementary strengths of eDNA and morphological approaches in biodiversity assessments. By providing comparative insights into fish diversity patterns, this study underscores the importance of using multi-method approaches to improve freshwater biodiversity monitoring and conservation strategies. Full article

Optimal application of nitrogen fertilizer is critical for soil characteristics and soil health. This study examined the effects of three rates of nitrogen fertilizer applications, which are lower rate (Treatment 1 (T1)-241 kg/ha), recommended rate (Treatment 2 (T2)-269 kg/ha), and higher rate (Treatment 3 (T3)-297 kg/ha), and their impacts on soil temperature, soil moisture and soil electrical conductivity at two different depths (0–30 cm and 30–60 cm) in maize cultivation at the Prairie View A & M university research farm in Texas. Soil moisture, soil temperature, and electrical conductivity (EC) sensors were installed in 27 plots to collect these data. Results showed that EC is lower at surface depth with all fertilizer application rates than at root zone soil depths. In the meantime, EC is increasing in the root zone soil depth with the increase in fertilizer rate. This study indicated that the moderate application (269 kg/ha, T2) which is also recommended rate, showed better soil health parameters and efficiency in comparison to other application rates maintaining stable and moderate electrical conductivity values (0.2 mS/cm at depth 2) and the highest median moisture content at the significant root zone depth (about 0.135 m³/m³), reducing nutrient leaching and salt accumulation. Also, a humid, warm climate in southern Texas specifically affects increasing nitrogen losses via leaching, denitrification, and volatilization compared to cooler regions, which requires higher application rates. Plant growth and yield results further confirmed that the recommended rate achieved the greatest plant height (157.48 cm) compared to T1 (153.07 cm). Ear diameters were also higher at the recommended rate, reaching 4.65 cm ears than in Treatment 3. However, grain productivity was highest under the lower fertilizer rate T1, with wet and dry yields of 11,567 kg/ha and 5959 kg/ha, respectively, compared to 10,033 kg/ha (wet) and 5047 kg/ha (dry) at T2, and 7446 kg/ha (wet) and 4304 kg/ha (dry) at T3. These findings suggest that while the moderate fertilizer rate (269 kg/ha) enhances soil health and crop growth consistency, the lower rate (241 kg/ha) can maximize productivity under the humid, warm conditions of southern Texas. This research highlights the need for precise nitrogen management strategies that balance soil health with crop yield. Full article

The Songnen Grassland, a typical saline–alkali ecosystem in Northeast China, is increasingly degraded by soil salinization. Arbuscular mycorrhizal fungi (AMF) are critical for enhancing plant tolerance to saline–alkali stress via root symbiosis. To investigate the species diversity and community structure of AMF in the rhizosphere of salt-tolerant plants in the Songnen Grassland, this study combined morphological identification with high-throughput sequencing (based on virtual taxa, VTs, from the MaarjAM database) to analyze the composition and distribution characteristics of AMF in the rhizosphere of eight salt-tolerant plant species, including Arundinella anomala, Leymus chinensis, Taraxacum mongolicum and others. Morphological identification revealed a total of 22 AMF species belonging to 7 genera. Among these, the genus Glomus was the dominant genus, comprising eight species (accounting for 36.4% of the total species), followed by the genus Acaulospora (five species, 22.7%), the genus Rhizophagus (four species, 18.2%), the genus Ambispora (two species, 9.1%), and the remaining genera each represented by one species (4.5%). High-throughput sequencing analysis identified a total of 40 virtual taxa (VTs) with clear taxonomic assignments belonging to six genera. The genus Glomus accounted for the highest proportion (34 VTs, 85%) with a relative abundance of 89.33%, representing the overwhelmingly dominant group. Rhizosphere soil electrical conductivity (EC) of the eight plant species indicated a significant gradient (high EC group: A–D and G, 2.07–2.61 mS/cm; low EC group: E, F, H, 0.20–0.48 mS/cm). The AMF diversity in the high EC group was significantly higher than that in the low EC group, indicating that AMF in the rhizosphere of salt-tolerant plants enhanced plant tolerance to high-salt environments, and their diversity did not decrease with increasing salinity but instead remained at a high level. Plant-specific AMF community characteristics were evident. Hierarchical clustering analysis further confirmed that the AMF community composition in the rhizosphere of Taraxacum mongolicum and Vicia amoena differed significantly from that of the other plant species, indicating that plant species have a key driving role in AMF community structure. These findings provide critical insights into the plant–AMF symbiotic mechanisms underlying saline–alkali adaptation and offer a theoretical basis for selecting efficient AMF strains to support ecological restoration of saline–alkali lands. Full article

The accurate assessment of soil fertility is critical for guiding nutrient management and promoting sustainable agriculture in semi-arid agroecosystems. In this study, a machine learning-based Soil Fertility Index (SFI) model was developed using regularized regression techniques to evaluate fertility across a dryland maize-growing region in southeastern Türkiye. A total of 64 composite soil samples were collected from the Batman Plain, characterized by alkaline and salinity-prone conditions. Five soil chemical indicators, electrical conductivity (EC), pH, organic matter (OM), zinc (Zn), and iron (Fe), were selected for SFI estimation using a standardized rating approach. The dataset was randomly split into training (80%) and test (20%) subsets to calibrate and validate the models. Ridge, Lasso, and Elastic Net regression models were employed to predict SFI and assess variable importance. Among these, the Lasso model achieved the highest predictive accuracy on test data (R² = 0.746, RMSE = 0.060), retaining only EC and Zn as significant predictors. Ridge and Elastic Net captured OM and pH, though their contributions were minimal (|β| < 0.01). Spatial predictions showed moderate alignment with observed SFI values (range: 0.48–0.76), but all models underestimated high-fertility zones (>0.69), likely due to coefficient shrinkage. Despite its simplicity, the Lasso model offered superior interpretability and spatial resolution. The results reveal the potential of interpretable machine learning for supporting sustainable, site-specific fertility assessment and informed nutrient management in data-scarce and environmentally vulnerable regions. Full article

Plant Growth Promoting Rhizobacteria, PGPR, can protect plants against soil-borne diseases and abiotic stress conditions. The primary objective of this study was to evaluate the effects of different PGPRs (TF1, TF2, TF3, and TF4) on the rhizosphere microbial community of silage maize in a saline–alkaline field via Illumina MiSeq high-throughput sequencing technology. Results demonstrated that different PGPRs significantly increased the harvest density (by 21.31–45.16%), plant height (by 9.12–19.98%), stem diameter (by 30.07–45.78%), and biomass (by 33.20–65.36%) of silage maize, TF3 treatment significantly increased the fresh weight (by 32.50%), while the other treatments could increase the fresh weight but not significantly. Four microbial agents significantly reduced the contents of soil available phosphorus (AP), electrical conductivity (EC), and neutral phosphatase activity (NPA), while significantly increasing the contents of available potassium (AK), ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃⁻-N), chitinase activity (ChtA), and urease activity (UA). Specifically, TF2 and TF3 treatments significantly decreased the soil pH value, while not for TF1 and TF4. Microbiome analysis showed that four microbial agents significantly increased the relative abundances of beneficial microorganisms, such as Arthrobacter, Blastococcus, MNDI, Chaetomidium, Alternaria, Sarocladium, Acremonium, and Clonostachys, and significantly decreased the relative abundances of Gibberella and Fusarium. Mental analysis showed that the soil bacterial community structure did not significantly correlate with soil biochemical properties, while the soil fungal community structure significantly and positively correlated with pH. Maize yield significantly and positively correlated with NH₄⁺-N, OM, AP, EC, UA, ChtA, and NPA. Full article

Hemp stalk, a widely available agricultural waste, is an ideal eco-friendly raw material for biochar production. Carbonization experiments were conducted as a novel approach for the scalable and value-added utilization of hemp stalk under oxygen-exclusion conditions. The effects of feedstock types—Hibiscus cannabinus (KS), Corchorus spp. (JS), and Boehmeria spp. (RS)—and pyrolysis temperatures on biochar properties were analyzed through the measurements of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy. The pH and electrical conductivity (EC) of biochars increased with increasing pyrolysis temperature. Notably, EC was significantly higher for RS (940–2278 μS/cm) than for KS (517–879 μS/cm) and JS (583–863 μS/cm). The C content in these three biochars increased as the temperature increased, whereas the H/C atomic ratio decreased, most notably in JS (by 0.33%). According to FTIR and XRD data, with the pyrolysis temperature increasing, the acidic oxygen-containing groups on biochar surfaces reduced. KS700, with superior aromatic structure and stability, may be able to effectively adsorb heavy metal ions. RS700, with relatively high pH and EC, was suitable for alleviating soil acidification and nutrient deficiency. The feedstock and pyrolysis temperature significantly affected the element content, pore structure, and stability of biochars derived from hemp stalk. Full article

Forest litter plays a critical role in regulating the water balance of forest ecosystems, particularly in semi-arid regions where hydrological stability is under pressure due to climate change. This study investigates the maximum water holding capacity (MWHC) of litter layers across three ecologically distinct regions in Türkiye—Kastamonu, Kütahya, and Muğla—to evaluate how structural and physicochemical characteristics influence the maximum water holding capacity (MWHC) of litter layers. Litter samples classified into humus, fermenting debris, and needles were analyzed for MWHC, pH, electrical conductivity (EC), and total dissolved solids (TDSs). The results revealed that both the type of litter and regional ecological conditions significantly affect MWHC, with humus layers and moist environments exhibiting the highest water holding capacity. Additionally, MWHC showed moderate positive correlations with EC and TDS, highlighting the importance of chemical composition in water dynamics. The findings underscore that forest litter should be regarded as a dynamic and functional hydrological component, not merely residual biomass. This perspective is vital for sustainable watershed planning and adaptive forest management. The study supports the development of integrated management strategies aligned with the United Nations Sustainable Development Goals (SDGs), particularly SDG 6 (Clean Water and Sanitation), SDG 13 (Climate Action), and SDG 15 (Life on Land). Full article

Groundwater is essential for irrigated agriculture, yet its use remains unsustainable in many regions worldwide. In countries like Pakistan, the situation is particularly pressing. The irrigated agriculture of Pakistan heavily relies on groundwater resources owing to limited canal-water availability. The groundwater quality in the region ranges from good to poor, with the lower-quality water adversely affecting soil structure and plant health, leading to reduced agricultural productivity. The delineation of quality zones with respect to irrigation parameters is thus crucial for optimizing its sustainable use and management. Therefore, this research study was carried out in the Lower Chenab Canal (LCC) irrigation system to assess the spatial distribution of groundwater quality. The geostatistical analysis was conducted using Gamma Design Software (GS+) and the Kriging interpolation method was applied within a Geographic Information System (GIS) framework to generate groundwater-quality maps. Semivariogram models were evaluated for major irrigation parameters such as electrical conductivity (EC), residual sodium carbonate (RSC), and sodium adsorption ratio (SAR) to identify the best fit for various Ordinary Kriging models. The spherical semivariogram model was the best fit for EC, while the exponential model best suited SAR and RSC. Overlay analysis was performed to produce combined water-quality maps. During the pre-monsoon season, 17.83% of the LCC area demonstrated good irrigation quality, while 42.84% showed marginal quality, and 39.33% was deemed unsuitable for irrigation. In the post-monsoon season, 17.30% of the area had good irrigation quality, 44.53% exhibited marginal quality, and 38.17% was unsuitable for irrigation. The study revealed that Electrical Conductivity (EC) was the primary factor affecting water quality, contributing to 71% of marginal and unsuitable conditions. In comparison, the Sodium Adsorption Ratio (SAR) accounted for 38% and Residual Sodium Carbonate (RSC) contributed 45%. Therefore, it is recommended that groundwater in unsuitable zones be subjected to artificial recharge methods and salt-tolerated crops to enhance its suitability for agricultural applications. Full article

This study investigates the adsorption behavior of 4-methylbenzylidene camphor (4-MBC), a persistent ultraviolet filter, onto microplastic fibers (MPFs) released from domestic textiles, under environmentally relevant conditions. Two types of MPFs were used: MPF A, a heterogeneous blend of synthetic and natural fibers, and MPF B, a uniform polyester source. Adsorption experiments were conducted in municipal wastewater, Danube River surface water, and laundry effluent. Kinetic data best fit the pseudo-second-order model (R² > 0.95), and the Elovich model indicated chemisorption involving heterogeneous binding sites. MPF A exhibited superior adsorption capacities (qₑ = 85.4–90.1 µg/g) compared to MPF B (58.8–66.8 µg/g). Langmuir isotherms yielded maximum adsorption capacities of 204.9 µg/g for MPF A and 116.7 µg/g for MPF B (R² = 0.929–0.977), while D–R isotherm energies (12.0–21.7 kJ/mol) confirmed specific interactions, such as π–π stacking and hydrogen bonding. Adsorption efficiency was highest in municipal wastewater (total organic carbon—TOC = 13.12 mg/L, electrical conductivity—EC = 1152 µS/cm), followed by laundry and surface waters. These findings emphasize the critical role of polymer composition and matrix complexity in pollutant transport, suggesting MPFs are effective transporters of hydrophobic micropollutants in aquatic systems. Full article

The vital role of arbuscular mycorrhizal (AM) fungi in tea plant growth is well established; however, the mechanisms underlying how increasing cultivation chronosequence (CC) influences AM fungal distribution remain unclear. An investigation was conducted to investigate the temporal dynamics of AM fungal indices and soil properties across a 100-year tea CC (10-, 30-, 60-, and 100-year CC) in Xinyang Maojian tea (Camellia sinensis L.) plantations (Xinyang, Henan Province, China). Principal coordinate analysis was conducted to reveal the significant reorganization of AM fungal indices during early-to-mid stages (PCoA1: 89.2%, p < 0.05), with triphasic development. Mycorrhizal colonization (MC), hypha biomass (hypha), and spore density (SD) surged by 100% during 10–30 years; SD peaked at 60 years (164 spores g⁻¹) before declining, while glomalin-related soil protein (GRSP) accumulated significantly only at 100 years (p < 0.05). Concurrently, soil acidification (pH decreased from 6.37 to 4.84) and phosphorus depletion (AP from 119.6 mg kg⁻¹ to 32 mg kg⁻¹) intensified by 60 years, contrasting with the significant accumulations of soil organic organisms (SOM) (from 10.6 g kg⁻¹ to 36.4 g kg⁻¹), electrical conductivity (EC) (from 0.019 to 0.050 mS·cm⁻¹), and microaggregate accumulation (MAR) (from 25.8% to 40.3%) during the period. The linear regression model was performed to validate the significant effects (p < 0.05) of CC on the AM indices (MC, SD, hypha, and GRSP) and soil physiochemical characteristics (EC, moisture, and SOM). Variance partitioning attributed 97.4% of the total variation, while interactions among cultivation ages, nutrient characteristics (SOM and AP), and non-nutrient characteristics (pH, EC, moisture, and aggregates) accounted for 23.0%. To identify the driving factors of AM fungi indices, Pearson correlation and redundancy analysis (RDA) were performed, and EC (26.5%) and pH (20.9%) were identified as the paramount regulators of hyphal integrity and colonization efficiency. It was found that 60 years worked as a critical transition point for targeted interventions (e.g., organic amendments and pH buffering) to mitigate rhizosphere dysfunction and optimize mycorrhizal services in perennial monocultures. Full article

Soil salinity and sodicity are escalating global threats to agricultural productivity, severely limiting crop yield and quality. In the Igdir Plain of Türkiye, high summer temperatures, minimal precipitation, and a shallow groundwater table have intensified salinity-related challenges, currently affecting one-third of the arable land. Despite the substantial impact of salinity stress on eggplant (Solanum melongena L.) production, studies addressing plant tolerance mechanisms under real field conditions remain limited. In this study, eggplant was cultivated in eight distinct soil classes under open-field conditions to evaluate the effects of soil salinity and saline-alkalinity on morphological, physiological, and biochemical traits. Increasing soil exchangeable sodium percentage (ESP) and electrical conductivity (ECe) levels significantly suppressed plant height, root length, stem diameter, and leaf area, along with over 90% reductions in shoot and root biomass. Salinity impaired the uptake of essential nutrients (Ca, K, P, and Fe), while promoting toxic Na⁺ accumulation in leaves. This ionic imbalance induced oxidative stress, as indicated by elevated malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and antioxidant enzyme activities (SOD, CAT, APX), all of which were strongly correlated with proline accumulation. The results highlight a coordinated plant response under salinity stress but also reveal the insufficiency of natural defense mechanisms under high salinity levels. Unless supported by external interventions to improve stress resilience and ensure productivity, growing eggplant in saline–alkaline soils should be avoided. Full article

Straw return directly increases carbon inputs, enhancing soil organic carbon (SOC) stocks. However, long-term straw return leads to carbon saturation in the topsoil (0–20 cm). While most studies focus on the topsoil, the effects of long-term straw return on deep soil (100–200 cm) carbon sequestration remain poorly understood. This study investigated carbon dynamics in an arid region by analyzing 0–200 cm soil profiles under different straw return treatments: control (uncultivated) and cotton straw return for 5 (SR5), 10 (SR10), and 20 years (SR20). Straw return significantly improved soil properties by reducing electrical conductivity (EC), increasing nutrient availability, and enhancing bacterial activity. SR20 resulted in the most pronounced SOC increase (18.6–252.7%) across the entire profile and significantly enhanced soil inorganic carbon (SIC) (27.7–52.7%) in deep layers. In contrast, SOC in the topsoil (0–20 cm) increased initially but plateaued after 5–10 years. Principal component and random forest analyses showed that SOC sequestration was primarily driven by sucrase, urease, available phosphorus, dissolved organic carbon (DOC), microbial diversity indices, and available calcium (p < 0.05), while SIC dynamics were significantly influenced by sucrase, urease, DOC, CO₂ emissions, available calcium, and EC (p < 0.05). These findings underscore the importance of exploring subsoil carbon sequestration mechanisms in arid ecosystems. Full article

The conversion of wetlands into croplands often leads to significant losses of peat soil salinity and soil organic matter (SOM), though quantifying these changes is challenging due to limited historical data. In this study, we compared current soil physicochemical properties with rare historical data from the Mezzano Lowland (ML) in Northeastern Italy, a former wetland drained over 60 years ago. The transformation, which affected approximately 18,100 hectares, was achieved through the construction of a network of drainage canals and pumping stations capable of removing large volumes of water, enabling intensive agricultural use. Results showed a marked decrease in electrical conductivity (EC) and sulphate concentration, indicating extensive salt leaching from the upper peat soil layers. EC dropped from historical values up to 196 $\mathrm{m}$$\mathrm{S}$/cm (1967–1968) to a current maximum of 4.93 $\mathrm{m}$$\mathrm{S}$/cm, while sulphate levels declined by over 90%. SOM also showed significant depletion, especially in deeper layers (50–100 cm), with losses ranging from 50 to 60 $\mathrm{wt}\%$, due to increased aeration and microbial activity post-drainage. These climatic and environmental changes, including a marked reduction in soil salinity and sulphate concentrations due to prolonged leaching, have likely shifted the Mezzano Lowland from a carbon sink to a net source of CO₂ and CH₄ by promoting microbial processes that enhance methane production under anaerobic conditions. To detect residual peat layers, we used Ground-Penetrating Radar (GPR), which, combined with soil sampling, proved effective for tracking long-term peat soil changes. This approach can inform sustainable land management strategies to prevent further carbon loss and maintain peat soil stability. Full article

Hydrangeas are economically important ornamental plants whose growth and flower characteristics depend on irrigation water quality (IWC), i.e., hydrogenionic potential (pH) and electrical conductivity (EC). Unfavorable IWC causes plant stress, reduced growth and tissue damage, leading to physiological responses such as proline accumulation (for stress protection) and increased malondialdehyde (MDA, an indicator of damage). A greenhouse pot experiment was conducted as a three-factor study in three replicates. The study examined the impact of different pH levels (4, 5, and 6, compared to a control treatment of pH 7), and EC levels (2, 3, and 4 dS m⁻¹, compared to a control treatment of 1 dS m⁻¹) on biomass, i.e., plant height (cm), stem number (n), flower number (n), leaf number (n) and weight (g), flower weight (g) and diameter (cm), growth index (GI) and the proline and MDA concentrations in two hydrangea varieties (Early Blue and Bianco). Study results showed a significant impact of (p = 0.0001) pH on all tested morphological properties, except flower diameter. Notably, pH 6 maximized biomass accumulation, i.e., plant height (56.6 cm), leaf number (n = 97) and weight, flower weight (156.8 g), and GI (36 cm), while pH 4 promoted the highest number of flowers (n = 10) and stems (n = 10), which are both crucial for aesthetic and market value. EC significantly (p = 0.001) affected plant height (EC 2 = 56.3 cm), flower (EC 2 = 181.9 g) and leaf weight (EC 3 = 148.2 g), and growth index (EC 2 = 27.2 cm). The lowest stress indicators (proline and MDA concentrations) were recorded at pH 6 (MDA = 0.215 µmol g⁻¹ FW, proline = 659.5 µmol g⁻¹ FW) and EC 2 (MDA = 0.551 µmol g⁻¹ FW, proline = 4068.2 µmol g⁻¹ FW). The highest MDA and proline concentrations were observed under extreme conditions of pH 4 (MDA = 1.257 µmol g⁻¹ FW, proline = 12,811.7 µmol g⁻¹ FW) and EC 4 (MDA = 0.692 µmol g⁻¹ FW, proline = 4880.8 µmol g⁻¹ FW). No significant effect of variety on proline and MDA concentrations was observed, while the highest GI was recorded for the Early Blue variety (24.3 cm). This research identifies pH 6 and EC 2 as key conditions for optimizing hydrangea biomass and reducing stress, offering practical guidelines for growers. The findings provide a foundation for developing precise irrigation water quality strategies in the commercial production of ornamental plants. Full article

The current study focuses on a preliminary evaluation of the use of solid residues produced from the distillation of selected medicinal and aromatic plants (MAP) as fertilizers for alkaline soils. Specifically, the residues of hemp (Cannabis sativa L.), helichrysum (Helichrysum Italicum (Roth) G. Don), lavender (Lavandula angustifolia Mill.), oregano (Origanum vulgare L.), rosemary (Rosmarinus officinalis L.) and sage (Salvia officinalis L.) were added in an alkaline and calcareous soil at the rates of 0 (control), 1, 2, 4 and 8%, in three replications (treatments), and the treated soils were analyzed. The results showed that upon application of the residues, soil electrical conductivity (EC), organic C, total N and the C/N ratio significantly increased, especially at the 4 and 8% rates. The same was found for soil available P, K, B, Cu and Mn. The effects of the residues on soil pH, cation exchange capacity (CEC) and available Zn and Fe were rather inconclusive, whereas soil available N significantly decreased, which was somewhat unexpected. From the different application rates tested, it seems that all residues could improve soil fertility (except N?) when they were applied to soil at rates of 2% and above, without exceeding the 8% rate. The reasons for the latter statement are soil EC and available Mn: the doubling of EC upon application of the residues and the excessive increase in soil available Mn in treatments with 8% residues raise concerns of soil salinization and Mn phytotoxicity risks, respectively. This work provides the first step towards the potential agronomic use of solid residues from MAP distillation in alkaline soils. However, for the establishment of such a perspective, further research is needed in respect to the effect of residues on plant growth and soil properties, by means of at least pot experiments. Based on the results of the current study, the undesirable effect of residues on soil available N should be investigated in depth, since N is the most important essential element for plant growth, and possible risks of micronutrient phytotoxicities should also be studied. In addition, application rates between 2 and 4% should be studied extensively in order to recommend optimum application rates of residues to producers. Full article