Search Results (411)

Natural saline–alkaline soils are widespread in Central Asia, yet microbial responses to salinity gradients and ionic composition remain poorly resolved. We profiled bacterial communities (16S rRNA V3–V4, Illumina MiSeq) in 20 topsoil (0–20 cm) samples from four regions of Kazakhstan spanning non-saline to highly saline conditions. Soil chemistry included pH, total mineralization (dry residue), and major ions (Na⁺, Cl⁻, SO₄²⁻, HCO₃⁻, Ca²⁺, Mg²⁺, K⁺). Alpha (Chao1, Shannon, observed ASVs) and beta diversity (Bray–Curtis; ANOSIM; PCoA) were evaluated across salinity classes. Soils were alkaline (pH 7.91–10.47) and covered a broad salinity range (256–26,312 mg/L), driven mainly by Na⁺ with chloride and/or sulfate. Alpha diversity remained stable across salinity classes, though dispersion increased under high salinity. Community composition differed significantly among classes (ANOSIM R = 0.428, p = 0.005), with partial PCoA separation and overlap, indicating gradual turnover along the salinity gradient. In contrast, fungal communities showed no significant response to salinity, with stable alpha and beta diversity across all samples and consistent dominance of Ascomycota. Communities were dominated by Actinomycetota (formerly Actinobacteriota), Bacteroidota, and Pseudomonadota (formerly Proteobacteria). Bacteroidota increased in highly saline soils (FDR q = 0.036), whereas Acidobacteriota decreased (FDR q = 0.052). Thermodesulfobacteriota (formerly Desulfobacterota) correlated positively with sulfate, and Cyanobacteriota negatively with chloride. Overall, Kazakhstan’s saline–alkaline soils show stable bacterial alpha diversity but moderate, ion-linked compositional shifts with enrichment of halotolerant taxa. Full article

A field experiment was conducted in three ecological zones to evaluate the effects of broadcast sowing (BS), drill sowing (DS), and ridge–furrow precision sowing (RFS) on winter rapeseed (Brassica rapa L.) grown in lightly saline–alkaline soils, using two cultivars (L6 and L7). RFS improved soil temperature and soil moisture conditions across the zones. Its warming effect was most pronounced in the JT zone, where soil temperatures at seedling and flowering stages were 9.7% and 10.3% higher than under BS, respectively. RFS also showed a moisture-conservation advantage at regreening, with soil moisture 13.8% and 6.6% higher than under BS and DS, respectively. In addition, RFS reduced soil salinity and increased soil total carbon, available potassium, and ammonium nitrogen contents. Plants under RFS showed higher SPAD values, net photosynthetic rates, and transpiration rates at seedling and regreening stages, along with higher antioxidant enzyme activities and lower MDA accumulation. RFS advanced key phenological stages, improved overwintering survival, and produced the highest yield. Compared with BS and DS, respectively, RFS increased the mean yield of L6 by 11.46% and 6.97%, and that of L7 by 16.02% and 10.52%. Overall, RFS promoted yield formation by improving soil conditions, photosynthetic activity, and stress resistance. Full article

Straw return and tillage practices can alter the soil properties and regulate the bacteria communities, which mediate nitrogen (N) transformation and accumulation. This study aims to elucidate the mechanisms of microbially driven N retention, providing a foundation for soil management strategies. A field experiment was conducted in 2019–2022, six treatments were set up, including rotary tillage with/without straw (RTSR and RTNS), deep tillage with/without straw (DTSR and DTNS), subsoiling with/without straw (STSR and STNS). Soil properties, N pools/fractions and bacterial communities were measured. The results showed that straw return and tillage practices ameliorated soil environment (reducing bulk density (by 7–8% via DTSR and STSR) and salinity (with 57% and 26% increase in DTSR and STSR compared with RTSR, while rotary tillage significantly reduced salinity), increasing soil organic matter (via RTSR treatment, with 5–16% significant increase in two years) and effectively promoting N accumulation. The number of OTUs and the α-diversity significantly increased in 2022 compared with 2021. Specifically, tillage was the main driver of bacterial α-diversity, but there was no significant influence on bacterial β-diversity. Mental test results showed that N availability is a pivotal environmental factor shaping the bacteria α- and β-diversity. Structural equation modeling revealed that SON accumulation directly drove N accumulation via the “environmental improvement–specific microbial community structure” pathway. STSR is the optimal treatment for promoting N accumulation by maintaining active SON levels, which is an effective strategy for sustainable N management in the Yellow River Delta (YRD). Full article

Nano-/microplastics (NMPs) accumulation in agricultural soils has become a growing environmental concern due to its negative impacts on soil health, crop productivity, and food safety. Biochar has gained considerable attention as a sustainable soil amendment capable of improving soil quality and mitigating emerging pollutants. This review examines the role of biochar and modified biochar in reducing the mobility, bioavailability, and plant uptake of NMPs through adsorption, aggregation, and immobilization mechanisms. In addition, biochar improves soil fertility by enhancing nutrient retention, water holding capacity, soil structure, and microbial activity, while also contributing to climate change mitigation through carbon sequestration. However, certain biochars may negatively affect saline–alkaline soils because of their high pH and salinity. Generally, biochar application offers multiple environmental benefits, including soil restoration, pollutant mitigation, and enhanced agricultural sustainability. This review synthesizes recent advances in understanding the mechanisms by which biochar influences NMPs behavior in soil–plant systems and highlights current knowledge gaps and future research directions needed to support its effective application in sustainable agriculture. Full article

Soil depth and habitat degradation can reshape fungal communities in salt-affected wetlands, but their effects on fungal ecological processes remain insufficiently understood. This study examined soil fungi in the Halahai Provincial Nature Reserve and adjacent converted farmland in the western Songnen Plain, Northeast China, where salt-affected meadow soils correspond mainly to Solonetz. Four habitat types—reed wetland, meadow steppe, degraded Suaeda saline patch, and converted farmland—were sampled at 0–20 cm and 20–40 cm soil depths. Soil properties, fungal diversity, taxonomic composition, environmental associations, niche breadth, assembly processes, and FUNGuild-based trophic modes were analyzed using ITS sequencing. Degraded Suaeda soils showed the strongest salinity–alkalinity stress, with pH values of 10.34–10.30 and electrical conductivity of 1.70–1.75 dS·m⁻¹. Fungal richness was highest in surface-converted farmland, with a Sobs value of 423.33, and lowest in deeper degraded Suaeda soil, with a Sobs value of 86.00. Ascomycota dominated most groups, especially degraded Suaeda soils, where its relative abundance reached 75.29–76.80%. ANOSIM confirmed significant community dissimilarity among habitat-depth groups (R = 0.56878, p = 0.001). Specialists accounted for 68.07% of fungal taxa, and stochastic processes, especially drift and dispersal limitation, contributed substantially to assembly. These results indicate that soil depth, salinity–alkalinity, and habitat conversion jointly regulate fungal community structure and ecological processes in degraded soda saline–alkali wetlands. Full article

Soil salinity and alkalinity are major constraints to agricultural productivity in arid regions, particularly where treated wastewater (TWW) is used for irrigation. This study evaluated the spatial variability of water and soil physicochemical properties along Wadi Hanifa, Saudi Arabia, and compared soils from two farms irrigated with TWW for approximately 5 and 15 years to assess the effects of irrigation duration on soil properties. Soil samples were collected from 25 locations along the Wadi using a handheld Global Positioning System (GPS), and water and soil properties were analyzed using standard laboratory procedures. The treated wastewater exhibited moderate electrical conductivity (EC = 2.0 dS m⁻¹) and low sodicity hazard (SAR = 1.55), indicating its suitability for irrigation under appropriate management practices. Soils were predominantly coarse-textured and showed considerable spatial variability in salinity and chemical composition. Soil pH remained relatively stable (7.33–8.07), while EC ranged from 0.88 to 2.64 dS m⁻¹, indicating non-saline to moderately saline conditions across the study area. Comparison of soil profiles from the two farms revealed greater salinity in subsurface layers, particularly at the farm irrigated with TWW for 15 years, where EC reached 4.15 dS m⁻¹ and Na⁺ concentrations reached 16.4 meq L⁻¹. These observations suggest salt redistribution and accumulation within deeper soil horizons under prolonged irrigation. Overall, soil and water quality in Wadi Hanifa are strongly influenced by spatial variability, coarse soil texture, and arid climatic conditions. The findings highlight the importance of regular monitoring of salinity and sodicity indicators, together with adequate leaching and drainage practices, to ensure the sustainable use of treated wastewater for agricultural production in arid environments. Full article

Soil salinization threatens agricultural production, and increasing extreme rainfall may alter natural leaching processes in coastal saline–alkaline soils. However, the relationships among salt ion migration, alkalinity changes, nutrients, and bacterial communities under natural rainfall leaching remain unclear. Therefore, a phased natural rainfall leaching experiment was conducted from June to September 2025 using moderate to severe NaCl-type saline–alkaline soil from Dongying in the Yellow River Delta. The results showed that natural rainfall leaching significantly reduced soluble salt ions, especially Na⁺, Cl⁻, and SO₄²⁻, and rapidly alleviated early salt stress. However, soil pH did not decline continuously with salt reduction, but fluctuated under the buffering effect of the carbonate system, indicating that desalination was not necessarily accompanied by alkalinity alleviation. Available nutrients showed stage-dependent changes, with HN and AK increasing around the middle leaching stage. Bacterial community composition and co-occurrence networks also changed during leaching, and these changes were more closely associated with salt ions and HCO₃⁻/pH than with available nutrients. These results suggest that post-rain management of saline–alkaline soils should not rely only on total salinity, but should also consider major salt ions, pH/HCO₃⁻, and nutrient availability. Full article

The utilization of saline–alkali lands and the competition between medicinal plants and grain crops are urgent issues. This study aimed to evaluate the effects of combined biochar and phosphogypsum application on soil physicochemical properties, microbial communities, and safflower growth, yield, and bioactive component accumulation in moderately saline–alkali soil of western Jilin, and to identify key soil factors driving these responses. To achieve this, outdoor pot experiments were conducted using safflower (Carthamus tinctorius L.), with the application of 1% biochar + 1% phosphogypsum to moderately saline–alkali soil. The results showed that the amendment significantly reduced bulk density (BD), pH, sodium adsorption ratio (SAR), total alkalinity (TA), and exchangeable sodium percentage (ESP), while increasing soil water content (SWC), soil organic matter (SOM), nitrogen, phosphorus, potassium, and beneficial ions. Soil sucrase, urease, alkaline phosphatase, and catalase activities were enhanced. Copiotrophic taxa (Pseudomonadota, Sphingomonas, Vicinamibacter) increased, whereas oligotrophic taxa (Gemmatimonadetes, Longimicrobium, Luteitalea) decreased, with stronger effects on bacteria than fungi. Safflower growth indices improved; leaf Na⁺/K⁺ ratio, superoxide radicals, and malondialdehyde decreased; and soluble protein, proline, and antioxidant enzyme activities increased. Bioactive components (hydroxysafflor yellow A, kaempferol) and yield reached 1.41%, 0.056%, and 343.23 mg/plant, representing 1.74–27.68-fold increases over moderate and mild saline–alkali soils. Correlation analysis identified SOM, total nitrogen (TN), available phosphorus (AP), BD, SWC, pH, SAR, TA, and ESP as key factors. In conclusion, co-application of 1% biochar and 1% phosphogypsum improves soil physicochemical and microbial properties, alleviates saline–alkali stress, and enhances safflower quality and yield. Full article

A significant abiotic stressor that negatively impacts plant seed germination and seedling establishment is soil salinization, especially in staple crops like wheat (Triticum aestivum L.). The complex ionic stressors that make up salinity include divalent salts (MgCl₂), alkaline salts (NaHCO₃), and neutral salts (NaCl, KCl), each of which has unique effects on osmotic and ionic toxicity. The present understanding of how various ionic salt stressors affect the dynamics of wheat germination and the early development of seedlings is summarized in this article. We talk about physiological and biochemical reactions, possible adaptive mechanisms, and the ionic specificity of toxicity. Important research findings show that: (1) germination rate and seedling vigor are reduced in response to salt content; (2) growth parameters are affected by ionic composition; and (3) genotypic variability in salt sensitivity is observed in response to salinity stress. Improving wheat performance in saline soils and developing breeding plans for salt tolerance require an understanding of these dynamics. Full article

Drought and soil salinization severely limit the productivity of global agriculture and forestry, highlighting the urgency of identifying stress-resistant genes for molecular breeding. B-box (BBX) proteins constitute a class of zinc finger transcription factors that play significant roles in plant abiotic stress responses. Amorpha fruticosa (A. fruticosa) is a perennial woody plant with exceptional adaptability to harsh environments, serving as a valuable resource for mining stress-resistant genes. In this study, the AfBBX gene was cloned from A. fruticosa, and its function in stress tolerance was systematically analyzed. Bioinformatics analysis confirmed that AfBBX contains a conserved ZnF-BBOX domain and shares functional conservation with the BBX protein family. Quantitative real-time polymerase chain reaction (qRT-PCR) revealed tissue-specific expression of AfBBX, with the highest expression in stems and the lowest in young leaves. Furthermore, AfBBX expression was dynamically regulated in roots and leaves of A. fruticosa under treatments of 5 μM ABA (drought mimic), H₂O₂ (oxidative stress), 10% PEG600 (osmotic stress), and NaHCO₃ (alkaline stress). Transgenic tobacco lines overexpressing AfBBX showed enhanced tolerance to osmotic and salt–alkali stresses at both germination and seedling stages. Meanwhile, compared to wild-type (WT) tobacco, transgenic lines exhibited higher germination rates, longer root lengths, and greater fresh weights under stress conditions. Under natural drought and salt–alkali stresses, transgenic tobacco maintained higher chlorophyll fluorescence intensity (Fv/Fm values), elevated activities of antioxidant enzymes [superoxide dismutase (SOD)], and reduced malondialdehyde (MDA) content. In conclusion, AfBBX enhances stress tolerance by mitigating photosystem damage, increasing reactive oxygen species (ROS) scavenging capacity, and reducing membrane lipid peroxidation. The findings from this study provide novel insights into the molecular mechanism underlying AfBBX-mediated stress resistance and offer valuable genetic resources for breeding drought- and salt-tolerant crops and forest trees. Full article

Reclaiming saline–alkaline soil is critical for food security and land expansion. While paddy rice is the key pioneer crop for remediation, the soil fertility–yield relationship remains poorly understood. To optimize remediation strategies, this study evaluated soil fertility under 16 agronomic treatments—integrating irrigation quality, fertilizer regimes, and soil amendments—across three rice growth stages (tillering, heading, and maturity) in the Yellow River Delta using the minimum data set (MDS), integrated soil fertility index (SFI), and random forest models. Saline water irrigation increased soil salinity by 24.6%, while straw returning and desulfurization gypsum reduced salinity by 18.3% and 22.7%, respectively. Straw, biochar, and desulfurization gypsum significantly influenced soil organic carbon (SOC), total nitrogen (TN), inorganic nitrogen (NH₄⁺-N, NO₃⁻-N), and available phosphorus (AP), with effects varying across growth stages. Growth-stage-specific MDS indicators were significantly correlated with SFI based on the total data set (R² = 0.70, 0.65, and 0.81, p < 0.01), and stage-specific SFI was significantly positively related to rice yield. Notably, heading-stage SFI, although relatively low, explained the highest yield variance (R² = 0.51, p < 0.01) and prediction accuracy (%IncMSE = 25.22), especially under conventional NPK combined with full straw incorporation and desulfurization gypsum. These findings highlight the critical role of heading-stage soil fertility in regulating rice production, providing a targeted nutrient management blueprint for saline–alkaline paddy fields in the Yellow River Delta. Overall, this study offers a reliable scientific template to enhance yield and promote sustainable agriculture in comparable saline–alkaline paddy fields globally. Full article

Rice seedlings are typically grown in high-phosphorus nursery soils in practice, which reduces rice root growth and the plant’s ability to adapt to adverse conditions after transplantation to the paddy field. Thus, it is important to improve rice root development in high-phosphorus nursery soils. Rice root developments are closely connected with soil microorganisms. Arbuscular mycorrhizal fungi (AMF) can promote rice root growth and help improve rice performance in resisting adverse conditions. To illustrate the mechanisms of rice seedlings with AMF inoculation under suitable and high-phosphorus nursery soils in resisting adverse conditions, rice seedlings were cultivated in suitable and high-phosphorus nursery soils inoculated with AMF JD5 (Paraglomus sp.) and transplanted into soda saline–alkaline soils following successful AMF inoculation. Results showed that under high-phosphorus conditions, AMF JD5 inoculation significantly promoted plant height and root elongation, likely through increased total chlorophyll content. Concurrently, proline content was reduced, whereas soluble sugar and soluble protein contents were elevated, indicating alleviation of osmotic stress induced by saline–alkaline conditions. Moreover, AMF JD5-inoculated seedlings exhibited increased CAT activity, which efficiently scavenged reactive oxygen species (ROS) generated under salt–alkaline stress and reduced lipid peroxidation. However, thiobarbituric acid reactive substances (TBARS) content was significantly decreased with AMF inoculation in high-phosphorus conditions. Collectively, these findings suggest that AMF JD5 inoculation in high-phosphorus nursery soils establishes a physiological and biochemical foundation that maintains rice resilience against saline–alkaline stress throughout early growth. Full article

Glaze flaking is widespread in Hongzhou kiln celadon dating from the Eastern Han to the Tang Dynasty, yet its underlying mechanism cannot be attributed to a single factor. In this study, 11 Hongzhou kiln celadon specimens from the Eastern Han, Southern Dynasties, and Sui–Tang periods were examined using microscopic observation, SEM–EDS, Raman spectroscopy, crack-width measurements, glaze-area analysis, water-absorption tests, and burial environment analysis to investigate the characteristics and causes of glaze flaking. The results show that crazing-crack width is significantly and positively correlated with the extent of glaze flaking. The body–glaze interlayer generally exhibited heterogeneous features, including anorthite crystallization, unmelted quartz grains, bubbles, and locally phase-separated droplets. Anorthite crystals and adjacent regions were frequently associated with crystal-shaped corrosion pits, irregular voids, and localized structural loosening; degraded areas showed depletion of Ca and Si and relative enrichment of Al and Fe. The burial soils were generally neutral to slightly alkaline and showed no evident salt accumulation, suggesting that high salinity was not the primary direct cause of glaze flaking in these samples. These findings suggest that glaze flaking in Hongzhou kiln celadon results from the interaction between firing-induced heterogeneity at the body–glaze interface and prolonged post-burial corrosion. Crazing and interconnected cracks acted as pathways for moisture and soluble ions to penetrate the body–glaze interlayer, triggering selective corrosion of Ca-rich crystalline phases and adjacent glassy phases and ultimately causing interfacial destabilization and glaze loss. Full article

Rapid alkalinization factor (RALF) peptides are recognized as multifunctional regulators of plant stress responses, yet their roles in woody species remain poorly defined. Here, we identified a RALF22-like peptide from poplar ‘Shanxin’ (Populus davidiana × P. bolleana; PdbRALF22-like) and investigated its roles in salt tolerance and disease resistance. Synthetic PdbRALF22-like peptide elicited a rapid ROS burst in poplar leaf discs. In Nicotiana benthamiana, which was otherwise unresponsive to the peptide, transient expression of either of two poplar FERONIA-like receptor kinases (PdbFER-like-1 and PdbFER-like-2) enabled peptide-triggered ROS production, consistent with receptor-matched responsiveness in a heterologous context. Using CRISPR/Cas9, we generated a PdbRALF22-like knockout line and assessed salt tolerance in vitro and soil-grown assays. Under salinity, the mutant showed sustained rooting at high NaCl concentrations and improved growth relative to wild type. After 0.2 M NaCl treatment, soil-grown mutant plants exhibited reduced wilting and leaf injury. Evans Blue, DAB, and NBT staining indicated reduced membrane damage and lower accumulation of hydrogen peroxide and superoxide in the mutant. Significantly, the same knockout line displayed increased susceptibility to infection by the poplar leaf spot fungus, with larger lesions and higher pathogen biomass, accompanied by reduced ROS output and lower induction of the defense marker gene PdbPR1. Collectively, PdbRALF22-like negatively regulates salt tolerance while contributing positively to disease resistance, and represents a regulatory node linking salinity tolerance and disease susceptibility in poplar ‘Shanxin’, with poplar FER-like receptors providing a plausible route for peptide-triggered ROS signaling. This work expands our understanding of RALF peptide signaling in woody plants. Full article

Population growth and climate change demand technologies for the efficient use of water in agriculture. This study aimed to synthesize and characterize hybrid hydrogels of polyacrylamide and white angico gum (Anadenanthera colubrina), reinforced with kaolinitic clay and soapstone, for potential application as soil conditioners and nutrient carriers. The hydrogels were obtained via radical polymerization, followed by alkaline hydrolysis (0.1 mol L⁻¹ NaOH) to convert amide groups into carboxylates. The results indicated that the HPAD formulation [constituted by white angico gum (1:1); 5% (w/w) kaolin and 5% (w/w) steatite (soapstone)] presented the best balance, with a maximum compressive force greater than 200 N, thermal stability up to 310 °C, and a swelling capacity of 60 g/g in saline medium, surpassing the limits of viability for use in soil. The kinetics followed the pseudo-second-order model, and the point of zero charge (pH 9.0–11.7) favored phosphate retention. It is concluded that the HPAD hydrogel, one of several hydrogel formulations developed in this study, is a viable and safe technical alternative, with non-toxicity exceeding 80% in Artemia salina assays and capable of optimizing water and nutrient efficiency in agricultural systems. Full article