Abstract:[Objective] The key mechanisms by which amorphous iron oxide regulates the mechanical properties of Benggang soil were analyzed from a microscopic perspective in order to provide a theoretical basis for the prevention and control of Benggang erosion. [Methods] Kaolinite, the dominant clay mineral in soil from a typical Benggang area of Fujian Province, was selected as the research object. By incorporating amorphous iron oxide at different concentrations(1, 2, 3, and 10 g/kg) into kaolinite and utilizing X-ray diffraction(XRD), scanning electron microscopy(SEM), and direct shear tests, this study analyzed its regulatory effects on soil microstructure and shear strength parameters. [Results] XRD analysis revealed that amorphous iron oxide did not undergo a chemical reaction with kaolinite but primarily altered mineral characteristics through physical coating. The concentration of amorphous iron oxide significantly influenced the distribution of cemented aggregates across different particle sizes, demonstrating a pronounced regulatory role in the formation of aggregates within the 2—250 μm range. Among microstructural parameters, only particle long-axis and roundness exhibited significant changes. The long-axis decreased by 22% in samples with the 3 g/kg treatment, while roundness was reduced by 25% in samples with the 2 g/kg treatment. The coefficients of variation for all other parameters remained below 15%. The treatment with 3 g/kg consistently exhibited the highest shear strength across all confining pressure levels. The enhancement in shear strength was closely associated with the observed microstructural alterations. Further analysis indicated that the 3 g/kg treatment resulted in the most substantial improvement in cohesion, which increased by 24.82% compared to pure kaolinite. In contrast, the internal friction angle varied by less than 5.30%. [Conclusion] Amorphous iron oxide enhances soil shear strength by optimizing soil structure through cementation and encapsulation.

Abstract:[Objective] The water-holding characteristics and strength characteristics of unsaturated lime-stabilized loess cushion layers were investigated, and the influence of different lime contents on its matric suction and strength was revealed, in order to provide guidance and reference for the construction and theoretical research of loess building foundations and subgrades. [Methods] Laboratory soil-water characteristic tests and unsaturated triaxial tests were conducted to study the soil-water characteristics, unsaturated strength, and softening constitutive model of lime-stabilized unsaturated loess. Four lime contents(0, 3%, 6%, and 9%) were set to reveal the influence of lime content on matric suction. The matric suction was set at 0, 50, 100 kPa, and 200 kPa, respectively, to explore its influence on strength. [Results] ① Matric suction increased with increasing lime content.② A soil-water characteristic model considering the influence of lime content was proposed, and this model could accurately describe the soil-water characteristics of lime-stabilized loess. A nonlinear model capable of describing the softening behavior of lime-stabilized loess was established by introducing a damage variable.③ The cohesion and internal friction angle of the stabilized soil increased as the lime content increased. When the lime content was 9%, with the increase of matric suction, the cohesion of the lime-stabilized loess gradually increased, while the change in the internal friction angle was very small. [Conclusion] The lime content on the soil-water characteristics of stabilized loess has a significant influence. Additionally, the nonlinear model can accurately describe the stress-strain curve of lime-stabilized soil, yielding relatively good results.

Abstract:[Objective] The mechanisms through which seasonal freeze-thaw cycles, coupled with initial water content, attenuate the collapsibility of Ili loess were revealed, and a quantitative relationship between microstructural reconfiguration and macroscopic collapsibility variations was established, in order to provide a theoretical basis for prevention and control of loess landslides in seasonally frozen soil regions. [Methods] Freezethaw cycling tests were performed on samples with different initial water contents and cycle numbers, accompanied by laboratory collapsibility tests and scanning electron microscope(SEM) observations. Image and statistics-based analyses were conducted to quantitatively characterize microscopic parameters such as pore size distribution, directional frequency, pore abundance, and pore fractal dimension. Correlations between these parameters and the collapsibility coefficient were established, forming an integrated macro-micro analytical framework. [Results] ① The collapsibility coefficient decreased significantly with an increase in freeze-thaw cycles for all water contents, and samples with lower water contents were more sensitive. For loess with a water content of 14.2%, the peak collapsibility coefficient decreased from 0.094 to 0.084 after nine cycles, a reduction of approximately 10.6%. For loess with a water content of 20.2%, the peak collapsibility coefficient decreased from 0.079 to 0.076 after nine cycles, a reduction of about 3.8%.② Freeze-thaw cycles weakened interparticle cementation and altered particle connections and arrangement, thereby driving internal structural reorganization toward a new stable state.③ The pore system underwent systematic evolution. The proportion of large pores declined, the pore-size spectrum became finer and more uniform, pore directions were re-arranged, and both pore abundance and pore fractal dimension changed accordingly.④ The microstructural statistical patterns were consistent with qualitative observations and the macroscopic evolution of collapsibility. [Conclusion] Freeze-thaw cycles reduce interparticle bonding and remodel the pore-particle structure. Consequently, the reduction of large pores and changes in fractal dimension constitutes the core mechanisms driving the macroscopic weakening of collapsibility. Based on this, a physical process model of ‘freeze-thaw → microstructural reconfiguration → collapsibility response' is established, providing theoretical support for the monitoring and prevention of loess landslides in seasonally frozen soil regions such as the Ili area.

Abstract:[Objective] The amount of wind-blown sand entering gullies and its migration paths and deposition processes within the gully slopes in the coarse sand area in the middle reaches of the Yellow River were analyzed in order to provide a scientific basis for wind and sand prevention and control in the Yellow River basin. [Methods] Taking the Shajiawan small watershed as the study area, sand drift potential（DP） was calculated based on field monitoring and laboratory analysis using sand samplers, and the actual wind erosion potential（DP_a） was derived by incorporating the rainfall inhibition effect. The wind-sand deposition amount in the gully was estimated using a function fitting method. Combined with the soil particle size characteristics of the gully slopes, the wind-sand transport paths and sedimentary characteristics were systematically analyzed. [Results] ① The Shajiawan small watershed was characterized by a high wind energy environment. The annual sand drift potential was 441.95 VU, with a directional variability index of 0.42. The direction of the annual synthetic sand drift potential was perpendicular to the main channel, and the annual wind erosion modulus of the channel was-0.40 t/hm². Sand drift potential and wind-sand deposition were highest in spring, accounting for 53.74% and 40.25% of the annual total, respectively.② The annual actual wind erosion potential（DP_a） considering rainfall suppression was 293.04 VU, which was 27% lower than the sand drift potential. The suppression effect was most pronounced when high wind speeds occurred simultaneously with heavy rainfall.③ As the slope position decreased, the sediment composition changed from silt（76.20%） to predominantly fine sand（74.70%）, with the average particle size changing from 5.52 φ to 2.89 φ. The soil particles became significantly coarser, and the movement mode changed from suspension to saltation. [Conclusion] The process of wind-blown sand entering gullies occurs under the combined effects of high wind energy and gully terrain obstruction, with sediments entering the gullies through saltation.

Abstract:[Objective] The macroscopic and microscopic mechanisms of loess strength degradation under the coupled effects of wet-dry cycles and soluble salt content were analyzed in order to provide a basis for engineering construction and geologic disaster prevention and control in the Ili region. [Methods] The typical loess from the Ili region was taken as the research object. The influence of different numbers of wet-dry cycles and different soluble salt contents on the mechanical properties and microstructure of loess was analyzed through triaxial shear tests, scanning electron microscope(SEM) tests, and nuclear magnetic resonance(NMR) tests. [Results] ① The cohesion decreased by approximately 17.5% after only 10 wet-dry cycles(η=0%). When the soluble salt content increased from 0% to 2%(N=0), cohesion decreased by about 3.5%. However, under their coupled effects(N=10, η =2%), cohesion decreased by 24.3%, demonstrating a significant synergistic deterioration effect.② Soluble salts exerted a highly significant influence on both cohesion and internal friction angle, while wet-dry cycles had a highly significant influence on cohesion and a significant influence on internal friction angle.③ Under low confining pressures, the failure mode of loess shifted from brittle to plastic failure. Under high confining pressures, although the strength remained relatively high, degradation continued.④ With increasing numbers of wet-dry cycles and soluble salt content, fracture development occurred, gradually increasing the pore fractal dimension and pore area ratio of loess. A reduction in micropores, along with a sharp expansion of mesopores and macropores, leading to increased porosity and enhanced connectivity within the pore system. [Conclusion] Under the coupled conditions of wet-dry cycles and soluble salts, the synergistic effects of repeated swelling and shrinkage driven by the wet-dry cycles and crystallization stresses generated by salt dissolution and recrystallization jointly disrupt soil structure. This process leads to strength degradation and structural degradation in Ili loess.

Abstract:[Objective] The patterns of soil erosion on slopes in the Xin’an River basin were evaluated in order to provide scientific support for regional soil erosion control and sustainable ecological development. [Methods] Through artificial rainfall simulation experiments,the runoff and sediment yield processes,and their differential erosion characteristics were systematically analyzed under different combinations of rainfall intensity and slope gradient for yellow soil and red soil in the river basin,and a quantitative relationship model between hydrodynamic parameters and sediment yield intensity was established. [Results] ① The runoff rate and sediment yield rate on the slopes of both yellow soil and red soil exhibited a steep initial increase during rainfall onset,followed by gradual stabilization,with both increasing with higher rainfall intensity and slope gradient.Red soil slopes demonstrated higher runoff and sediment yield capacity than yellow soil slopes,particularly under a rainfall intensity of 60 mm/h.② Rainfall intensity and slope gradient synergistically exacerbated runoff and sediment erosion,with rainfall intensity dominating the runoff and sediment transport processes on red soil slopes.When the slope gradient reached 15°and rainfall intensity increased to 60 mm/h,the contribution of slope to sediment loss on yellow soil slopes increased to 59.06%.③ A high correlation was observed between runoff and sediment yield on both soil types.Yellow soil slopes generally exhibited a nonlinear relationship characterized by Y=a/[1+exp^-b（X-c）].In contrast,due to rapid saturation caused by poor structure,red soil slopes showed synchronous linear growth between sediment yield and runoff yield under a rainfall intensity of 60 mm/h,described by the function Y=a+bX.④ Among the slope hydraulic parameters,average velocity （V） could effectively predict the sediment yield trend of yellow soil （R²=0.52）,while the Froude number （F_r） was more suitable for predicting the sediment yield dynamics of red soil （R²=0.44）. [Conclusion] This study clarifies the coupling mechanisms of rainfall intensity and slope gradient in soil slope erosion within the Xin’an River basin.It is recommended that rainfall intensity regulation should be strengthened in red soil areas,while slope management should be emphasized in yellow soil areas to curb the exacerbation of soil erosion.

Abstract:[Objective] The variation patterns of soil moisture and nutrients under different artificial forests in the Loess Plateau were analyzed, and the impact of vegetation restoration on ecosystem structure and function was comprehensively evaluated, in order to provide a scientific basis for the sustainable management of regional artificial forests. [Methods] Typical artificial forest plots in loess regions of Gansu Province were selected as research subjects. Using soil moisture data at a depth of 6 meters and soil nutrient data at a depth of 1 meter collected from various regions between August and September 2022, the distribution characteristics of soil moisture and nutrients under different artificial forests in loess regions were analyzed, and the differences in soil moisture and nutrients under artificial forests across different regions were explored. [Results] ① In different regions, soil moisture profiles under artificial forests gradually decreased with increasing soil depth, indicating a progressive drying process. However, when artificial forests reached maturity or aging stages, soil moisture partially recovered. Geographically, in loess regions of Gansu Province, the average soil moisture under artificial forests showed an increasing trend from north to south and from west to east.② In terms of soil nutrients, most soils in each region were alkaline, with low contents of organic matter, total nitrogen, total phosphorus, and total potassium. Alkali-hydrolyzable nitrogen was highest in Longxi County and lowest in Zhenyuan County. Available phosphorus was highest in Heshui County and lowest in Tianshui County. Available potassium was highest in Heshui County and lowest in Zhenyuan County. [Conclusion] During vegetation restoration in the Loess Plateau, soil moisture and nutrient distribution characteristics of different microtopographies should be considered, and the planting principle of ‘right tree in the right place' should be followed to reasonably configure tree, shrub, and grass planting patterns to improve the soil environment. This approach plays a positive role in ecological management in the Loess Plateau.

Abstract:[Objective] The dynamic variations in salt ions in coastal saline soil and the differences in maize growth indicators after the addition of different amendments were analyzed in order to provide scientific basis for the further refinement of management measures for desalination and amelioration of coastal saline soil. [Methods] A field-controlled experiment was conducted in the Dafeng coastal reclamation area of Yancheng City,with maize（Liyu 88） as the aboveground crop.A total of ten treatments were set up:control （CK）,and compound fertilizer combined with low ①,medium ②,and high ③ levels of biochar （BC₁-BC₃）,desulfurized gypsum （DG₁-DG₃）,and chicken manure （CM₁-CM₃）.The response characteristics of the physicochemical properties and salt ions of coastal saline soil,as well as maize growth,were analyzed. [Results] ① All amendments improved the soil physicochemical properties,salt ion contents,and ion composition to some extent.However,the addition of desulfurized gypsum was more effective in improving the core physicochemical properties of coastal saline soil,significantly reducing soil pH value and electrical conductivity （EC）.The medium level of desulfurized gypsum（DG₂） was most effective in ameliorating soil salt ions,significantly reducing the contents of Na⁺ and Cl^- and the sodium adsorption ratio （SAR）.Additionally,this treatment promoted the accumulation of K⁺,Ca²⁺,Mg²⁺,and SO₄^2-,but had little influence on NO₃^-.② The promoting effect of maize growth by desulfurized gypsum addition was superior to that of biochar and chicken manure.Notably,the medium level of desulfurized gypsum （DG₂） treatment resulted in the highest maize yield among all treatments over the two years,reaching 2.337 t/hm² and 2.190 t/hm²,respectively. [Conclusion] Among the different amendment levels tested,the medium-level addition of desulfurization gypsum （5 t/hm²）(DG₂) is the most effective for enhancing soil desalination and increasing maize yield in coastal saline soil,and can be prioritized for the soil amelioration.

Abstract:[Objective] The restoration effects of three measures: fenced enclosure, reseeding and grazing prohibition, on the vegetation characteristics and diversity of different types of degraded grasslands in Ili, Xinjiang were analyzed in order to provide a scientific basis for vegetation restoration of degraded grasslands and sustainable development of regional animal husbandry in Ili. [Methods] Taking the degraded grasslands in Ili, Xinjiang as the research objects, 22 sample plots were selected for field investigation, with free grazing areas serving as the control. The vegetation restoration effects of fenced enclosure, reseeding, and grazing prohibition on six grassland types-mountain meadow, lowland meadow, temperate meadow, temperate desert steppe, alpine meadow, and alpine steppe-were analyzed. [Results] ① After fenced enclosure, vegetation height, coverage, aboveground biomass, and litter biomass of the six grassland types increased significantly by 66%, 50%, 48%, and 52%, respectively, and diversity indices such as the Simpson index also showed significant increases(p<0.05). After reseeding, community vegetation coverage, aboveground biomass, and the Simpson index increased significantly by 57%, 70%, and 10%, respectively(p<0.05). After grazing prohibition, plant species, community vegetation coverage, and aboveground biomass of the mountain meadow increased significantly by 32%, 51%, and 29%, respectively(p<0.05).② Fenced enclosure showed the most prominent restoration response in the temperate desert steppe, with increases in the Simpson index, plant species, community coverage, and aboveground biomass all higher than those in other grassland types. Reseeding had the optimal effect on improving productivity in the alpine meadow, with increases in aboveground biomass and vegetation coverage significantly higher than those in the temperate desert steppe. Grazing prohibition only exhibited short-term restoration effects in the mountain meadow.③ Significant correlations were found between vegetation characteristics and diversity indices of degraded grasslands. Aboveground biomass was extremely significantly positively correlated with litter biomass and vegetation coverage(p<0.01), while aboveground biomass, community vegetation coverage, litter biomass, and plant species were significantly negatively correlated with bare land area(p<0.05).④ All three restoration measures were effective for restoring degraded grasslands in Ili, among which reseeding was the most effective measure for improving community vegetation coverage and aboveground biomass. [Conclusion] Fenced enclosure, reseeding, and grazing prohibition can significantly promote the vegetation restoration of degraded grasslands in Ili, Xinjiang, and the restoration effects of different measures are specific to grassland types. Reseeding has the best effect on improving community productivity.

Abstract:[Objective] The characteristics of agricultural non-point source pollution load in Qinghai Province were analyzed in order to provide important references for formulating agricultural pollution control and ecological protection policies in Qinghai and other ecologically fragile areas. [Methods] Based on statistical data from Qinghai Province from 2009 to 2023,emissions of total nitrogen （TN）,total phosphorus （TP）,chemical oxygen demand （COD）,and ammonia nitrogen （NH₃-N） from crop farming,livestock and poultry breeding,and rural domestic sources were estimated using the pollutant generation and discharge coefficient-based method.Sensitivity analysis was conducted by selecting uncertain parameters.The contribution characteristics of pollution sources and pollutants were assessed using the equivalent standard pollution load method. [Results] From 2009 to 2023,the total agricultural non-point source pollution emissions in Qinghai Province showed an increasing trend,rising from 2.17×10⁵ t to 3.65×10⁵ t,an increase of 67.9%.In terms of pollutant type,COD emissions were the largest,ranging from 19.06×10⁴ t to 3.34×10⁵ t and accounting for 87.72%—91.63% of the total emissions.TN emissions ranked second,ranging from 2.23×10⁴ t to 2.52×10⁴ t and accounting for 6.91%～10.28%.Regarding the pollution source structure,livestock and poultry breeding was the primary emission source,with emissions of 1.74×10⁵—3.24×10⁵ t,contributing 80.21%—88.89% of the total emissions.Rural domestic sources ranked second,emitting 2.78×10⁴—2.95×10⁴ t and accounting for 7.71%—12.79%.Sensitivity analysis indicated that livestock and poultry breeding was the most sensitive to regional pollution load regulation,identifying it as the priority for control.The total annual equivalent standard pollution load ranged from 4.42×10¹⁰ m³ to 5.69×10¹⁰ m³.Among these,TN had the largest equivalent standard pollution load of 2.23×10¹⁰ m³ to 2.52×10¹⁰ m³,accounting for 44.30%—50.61%,making it the primary pollutant.Livestock and poultry breeding had the largest equivalent standard pollution load of 2.72×10¹⁰ m³ to 4.31×10¹⁰ m³,accounting for 61.69%—75.78%,identifying it as the dominant pollution source.Considering the equivalent standard pollution load characteristics of both pollution sources and pollutants,TN from livestock and poultry breeding constituted the largest portion of the equivalent standard pollution load at 1.17×10¹⁰ to 1.68×10¹⁰ m³,representing 26.29%—29.46% of the total. [Conclusion] Addressing agricultural non-point source pollution in Qinghai Province should prioritize the control of livestock and poultry breeding,with TN and COD identified as the key pollutants to control,so as to effectively reduce the regional agricultural pollution load and strengthen the ecological security barrier of the plateau water system.

Abstract:[Objective] The spatiotemporal evolution characteristics of mountain-oasis-desert ecosystem service value （ESV） in the Manas River basin from 2000 to 2023,as well as the differences across various landforms were analyzed in order to provide a scientific basis for optimizing land use planning and ecological protection in the river basin,and for formulating regional zoning management and development strategies. [Methods] Land use change information was extracted from remote sensing data spanning from 2000 to 2023.The equivalent factor method was used to assess the ESV across the river basin.Subsequently,correlation analysis was conducted to examine the spatiotemporal evolution characteristics of ESV and its relationships with land use changes. [Results] ① Land use dynamics were characterized by significant cropland expansion （net increase of 3 267.19 km²,total transfer-in of 3 621.11 km²） and grassland contraction （net loss of 3 493.61 km²）.Cropland expansion was predominant in the oasis zone,while the mountainous zone exhibited degradation of natural ecological land.② The total ESV of the river basin exhibited an overall downward trend,with a cumulative loss of 2.74×10¹⁰ yuan over 23 years.A particularly sharp decline （33.90%） was observed from 2005 to 2010.③ Among ESs categories,hydrological regulation value experienced the greatest reduction (1.93×10¹⁰ yuan),while the values of food production,raw material supply,and nutrient cycling increased.④ Spatially,high-ESV zones were concentrated in the southern mountainous glacier region and the Manas Lake region,while desert zones were identified as lowESV zones.The ESV across the three geomorphic zones ranked as follows:oasis zone>mountainous zone>desert zone. [Conclusion] Agricultural expansion-driven land use transition is identified as the primary factor exacerbating the degradation of ecosystem service functions in the Manas River basin.It is recommended to establish geomorphology-based zonal regulation mechanisms.Emphasis should be placed on mitigating the tradeoff between food production and other ecological functions in the oasis zone,ensuring the rational allocation and efficient utilization of scarce water resources,and promoting the orderly management of ecosystem services and the coordinated development of ecology and economy in this arid region.

Abstract:[Objective] The spatiotemporal evolution trends and driving mechanisms of vegetation cover in the Dongting Lake area from 2000 to 2022 were investigated, in order to identify key influencing factors and their contribution levels, and provide scientific references for regional ecological restoration and sustainable development. [Methods] Based on the Google Earth Engine cloud platform, the kernel normalized difference vegetation index(kNDVI) was constructed using MOD13A1 V6 data. The Theil-Sen Median trend analysis, Mann-Kendall test, Hurst index, and structural equation model(SEM) were integrated to systematically analyze the spatiotemporal variation characteristics of kNDVI in the Dongting Lake area. The coupling mechanisms among climatic factors, human activities, and topographic factors were comprehensively assessed. [Results] ① From 2000 to 2022, the kNDVI in the Dongting Lake area showed an overall increasing trend(0.025/10 a, p<0.001), with a spatial pattern of higher values in the eastern, southern, and western parts and lower values in the central and northern parts.② Vegetation cover exhibited persistent improvement, with the Hurst index predicting that persistently improved areas accounted for 57.87%, persistently stable areas for 38.97%, and persistently degraded areas for only 3.61%.③ The SEM demonstrated that the total effects of driving factors on kNDVI changes were ranked as follows: nighttime light > population density > elevation > slope > land use > soil moisture > temperature > aspect > precipitation. [Conclusion] Over the past 23 years, vegetation cover in the Dongting Lake area has shown overall improvement. Human activities are the primary negative driving factor of vegetation change, climatic factors play a positive promoting role, and the effects of topographic factors remain relatively limited.

Abstract:[Objective] The formation mechanisms of clustered slope debris flows in Mentougou District, Beijing City, were analyzed in order to provide a theoretical basis for the prevention and control of this type of deloris flow. [Methods] A multi-source data fusion approach combined with field verification was adopted.① Maxar WorldView 0.3 m high-resolution remote sensing images were applied for the first time to identify the spatial distribution, flow paths, and depositional characteristics of the group-occurring slope debris flows.② UAV oblique photogrammetry was used to obtain high-precision topographic data of typical disaster sites. [Results] The group-occurring slope debris flows in Wangping Village resulted from the triple coupling of ‘geological environment basement-extreme rainfall-human engineering disturbance'. Geologically controlled by an anticline structure, with slope gradients ranging from 19.49° to 36.54°, the ‘dual structure' formed by residual-slope deposits and bedrock provided material sources and sliding boundaries for the debris flows. Extreme rainfall(cumulative rainfall >700 mm, maximum rainfall intensity of 111.8 mm/h) led to soil saturation and triggered the flows. Human engineering disturbances altered slope topography and reduced slope stability. The disasters were concentrated along the anticlinal axis, characterized by small scale, high group occurrence, and strong concealment. [Conclusion] An integrated model of ‘combining prevention and control, ecological-economic synergy' is proposed.① Flexible barriers are deployed in the material source initiation areas and upstream of protected objects(residential areas, railways), saving 70% of the investment compared to traditional reinforced concrete barrier dams.② The application of geocells combined with grass planting measures in erosional gullies saves 52% of costs compared to traditional stone masonry retaining walls and reduce soil loss by over 90%.

Abstract:[Objective] The changes in ecological environment quality and their driving factors in the Yellow River Source Park of the Three-River-Source National Park from 2000 to 2024 were investigated in order to provide a scientific basis for ecological protection and sustainable development in this region. [Methods] Based on the Google Earth Engine platform, MODIS images were acquired and processed to construct remote sensing ecological index(RSEI) for monitoring changes in ecological environment quality in the Yellow River Source Park from 2000 to 2024. Additionally, the geodetector model was utilized to quantitatively analyze the effects of climate, topography, and human activities on these changes. [Results] ① From 2000 to 2024, the annual mean RSEI in the Yellow River Source Park ranged between 0.527 and 0.689, showing a fluctuating upward trend with an average increase rate of approximately 0.003 1 per year. Spatially, the ecological environment quality exhibited a distribution pattern of ‘poor in the north and good in the south'.② The area with improved ecological environment quality accounted for 81.50%, which was significantly higher than the degraded area(9.38%), indicating remarkable ecological improvement.③ In single-factor detection, precipitation had the strongest explanatory power, followed by temperature and DEM. In interaction detection, the interaction between precipitation and temperature had the greatest influence, followed by the interaction between precipitation and DEM. The influence of climate and topographic factors gradually weakened, while the impact of human activities progressively strengthened. [Conclusion] From 2000 to 2024, the ecological environment quality in the Yellow River Source Park continuously improved. Precipitation, temperature, and DEM are the main driving factors affecting ecological quality, and the ecological protection and restoration efforts undertaken by humans have achieved remarkable results. Future work should focus on gradually advancing ecological management in key and challenging areas while ensuring the continuous improvement of the ecological environment in the study area.

Abstract:[Objective] The variation characteristics of different precipitation grades in Jilin Province from 1960 to 2024 were analyzed in order to provide a scientific basis for the sustainable management of water and soil resources and the prevention and control of drought and flood disaster risks in the province. [Methods] Based on daily precipitation data from 47 meteorological stations in Jilin Province from 1960 to 2024, methods including linear trend analysis, correlation analysis, and Hurst exponent were employed to investigate the spatiotemporal variation characteristics and trend persistence of precipitation amount, precipitation days, and precipitation intensity across different grades. [Results] During the study period, the precipitation structure in Jilin Province underwent significant changes. Both light precipitation amount and light precipitation days showed decreasing trends(p<0.05), while rainstorm amount and rainstorm days increased significantly(p<0.05). Precipitation intensity exhibited an increasing trend for all grades except for heavy rainstorm intensity, which showed a slight decline. Moderate rain contributed the most to total precipitation(33.44%), followed by light rain(33.14%). Light rain had the highest occurrence frequency(83.11%). However, both its contribution and occurrence frequency showed decreasing trends, whereas those of rainstorms increased significantly. Changes in total precipitation amount were mainly influenced by heavy rain, changes in total precipitation days were dominated by light rain days, and total precipitation intensity was closely related to the amount and days of heavy rain and rainstorms. Spatially, precipitation amounts and days for all grades exhibited a pattern of higher values in the southeast and lower values in the northwest, while precipitation intensity showed considerable spatial heterogeneity across different grades. Notably, the transformation of precipitation structure characterized by increased rainstorm events and decreased light rain events was widespread across the province, albeit with regional variations in its intensity. The interaction of geofactors significantly controlled the spatial differentiation of light and moderate precipitation amounts and days. In contrast, precipitation of rainstorm grade and above was more influenced by local weather systems, showing weaker correlations with geofactors. Hurst exponent analysis indicated that, except for the future trend of heavy rainstorm intensity which might reverse, the historical change trends of other precipitation indicators all exhibited strong persistence. [Conclusion] The precipitation structure in Jilin Province is evolving towards a more extreme pattern characterized by increased rainstorm events and decreased light rain events. Greater attention should be paid to this issue in future research and policy-making related to regional water-soil security and meteorological disaster prevention.

Abstract:[Objective] The spatiotemporal distribution of abandoned farmland in the core black soil protection area of Jilin Province from 2000 to 2023 was analyzed, the main driving factors of farmland abandonment were clarified, and the soil and water conservation effects of abandoned farmland are evaluated, in order to provide a theoretical basis for remote sensing monitoring of abandoned farmland and research on soil and water conservation effects in similar regions. [Methods] Based on the Google Earth Engine（GEE） platform and Landsat long-term time-series imagery, this study integrated multidimensional characteristics and combined random forest with LandTrendr change detection method to map the spatiotemporal distribution of abandoned farmland in the study area. Additionally, the key driving factors were analyzed using the geodetector. Finally, a comprehensive evaluation of the soil and water conservation effects of abandoned farmland was conducted using a combination weighting method based on AHP-EM-product normalization. [Results] ① The RF-LT model achieved an overall accuracy greater than 85% and a Kappa coefficient of at least 0.8, indicating high classification accuracy and good overall performance.② The area of abandoned farmland initially increased and then experienced a fluctuating decline after peaking at 459 km² in 2013. Spatially, it first increased then decreased, and finally showed local increases, with relatively scattered distribution of abandoned farmland.③ Night-time light intensity, average parcel area, and elevation had high explanatory power for farmland abandonment, with q-values all exceeding 0.4. Furthermore, the interaction between slope and average parcel area was the most significant, with a q-value of 0.997.④ The comprehensive scores of soil and water conservation effects for abandoned farmland in the study area with abandonment durations of 5, 10, 15, 20, and over 20 years were 0.388 6, 0.477 3, 0.801 4, 0.604 4, and 0.443 8, respectively, showing an initial increase followed by a decrease. [Conclusion] The moderate abandonment within a certain period has a positive impact on soil and water conservation, specifically reflected in the improvement of ecological diversity and soil properties.

Abstract:[Objective] The non-stationary dynamic characteristics of surface soil moisture under microtopographic conditions were systematically analyzed in order to provide important scientific support for optimizing water management strategies and constructing self-sustaining ecosystems in ecological restoration of arid regions. [Methods] Based on continuous monitoring data and the Pettitt test,abrupt change points of soil moisture during the frozen soil thawing period were quantitatively identified and stages were divided.The regulatory mechanisms of microtopography on soil moisture dynamics at different depths were revealed,and a snow-topography-moisturesoil response chain was constructed.The ARIMA （1,1,1） model was applied to predict soil moisture trends. [Results] ① During the early thawing period,shallow soil moisture （10 cm and 20 cm） in the restored area increased significantly,with maximum values of 0.312 m³/m³ and 0.199 m³/m³,and average increases of 22.1% and 19.4%,respectively.In the control area,the maximum values were 0.231 m³/m³ and 0.186 m³/m³,with average increases of only 14.6% and 12.5%.Moisture recharge in soil layers at 30 cm and below was relatively weak,with no significant difference between the restored and control areas.②During the mid-thawing period,soil moisture at 10 cm and 20 cm in the restored area gradually decreased but remained higher than that in the control area.Moisture at 30 cm and 40 cm in the restored area increased slowly,with maximum values of 0.155 m³/m³ and 0.139 m³/m³,respectively,while in the control area,the values were 0.127 m³/m³ and 0.129 m³/m³.③During the late thawing period,soil moisture stabilized,while groundwater moisture decreased.Shallow soil moisture in the restored area showed relatively large fluctuations,enabling ephemeral plants to rapidly complete their life cycle by utilizing moisture pulses.The ARIMA （1,1,1） model performed well in predicting soil moisture at depths of 10 cm and 20 cm,with Nash-Sutcliffe efficiency coefficients of 0.85 and 0.82,respectively,indicating high predictive accuracy. [Conclusion] Microtopography restoration significantly enhances shallow soil moisture during the seasonal frozen soil thawing period,improving water availability for the early spring germination of ephemeral plants.Level trenches,as a near-natural restoration measure,demonstrate good ecological regulation potential and promotion value.

Abstract:[Objective] A comprehensive quantitative evaluation of the overall effectiveness and that under different value realization models of typical cases in northwest China was conducted, and the feasibility of the evaluation indicator system for evaluating the effectiveness of typical cases was further verified, in order to provide references for other regions to extract relevant typical cases. [Methods] 29 typical cases in northwest China were selected as the study objects. A three-dimensional evaluation system encompassing ‘resources-mechanismsbenefits' was established. The entropy value method and the comprehensive index method were used to calculate the overall effectiveness, stage-specific effectiveness, and effectiveness of different models in realizing ecological product value. [Results] ① The overall effectiveness of ecological product value realization varied significantly across cases, with 16 cases falling below the average score of 36.47, indicating that there was still room for improvement in value realization. The synergy among multiple mechanisms constituted the core stage in the process of ecological product value realization. The output of comprehensive benefits was influenced by factors such as policy time lags, which resulted in relatively slow performance and lower scores.② All existing ecological product value realization models incorporated industrialization pathways. The effectiveness scores for the ‘transaction+industrialization' ‘restoration+transaction+industrialization' and ‘compensation+industrialization' models were 46.27, 41.72, and 38.62, respectively, indicating relatively good performance.③ Both the ‘industrialization' and ‘restoration+industrialization' models prioritized multi-mechanism synergy as their primary achievement, while the ‘compensation+industrialization' model achieved the highest score(48.86) in comprehensive benefit output. [Conclusion] The realization of ecological product value in northwest China has achieved phased results, yet it still faces the challenge of relatively low comprehensive benefit output. In the subsequent efforts to promote ecological product value realization, it is essential to be guided by the goal of maximizing comprehensive benefits, establish and improve multi-mechanism synergy, and continuously optimize the market transaction environment.

Abstract:[Objective] The impact of seasonal drought on water use efficiency(WUE) of ecosystems and its carbon-water coupling mechanisms was analyzed in order to provide a scientific basis for enhancing vegetation carbon sequestration capacity, optimizing water resource allocation, and formulating ecosystem protection strategies. [Methods] Based on data from China's terrestrial ecosystems from 2001 to 2023, the spatiotemporal dynamics and seasonal patterns of WUE and its responses to drought were systematically assessed using trend and correlation analyses. By integrating the XGBoost-SHAP interpretable machine learning model with LOWESS fitting, the nonlinear response characteristics and threshold effects of drought stress factors were further quantified. [Results] The frequency of extreme drought events and the WUE of vegetation in China both exhibited pronounced seasonal patterns. Extreme droughts occurred most frequently and extensively in spring, while WUE reached its peak in summer. Its seasonal variations were jointly driven by gross primary productivity(GPP) and evapotranspiration in spring, gradually shifting to a ‘ GPP-dominated' pattern in summer and autumn, with a decreasing gradient from south to north. In spring, WUE was co-regulated by soil moisture and evapotranspiration, whereas in summer and autumn, it was primarily controlled by soil moisture. [Conclusion] The impact of drought on WUE exhibits significant seasonal differences and is primarily constrained by soil moisture conditions. Enhancing water management during the key controlling seasons and optimizing vegetation structure are essential strategies for improving ecosystem drought resilience and mitigating climate change and ecological risks.

Abstract:[Objective] The positive role of ecological management projects in the ‘carbon reduction-pollution reduction-green expansion-economic growth' system of the urban agglomeration in the middle reaches of the Yangtze River was analyzed, and its spatiotemporal evolution patterns, influencing mechanisms, and future development trends were systematically revealed, in order to provide a scientific basis for the regional coordinated advancement of carbon reduction, pollution reduction, green expansion, and economic growth. [Methods] Based on data from 2003 to 2023, an evaluation system comprising 30 indicators was constructed. The entropy method, coupling coordination degree model, spatiotemporal geographically weighted regression model, and ARIMA prediction model were comprehensively employed to systematically analyze the spatiotemporal evolution patterns, driving mechanisms, and future trends of coupling coordination in this region. [Results] The results showed that:① the mean coupling coordination degree(0.44—0.75) showed an upward trend during the study period. However, significant inter-provincial and intra-provincial differences were observed. Hubei Province had the highest coupling coordination degree(0.82), while Hunan Province lagged relatively behind(0.74).② The driving factors exhibited spatiotemporal heterogeneity. The level of digital economy and industrial structure upgrading served as a positive driving factor, while the contribution of technological investment was not significant. Government intervention exerted a certain inhibitory effect due to the conflict between administrative governance and marketization.③ The high consistency between the actual and predicted values in 2023 confirmed the reliability of the future trend prediction. It was projected that by 2030, the coupling coordination degree of core cities such as Wuhan, Changsha, and Nanchang would approach or exceed 0.85. However, the growth rate of small and medium-sized cities would be slow, and inter-provincial disparities would narrow. [Conclusion] From 2003 to 2023, the coupling and coordinated development level of carbon reduction, pollution reduction, green expansion, and economic growth in the region has been continuously increasing and is expected to maintain an upward trend. Significant inter-provincial and intra-provincial differences are observed in development levels within the region. It is recommended to strengthen the radiating role of core cities, promote industrial transformation and the application of scientific and technological achievements, improve the ecological compensation mechanisms, and implement targeted policies based on the spatiotemporal differences of driving factors to facilitate regional coordinated development.

Abstract:[Objective] The spatiotemporal evolution characteristics of regional land use and carbon storage were analyzed,in order to predict future changes in land use and carbon storage,thereby provide a scientific basis for achieving the 'dual carbon' goals and sustainable development.[Methods] Taking Pingxiang City as a case study,this study analyzed the spatiotemporal evolution characteristics of land use and carbon storage,explored the impact of land use change on carbon storage,and identified areas requiring protection and restoration through hot and cold spot analysis. Subsequently,the PLUS model was used to predict land use and carbon storage under different scenarios in 2035.[Results] ① From 2010 to 2024,the expansion of cultivated land and artificial surfaces encroached on forests with higher carbon density,leading to a reduction of carbon storage of 2.29×10⁶ t. ② Two areas with relatively high hot spot intensity in the central-southern region were fragmented. Measures should be taken to make them more concentrated to improve carbon sequestration efficiency. ③ Among the predictions under the natural development, cultivated land protection, ecological protection, and urban development scenarios,carbon storage under the ecological protection scenario decreased by only 0.24%,while the other three scenarios showed significant reductions due to newly scattered artificial surfaces within forests in the central-southern region.[Conclusion] In Pingxiang City,the expansion of artificial surfaces and cultivated land leads to a reduction in forests and a decline in carbon storage. Therefore,it is necessary to protect forests in the central-southern region,optimize the layout of artificial surfaces,and minimize carbon loss under the ecological protection scenario.

Abstract:[Objective] The value conversion of agricultural ecological products empowered by the digital economy was explored in order to provide a theoretical basis for building digital villages and increasing farmers' income. [Methods] The ecological value of agricultural ecological products was calculated using the functional value method, and the value conversion efficiency of agricultural ecological products in 99 cities along the Yangtze River economic belt from 2012 to 2022 was measured using the super-efficiency SBM model. The variation trend of value conversion efficiency was analyzed through kernel density analysis. The impact mechanisms of the digital economy on the value conversion efficiency of agricultural ecological products were explored using the two-way fixed effects model. Furthermore, the spatial Durbin model was used to test whether there were spatial spillover effects of the digital economy on the value conversion efficiency of agricultural ecological products in the Yangtze River economic belt. [Results] ① The value conversion efficiency of agricultural ecological products in the Yangtze River economic belt showed an upward trend, with slight polarization observed.② The digital economy significantly enhanced the value conversion efficiency of agricultural ecological products.③ The digital economy improved the efficiency by promoting green technology innovation and green finance. Heterogeneity analysis indicated that in the lower reaches of the Yangtze River economic belt and in resource-based cities, the digital economy was more conducive to improving the efficiency of agricultural ecological product value conversion.④ The digital economy had a significant spatial spillover effect on the value conversion efficiency of agricultural ecological products. [Conclusion] The digital economy significantly promotes the value conversion efficiency of agricultural ecological products, exhibiting mediation effects, heterogeneity, and spatial spillover effects, which should be fully considered when promoting the conversion of agricultural ecological product value.

Abstract:[Objective] The spatiotemporal differentiation patterns of ecosystem service value(ESV) in typical estuarine deltas of coastal regions in China(hereinafter referred to as the Pearl River delta, Yangtze River delta, and Yellow River delta) were systematically analyzed, in order to provide a scientific basis for the formulation of regional coordinated development and ecological conservation strategies. [Methods] By comprehensively utilizing multi-source spatiotemporal data and combining spatial analysis with econometric modeling methods, this study investigated the spatiotemporal evolution characteristics of ESV in typical estuarine deltas in 1985—2024. [Results] ① During the study period, the urbanization levels of all regions continuously increased, but the spatial patterns showed significant differences. The Pearl River delta presented a ‘core-subcenter' clustered structure, the Yangtze River delta showed a ‘metropolitan area + development axis' pattern, and the Yellow River delta exhibited a dispersed, point-like development pattern.② The spatial distribution characteristics of ESV differed substantially among regions. The Pearl River delta showed high-value clustering in the southwest, the Yangtze River delta exhibited a pronounced south-north gradient differentiation, and the Yellow River delta formed a concentric structure characterized by low values in the center and high values in the periphery.③ The spatial correlation between urbanization and ESV showed regional differences. The Pearl River delta and Yangtze River delta demonstrated a significant positive spatial correlation, whereas the Yellow River delta showed a negative correlation, revealing the differences in human-environment relationships at different stages of development. [Conclusion] In response to the demands for high-quality development and ecosystem service enhancement in typical estuarine deltas, differentiated development pathways should be adopted. The Pearl River delta should strengthen coordinated spatial governance, the Yangtze River delta should enhance integrated ecosystem management, and the Yellow River delta should establish mechanisms for realizing ecological value oriented towards resource development and climate adaptation.

Abstract:[Objective] The spatiotemporal variation characteristics of water ecosystem services in the Haihe River basin were analyzed, and the impact patterns of climate, land use change, and water ecological governance measures on water ecosystem services were explored, in order to provide a scientific basis for the healthy management of water resources in the river basin. [Methods] Water yield and water purification were selected as the core water ecosystem services in the Haihe River basin. Using the InVEST model, the water yield and water purification functions were simulated for nine periods from 1985 to 2023 in the river basin. Scenario analysis was applied to calculate the contribution rates of climate and land use to changes in water ecosystem services, and the GTWR model was used to quantify the impacts of climate, land use, and water ecological governance factors on water ecosystem services. [Results] ① From 1985 to 2023, water yield exhibited an overall fluctuating upward trend, with a multi-year average of 105 mm. Spatially, water yield increased in the central and southwestern regions and decreased in other regions.② From 1985 to 2023, the total nitrogen(TN) export, representing the water purification function, showed a fluctuating upward trend, while the total phosphorus(TP) export declined continuously and then stabilized. Spatially, N and P exports increased in the southern region and decreased in the northern region.③ The contribution rates of climate and land use to changes in water yield were 56% and 44%, respectively. Increases in inter-basin water transfer volume, precipitation, and water area enhanced water yield, while increases in temperature and evaporation inhibited it. The contribution rate of climate to changes in both N and P exports was 61%, and that of land use was 39%. Increases in wastewater treatment and reuse volume, evaporation, and water area promoted the water purification function, while increases in temperature and precipitation inhibited it. [Conclusion] The spatiotemporal heterogeneity of water ecosystem services in the Haihe River basin is jointly driven by climate, land use, and water ecological governance measures. High-intensity human development activities have increased water resource utilization intensity and simultaneously caused degradation of the water purification function, while water ecological governance measures have effectively alleviated this trend.

Abstract:[Objective] The evolution characteristics and driving factors of water-related ecosystem services(WRESs) in Hebei Province under land use and land cover change(LUCC) and climate change(CC) scenarios in the future were quantitatively evaluated, and their multiscale uncertainties were revealed, in order to provide a scientific basis for regional water ecosystem management. [Methods] This study integrated the MRI-ESM2-0 climate model, the future land use simulation(FLUS) model, and the integrated valuation of ecosystem services and tradeoffs(InVEST) model to evaluate the integrated effects of CC and LUCC on water conservation(WC) and soil erosion(SE) in Hebei Province, and to reveal their multiscale uncertainties. [Results] From 2024 to 2050, WC in Hebei Province showed an overall upward trend under both climate scenarios. Under the SSP245 scenario, WC increased first and then stabilized, while it continuously increased under SSP585. SE exhibited an overall declining trend, decreasing steadily under SSP245 but first increasing and then decreasing under SSP585. CC played a dominant role in influencing WRESs, with its contributions to WC and SE reaching up to 99.30% and 93.14%, respectively. However, its influence gradually weakened over time. The contribution of LUCC to WC declined over time, while its contribution to SE, though smaller, gradually increased. Uncertainty driven by CC was generally higher than that driven by LUCC, and overall uncertainty decreased over time across all scales. [Conclusion] Water-related ecosystem services in Hebei Province are projected to show an overall trend of “enhanced water conservation and reduced soil erosion”. The synergistic effects of climate humidification and ecological protection significantly improve regional hydrological regulation and ecological stability. Strengthening ecological restoration and implementing zonal management are key pathways to enhance regional water security and mitigate climate risks.

Abstract:[Objective] The spatiotemporal evolution and scale-dependent driving mechanisms of newly cultivated land（NCL） in western Jilin Province were analyzed, and cultivated land protection zones were delineated, in order to provide a scientific basis for spatially differentiated cultivated land reclamation and precise management. [Methods] Based on land use data from six periods between 2000 and 2024, methods including spatial autocorrelation analysis, geodetector, and self-organizing feature map（SOFM） clustering were used to systematically examine the multi-scale driving mechanisms of NCL and to delineate cultivated land development and protection zones. [Results] ① The total cultivated land area showed a pattern of “decrease followed by an increase”. NCL increased steadily after 2010, reaching 3.51×10⁶ hm² by 2023. Spatially, NCL was highly clustered（global Moran's I: 0.293—0.415）.② The driving factors exhibited significant scale effects. Reserve cultivated land availability was the dominant factor at the county level（q= 0.618）, while settlement accessibility and water resource conditions were more influential at the township and village levels. At the 5 km grid scale, landscape pattern factors became the core drivers.③ Significant interactive effects were identified between socioeconomic factors such as population density and cultivated land condition factors.④ Four distinct functional zones were delineated: ecologically constrained and vulnerable zones mainly in the east and northwest, where natural constraints strongly limited the potential of NCL; cultivated land priority protection zones in areas with convenient transportation and stable cultivated land use, where strengthened protection of basic cultivated land was required; cultivated land potential development zones with abundant reserve cultivated land resources suitable for reclamation and expansion; and NCL key control zones primarily in urban-rural fringes, where strict land development control and ecological protection policies were necessary. [Conclusion] NCL in western Jilin Province is concentrated in cultivated land-dense areas in the western and southwestern parts of the study area. The driving mechanisms exhibit pronounced scale effects, and the interactions between socioeconomic and cultivated land condition factors are significant. Therefore, differentiated management measures should be implemented to optimize the layout of NCL and coordinate food security with ecological protection.

Abstract:[Objective] The spatiotemporal variation characteristics and driving mechanisms of net ecosystem productivity（NEP） were investigated in order to provide a scientific basis for the refined evaluation of regional carbon budgets and the optimization of ecological and environmental management strategies. [Methods] Xuzhou City, a resource-exhausted city in Jiangsu Province, was selected as the study area. By integrating MOD17 A3 remote sensing products with meteorological observation data, and applying Theil-Sen median regression analysis, coefficient of variation, Hurst index, and optimal parameters-based geodetector methods, the spatiotemporal evolution patterns, fluctuation characteristics, future trends, and driving factors of vegetation NEP in Xuzhou from 2001 to 2023 were quantitatively analyzed. [Results] ① The multi-year mean NEP in Xuzhou was 141.36 g/（m²·a）(calculated as C), showing a statistically significant upward trend with an annual increase of 1.690 g/（m²·a）. Spatially, NEP exhibited a clear gradient pattern, with higher values in the northwest and southeast and lower values in the central region, forming a pronounced southeastward-increasing distribution.② From 2001 to 2023, NEP increased in 67.70% of the study area, while 13.49% experienced a decline. Highvolatility regions covered a much larger area than low-volatility regions, indicating relatively low NEP stability during the city's transition.③ Hurst exponent analysis（mean value: 0.425） indicated a tendency for future NEP trends to reverse compared with those observed over the past 23 years.④ Optimal parameters-based geodetector results identified the main driving factors of NEP variation in Xuzhou, ranked by explanatory power, as vegetation cover, environmental pollution, soil and water conservation capacity, socioeconomic development, and human activity intensity. Climate factors（temperature and precipitation） and landscape patterns played secondary roles. [Conclusion] Although Xuzhou has gradually enhanced its carbon sink capacity during the transition period, its overall stability remains limited, and there is a potential risk of future functional reversal. To maintain and strengthen regional carbon sink capacity, it is necessary to optimize vegetation restoration pathways, improve pollution control, and achieve a balanced integration of socioeconomic development and ecological protection.

Abstract:[Objective] The current research status and development trends in the field of plant diversity in desertified areas were analyzed, and the evolution of research hotspots and future directions were clarified, in order to provide a theoretical basis for understanding ecosystem responses, guiding ecological restoration, and informing global desertification control. [Methods] Using CiteSpace 6.4 R1, a multi-dimensional analysis is conducted on literature from CNKI(1961—2024, 1 397 articles) and Web of Science(1999—2024, 2 899 articles) databases. [Results] ① Research on plant diversity in desertified areas showed phased growth. The average annual growth rate of Chinese literature was 8.7%, with core journals represented by the Journal of Ecology, while English literature is widely distributed in interdisciplinary journals such as Frontiers in Microbiology.② Cross-regional research networks were formed by institutions including the Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, and the University of California System. Chinese scholars focued on desert ecosystem structure and functional responses, while international research emphasized microbial interactions and genetic diversity.③ Keyword evolution showed that research hotspots had shifted from drought physiology(before 2000) to water-community coupling mechanisms(2000—2010), and had expanded to ecological resilience assessment and the integration of multi-omics technologies since 2020.④ The analysis of emergent words revealed that Chinese literature focused on the dynamic regulation of environmental factors, while English literature concentrated on the ecological stoichiometry of carbon, nitrogen, and phosphorus, as well as abiotic stress mechanisms. [Conclusion] This study provides a direct species resource base, mechanistic knowledge, and technical support for global desertification control. Future research should integrate multi-scale data models and cross-border monitoring networks to deepen the understanding of ‘plant-microbe-environment' interactions, thereby providing more accurate support for ecological barrier construction and the restoration of degraded ecosystems.

Abstract:[Objective] The progress on microbial-biochar interaction mechanisms in saline-alkali soil improvement was systematically reviewed, in order to elucidate the mechanisms of synergistic effects, and identify potential risks, and provide a theoretical basis for the systematic development and risk management of this technology. [Methods] Using the bibliometric method, this study systematically reviews the research progress and development trends in the synergistic improvement of saline-alkali soil using microorganisms and biochar. It focuses on analyzing their synergistic mechanisms in physical structure construction, chemical environment regulation, and biological function enhancement. Furthermore, potential risks in the ‘material-strain-environmentmanagement' synergistic regulation, such as salt input and microbial competition, are discussed. [Results] This combined approach provides physical shelter and electron transfer channels through biochar, along with microbialmediated salt transformation and metabolic feedback, thereby synergistically enhancing soil functions. It can significantly reduce the electrical conductivity of saline-alkali soil, increase crop yield, and enhance the abundance of functional genes associated with the nitrogen cycle. [Conclusion] The microbial-biochar combined technology is a green and sustainable strategy for saline-alkali land management. Its synergistic mechanisms involve multidimensional physical, chemical, and biological effects, demonstrating promising application potential in both laboratory and field experiments. Future efforts should continue to focus on combination optimization, mechanism elucidation, regional adaptation, and technology integration to promote the standardized and large-scale application of this technology.

Abstract:[Objective] The research progress on the ecological environment of key lakes in the Yangtze River economic belt was systematically reviewed. Using bibliometric methods, research hotspots, development trajectories, and frontier trends were identified in order to provide scientific references for subsequent research and policymaking. [Methods] Based on the core databases of the China National Knowledge Infrastructure(CNKI) and the Web of Science(WOS), this study retrieved Chinese and English publications related to the ecological environment of key lakes in the Yangtze River economic belt from 1979 to the present. A total of 5 081 Chinese and 2 243 English publications are included. CiteSpace 6.3. R1 software was used to conduct keyword co-occurrence analysis, cluster analysis, burst word detection, and timeline mapping. A multidimensional visualization analysis is carried out, focusing on annual publication volume, research hotspots, and evolutionary trends. [Results] ① The annual publication volume can be divided into four stages: initial(1979—1995, with an average of fewer than 50 publications per year), slow growth(1996—2003), rapid growth(2004—2015), and enhanced international influence(2016 to present). National policies and major environmental events(such as the Taihu Lake cyanobacterial bloom event) have significantly affected the research trajectory.② Research hotspots focus on five major themes: mechanisms and control of lake eutrophication; characteristics and risk assessment of water and sediment pollution; driving effects of climate change and human activities on lake ecology; ecological restoration and biodiversity conservation; and application of remote sensing and intelligent monitoring technologies.③ Research frontiers have gradually shifted from early localized pollution control to multidimensional and systematic research. This shift is particularly evident in strong burst words in recent years, including ‘climate change'(2022 to present), ‘landscape pattern'(2015 to present), and ‘ecosystem services'(2019—2021), reflecting a growing focus on the synergy of social-ecological system and the integrated relationship between rivers and lakes. [Conclusion] Research on the ecological environment of lakes in the Yangtze River economic belt has formed a complete research chain, from problem identification to driver analysis, and to governance response, establishing a distinct theoretical and practical framework. Future efforts should focus on further strengthening the research on multiscale coupling mechanisms, cross-regional ecological compensation, and coordinated optimization of land use control mechanisms for lakes, as well as deepening the application of nature-based solutions(NbS) in lake restoration, so as to support ecological protection and high-quality development of the Yangtze River economic belt.