Abstract:[Objective] The characteristics of heavy metal content in paddy soil at Qianjiangyuan National Park were explored, and its pollution level was assessed. The sources of heavy metals were analyzed, and the associated human health risks were evaluated, in order to provide a reference basis for the prevention and control of soil heavy metal pollution and soil protection. [Methods] The pH value and contents of heavy metals, including Cd, Pb, Hg, Cr, As, Ni, Cu, and Zn, of 61 soil samples were determined. Index, factor and cluster analyses were employed to assess the characteristics of and ecological risks posed by the heavy metal pollution, analyze their sources, and evaluate human health risks. [Results] ① The surface soil of the paddy fields was acidic. The average Cd, Pb, Hg, Cr, As, Ni, Cu, and Zn contents were 0.19, 32.74, 0.13, 67.06, 4.43, 24.90, 21.51, and 94.60 mg/kg, respectively. The average contents of Hg, Cr, Ni, Cu, and Zn exceeded the Zhejiang provincial soil background values by 1.32, 1.71, 2, 1.19, and 1.13 times, respectively. ② The average contents of the eight heavy metals were lower than the corresponding risk screening values for agricultural land soil, as represented by the average heavy metal content in the paddy fields. The exceedance rates of sampling points for Cd, Ni, and Cr were 6.56%, 3.28%, and 1.64%, respectively. ③ The results of factor analysis and the other methods showed that the soil heavy metal sources were predominantly anthropogenic and were the result of a combination of human and natural influences. The overall carcinogenic health risk for children was deemed tolerable. [Conclusion] The level of heavy metal pollution in the paddy soil at Qianjiangyuan National Park was low, as was the overall ecological risk. However, pollution risks were associated with Cr and Ni. The heavy metal As is the primary carcinogenic factor affecting human health.

Abstract:[Objective] The effects of three types of microalgal fertilizers and their varying application rates on soil salinity, physiological indicators, and maize yield were explored, in order to provide a new scientific basis for the enhancement of saline soil. [Methods] A field experiment was conducted using saline alkali collected from the Tumochuan Plain. Three kinds of microalgal fertilizer (designated as W₁, W₂, and W₃) were formulated for the experiment. Each microalgal fertilizer was established with three levels of application (15, 30, and 45 L/hm², designated as N₁, N₂, and N₃, respectively), a control without fertilizer, resulting in a total of 10 treatments. [Results] ① Regarding the physical and chemical parameters of soil, the application of microalgal fertilizer considerably decreased soil bulk density by 4.11% to 12.34% compared to the control treatment. Soil porosity increased from 10.82% to 38.31%. The soil pH value and salt concentration fell by 1.82%—9.9% and 17.12%—47.66%, respectively. ② As for maize growth, compared with the control treatment, the plant height, stem diameter, and leaf area index of maize subjected to the microalgal fertilizer treatment increased from 1.12% to 18.47%, 1.15% to 29.02%, and 22.5% to 74.14%, respectively. The 100-grain weight and yield improved by 16.02%—48.31% and 15.73%—41.31%, respectively. Maize yield had a significantly negative correlation with soil bulk density and pH value while demonstrating a significantly positive correlation with the leaf area index. [Conclusion] The effect of the W₂ microalgal fertilizer applied at a rate of 30 L/hm² (W₂ N₂ treatment) on improving saline soil and increasing maize yield was better; it should therefore be given priority when selecting microalgae to improve saline soil in the Tumochuan Plain.

Abstract:[Objective] The seepage behavior of granite colluvial soil under a low hydraulic gradient was explored，in order to provide a scientific basis for regional engineering construction and geological disaster prevention and mitigation. [Methods] Constant head permeability tests were conducted on granite colluvial soil with varying initial dry densities to analyze its seepage characteristics under low hydraulic gradient. [Results] The relation curves between seepage velocitiy (v) and hydraulic gradient (i) (v-i) of granite colluvial soil exhibits varying degrees of seepage fluctuation under low hydraulic gradients. The permeability coefficient increases with the hydraulic gradient across all dry density conditions. When the hydraulic gradient reached the critical hydraulic gradient (i_cr), the permeability coefficient remained stable and undergoes approximately linear seepage. At this time, the permeability coefficient decreases logarithmically with the increase of dry density. Additionally, under low dry density conditions, the transition in the critical hydraulic gradient fluctuates significantly. However, when the dry density exceeds 1.5 g/cm³, the critical hydraulic gradient (i_cr) increases linearly with dry density. [Conclusion] The saturated seepage behavior of granite colluvial soil under different dry density conditions exhibits fluctuation characteristics under a low hydraulic gradient. The internal mechanism driving these fluctuations is closely related to variations in pore structure. These findings offer a novel perspective on the seepage process of granite colluvial soil and provide a reference for consolidation analysis and seepage stability calculation in engineering applications.

Abstract:[Objective] The effects of different initial moisture content and rainfall intensities on the splashing characteristics and processes of red soil macro-aggregates were explored, in order to provide a scientific basis for understanding and preventing the splash erosion process of red soil macro-aggregates. [Methods] Red soil macro-aggregates (2—5 mm) were selected for study. Artificially simulated rainfall experiments were conducted to explore the variation patterns of splash erosion and splash erosion rate with four rainfall intensities (30, 60, 90, and 140 mm/h) and four initial moisture content levels of moisture content (10%, 20%, 30%, and saturation). [Results] ① Under the same initial moisture content, the ranges of splash erosion amount for macro-aggregates of red soil at four different rainfall intensities were from 0.05 to 0.27 g, from 0.03 to 0.19 g, from 0.16 to 1.41 g, and from 0.03 to 1.48 g. ② At the same rainfall intensity, the splash erosion of the aggregates under saturated initial moisture conditions all increased significantly (p＜0.05). ③ At the four rainfall intensities, the splash erosion of the aggregates under saturated initial moisture conditions increased by 1.50, 1.11, 3.80, 3.21 times, respectively, compared to the sum of the splash erosion under unsaturated initial moisture conditions (10%, 20%, and 30%). ④ The initial moisture content, rainfall intensity, and their interaction all exerted direct positive effects on the splash erosion of the aggregates, with effect sizes of 0.646, 0.415, and 0.361, respectively. [Conclusion] At an initial moisture content of 20%, an increase in rainfall intensity did not significantly impact the splash erosion of red soil macro-aggregates. Under other initial moisture content conditions, the splash erosion of the red soil macro-aggregates was sensitive to changes in rainfall intensity at the same initial moisture content. Macro-aggregates of red soil were more susceptible to the impact of splash erosion under heavy rainfall (90 mm/h) or extreme rainfall (140 mm/h). At the same rainfall intensity, the saturated initial moisture content increased the occurrence and severity of splash erosion. The initial moisture content and rainfall intensity showed significant, positive correlations with changes in red soil macro-aggregates. Additionally, the initial moisture content was a key factor influencing splash erosion.

Abstract:[Objective] The impact of different litter inputs on soil nitrogen fractions during the process of returning farmlands to forests in typical black soil regions was explored, in order to provide a theoretical basis for soil nutrient regulation, tree species selection for afforestation, and vegetation restoration. [Methods] The experiment included three treatments (Populus alba litter, Larix gmelinii litter, and maize straw) and a blank control. The litter from each treatment was mixed with air-dried soil and incubated at 25 ℃ for 28 days. The content of soil nitrogen components and the activities of the two enzymes 〔β-glucosidase (βG) and urease (URE)〕 were then measured. Variance analysis and Pearson’s correlation were used to investigate how different litter inputs affect soil nitrogen and enzyme activities in black soil regions. [Results] Variance analysis showed that at 3, 7, 14, and 28 days, the total nitrogen (TN) values in the P. alba litter treatment were significantly higher than those in the control, L. gmelinii litter, and maize straw treatments (p<0.05). The input of the three kinds of litter did not significantly impact the soil available nitrogen (AN) content. For microbial biomass nitrogen, inorganic nitrogen, and enzyme activities (MBN), the P. alba litter treatment displayed a significantly greater increase at 7 and 14 days compared to the control and the other two treatments (p<0.05). At 28 days, the MBN values in both the P. alba and L. gmelinii litter treatments were significantly higher than those in the control and maize straw treatments (p<0.05). All litter treatments significantly reduced the soil’s inorganic nitrogen content. βG was highly or significantly negatively correlated with NH⁺₄-N and NO^-₃-N; it was highly positively correlated with URE, TN, and AN. URE was significantly or highly significantly correlated with TOC, MBN, and TN and negatively correlated with NH⁺₄-N. [Conclusion] The decomposition of the three types of exogenous inputs was closely linked to the soil’s TN, the AN, MBN, inorganic nitrogen, and enzyme activities. Litter input promoted soil nutrient cycling and accumulation, with litter input from the broadleaf tree species P. alba having the most significant impact on improving soil nitrogen and enzyme activities.

Abstract:[Objective] The water holding characteristics of soil and litter in low-efficiency of Chinese fir trees with different gap sizes and ages were investigated to provide a theoretical basis for improving the tree quality in low-efficiency Chinese fir forests. [Methods] Gap ages of 4, 15, 30, and 50 years were selected based on the results of the space-time substitution method, and the climax community was used as the control. Four treatments were set for each gap age: small (≤50 m²), medium (50—100 m²), and large (≥100 m²) gaps, as well as a non-gap control. The water holding characteristics of soil and litter were determined using the cutting-ring method, oven drying method, and litter soaking methods, respectively. [Results] ① Only the gap age had a significant effect on the water-holding characteristics of soil and litter, whereas the gap size and the interaction between gap age and size had no significant effect. ② The best soil water holding capacity was observed in the 4-year-forest gap, and the best standing crop, maximum water-holding capacity, maximum water-holding rate, natural water holding capacity, and effective storage capacity of semi-decomposed litter was observed in the 15-year-forest gap. ③ The water holding rate of litter in different gap ages changed with soaking time; the middle and large gaps performed the best, and the water-holding capacity of the semi-decomposed layer was stronger than that of the undecomposed layer. ④ The natural water-holding capacity of semi-decomposed litter was significantly positively correlated with soil capillary porosity, field water-holding capacity, and capillary water-holding capacity. [Conclusion] The water-holding capacity of soil and litter was good in the 4 and 15-year-forest gaps. Based on our results, the artificial opening of a medium-sized forest gap could be used as an important technical means to improve the quality of low-efficiency Chinese fir forest.

Abstract:[Objective] The hydrological process of litter mixed with soil in typical Robinia pseudoacacia mixed plantation was explored, in order to provide an important basis for improving the water conservation capacity of typical vegetation in the hilly area of the Loess Plateau. [Methods] We focused on five types of mixed artificial forests in Wuqi, Shaanxi (R. pseudoacacia×Pinus tabuliformis, R. pseudoacacia×Sophora viciifolia, R. pseudoacacia×Hippophae rhamnoides, R. pseudoacacia×Prunus persica, R. pseudoacacia×Armeniaca sibiric) and on pure Robinia pseudoacacia forests. We used a immersion method to determine the moisture content of soil that was mixed with different types and amounts of litter. We analyzed the evaporation process. [Results] ① The litter mixture in the vegetation plots was 204～2 087 g/m², the total average amount of litter in the soil was 733.53 g/m², and the average depth of the litter was 1.3～1.9 cm. ② The soil moisture of the six types of mixed plantations was ranked as follows: artificially mixed with litter soil > undisturbed mixed with litter soil > bare soil. The capillary water content of the pure R. pseudoacacia forest and R. pseudoacacia×S. viciifolia was significantly higher than in the other plots. ③ The overall trends in soil water evaporation when 700 g/m² litter was mixed with the soil in the six plantations were highly consistant: the soil water content decreased over time. The litter addition to the soil of the R. pseudoacacia×S. viciifolia and R. pseudoacacia×Armeniaca sibiric forests considerably increased the soil water content, whereas the soil water content of the soil mixed with litter in the R. pseudoacacia×H. rhamnoides forest slightly increased compared with the control. ④ The soil moisture content of the same forest type was higher than that of the unmixed soil after different amounts of litter were added. The maximum soil moisture contents of the pure R. pseudoacacia forest as well as R. pseudoacacia×Armeniaca sibiric and R. pseudoacacia×P. armeniaca forests were reached when the litter content was 1 000 g/m², and the maximum soil moisture content was reached in the R. pseudoacacia×H. rhamnoide forest when the litter content was 700 g/m². [Conclusion] Incorporating litter into the soil increased the soil moisture content, especially capillary moisture, and the effects of artificially added litter were more pronounced than those of naturally added litter. The type of forest also influenced the surface soil moisture levels. On the Loess Plateau, planting R. pseudoacacia×S. viciifolia and R. pseudoacacia×A. sibiric should be prioritized to increase water conservation in the region.

Abstract:[Objectives] The effects of different irrigation treatments on gaseous nitrogen loss and nitrogen cycle functional genes in a greenhouse cucumber ecosystem were explored to provide data support for further studies on gaseous nitrogen loss in a greenhouse farmland system under different irrigation methods. The results provide a theoretical basis for the formulation of irrigation schemes in greenhouse vegetable production systems in China. [Methods] Facility cucumbers were chosen as the research subjects for field experiments. The experimental designs included traditional irrigation (100% IWD), 25% water-saving irrigation (75% IWD), and 50% water-saving irrigation (50% IWD). Through in situ field monitoring experiments, continuous observations and records of N₂O emissions and ammonia volatilization from the soil of facility cucumbers were made using static chamber-gas chromatography and ventilation absorption. Nitrogen cycle functional genes were identified using high-throughput qPCR gene chip technology. [Results] ① Among the various irrigation treatments, the cumulative emissions of N₂O were as follows: 100% IWD > 75% IWD (p<0.05) and 100% IWD > 50% IWD (p<0.05). ② Cumulative ammonia volatilization was 75% IWD > 50% IWD > 100% IWD (p<0.05). ③ The overall abundance of nitrogen cycle functional genes in the soil changed significantly (PERMANOVA, F=241.82, p=0.001). ④ Cucumber yield was 100% IWD > 75% IWD > 50% IWD (p<0.05). [Conclusion] Irrigation at 50% significantly increased nitrification gene abundance, whereas 75% and 50% irrigation significantly decreased denitrification gene abundance. Denitrification was the main factor affecting N₂O gas production in surface soil treated with 100% irrigation. Reducing the irrigation water volume by 25% led to a decrease in denitrification gene abundance in the surface soil and weakened the denitrification process in the surface soil, reducing N₂O emissions. However, reducing irrigation water by 50% did not significantly change denitrification gene abundance or N₂O emissions at the soil surface.

Abstract:[Objective] The land use and the evolution process of orchard rocky desertification in Guanyan underground river basin along the eastern bank of Lijiang River from 2010 to 2020 were analyzed, and the distribution characteristics and internal evolution law of orchard rocky desertification landscape pattern were explored, so as to provide geological basis and decision-making suggestions for ecological protection and restoration and sustainable utilization of landscape resources in this area and even in Lijiang River basin. [Methods] Taking the land use type and rocky desertification in Guanyan underground river basin as the research object, based on the second and third national land survey data and remote sensing image data, the GIS technology platform and area transfer matrix model were used to analyze the evolution law of orchard rocky desertification in the study area. [Results] ① Cultivated land, orchards, and forest land were the main land uses in the underground river basin. The areas of cultivated land and grassland decreased, while the areas of orchard, forest land, water, and other land increased. ② The area of rocky desertification in orchards in the Guanyan underground river basin decreased by 1.34 km² from 2010 to 2020, a reduction of 7.90%. Overall, the rocky desertification was continuously decreasing in the orchards. However, the areas affected by moderate and severe rocky desertification increased. A total of 1.51 km² of nonrocky desertification area transformed into rocky desertification. ③ In a 1.79 km² area, the orchard rocky desertification decreased; however, the desertification worsened in a 1.78 km² area from 2010 to 2020. [Conclusion] Overall, the rocky desertification in orchards within the watershed was decreases. However, rocky desertification was increasing and expanding to some new areas, which mainly manifested as the spread of rocky desertification in the orchard and in some forested areas. Therefore, the focus of ecological environmental restoration and protection in the underground Guanyan river basin should be on strengthening the scientific planting and management of existing orchards, gradually restoring shrubs and other vegetation, vigorously developing agroforestry planting methods, and preventing further increases in rocky desertification through the application of on existing rocky desertification control measures.

Abstract:[Objective] The effects of parent material and land use patterns on the erosion resistance of typical red soils were explored, in order to provide fundamental data and references for soil erosion control and rational utilization of red soil resources in red soil regions. [Methods] The typical red soil of the Weishui River basin in Hunan Province was taken as the research object. A total of 16 types of red soil-including dry land, paddy fields, gardens, and forests, which were derived from four typical soil parent materials (Quaternary red clay, sandstone, plate shale, and granite)-were selected to study the differences in the anti-erodibility of red soils with different parent materials and land-use types. [Results] ① Land-use types significantly (p＜0.05) affected red soil anti-erodibility. The anti-erodibility and water stability indexes of paddy fields, gardens, and forests were significantly higher (p＜0.05) than those of dry land. ② There was no significant (p>0.05) difference in the anti-erodibility of red soil derived from different parent materials, and the interaction between them and land-use type on anti-erodibility was not significant. ③ Land-use types significantly (p＜0.05) changed the content of water-stable aggregate (WSA_0.25) and soil organic matter. The WSA_0.25 of forests was significantly (p＜0.05) higher than that of dry land, and the content of the soil’s organic matter in paddy soil was significantly (p＜0.05) higher than that of dry land, gardens, and forests. ④ The effect of soil-forming parent materials on WSA_0.25 was not significant (p＞0.05), but they significantly (p＜0.05) changed the content of organic matter and clay in red soil, which were significantly (p＜0.05) lower in soil derived from granite than that derived from the other three parent materials. ⑤ Correlation analysis showed that the anti-erodibility and water-stable indexes were significantly (p＜0.05) correlated with WSA_0.25 and the soil's organic matter. [Conclusion] Both land-use types and parent materials can affect the anti-erodibility of red soil by changing WSA_0.25 and the soil's organic matter, but the impact of land-use type on anti-erodibility is significantly stronger than that of the parent material. Hence, the prevention and control of soil and water loss in red soil should be based on the optimization of the adjustment and layout of land-use types, taking soil parent materials into account.

Abstract:[Objective] The causes of aeolian sand hazards in the Milan-Gobi section of the Golmud-Korla railway were investigated to propose a targeted configuration mode for sand-control systems. [Methods] This study analyzed regional wind conditions, monitored the amount of sand transported along the line, and assessed the protection efficiency of the test section of the protection system through field observations. [Results] ① The Milan Gobi area of the Golmud-Korla railway is a high wind energy environment; the main sand driving winds are NE and ENE, and the annual sand transport volume reaches 2.15～3.45 m³/a. ② The sand in Gobi mobile dunes is mainly medium- and fine-grained, whereas sand particles within 40 cm below the surface are mainly fine-grained. After construction damage sand is easily generated, creating a new sand source. ③ The sand resistance rates of the single HDPE plate, reed bundle, and galvanized chicken wire barrier were 96.42%, 93.85%, and 76.60%, respectively; the sand resistance rates of the double fences were 97.95%, 98.71%, and 92.78%, respectively. The sand resistance rate of the entire protection system exceeded 95%. The amount of sand deposited in the zigzag sand barrier was large, and the corner of the barrier was easily buried by sand deposits. [Conclusion] A sand control system that combines a linear HDPE board sand barrier with a large reed bundle grid is suitable for the sand control system configuration mode in the Milan Gobi area of the Golmud-Korla railway.

Abstract:[Objective] Temporal and spatial changes in soil water in different ecological zones of the Ningxia Hui Autonomous Region and their influencing mechanisms were explored to provide a scientific basis for ecological construction and water resource management in this region. [Methods] Taking the Ningxia Hui Autonomous Region as the research area, based on remote sensing inversion data of soil moisture, meteorology, vegetation cover NDVI, and land use from 2003 to 2022, trend analysis, the mutation test, Hurts index, and parameter optimal geographic detector were used to explore the temporal and spatial changes of soil moisture and their influencing mechanism. [Results] ① From 2003 to 2022, annual soil moisture in Ningxia showed a significant upward trend, with 68.99% of the region experiencing increases and 31.01% experiencing decreases. Regionally, soil moisture declined slightly in the Northern Yellow River irrigation area (-0.022%/a), increased modestly in the central arid zone (+0.030%/a), and increased significantly in the southern mountainous area (+0.107%/a), with a significant change in 2012. Spatially, soil moisture was high in the north and south and low in the center, with multi-year averages ranked as follows: Northern Yellow River irrigation area (11.40%) > southern mountainous area (10.70%) > central arid zone (8.40%). ② Hurst index predictions suggested that 49.09%, 60.43%, and 62.91% of the northern, central, and southern regions, respectively, are likely to experience declining soil moisture, highlighting the risks of salinization and drought in the north and center. ③ Geographic detector analysis identified NDVI and topography as the primary drivers of soil moisture distribution, with an increasing influence of precipitation over time. [Conclusion] Soil moisture trends in Ningxia from 2003 to 2022 displayed regional heterogeneity and complexity, and future changes are expected to follow similar patterns. NDVI, topography, and precipitation collectively shaped the soil moisture dynamics. These factors must be integrated into soil resource management strategies to support ecological and water resource optimization in the region.

Abstract:[Objective] The functional structure of the watersheds was quantitatively analyzed， and the influencing factors on the development of the watersheds were explored, in order to comprehensively understand the efficacy of constructing ecologically clean watersheds in the mountainous areas of Northern Beijing City, and provide a theoretical basis for the comprehensive management and development of the watersheds in the mountainous areas. [Methods] The small watersheds in Diaoliushi, Yushuidong, Gubeikou, and Huluhe River in the Yanqing, Huairou, Miyun, and Changping Districts, respectively, were selected as representative areas, and the main characteristics and governance objectives of each area was combined to construct a comprehensive benefit evaluation index system for these small watersheds in the mountainous areas of Northern Beijing City. The comprehensive benefit evaluation of the small watersheds was conducted via an analytic hierarchy process and weighted comprehensive index method, and the main influencing factors of constructing ecologically clean watersheds were revealed by the systematic obstacle degree model. [Results] ① Different results were found for the comprehensive management of each small watershed. The Hulu River watershed was upgraded from the primary to intermediate standard, and the comprehensive construction of the Zhujiushi, Yushuidong, and Gubeikou watersheds reached the primary standard. ② The obstacle degree model, which was introduced to quantify the contribution of different influencing factors, provided accurate evaluations. ③ In the future development process of small watersheds in the mountainous areas in Northern Beijing City, attention should be paid to the soil erosion modulus, economic production ratio and land productivity, Engel coefficient (household food expenditure ratio) and the proportion of rural employees, and the chemical oxygen demand (COD) content for the ecological, economic, social, and water-quality improvement benefits, respectively. [Conclusion] ① The comprehensive benefit evaluation system of small watersheds proposed in this study is practical and feasible in the mountainous areas in Northern Beijing City. ② Through the management of ecologically clean watersheds, the water environment and soil erosion were effectively controlled, the industrial structure in the watersheds was gradually enhanced, the ecological and human settlements were improved, and the coordinated development of soil and water resources, ecological environment, and economy and society were promoted.

Abstract:[Objective] A comprehensive evaluation of the causative factors and mechanisms of debris flows in Baise City, Guangxi, China was conducted , in order to provide scientific basis for the prevention and risk prediction of railway debris flow disasters in mountainous areas. [Methods] Based on a field investigation, historical remote sensing image analysis, among other methods, the characteristics and disaster-causing factors of railway debris flow in mountainous areas were analyzed. The debris flow occured on April 19th, 2024 (“4·19”)was theoretically calculated to obtain the dynamic parameters such as rainstorm peak discharge, debris flow peak discharge, and the quality of run-out solid materials under different working conditions. [Results] ① The railway debris in Baise City, Guangxi has a typical valley type flow, with a catchment area of 0.48 km², a main gully length of 1.03 km, an average longitudinal slope of 319.42‰, a relative height difference of 329 m, and well-developed material sources in the gully, including channel, slope, and landslide material sources. ② The peak discharge of the rainstorm caused by the “4·19” rainfall was 6.23 m3/s. After the superposition of various environmental degradation factors, the peak discharge of the debris flow reached 23.16 m³/s, which was 3.72 times greater than the peak discharge of the rainstorm, and 1.934×10⁴ m³ of solid materials move with this discharge at one time, which exceeds the interception and discharge capacity of existing measures. ③ In recent years, deforestation, excavation of access roads, forest fires, and arid climate have led to environmental degradation in the watershed, which are the main reasons for the occurrence of debris flow. [Conclusion] The environmental degradation is the core reason for the formation of debris flow in study area. The dynamic parameters such as the discharge of debris flow under different working conditions are consistent with the actual situation, which can provide a theoretical basis for the design of the prevention and control project.

Abstract:[Objective] Real-time monitoring and scientific early warning of landslide risk at waste disposal areas along mountainous highway from three perspectives-space, air, and ground were conducted to provide key data and technical support for accurately monitoring the safety status of slag abandonment sites. The results provide a theoretical reference for the formulation of landslide risk assessment and control strategies for waste disposal areas. [Methods] Xuanwe-Qujing Expressway waste disposal areas (38^#, 41^#, and 45^#) were selected as the research objects, and a real-time dynamic waste disposal area landslide safety early warning and monitoring platform was constructed using modern monitoring and network communication technologies. By integrating satellite remote sensing technology and unmanned aerial photogrammetry with ground sensors, the pattern of slope feature variation and surface deformation in the waste disposal areas from 2015 to 2024 at multi-spatial and multi-temporal scales was analyzed. In addition, the early warning of landslide risk was determined by utilizing evidence of cumulative deformation and deformation rate. [Results] ① Vegetation was gradually reestablished within the disturbed areas, and the overall vegetation coverage of the waste disposal areas in 38^#, 41^#, and 45^# increased by an average of 50% from 2018 to 2024. ② The actual disturbed areas of 38^# and 41^# were only 0.04 beyond the designed disturbed area, whereas the disturbed range of 45^# remained unchanged. Furthermore, the amount of slag and disturbed area, maximum pile height, slope, and slope ratio were in line with the stability requirements for landslides, indicating that the overall slopes of the waste disposal areas maintained a stable state, and the possibility of landslide risk was low. ③ The total average deformation rate of each monitoring point showed that cumulative deformation in the direction of 41^#JCD3-elevation reached a maximum value of 1 815.4 mm, which is within the critical interval of cumulative deformation with respect to warning level, and the landslide deformation exhibited a decreasing trend. Thus, the likelihood of landslide risk is reduced. [Conclusion] Based on the early warning judgment method, the landslide warning level of different waste disposal areas was level Ⅰ (the lowest risk level), and when the cumulative amount of displacement reached the preset threshold that triggered the early warning system, the intelligent space-air-ground monitoring performance was effectively verified.

Abstract:[Objective] Through a series of laboratory and field experiments, a computational model of quantum dot spectral suspended sediment monitoring equipment was optimized, and the sources of error were analyzed to lay the foundation for further improvement and application of the equipment. [Methods] An in situ suspended sediment concentration monitoring system using quantum dots was constructed in a laboratory. Reproducibility tests were performed on samples with different sediment concentrations. Laboratory data were divided into training and testing sets, and accuracy analysis was performed to select the best computational model. For the field experiment, the equipment was installed at the Luoyu Gou site at the Tianshui Soil and Water Conservation Monitoring Station. The sediment concentration, measured using the manual replacement method, served as the true value. A comparative analysis was conducted for eight runoff and sediment transport events that occurred between August and September 2023. [Results] The relative errors between the designed and manually measured sediment concentrations ranged from -12% to -28%. The relative standard deviations of the repeatability tests for manually measured sediment concentrations ranged from 0.1% to 5.0%. The fitted index regression model (model 1) and quadratic polynomial regression model (model 2) had determination coefficients of 0.966 and 0.996, respectively, for the training set. For the testing set, model 2 outperformed model 1 in three of the four accuracy evaluation metrics with a determination coefficient of 0.991. The determination coefficient for the field comparison data was 0.939 with an average absolute error of 9.1 g/L. [Conclusion] The quantum dot spectral suspended sediment monitoring equipment demonstrated good stability and reliability. Future improvements in application effectiveness can be achieved by optimizing the installation method, expanding the hardware range, and optimizing the computational model.

Abstract:[Objective] The effects of cementation solution concentration, plant fibers, microbial fertilizers and superabsorbent polymers on the mechanical and ecological properties of microbial-enhanced ecological substrates were analyzed. The adaptability of plants to substrates with different ratios was investigated，and the best formula of slope greening substrate was selected，in order to provide theoretical support and practical guidance for the preparation of novel ecological substrates and slope vegetation restoration. [Methods] An orthogonal test was performed to evaluate the influence of cement concentration, plant fiber, compound microbial fertilizer and superabsorbent polymers on microbial-enhanced ecological substrate. Thereafter, the shear strength of the substrate with different proportions was compared, and the micro-mechanism of the strength improvement of the microbial-enhanced ecological substrate was analyzed by a high-definition microscope. A pot experiment was conducted to study the seedling emergence characteristics and vegetation growth of tall fescue and alfalfa in different substrate ratios. Based on the characteristics of shear strength and plant growth, the optimal substrate formula was screened using the entropy method. [Results] ① The microbial curing significantly improved the shear strength of the substrate, and increased cohesion and the internal friction angle by 179.78%—355.65% and 35.69%—58.97%, respectively. ② The concentration of cementing solution was the most significant factor affecting the emergence time and rate of plants; as the concentration of the cementing solution increased, the time to emergence increased and the emergence rate decreased significantly. ③ The growth indices of the plants in the substrate group improved significantly compared to those in the control group. The growth and development of tall fescue were best in the substrate with a cementing solution concentration of 0.2 mol/L, and the mass ratio of plant fiber, compound microbial fertilizer, and superabsorbent polymers of 1∶2∶0.09. Alfalfa had the best growth and development in the substrate with a cementing solution concentration of 0.2 mol/L, and plant fiber, compound microbial fertilizer, and superabsorbent polymers mass ratio of 3∶1∶0.06. [Conclusion] The shear strength of microbial-solidified ecological substrates was significantly higher than that of the matrix soil, and 0.2 mol/L was the best cementing solution concentration. At this concentration, the optimal ratios (plant fiber: composite microbial fertilizers: superabsorbent polymers) for tall fescue and alfalfa were 1∶2∶0.09 and 3∶1∶0.06, respectively.

Abstract:[Objective] The ecosystem services and econormic value of bamboo-shaped ditches in the typical red soil region Southern China were explored, in order to provide references for the value accounting of similar soil and water conservation measures, and to offer a basis for the promotion and application of bamboo-shaped ditches. [Methods] Taking Xingguo County, Ganzhou City, Jiangxi Province as the study area, the ecosystem services such as soil conservation, water conservation, carbon sequestration and sink enhancement, and mitigation of non-point source pollution and their values in a bamboo-shaped ditch were comprehensively analyzed through using a topographic survey, as well as through field investigations, sampling, and testing of physicochemical properties of the soil, and applying the alternative cost and market value methods. [Results] The soil conservation function and value at different slopes was highest at the top of the slope 〔74.86 Yuan/(m²·a)〕 in the bamboo-shaped ditch; the water conservation function and value was highest in the middle of the slope 〔5.16 Yuan/(m²·a)〕; the carbon sequestration and sink enhancement function and value was highest at the bottom of the slope 〔0.25 Yuan/(m²·a)〕; and the mitigation of surface pollution function and value was highest at the top of the slope 〔0.34 Yuan/(m²·a)〕 . The total value of the ecological service function of the bamboo-shaped ditch varied at different slope gradients, specifically 78.63 Yuan/(m²·a) at the top of the slope, 57.11 Yuan/(m²·a)at the middle of the slope, and 60.51 Yuan/(m²·a)at the bottom of the slope. [Conclusion] Bamboo-shaped ditch measures have important ecological service function values in the typical red soil region in Southern China, and different slopes show significant differences in the value of ecological service functions.

Abstract:[Objective] The effects of tillable earth bund (TEB) technology on soil structure, crop yield, and soil and water conservation in sloping cultivated land within the black soil region of Northeast China were examined, in order to provide a scientific basis for optimizing soil and water conservation strategies in this area. [Methods] The experimental field (EF) was located on sloping cultivated land with an average gradient of 5°. The study area included a region constructed with TEBs and a nearby field with conventional tillage practices that were similar in slope and area but without constructed bunds; it was selected as the control field for conventional tillage (CTF). Within the EF, soil samples were collected from the TEB-constructed area and the traditional tillage area without bunds. Changes in soil bulk density, aggregate characteristics, and soil moisture were compared before and after the rainy season. Runoff depth, soil erosion, and crop yield were also monitored. [Results] After the rainy season, soil bulk density increased across all regions, while the proportion of ＞0.25 mm water-stable aggregates (WSA_＞0.25) and mean weight diameter (MWD) decreased. Soil bulk density in the EF was significantly lower than in the CTF (p<0.05), with the lowest value observed in the TEB area (1.18 g/cm³). The content of ＞2 mm aggregates in the EF was significantly higher than that in the CTF (p<0.05), with the smallest reduction occurring in the TEB. The WSA＞0.25 and MWD in the TEB area were 10.58% and 0.36 mm higher than those in the CTF, respectively (p＜0.05). Throughout the growing season, soil moisture in the EF was significantly higher than that in the CTF, whereas runoff depth and soil erosion declined by 35.10% and 51.60%, respectively. The TEB area exhibited the highest seedling emergence and maize yield. [Conclusion] TEB technology effectively enhances soil structure, water retention, and water-soil conservation while boosting crop yield. This technology is well suited for large-scale implementation on sloping cultivated land across the black soil region of Northeast China.

Abstract:[Objective] The efficacy of the non-landslide sampling method and a model with excellent feature extraction in evaluating landslide susceptibility were explored, so as to provide theoretical support and scientific guidance for regional landslide prevention and control work. [Methods] A non-landslide sample optimization method based on Convolutional Auto-Encoder (CAE) was proposed, which was built based on the buffer sampling strategy. This method optimizes non-landslide samples by learning the features of landslide samples and using reconstruction errors. For the evaluation model, the Convolutional Block Attention Module (CBAM) was integrated into the Residual Network (ResNet) to construct the ResNet-CBAM landslide susceptibility model, which captures deeper, and more complex and representative features. Taking the Wanzhou District, Chongqing City in the Three Gorges reservoir area as the study area, 12 influencing factors (e.g., such as elevation) were selected. Four models, namely, SVM, DNN, CNN, and ResNet-CBAM, were used to compare and analyze the evaluation accuracy and results of buffer zone sampling versus CAE-based optimized sampling. [Results] Under the same evaluation model, the CAE-based optimization sampling strategy for non-landslide samples yielded higher reliability and accuracy. Under the same sampling strategy, the ResNet-CBAM model outperformed the other models in terms of accuracy, precision, recall, F₁ score, and area under the curve (AUC) values. The evaluation results were similar across models, with higher and very higher susceptibility areas predominantly located in regions with lower vegetation cover and frequent human activity, such as along the Yangtze River. Moreover, the ResNet-CBAM model with CAE-based optimized sampling demonstrated superior prediction results and was more suitable for landslide susceptibility evaluation in this area. [Conclusion] Wanzhou District exhibits a high landslide susceptibility index, with numerous potential landslide risk zones identified within the area. The non-landslide sampling strategy and ResNet-CBAM evaluation model based on CAE optimization can effectively improve the accuracy of landslide susceptibility evaluations.

Abstract:[Objective] The applicability of long-term and high-resolution land cover products in karst areas of Southern China was explored to provide new data support for revealing the characteristics of vegetation evolution in karst rocky desertification areas of Yunnan Plateau. [Methods] Precision testing, Sen’s slope, a transition matrix, and other methods were used to evaluate the accuracy of CLCD_v1.0.2 land cover data, with a resolution of 30 m, from 1985 to 2022, using Shilin County in the central part of the Yunnan Plateau as an example. The spatiotemporal characteristics of the expansion of the vegetation in the karst rocky desertification areas on the Yunnan Plateau were studied based on these data. [Results] ① The overall accuracy of the validation samples in the study area was 87.85% and the kappa coefficient of 0.83. The user accuracy of forest land was the highest at 95.24%, whereas that of grassland was the lowest at 73.76%. ② Arable land, forest land, and grassland were the main vegetation types in Shilin County, with average annual areas of 810.20, 632.85, and 245.74 km², respectively. Shrubs and unvegetated areas cover relatively small areas, at 14.90 and 15.31 km², respectively. From 1985 to 2022, the areas of cultivated land, forest land, and unvegetated areas in Shilin County increased by 34.17, 112.24, and 10.79 km², respectively. Shrub and grassland areas decreased overall by 15.62 and 141.58 km², respectively. The forest and unvegetated areas markedly increased, whereas the grassland considerably decreased trend from 1985 to 2022; forested land and grassland were the main cultivated land types. Forest land mainly changed to cultivated land, grassland mainly converted into cultivated and forest land, and shrubland mainly converted into forest land. The conversion of other vegetation types to forest land concentrated in the core and buffer zones of the Shilin World Natural Heritage Site and the Guishan National Forest Park as well as the edge of the Shilin rift basin. [Conclusion] The CLCD data met the requirements for vegetation evolution analysis in the karst rocky desertification areas. The pattern in the spatial changes of the vegetation in the karst rocky desertification areas compensated for the reduction in arable land area caused by the construction of protected areas and reflects the spatial scope and effectiveness of the implementation of policies, such as returning farmland to forests and halting afforestation on mountains.

Abstract:[Objective] The differences in near-surface micrometeorological characteristics inside and outside photovoltaic (PV) power plants were revealed, and the impact of large-scale PV power plant deployment on near-surface microclimate in Mu Us sandy land was evaluated, in order to provide a scientific basis for wind-sand control and ecological restoration in PV power plants. [Methods] Observational data were gathered from automatic weather stations to assess how the layout of photovoltaic power stations in the Mu Us sand land affects the near-surface microclimate. Microclimate elements (wind speed, wind direction, air temperature, relative humidity, and radiation) were compared between control points and various observation points within the station. [Results] ① Compared to the control area, both types of photovoltaic arrays exhibited significant changes in wind direction at a height of 2 m, presenting a more monotonous pattern. ② The temperature within the photovoltaic array areas was reduced. The maximum temperature decreases recorded between and beneath the fixed adjustable photovoltaic panels were 0.92 ℃ and 0.97 ℃, respectively. In comparison, the horizontal, single-axis photovoltaic panels showed maximum temperature reductions of 2.24 ℃ and 2.46 ℃ between and beneath the panels, respectively. ③ The relative humidity of the air in the photovoltaic array area increased, with the greatest increments occurring in the fixed adjustable photovoltaic area in December, where the inter-panel and under-panel areas increased by 3.77% and 2.31%, respectively. The horizontal, single-axis photovoltaic area experienced the largest increase in March, with inter- and under-panel areas rising by 15.86% and 15.44%, respectively. ④ The impact of the photovoltaic arrays on radiation was predominantly observed beneath the panels, with maximum reductions in solar radiation beneath the fixed adjustable and horizontal, single-axis photovoltaic panels of 91.30% and 88.27%, respectively, and maximum reductions in photosynthetically active radiation of 91.06% and 82.29%, respectively. [Conclusion] The deployment of large-scale photovoltaic power stations can alter wind direction, reduce air temperature, increase relative humidity, and decrease surface solar radiation and photosynthetically active radiation. Notably, the horizontal, single-axis photovoltaic array outperformed the fixed adjustable photovoltaic array in terms of its capacity to lower temperature and increase humidity.

Abstract:[Objective] The spatial and temporal distribution characteristics and variation trend of long-term sequence rainfall erosivity in loess hilly and gully region during 1970—2020 were explored, and the main driving force of soil erosion in this region and its dynamic change law were revealed, in order to provide a useful reference for formulating regional soil and water conservation prevention and control strategies and repairing fragile Loess Plateau ecosystem. [Method] Based on the rainfall data of 67 meteorological stations in the region from 1970 to 2020, a simple algorithm model based on daily rainfall, Machisplin interpolation method, Mann-Kendall method and wavelet analysis method were used to study the abrupt change point, trend change, periodicity and spatial distribution characteristics of the time series of rainfall erosive power in the hilly and gully region of Loess Plateau in the middle reaches of the Yellow River. [Results] The average annual rainfall erosivity range in this region was 739.97～1749.03 (MJ·mm)/(hm²·h), spatially decreasing from southeast to northwest. The overall erosive power of rainfall weakly increased interannually, with highest and lowest annual values of 1915.09 MJ and 741.18 (MJ·mm)/(hm²·h) in 2013 and 1974, respectively. The rainfall erosivity intensity was markedly stronger in the warm season than in the cold season, with an average annual rainfall erosivity of 599.01～1742.95 and 27.61～171.11 (MJ·mm)/(hm²·h), respectively. [Conclusion] The erosive power of rainfall in this area decreased from southeast to northwest, and the annual average erosive power of rainfall trended upward, but with notable interannual fluctuations. The increasing erosive power of rainfall in loess hilly and gully areas not only improves local climate conditions but also poses challenges to the stable functioning of local soil and water conservation measures and soil erosion control work.

Abstract:[Objective] The variability and persistence of runoff in the Bailong River, Gansu Province were comprehensively analyzed, and the contribution rates of climate change and human activities to annual runoff variations were analyzed quantitatively, in oreder to provide a theoretical basis for water resources planning and management in the Bailong River basin. [Methods] Based on annual and monthly rainfall and runoff data from Baiyun, Zhouqu, Wudu, and Bikou Stations in the Bailong River basin from 1961 to 2021, the Mann-Kendall trend test, sliding T-test, R/S analysis, and double cumulative curve method were employed to examine the evolution characteristics of runoff and identify the driving factors behind these changes. [Results] ① The annual runoff at Bailong River stations exhibited a declining trend to varying degrees, with runoff losses increasing from upstream to downstream. The linear tendency rates of runoff decline were Bikou station 〔-3.07×10⁸ m³/(10 a)〕 ＞ Wudu station 〔-1.49×10⁸ m³/(10 a)〕 ＞ Zhouqu station 〔-4.20×10⁷ m³/(10 a)〕 ＞ Baiyun station 〔-3.40×10⁷ m³/(10 a)〕. ② The maximum monthly runoff in the upper reaches of the Bailong River occurred in September, whereas in the middle and lower reaches, it peaked in July. Wudu station exhibited the highest extreme ratio of annual maximum runoff. ③Abrupt change points in runoff primarily occurred in 1969 and 1994, with negative change rates at all stations. This indicates that before the abrupt change, runoff was higher than the annual average, whereas after the abrupt change, it was lower. ④The Hurst index (H=0.53～0.77) suggests that runoff in the middle and lower reaches of the Bailong River will continue to decline in the future. ⑤ Climate change contributed 94.85% to the reduction in watershed runoff, while human activities accounted for 5.15%. [Conclusion] The runoff in the Bailong River basin has shown a significant downward trend following abrupt changes, and this trend is expected to persist in the future.

Abstract:[Objective] Integrated rainfall erosivity in Jiangsu Province was evaluated at different temporal and spatial scales, and the erosion density characteristics in Jiangsu Province were explored to provide an important reference for regional rainfall erosivity prediction and soil erosion control. [Methods] This study developed a station-satellite merged calculation method for rainfall erosivity based on rainfall data from 96 meteorological stations and precipitation products of GPM IMERG and ERA5. The rainfall erosivity of Jiangsu Province from 2001 to 2023 was reconstructed, and its erosivity density and prone area division were studied . [Results] ① Method reliability was confirmed because the fusion rainfall erosivity had a higher correlation coefficient, lower deviation, and lower root mean square error than did the rainfall erosivity calculated by satellites and stations. This method captures high values of rainfall erosivity and reduces uncertainty and error. ② The mean annual rainfall erosivity in Jiangsu Province from 2001 to 2023 was 4 709.39 MJ·mm/(hm²·h·yr); the spatial distribution was 'low in the north, high in the south’. Seasonal rainfall erosivity showed a pattern of 'more in summer, less in winter’. ③ Annual rainfall erosivity in Jiangsu Province showed an increasing trend from 2001 to 2023. The climate tendency rate showed a significant increasing trend in the south of Jiangsu Province in spring, summer, and autumn, and an insignificant decreasing trend in the north, which was the opposite in winter. ④ The annual erosivity density of Jiangsu Province was 4.96 MJ/(hm²·h), and the spatial distribution was 'high in the north, low in the south’. The areas most vulnerable to rainfall erosivity were east of Xuzhou, north of Lianyungang, west of Zhenjiang, and the northern part of Nanjing City. The less vulnerable areas were Yangzhou City and Taizhou City. [Conclusion] The estimation of regional rainfall erosivity based on site-satellite precipitation merged data is reliable, reduces uncertainty and error, and improves the accuracy of satellite remote sensing applied in the field of soil erosion.

Abstract:[Objective] The relationship between new quality productivity forces and agricultural carbon emission intensity was explored, the operational mechanisms and regional differences were revealed, in order to provide a scientific basis and data support for the synchronization of new quality productivity and green development. [Methods] A bidirectional fixed regression model was used to explore the relationship between new quality productivity forces and agricultural carbon emissions using provincial panel data of China from 2012 to 2022. A threshold model was then used to analyze the role of the rural-urban income gap in the effect of new quality productivity forces on agricultural carbon emissions. [Results] ① An inverted N-shaped relationship was found between new quality productivity forces and agricultural carbon emission intensity; that is, the effect of new quality productivity forces on agricultural carbon emissions first decreased, then increased, and finally decreased again. ② A threshold effect exists: regions with smaller urban-rural income gaps exhibit stronger emission reduction effects from new quality productivity forces. ③ The effect of new quality productive forces on agricultural carbon emission intensity differed among regions. The inverted “N” relationship was strong in the eastern region and insignificant in the central region, showing an “N” type relationship in the western region. [Conclusion] It is recommend obtaining an in-depth understanding of the phases of the characteristics of new quality productivity forces to facilitate their alignment with the development of low-carbon agriculture and enhance the emission reduction effects of new quality productive. The urban-rural income gap should be narrowed by increasing farmer incomes, thereby incentivizing technological and equipment upgrades among farmers and strengthening the emission reduction effect of new quality productive forces. Furthermore, regional differences should be recognized to help align new quality productive forces with the actual conditions in various regions and reduce agricultural carbon emission in agreement to local conditions.

Abstract:[Objective] The spatiotemporal evolutionary characteristics and driving factors of coupling coordination between the carbon emission efficiency of cultivated land use and food security in the Fenhe River basin were explored, in order to provide decision-making references for improving the level of coupling coordination. [Methods] The undesired output super-efficiency SBM model and entropy weight method were used to measure the carbon emission efficiency and food security in the Fenhe River basin from 2005 to 2021. Next, the spatiotemporal characteristics were analyzed. On this basis, coupling coordination and its driving factors were discussed using the coupling coordination degree model and an optimal parameter-based geographic detector model. [Results] ① The carbon emission efficiency of cultivated land use varied significantly among counties; most counties still had mid-and low levels of efficiency. ② The level of food security in the Fenhe River basin showed a trend of “increase-decrease-increase.” The high-value areas were primarily concentrated in the northeast and southern regions, while the low-value areas were located mainly in the upper reaches of the Fenhe River basin, the urban area of Taiyuan City, and the gorge region of Linghuo Mountain. ③ The level of coupling coordination between carbon emission efficiency and food security in the Fenhe River basin was relatively low, showing a spatial distribution feature of “low in the upstream and high in the middle and lower reaches.” Counties in the stage of imbalanced degradation were mostly characterized by lagging carbon emission efficiency, while those in the phase of transitional development were chiefly characterized by lagging food security. ④ Per capita cultivated land area, urbanization rate, and population size were the primary driving factors affecting the level of coupling coordination between carbon emission efficiency and food security. [Conclusion] Counties in the Fenhe River basin should focus on differences, improve the short boards, and optimize cultivated land use while strengthening support for agricultural science as well as technological and policy-related guidance, ultimately achieving simultaneous and coordinated development of the two.

Abstract:[Objective] The relationship between climate change and soil carbon sequestration capacity to reveal the effects of temperature, carbon dioxide (CO₂) concentration, and precipitation on soil organic carbon and its component pool were explored, in order to provide a theoretical basis for improving soil carbon sequestration capacity in the context of global climate change. [Methods] Using a Meta-analysis, 44 relevant studies were screened, and 281 research sample data were collected. Active and inert soil organic carbon components were characterized by particulate organic carbon (POC) and mineral-associated organic carbon (MAOC), respectively. The effects of climate change on soil carbon stocks and soil stability were analyzed. [Results] ① Atmospheric CO₂ concentration and soil POC and MAOC content showed a significantly negative correlation (p<0.05). POC content decreased with rising air temperature, whereas MAOC content increased slightly. POC was more sensitive to changes in air temperature than MAOC. Soil POC was positively correlated with an increase in precipitation and negatively correlated with a decline in precipitation, whereas soil MAOC content showed the opposite trend. ② The increase in air temperature and CO₂ concentration as well as the decrease in precipitation reduced the concentration of the soil total organic carbon, whereas the rise in precipitation increased the concentration of the soil total organic carbon. ③ The response of soil organic carbon and its components to changes in climatic factors was affected by soil depth and soil type. [Conclusion] The influence of climatic factors on the soil's organic carbon and its component content is clearly different. Moreover, changes in climatic factors reduce the storage or stability of the soil organic carbon pool and weaken the soil carbon sequestration capacity.

Abstract:[Objective] Carbon storage dynamics and its driving mechanism were explored aims to provide scientific basis and methodological reference for regional sustainable development as well as soil and water resource conservation. [Methods] Taking Taohe River basin in the Tibetan Plateau and Zuli River basin in the Loess Plateau as study areas, the direct and indirect effects of climate, vegetation, water and sediment on net primary productivity (NPP) were investigated. The influence threshold of different factors on NPP was quantified by means of elastic coefficient and density analysis. [Results] ① The mean NPP values (calculated by carbon) in the Taohe River and Zuli River basins were 276.47 and 136.86 g/m², respectively, with significant spatial variations. ② In the Taohe River basin, NPP was predominantly influenced by moisture parameters (P), followed by the normalized vegetation index (NDVI). In contrast, temperature (T) and soil erosion (A) had negative but relatively minor effects. In the Zuli River basin, NPP was primarily affected by NDVI and water retention (W_R), while T and A exhibited similar negative effects, though with a greater absolute value compared to the Taohe River basin. Spatially, the strongest explanatory power for NPP distribution was observed when T and NDVI interacted in both watersheds. ③ The threshold quantification results varied across methods. In the Taohe River basin, the thresholds for T and A effects on NPP were reached earlier, whereas in the Zuli River basin, the thresholds for P, NDVI, and W_R effects on NPP were attained first. [Conclusion] The dynamics of carbon storage exhibit distinct driving forces and their affecting threshold variations under different ecological and geographical conditions. Before the affecting values reach the “sustainable” threshold, excessive human intervention is unnecessary, but mainly carrying out some works related to climate monitoring. Once the affecting values reach the “restrictive” threshold, measures for rational water resources allocation, soil erosion control, and mitigation of river sediment transport should be taken promptly.

Abstract:[Objective] The distribution and differences in new productive forces of food and their coupling coordination in grain functional areas were explored，in order to provide a decision-making reference for promoting the development of new productive forces of food and guaranteeing food security in China. [Methods] Based on panel data of 30 provinces (Excluding Xizang Autonomous Region, Hong Kong and Macao Special Administrative Regions and Taiwan Province) in China from 2012 to 2022, we constructed an index system of new productive forces in food from the three dimensions of scientific and technological productivity, green productivity, and digital productivity using the entropy weighted-TOPSIS method, coupling coordination model, and spatial correlation model. [Results] ① China’s new productive forces of food level had been growing steadily, and all grain functional areas had been improved, but there was a development pattern of “grain main marketing area > grain main production area > production and marketing balance area”; in the three-dimensional system, scientific and technological productivity and digital productivity had improved significantly both at the national scale and in each grain functional area, while green productivity was relatively stable and needs to be developed. ② The coupling and coordination degree of China’s three-dimensional system of new productive forces of food had gradually increased, and had been transformed from a low-level coordination to a medium degree of coupling and coordination, but the coupling and coordination degree of grain production and marketing balance area was still relatively low. ③ The spatial structure of coupling and coordination degree of new productive forces of food showed a high degree of agglomeration to the main grain producing area and main grain marketing area, while the significant cold spot area was concentrated in the grain production and marketing balance area. [Conclusion] There is a need to increase research & development investment in the grain balance of production and marketing zones, focus on promoting the development of green productivity, and encourage spatial coupling between the balance of production and marketing zones and main grain marketing zones to promote the development of new-quality grain productivity.

Abstract:[Objective] The impact of supporting policies on land-use efficiency for resource-based cities in the Yellow River basin was explored, in order to provide theoretical reference for the efficient use of land and the implementation of supporting policies for resource-based cities in the Yellow River basin. [Methods] The urban land-use efficiency of resource-based cities in the Yellow River basin from 2008 to 2021 was measured using the undesired output super-efficient SBM model. The difference-in-differences and mediation effect models were employed to examine the impact of supporting policies on urban land-use efficiency, as well as their heterogeneity and channels of impact. [Results] ① During the study period, the overall urban land-use efficiency in the Yellow River basin exhibited an increasing fluctuation trend. In addition, the difference in land-use efficiency between resource-based cities and non-resource-based cities expanded after the implementation of the supporting policy. ② Supporting policies promoted the land-use efficiency of resource-based cities in the Yellow River basin, but the impact had a time-lag effect. ③ The impact of supporting policies had significant heterogeneity in different types of resource-based cities in different spatial locations. Supporting policies had a promotional effect on cities upstream of the basin but had an insignificant impact on cities midstream and downstream of the basin. The impact on mature cities and recessionary cities was more significant than that on growing and regenerating cities. ④ Furthermore, supporting policies could optimize land-use efficiency through industrial structure adjustment and environmental governance. [Conclusion] Policy tools must be used to guide urban development, adopt measures according to local conditions, and focus on industrial structure adjustment and environmental governance to improve the quality and efficiency of land use and embed land functions into the high-quality development of cities in the Yellow River basin to exert its advantages.

Abstract:[Objective] The distribution of climate comfortability and its spatiotemporal variations on the Loess Plateau were studied, and the correlation of comfortable climate with vegetation cover was analyzed, in order to provide insights into the environmental impacts of ecological restoration and the mechanisms for realizing the value of ecological products. [Methods] Based on the daily monitoring data of meteorological stations in the Loess Plateau from 1981 to 2020, the temporal and spatial variation of climate comfortability in the Loess Plateau was evaluated by using the temperature and humidity index. On this basis, the relationship between NDVI and climate comfortability around the site was quantitatively evaluated by using PKU GIMMS NDVI data. [Results] ① The climatic comfort period (very comfortable and comfortable) exceeded 135 days per annum in the central part of the Loess Plateau. The northwest experienced longer summer comfort periods, whereas the southeast experienced longer spring and autumn comfort periods. The northwest exhibited more uncomfortable days annually than the southeast, with fewer days categorized as less uncomfortable or uncomfortable. ② The climatic comfort period on the Loess Plateau accounts for 35.46% of the annual days, primarily from May to September. The period of climate discomfort (relatively comfortable, uncomfortable, and very uncomfortable) accounted for 64.54% of the days in a year and mainly occurred from October to the April of the following year. Extreme discomfort was the predominant climatic comfortability type in the Loess Plateau, representing 27.59% of the total days, mainly occurring from November to February. ③ The degree of climate comfort significantly or highly significantly increased at 85% of the stations on the Loess Plateau (p<0.05), with climate comfortability highly significantly increasing at 66.67% of the stations (p<0.01). The number of comfortable days significantly increased at 21.67% of the stations, with the largest increase occurring at Wutaishan station in Shanxi Province (18.89 days per 10 years). The number of extremely uncomfortable days significantly decreased at 86.67% of the sites, and the number of less comfortable days significantly increased at 56.67% of the sites (p<0.05). The annual NDVI of the Loess Plateau exhibited significant increasing trend from 1982 to 2020, with a significant or highly significant positive correlation between the NDVI and the degree of climate comfortability at 53.33% of the sites. [Conclusion] The climate comfort spatially varied across the seasons on the Loess Plateau from 1981 to 2020. Overall, the climate comfort ability increased in the study area. The increase in NDVI values was synchronized with the increase in climate comfortability. Ecological restoration shows the potential to further elevate regional climate comfortability.

Abstract:[Objective] The spatio-temporal characteristics and influencing factors of the green use efficiency of cultivated land in Guangxi Zhuang Autonomous Region were studied, in order to provide decision-making basis for promoting the management and efficient use of cultivated land and promoting the green development of agriculture. [Methods] An index system was established using panel data from 14 cities and regions between 2010 and 2021. The super-efficiency SBM model was applied to estimate the green use efficiency of cultivated land, while the spatio-temporal distribution patterns and evolution trends were visualized using the ArcGIS analysis tool. Additionally, the GTWR model was employed to reveal the spatio-temporal heterogeneity of influencing factors. [Results] ① Temporal trends: The green use efficiency of cultivated land in Guangxi Zhuang Autonomous Region underwent three distinct phases-steady growth, slow growth, and rapid growth-demonstrating an overall upward trend. However, notable differences were observed in the efficiency evolution curves across different cities. ② Spatial distribution: The efficiency levels were highest in Eastern and Southern Guangxi Zhuang Autonomous Region, moderate in western and Northern Guangxi Zhuang Autonomous Region, and lowest in Central Guangxi Zhuang Autonomous Region. The disparities between “east vs. west” and “north vs. south” gradually narrowed over time. ③ The impact mechanisms of various factors exhibited significant spatio-temporal heterogeneity. Positive factors contributed to rational resource allocation and industrial structure optimization, while negative factors exacerbated challenges such as soil degradation, labor shortages, and pollution intensification. [Conclusion] The green use efficiency of cultivated land in Guangxi Zhuang Autonomous Region displays substantial spatio-temporal variations. The multiple cropping index, agricultural machinery input intensity, and urban-rural income disparity exert strong influences. To enhance land use efficiency, future efforts should focus on leveraging the unique agricultural characteristics of different regions, formulating region-specific improvement strategies, and promoting differentiated agricultural development, ultimately fostering a more sustainable and efficient use of cultivated land in Guangxi Zhuang Autonomous Region.

Abstract:[Objective] The spatiotemporal evolution of water conservation services and its influencing factors in Southern Henan Province was explored, in order to provide decision-making references for water resources management in the north-south transition zone of China. [Methods] The water yield and water conservation services in South Henan Province from 2000 to 2020 were quantitatively assessed based on the InVEST model. The spatial aggregation of water conservation services was analyzed with spatial autocorrelation. The main influencing factors of water conservation services were explored with the help of optimal parameters-based geographical detector. And the degree and direction of the influences of different factors on water conservation services in localized space were revealed by combining with the geographically weighted regression model. [Results] ① From 2000 to 2020, water production and conservation services in Southern Henan Province showed a significant downward trend, with the water yield falling from 3.56×10¹⁰ m³ to 2.65×10¹⁰ m³, and water conservation declining from 1.87×10⁹ m³ to 1.23×10⁹ m³. ② There is clear aggregation in the spatial distribution of water conservation services in Southern Henan Province, with “high-high” and “low-low” aggregations dominating. ③ Climatic factors are the main elements influencing the formation of spatial heterogeneity in water conservation services; socioeconomic factors have less influence. ④ Locally, precipitation, NDVI, and GDP had positive effects on water conservation services in Southern Henan Province, whereas actual evapotranspiration and population density displayed negative effects. [Conclusion] Attention should be paid to optimizing the land use structure of Southern Henan Province, focusing on the central route of the south-north water transfer project, reasonably allocating water resources to ensure ecological security and environmental health, and promoting the sustainable growth of regional water resources.

Abstract:[Objective] The changes in urban resilience and land use efficiency in Guangdong Province from 2013 to 2022 were clarified, the spatio-temporal evolution patterns, coupling coordination status, and aggregation characteristics between the two were identified, in order to provide a scientific basis for promoting the coordinated development of resilient urban construction and intensive land use in the region. [Methods] The comprehensive evaluation method based on entropy weight method and CRITIC method, super-efficiency SBM model, coupling coordination degree model and spatial autocorrelation model were used to explore the regional differences and evolution characteristics of the coupling coordination between urban resilience and land use efficiency in 21 prefecture-level cities in Guangdong Province. [Results] ① Urban resilience in Guangdong Province continuously strengthened over the study period, increasing by 43.21%. However, disparities exist in urban resilience levels among cities, with a spatial distribution pattern characterized by a gradual decreased from the core to the periphery. ② Land use efficiency exhibited increased fluctuations, rising from 0.57 to 0.65. However, land use has not yet reached DEA optimality, and most prefecture-level cities display significant interannual volatility in land use efficiency. The spatial distribution pattern follows the trend of higher values in the Pearl River Delta and Western Guangdong, and lower values in Northern and Eastern Guangdong. ③ The overall coupling between urban resilience and land use efficiency was favorable and stable, with a strong positive correlation. The coupling coordination level had improved across the province, transitioning from the initial coordination stage to the intermediate coordination stage. ④ Spatially, a positive correlation existed between urban resilience and land use efficiency. However, localized agglomeration characteristics were not prominent. [Conclusion] To promote coordinated regional development of Guangdong Province, efforts should focus on strengthening the integration of resilient city construction and land spatial planning, optimizing policy direction, enhancing regional planning coordination, fostering complementary advantages among cities, and improving agglomeration efficiency.

Abstract:[Objective] The spatiotemporal dynamics and driving mechanisms of the eco-environment in the Liaohe River basin were revealed, and an ecological management zoning framework was established, so as to provide scientific support for regional ecological environment protection and sustainable development. [Methods] Based on the Remote Sensing Ecological Index (RSEI) from 2000 to 2022, the spatiotemporal dynamics in eco-environment quality from 2000 to 2022 were analyzed, and its key driving factors were identified. Combined with the spatial distribution pattern, change trend and driving factors of RSEI, a multi-dimensional ecological zoning framework was constructed, and the ecological management zoning of Liaohe River Basin was completed. [Results] ① The eco-environment quality in the Liaohe River Basin improved annually, with a spatial pattern of “poor in the middle, excellent in the east and west.” ② Precipitation was the primary driving factor of RSEI spatial variation, followed by land use, temperature, elevation, and slope. ③ Based on the zoning results, the entire basin can be divided into core ecological protection areas, ecological optimization areas, ecological monitoring areas, ecological restoration areas, and key ecological management areas. Core ecological protection areas are concentrated in the eastern basin, while key ecological management areas are located in the central basin. [Conclusion] From 2000 to 2022, the eco-environment quality of the Liaohe River basin continuously improved, with precipitation and land use being primary driving factors. In the future, prioritized conservation measures are needed to strengthen the protection of core ecological protection areas and more resources should be allocated to key ecological management areas.

Abstract:[Objective] The change in cultivated land use patterns in Yunnan Province was studied from multiple perspectives, and the risk level of cultivated land use was divided to inform protection policies and management strategies to provide a reference for the protection of cultivated land in other areas. [Methods] Utilizing land use survey data from 2011 and 2021, and adopting a quantity-quality-ecology tripartite perspective, we comprehensively analyzed the characteristics of changes in cultivated land use patterns by employing landscape indices and the pressure-state-response (PSR) model. Based on the state-space model, we categorized the risk levels of cultivated land use. [Results] ① Regional variations were observed in the changes of cultivated land quantity in Yunnan Province from 2011 to 2021, with districts and counties exhibiting significant changes and displaying a distribution pattern characterized by 'overall scattered and local aggregation.’ ② The average soil layer thickness of cultivated land decreased, the content of soil organic matter and cation exchange capacity increased, and the patch density (PD) of cultivated land increased by 1.251; aggregation index (AI) and mean shape index (MSI) decreased by 5.672% and 0.055, respectively, indicating that the degree of farmland fragmentation increased, agglomeration weakened, and patch shape tended to be regular. ③ The overall level of ecological security of cultivated land declined, revealing a spatial pattern of 'high in the south, low in the north, polarized in the middle.’ Based on the dynamic changes in cultivated land, we conducted risk zoning for cultivated land use in Yunnan Province and proposed regulatory suggestions. [Conclusion] Northeast, southwest, and central Yunnan are hotspots for cultivated land change in Yunnan Province. Although soil quality across the province has improved, soil fragmentation has intensified. The ecological security level of cultivated land has shown a downward trend, necessitating precise management tailored to local conditions and risk zones.

Abstract:[Objective] The strength and driving factors of trade-offs and synergies among different ecosystem services in major grain-producing areas were explored, in order to provide theoretical support and a decision-making basis for the management of regional ecosystem services. [Methods] Taking Northern Anhui Province as the research object, this study measured the five ecosystem services of water production, carbon storage, soil conservation, habitat quality, and grain productivity from 2000 to 2023, and used Moran’s I to measure the spatial autocorrelation of each element. The dynamic ecosystem synergistic trade-off index was used to quantify the strength of the trade-off/synergistic relationships between the changes in each ecosystem service over a 23-year period, and an optimal parameters-based geographic detector was used to identify the driving forces of natural and social factors. [Results] ① Over the past 23 years, the internal grain productivity service in Northern Anhui Province’s grain-producing area has increased by 91.97%, whereas other ecosystem services have decreased. ② The characteristics of the trade-off/synergistic relationships between ecosystem services are spatially heterogeneous; they are divided into four categories: strip-shaped, point-shaped, homogeneous, and scattered. The main supporting services have significantly influenced the spatial distribution of trade-off/synergistic relationships between different ecosystem services. ③ The intensity of the ecosystem service trade-off/synergy is driven by natural factors (soil erosion power, NDVI). The interaction between natural and social factors also enhances spatial differences in trade-off synergy. [Conclusion] There is significant spatial heterogeneity in the synergistic effects of ecosystem service trade-offs in the main grain-producing areas of Northern Anhui Province. Natural factors are the chief driving factors, and the interaction between nature and society enhances spatial differences.

Abstract:[Objective] As a key economic zone in central China and an industrial base dominated by energy and heavy chemicals, Taiyuan City, Shanxi Province aims to achieve high-quality growth by deeply understanding the relationship between urban transformation and ecological-environmental quality as well as the characteristics of land-use transition and its impact on habitat quality. This understanding provides a basis for and support for urban land use transitions. [Methods] The geoscience information map, drive-pressure-state-influence-response (DPSIR) framework, and InVEST model were employed to explore the characteristics of land-use transition as well as the spatiotemporal changes in ecological security and habitat quality in Taiyuan City from 2011 to 2021, and their impacts on habitat quality resulting from land-use transition. [Results] ① During the study period, the main manifestation of land-use transition in Taiyuan was the mutual conversion among land for cultivation, forests, construction, and grasslands. Grasslands had the largest outflow area, whereas land for forest and construction had the largest inflow areas. ② Taiyuan City’s ecological security index showed an upward trend, rising from 0.266 1 in 2011 to 0.725 5 in 2021. However, habitat quality exhibited a slow downward trend, declining from 0.576 8 in 2011 to 0.573 5 in 2021. ③ The index for ecological-environmental quality revealed a slight downward trend from 2011 to 2021 but remained fairly stable overall. Conversion from cultivated land to grasslands contributed the most to habitat quality, with a contribution rate of 3.354%. The primary reason for the decline in habitat quality was the conversion of land meant for cultivation to land meant for construction, with a contribution rate of 8.838%. [Conclusion] The characteristics of land-use transformation in Taiyuan City are clear. Changes in land use have degraded the ecological environment, and there are differences in ecological security and habitat quality. The mutual conversion between land for cultivation, forests, construction, and grasslands is the main factor affecting the quality of the ecological environment.

Abstract:[Objective] The spatio-temporal distribution characteristics and interaction mechanisms of coal, water, and soil resources in the Ningdong coal and power base from 2003 to 2023 were explored, in order to provide a theoretical basis for the optimal allocation of resources and ecological environment protection in this region. [Methods] Based on multi-source data, the spatiotemporal evolution characteristics of coal, water, and soil resources were studied using methods such as a land-use transfer matrix and growth rate analysis, and the balance of water resource utilization was evaluated in combination with supply and demand analysis. [Results] ① From 2003 to 2023, coal production in Ningdong continued to increase, with an average annual growth rate of 5.89%. Coal mines were mainly distributed in the central and northern parts of the base, and the areas of industrial and mining land use had increased significantly. The supply and demand of water resources were unbalanced. Surface water relied mainly on water diversion from the Yellow River, and groundwater exploitation was restricted. The water body area increased from 21.45 to 45.66 km². ② The dominant land use type was grassland, but its area decreased. Industrial and mining residential land use expanded significantly, and its proportion increased from 1.40% in 2003 to 8.12% in 2023; the land resource utilization rate increased from 6.14% to 18.42%. ③ The development of coal, utilization of water resources, and changes in land use interacted with each other. Coal mining affected water resource demand and land occupation. The distribution of water resources influenced the ecological patterns of mining areas. Changes in land use further regulated coal mining layouts. [Conclusion] Coal development has a significant impact on soil and water resource utilization. Efforts should be made to optimize the allocation of water resources, improve the efficiency of land use, and promote the green and low-carbon development of Ningdong coal and power bases.