Abstract:[Objective] The biological diversity and the anti-tensile mechanical properties of plant roots in the Ngoring Lake area were investigated, to provide data support for the effective prevention and control of geological disasters such as soil erosion and the sod layer slump of alpine grassland in the Ngoring Lake area, the source of the Yellow River, as well as a theoretical basis for the research on the failure mechanism of the sod layer. [Methods] Based on the sample survey results in the study area, single-root tensile tests were performed on the dominant herbaceous plants in the area; the differences in single-root tensile strength, single-root tensile intensity, single-root ultimate elongation and single-root modulus of elasticity of the different herbaceous plants and their relationship with the root diameter were comparatively analyzed in different root-diameter levels. [Results] The dominant herbaceous plants in the study area were Carex moorcroftii, Astragalus polycladus, Artemisia frigida, Poa annua, Leontopodium pusillum. and Lagotis brachystachya. Under the condition of root diameter range of 0.10—0.60 mm, the single root tensile strength and single root tensile intensity of the above six herbaceous plants exhibited the trend of power function growth and power function decrease, respectively, with the increase of root diameter. Furthermore, there was no significant functional relationship between the single-root ultimate elongation and single-root elastic modulus and root diameter. Considering the mechanical property indexes of single root tensile resistance, species importance value, and root type of different plant types, Poa annua exhibited the best soil fixation capacity in the Ngoring Lake area. [Conclusion] The root systems of the six dominant herbaceous plants in the study area have better soil-fixing potential, among which Poa annua has the strongest soil-fixing ability. This study’s results can provide a certain basis for the soil and water conservation work in the Ngoring Lake area.

Abstract:[Objective] The effects of different soil and water conservation measures on soil nutrients and plant diversity in open-pit coal mine dumps were explored, aiming to provide feasible technical measures for the ecological restoration of mine dumps and other abandoned lands. [Methods] Eight soil and water conservation measures combining soil and water-conservation-engineering and plant measures were deployed on the exposed slopes of the grassland open-pit coal mine discharge site, with no measures (CK) as the control. Sampling was conducted to investigate the characteristics of the plant community, as well as to determine the main physicochemical properties of the soil, compare and analyze the differences in the changes in the characteristics of the plant community, and soil properties of the different soil and water conservation measures. The redundancy method was used to analyze the correlation between plant community characteristics and soil properties. [Results] ① The soil and water conservation measures applied on the slope of the discharge site affected differently the main physicochemical properties of the soil, in which the soil quick-acting nutrient content changed significantly (p<0.05), and the soil quick-acting phosphorus content of the two measures-spreading mixed grass + ecological bag spacing 1m (Ⅱ) and spreading mixed grass + ecological bag spacing 2 m (Ⅲ)-reached 3.38 and 3.13 mg/kg, respectively. These increased by 53.6% and 42.3% compared to that of the control (CK) (2.20 mg/kg), respectively. The soil quick-effect potassium content of the three measures of spreading mixed grass + ecological bag spacing 2 m (Ⅲ), spreading mixed grass + geocell (Ⅶ), and spreading mixed grass + grass curtain (Ⅷ) was 108.25, 126.25, and 124.00 mg/kg, respectively. In contrast, the soil quick-effect potassium content of the control plot was only 53.25 mg/kg. ② The effects of soil and water conservation measures on plant community characteristics manifested mainly in the Simpson’s dominance index, which was significantly higher than that of the control (CK), except for the insignificant differences (p>0.05) between the spreading of sedge + salix psammophila sand barriers (Ⅵ) and the spreading of sedge + geocell (Ⅶ) (p<0.05). ③ The results of redundancy analysis showed that the Margalef richness, Simpson dominance index, and Shannon-Wiener diversity index were all significantly positively correlated with soil quick-acting phosphorus. The Louie evenness index was significantly positively correlated with soil total nitrogen, quick-acting potassium, and slow-acting potassium. [Conclusion] The implementation of soil and water conservation measures in open-pit coal mine dumps can improve the soil nutrient content and plant diversity, which has a positive effect on ecological restoration. The soil and water conservation measures of spreading mixed grass + ecological bag with an interval of 2 m (Ⅲ) and spreading mixed grass + salix psammophila sand barriers (Ⅵ) have a better ecological restoration effect, which can be popularized and applied as the main measures for ecological restoration of dumps in the mining area.

Abstract:[Objective] The effects of planting different perennial flowers on soil salinity and nutrients in the Yellow River delta were explored, in order to provide species reference for selecting suitable perennial flowers for ecological improvement of saline soil and assist the national strategy of the Yellow River and the construction of beautiful villages in saline-alkali areas. [Methods] The bare soil without planting perennial flowers was taken as the control, the soils planted with Iris lactea, Pennisetum alopecuroides subsp. purple, Dianthus plumarius, Gaillardia pulchella, Hemerocallis hybrida, and Sedum spectabile were examined to find the effects of perennial flowers planting on the soil salt content, electrical conductivity, Na⁺, Cl^-, available potassium, and available phosphorus content. [Results] ① The perennial flower planting showed ecological regulation effects on saline soil in the Yellow River Delta. Among them, I. lactea and P. alopecuroides significantly reduced the salt content in the 0—10 cm soil. At the same time, I. lactea also had a certain effect on reducing the salt content of 10—20 cm soil layer, and the trend of conductivity was consistent with the salt content. ② The contents of Na⁺ and Cl^- in the 0—10 cm soils were significantly reduced by G. pulchella and D. plumarius, and the removal effect of soil Cl^- by I. lactea and G. pulchella was significant. ③ Perennial flowers had no significant effect on the content of available potassium in topsoil but reduced the content of available phosphorus in the 10—20 cm soils except P. alopecuroides. [Conclusion] The improvement effect of I. lactea and P. alopecuroides on saline soil was better, and they could be given priority when selecting perennial flowers for ecological improvement of saline soil in the Yellow River delta. H. hybrida had the medium effect, whereas D. plumarius, G. pulchella and S. spectabile had poor effects.

Abstract:[Objective] The effectiveness of washing reagents in removing soil salinity was evaluated to provide theoretical guidance for soil amendments in coastal reclamation zones. [Methods] Slightly and heavily saline soils of paddy fields from the Chongming coastal reclamation zones in Shanghai City were selected as the research objects, and the effects of five types of washing reagent (potassium nitrate, iron nitrate, calcium nitrate, magnesium nitrate, and ammonium bicarbonate) concentrations and extraction times on soil salinity (Na⁺, K⁺, Ca²⁺, Mg²⁺, CO^2-₃, HCO^-₃, Cl^-, and SO^2-₄) removal efficiency were compared and analyzed. [Results] The five washing reagents promoted the removal of Na⁺ and Cl^- in the slightly saline soils, and the effect of potassium nitrate on Na⁺ removal efficiency was the most obvious, because the Na⁺ concentration in the eluate was increased by 9.9%—25.9% compared with that in the control. However, Cl^- was more easily removed by ammonium bicarbonate, and the increase ratio was approximately 9.6%—21.2% compared with the control. Potassium nitrate (3.0 mmol/L) showed the best results, considering the removal of soil salt ions and the loss of soil nutrients (K⁺, Ca²⁺, and Mg²⁺). The Na⁺, Cl^-, SO^2-₄, and Ca²⁺ concentrations in the eluate of the second washing by potassium nitrate were markedly lower than those after the first time, whereas it was not the case for HCO^-₃ and Mg²⁺. In this experiment, the five washing reagents showed negligible effects on the removal efficiency of Na⁺ and Cl^- in the heavily saline soils because the applied concentration was much lower than the salt ion content in the soils, and the increase rates of the two ions were 0.10%—1.0% and 0.01%—-4.40%, respectively, compared with the control. [Conclusion] The types, concentrations and times of washing reagents should be determined according to the types and contents of soil salt ions when improves soil in coastal reclamation zones. The application of washing reagents could be combined with irrigation measures.

Abstract:[Objective] The content and stoichiometric ratio of available trace elements in soil under different vegetation types in photovoltaic power plants were explored to provide a theoretical basis for accelerating the vegetation restoration of photovoltaic power stations in arid areas of Western China. [Methods] The soil of four vegetation types in the photovoltaic agriculture, forestry and animal husbandry demonstration base of Tumd Left Banner in Hohhot City, Inner Mongolia was taken as the research object, and the available trace elements and ecological stoichiometry characteristics of different vegetation soils were analyzed. Four vegetation types, namely natural vegetation, Pinus sylvestris, Astragalus membranaceus, and Medicago sativa, were selected to determine the nutrient status of the 0—20 cm and 20—40 cm soil layers. [Results] ① There were significant differences in the soil available trace elements among the four vegetation types, and the content of available trace elements was low. ② For the four vegetation types, the content of available trace elements in soil followed the order A. membranaceus plot > M. sativa plot > P. sylvestris plot > natural vegetation plots. ③ The chemical ratios of the soil trace element effective contents in the study area were 0.96, 31.95, 4.07, 33.50, 4.30 and 0.15 for Fe∶Mn, Fe∶Cu, Fe∶Zn, Mn∶Cu, Mn∶Zn and Cu∶Zn, respectively. ④ The soil trace nutrients in the study area were Fe, Mn, and Cu deficiencies; Fe was the main trace element limiting factor, and Mn and Cu were secondary limiting factors. [Conclusion] At the same time as vegetation restoration in this area, it is necessary to add micro-fertilizer appropriately, which can improve soil fertility to a certain extent and provide sufficient micronutrients for vegetation restoration in the study area.

Abstract:[Objective] The coupling relationship between undecomposed leaf litter traits and water conservation ability of 11 major tree species in Northeast China was explored, and their water retention and water loss processes were analyzed, in order to provide theoretical basis for clarifying the water conservation ability of main tree species in this area. [Methods] A total of 11 common tree species in Northeast China were used as the research object. The water holding and loss characteristics of undecomposed leaves were determined by indoor immersion and water loss experiments, and the physical and chemical properties of 12 kinds of leaves were then determined by vernier calipers, scanners, elemental analyzers, Klason method, and concentrated acid hydrolysis sugar determination method. The relationship between leaf traits and leaf water conservation ability was analyzed using regression analysis. [Results] The maximum water holding capacity, effective retention capacity, water loss ratio, and water loss rate of undecomposed litter of 11 species showed significant differences (p<0.05). The maximum water retention rate in descending order was Tilia mandshurica, Betula platyphylla, Tilia amurensis, Larix gmelinii, Fraxinus mandshurica, Juglans mandshurica, Quercus mongolica, Populus×canadensis, Pinus sylvestris var. mongolica, Pinus koraiensis, Picea koraiensis, and it was significantly positively correlated with the specific leaf area. In addition, there was a significant negative correlation between leaf thickness and leaf shape index (p<0.05). At 24 h, the water loss rates were (from low to high) Picea koraiensis, B. platyphylla, T. amurensis, T. mandshurica, Pinus koraiensis, Q. mongolica, F. mandshurica, Populus×canadensis, Pinus sylvestris var. mongolica, L. gmelinii, and J. mandshurica. The water loss rate was significantly positively correlated with leaf length, specific leaf area, and rough degree (p<0.05). [Conclusion] Specific leaf area was the most important leaf character affecting water conservation ability of undecomposed leaf litter, followed by leaf length, leaf thickness, leaf shape index, and roughness. T. mandshurica, B. platyphylla, and T. amurensis are tree species showing an excellent water conservation capacity of undecomposed litter.

Abstract:[Objective] The characteristics of water conservation capacity of the mixed combination models of Mytilaria laosensis and Castanopsis hystrix were explored, and the best mixed combination mode of water conservation capacity was selected, in order to provided a scientific basis for the construction, operation and management of water conservation forest in Xijiang River basin. [Methods] Nine mixed plantation patterns with three mixing proportions (i.e., 1∶3, 2∶2, and 3∶1) and three mixing modes (i.e., interplant mixing, strip and row mixing, and block mixing) of M. laosensis and C. hystrix were selected, and the pure plantations of both species served as controls. The differences in the water conservation capacity of litter and soil among the eleven planting models were evaluated, and the mixed plantation with the optimal water conservation capacity was identified using an entropy weight TOPSIS (technique for order preference by similarity to an ideal solution) model. [Results] ① The biomass, natural water storage, effective water interception, and maximum water interception in the litter layer ranged from 1.17 to 4.21, 0.38 to 2.29, 5.15 to 10.58, and 6.40 to 13.37 t/hm², respectively. These indices were positively and significantly correlated with the percentage of M. laosensis in the plantations (p<0.05). Compared to interplant mixing and block mixing, the strip and row mixing of the plantations yielded higher biomass and effective water interception in the litter layer. ② The natural moisture storage, capillary water storage, non-capillary water storage, and saturated water storage in soil at a depth of 0—30 cm ranged from 756.14 to 1 007.21, 1 130.73 to 1 388.40, 117.96 to 422.63, and 1 444.70 to 1 590.66 t/hm², respectively. Capillary and non-capillary water storage differed significantly among the plantations and were positively correlated with the percentage of M. laosensis in the plantations (p<0.05). ③ The mixed plantation of M. laosensis and C. hystrix with a ratio of 3∶1 and strip and row mixing exhibited the optimal water conservation capacity. The water conservation capacity of the other plantations ranked as follows: pure plantation of M. laosensis, other mixed plantation patterns, and pure plantation of C. hystrix. [Conclusion] The water conservation capacity of the mixed plantation of M. laosensis and C. hystrix was, to a certain extent, better than that of each pure plantation in the young stand stage, which was influenced by the mixing proportions and modes.

Abstract:[Objective] The effects of different planting densities on plant community structure, species diversity, and soil physicochemical properties of Pinus tabulaeformis plantation were studied, and the appropriate management density of soil and water conservation forest were determined to provide reference for the improvement of ecological function and sustainable development of P. tabulaeformis plantation in the arsenic sandstone area. [Methods] Taking P. tabulaeformis plantation on the slope of Xujiamen Qiangou in Xiheidai of Zhungeer Banner as the research site, the relationship between understory herbaceous plant community composition, species diversity and soil physical and chemical properties under four planting densities (950, 2 000, 3 250, 4 300 plant/hm²) was explored through field sampling and indoor investigation. [Results] ① There were 33 species from 9 families and 19 genera in the study area, and the number of plant species was the highest when the afforestation density was 3 250 plant/hm². The understory herbaceous plant communities of P. tabulaeformis were mainly Gramineae, Compositae, Fabaceae and Rosaceae. With the increase of afforestation density, the associated dominant species transited from sunny and mesophytic species to shady species. ② The species diversity index, plant height, biomass, soil organic matter, available nitrogen, phosphorus and potassium content, and soil water content in the understory herbaceous layer were 3 250 plants/hm²>4 300 plants/hm²>950 plants/hm²>2 000 plants/hm². ③ Afforestation density had significant effects on soil water content, organic matter and available nitrogen, phosphorus and potassium content (p<0.05), but had no significant effects on plant species diversity index (p>0.05). In the correlation analysis, soil organic matter, available nitrogen, phosphorus and potassium content were most closely related to the species diversity index of herbaceous layer. [Conclusion] The planting density of 3 250 plant/hm² was more conducive to the growth of understory plants and the improvement of soil fertility in the arsenic sandstone area of Zhungeer Banner.

Abstract:[Objective] The dynamic changes in soil moisture and its response to rainfall in earth-rocky mountain areas of North China were analyzed, and the characteristics and laws of its rainfall response recharge were revealed, aiming at providing a reference and theoretical basis for rational utilization of water resources and water conservation in this area. [Methods] This study focused on typical natural barren slopes in earth-rocky mountain area of North China, employing in-situ monitoring to collect real-time data on soil moisture at different slope positions for detailed analysis. The dynamic response characteristics of soil moisture to rainfall and its intrinsic patterns were studied. [Results] ① The average annual soil moisture content along the slope exhibited the following pattern: bottom slope (20.3%±5.5%) > top slope (19.5%±5.7%) > middle slope (15.9%±7.0%), and in the vertical profile, deeper soil layers had a higher moisture content than that in shallower layers. ② The response rate of soil moisture to rainfall was significantly faster in the middle slope (1.50 h) compared to that in the top (4.10 h) and bottom slopes (2.80 h), and in the vertical profile, deeper soil layers responded to rainfall more quickly than shallower layers. ③ The average rates of moisture replenishment and depletion due to rainfall were as follows: middle slope (1.4%/h, 0.3%/h) > top slope (0.9%/h, 0.2%/h) > bottom slope (0.7%/h, 0.1%/h), and in the vertical profile, the replenishment and depletion rates were higher in deeper soil layers than in shallower layers. [Conclusion] In the earth-rocky mountainous area of North China, when rainfall exceeds 2.7 mm, it can effectively recharge soil moisture on slopes. Additionally, the responses of the middle slope and deeper soil layers to rainfall were notably more rapid.

Abstract:[Objective] Forest type differentiation characteristics and spatial patterns of the forest water conservation function of Giant Panda National Park in Sichuan Province were examined, in order to provide guidance for the protection of forest resources and adaptive management of water resources in this area. [Methods] Based on the results of the cadastral and special forest resources survey in the Sichuan area of Giant Panda National Park, sample plots data, and multi-source remote sensing data, the integrated storage capacity method was applied to estimate the forest water conservation function. Its characteristics under different forest types and site conditions were then analyzed. [Results] ① The extent of water conservation of the forest ecosystem in this area was 1.71×10⁹ m³, yielding a water conservation of 1 061.27 m³/hm² per unit area. The soil layer served as the main reservoir for water conservation. Evergreen coniferous forests exhibited the strongest water conservation function. ② There were notable spatial variations in forest water conservation function, with higher levels in Ya’an, Mianyang, and Guangyuan City and lower levels in Aba Prefecture and Deyang City. ③ The forest water conservation amount mainly concentrated in areas with altitudes ranging between (1 500, 3 500］ meters, contributing 90.10% to the total water conservation amount. In addition, the forest water conservation per unit area significantly decreased as altitude increased (p＜0.01). ④ Forests on steep slopes (35°，45°］ had the highest forest water conservation amount, with a contribution rate of 24.01%. The forest water conservation per unit area showed a trend of first increasing and then decreasing as slope steepness increased (p＜0.01). [Conclusion] Reasonably adjusting the forest resources’ structure and optimizing forest resources’ distribution of Giant Panda National Park in Sichuan Province according to local conditions would help maximize the forest water conservation function in this area.

Abstract:[Objective] The optimal combination of three environmental materials for soil aggregate structure and physicochemical properties improvements were examined, in order to solve the problems of poor soil structure and serious soil and water loss in the process of soil reclamation in the alpine region of Qinghai-Xizang region. [Methods] Using the Qinghai Delni Copper Mine as the research site and utilizing the local serpentine residue soil and raw soil, the effect of mixing three kinds of materials, namely binder, long fiber, and rice husk, on the soil improvement was investigated through the soil cultivation simulation orthogonal test, and the ratio of the mixed materials with the best effect was screened out. [Results] Orthogonal polar results showed that the binder had a stronger effect on soil aggregates, total porosity, field water holding capacity, and soil bulk density, whereas long fibers and rice husk had a stronger effect on pH value and total salt content. Binder incorporation increased soil bulk density but decreased soil pore space compared to the control (CK). Long fibers and rice husk significantly decreased soil pH value, increased total porosity and field water holding capacity, and suitably increased total salt content. The optimal combination for soil aggregates and pH value was A₂B₂C₃ (binder 0.074 g/kg, long fiber 2.960 g/kg, rice husk 11.110 g/kg). Soil bulk density, total porosity, and field water holding capacity regulation were optimized using the combination A₁B₂C₂ (binder 0.037 g/kg, long fiber 2.960 g/kg, rice husk 7.410 g/kg), and the optimal combination for total salt content was A₃B₁C₂ (binder 0.111 g/kg, long fiber 1.480 g/kg, rice husk 7.410 g/kg). [Conclusion] The optimal formula for soil matrix restoration in the alpine mining area was obtained as A_1.5B₂C₂, that is, binder 0.056 g/kg, long fiber 2.960 g/kg, and rice husk 7.410 g/kg as the optimal ratios, which could improve the soil structure and enhances the capacity of soil and water conservation in the alpine mining area of Qinghai-Xizang region.

Abstract:[Purpose] Field investigations were carried in the three-river-source region, to provide a reference for soil erosion prevention and control in the region. [Methods] The investigation team travelled to Guoluo, Yushu, Hainan, and Huangnan Prefectures in Qinghai Province in three separate groups from July 25 to August 20, 2023. Woodlands, grasslands, farmlands, bare lands, roads, riverbanks, and mountain gullies in these areas were surveyed and analyzed. [Results] Grassland had the most complex type of soil erosion and was subjected to the joint action of multiple camp-force erosions such as wind erosion, water erosion, freezing and thawing erosion, and gravity erosion, resulting in serious soil erosion. In addition, grassland damage by highland rodents may be another important factor in the occurrence of grassland erosion. Forestland had erosion gullies in the standing forest; however, the overall risk of erosion was low due to engineered slope protection. The foot of the slope on which the shrub land is situated was more exposed to hydraulic and gravitational erosion and was at greater risk of erosion. The farmland was spread over a small area, with mild water erosion occurred in the field. For bare ground, fine gully erosion was more intense, and soil erosion was serious. Notably, on both sides of the road, the slopes were more severely eroded, and the excavation of the project has led to the destruction of the turf, sliding under gravity, and the emergence of larger exposed surfaces, which provide conditions for the occurrence of water erosion, leading to a larger network of erosion gullies that have already formed in some areas. [Conclusion] Soil erosion in the three-river-source region of Qinghai Province is complex and varied, with the intensification of human activities and the risk of further exacerbation of soil erosion in localized areas. There is an urgent need to conduct soil and water conservation work in the new era, and there is a need to strengthen basic research on soil erosion in the region, the deployment of the network of soil and water conservation monitoring stations, and intelligent management.

Abstract:[Objective] The temporal and spatial dynamic changes of desertification in the Kubuqi Desert during 2000—2023 were investigated, aiming to provide theoretical references and basic data support for the restoration of vegetation and ecological construction. [Methods] Based on the features of Landsat remote sensing images, the spatial and temporal distribution and change trend of land desertification in the Kubuqi Desert and its surrounding areas from 2000 to 2023 were studied by using enhanced vegitation index (EVI) remote sensing index gray segmentation, land desertification degree classification, land use dynamic attitude, abundance index and importance index. [Results] The total desertification area in the Kubuqi Desert decreased from 10 694.6 km² in 2000 to 8 837.56 km² in 2023. The area of extreme desertification was reduced from 6 272.11 km² to 1 461.15 km², that of severe desertification increased from 1 773.97 km² in 2000 to 2 874.48 km², of moderate desertification increased from 1 372.16 km² in 2000 to 1 965.84 km², and of mild desertification increased from 1 276.35 km² to 2 535.58 km². Considering the perspective of time series, the rate of extremely severe desertification from 2000 to 2023 was 3.33%, that of severe desertification was 2.70%, of moderate desertification was 1.88%, and of mild desertification was 4.29%. The area of extremely severe desert land types decreased from 6 272.11 km² in 2000 to 1 461.65 km² in 2023, with a total loss area of 4 949.72 km². From the spatial perspective, the distribution of extremely severe desert types changed from distributed over time to concentrated, becoming dominant from 2000 to 2010; the multiple-degree index of severe and moderate desertification types ranged between 7.69% and 16.15%, indicating that the long-term distribution of heavy and moderate desertification types was concentrated; mild desertification types were scattered and extensive over time. [Conclusion] From 2000 to 2023, the area of Kubuqi Desert showed a decreasing trend, and the ecological environment had been improved. In the future, the ecological restoration of this region will focus on the extremely severe desert area.

Abstract:[Objective] The spatiotemporal changes and sustainable utilization of water resources ecological footprint were explored in the middle reaches of the Yangtze River to provide decision-making references for the sustainable utilization of water resources in this region and in other provinces, metropolitan areas, and river basins. [Methods] This study selected the Hubei, Hunan, and Jiangxi provinces in the middle reaches of the Yangtze River from 2011 to 2021 as the research subjects. Employing the water resource ecological footprint model, a spatiotemporal analysis was conducted on the ecological footprint and related indicators of the three provinces. Based on the pressure-state-response model framework, an evaluation index system for sustainable water resource utilization in the middle reaches of the Yangtze River region was developed. [Results] ① The per-capita water resource ecological footprint and ecological carrying capacity of the three provinces showed an overall increasing trend, with the ecological carrying capacity exceeding the ecological footprint, resulting in an overall ecological surplus. Jiangxi Province had the highest per-capita ecological surplus of water resources, ranging from 3.186 to 7.966, whereas Hubei Province had the lowest, ranging from 0.304 to 2.603. ② The ecological footprint of each water account in the three provinces was predominantly industrial followed by domestic. Although ecological environmental water had the smallest share, it showed the most significant increase, particularly in Hubei Province. ③ The ecological footprint of water resources per ten thousand GDP exhibited a significant downward trend, with Jiangxi Province having the highest value and Hubei Province having the lowest, and the gap between the two gradually narrowed each year. ④ The pressure, state, and response indices for sustainable water resource utilization in the three provinces generally exhibited declining, rising, and increasing trends, respectively. The comprehensive evaluation indices exhibited a fluctuating upward trend; however, the rate of increase was modest and the overall index values remained relatively low. [Conclusion] Continued efforts are required to enhance the rational use of water for industrial and domestic purposes, promote the utilization of ecological and environmental water, and develop advanced measures to achieve sustainable water resource utilization. These findings can serve as a decision-making reference for water resource sustainability in the middle reaches of the Yangtze River and other provinces, city clusters, or basin areas.

Abstract:[Objective] The impact of changes in land use types on soil erosion amount in the control area of check dams was studied to provide a theoretical basis for the high-quality development of ecological construction in the dam control area. [Methods] The control area of the Shuiquanwan check dam in Weiyuan County, Gansu Province, was selected as the research site. The weighted average method was used to modify the soil erosion modulus from the literature, and the soil erosion amounts for different land use types in the control area were calculated. The change process and characteristics of land use types were analyzed based on remote sensing images, and the influence of changes in soil conservation measures on soil erosion was explored through Pearson correlation analysis. [Results] ① From 2005 to 2023, the main land use types in the dam-controled area of Shuiquanwan check dam were terraced fields, which accounted for more than 70%, while water bodies accounted for less than 0.1%. The transformation of land use types involved mutual changes among terraced fields, wasteland, sloping land, dredged land, and shrubland。② The total amount of soil erosion in 2005, 2010, 2018, and 2023 was 4.54×10³, 3.70×10³, 3.31×10³ and 3.95×10³ t, respectively. Soil erosion mainly occurred in sloping farmland, wasteland, dredged land, terraces, and shrubland, with wasteland exhibiting the largest annual erosion. Its proportion ranged from 41.74% to 49.46%, while residential land and roads accounted for less than 1%. ③ A significant negative correlation exists between slope-cultivated land and terrace area, with a correlation coefficient of 0.972. There was also a significant positive correlation between soil erosion and grassland area, with a correlation coefficient of 0.983. [Conclusion] The adjustment of agricultural structure and the development of agricultural technology are among the main driving factors for land use types and patterns changes. Comprehensive management of slope changes and small watersheds effectively reduces regional soil and water loss.

Abstract:[Objective] Slope gradient data was accurately obtained to address the limitation of slope gradient underestimation using the freely downloaded 30 m resolution digital elevation model (DEM) for farmland in Northeast China, in order to provide important data support for quantitatively evaluating soil erosion in the rolling hilly regions. [Methods] A 5 cm resolution DEM was generated from drone survey images and resampled to obtain 1, 5, and 12.5 m DEM resolutions. Combined with the 30 m DEM resolution, the optimal DEM resolution for slope gradient extraction in the study area was identified. Additionally, the histogram matching method was used to establish a slope gradient conversion model between the 30 m DEM resolution and the optimal DEM resolution for each slope gradient category. [Results] ① The slope gradient distributions derived from the five DEM resolutions indicated that the 1 m and 5 m DEM resolutions exhibited a strong similarity to the slope gradient distribution of the 5 cm DEM. Given that the 5 m DEM resolution corresponds to a 1∶10,000 scale topographic map, the 5 m DEM resolution was optimal for constructing the slope gradient conversion model. ② Using the histogram matching method, a univariate linear model and a univariate quadratic non-linear model were developed for slope gradient conversion between the 30 m and 5 m DEM resolutions across different slope gradient segments. The linear conversion model was suitable for slopes less than 7°, while the non-linear model was more appropriate for slopes greater than 7°. ③ After applying both linear and non-linear conversion models, the frequency distribution of slope gradients extracted from the 30 m DEM resolution closely matched that of the 5 m DEM resolution, significantly improving covariance and correlation coefficients. This reflected that the slope gradients after conversion from the 30 m DEM resolution can accurately represent ground undulation; additionally, the optimization results from the non-linear conversion model were superior to those from the linear conversion model. [Conclusion] The 5 m DEM resolution is the optimal resolution for extracting slope data in the study area. The developed conversion model for low-to-high resolution slope gradients showed that the non-linear slope conversion model has a better optimization effect than the linear slope conversion model.

Abstract:[Objective] The simulation method of flood evolution process caused by reservoir dam failures in urban areas was analyzed, in order to provide a scientific basis for risk prevention, early warning system development, and evacuation plans. [Methods] Using the upstream Jiangang and Changzhuang reservoirs in Zhengzhou City as case studies, a high-resolution digital elevation model was constructed based on GIS technology. The MIKE FLOOD coupling model was employed to integrate one-dimensional and two-dimensional models of reservoir dam failure, simulating the flood evolution process and exploring the characteristics of floods in downstream rivers and complex urban areas. [Results] Immediately following the dam failure, the peak discharge at the breach quickly reached its maximum. Peak outflow volumes from the Changzhuang and Jiangan reservoirs were 4 542.03 and 17 549.1 m³/s, respectively, with non-converging flood peaks. Portions of both banks downstream of the Jialu River, within 15.00 to 31.39 km from the Jiangan reservoir, were inundated, covering an area of 56.37 km². One hour after the breach of the Changzhuang reservoir, riverbanks began to overflow, resulting in increased inundation areas. The Jiangan reservoir dam failure occurred 4.25 h later. 1.25 h after the Jiangan reservoir breach, inundation depths significantly increased in the original inundation area, expanding further to the maximum inundation area 1.92 h later. Following the dam breaks of the Changzhuang and Jiangan reservoirs, the floodwater level rose above the top of the south-to-north water transfer protection embankment, and a large volume of floodwater surged into the main channel of the south-to-north water transfer, generally increasing the flood flow rate. [Conclusion] The peak flood flow from the Jiangan reservoir is significantly larger than that from the Changzhuang reservoir, making its dam break more harmful. After the dam breaks, a substantial amount of floodwater enters the main channel of the south-to-north water diversion Project, increasing the risk of erosion of dikes, slopes, and inlet and outlet lock chambers. This situation seriously affects the water conveyance safety of the main canal of the south-to-north water diversion project and the safety of people’s lives and property.

Abstract:[Objective] The development characteristics of erosion gullies at black soil area in rolling hilly area in Northeast China were explored, and the influencing factors of erosion gullies in sloping farmland were revealed, in order to provide scientific basis and data support for erosion gully control in the region. [Methods] The study selected 61 typical erosion gullies on sloping farmland at Guofu Town, Baiquan County, Helongjiang Province, as research sites. Factors such as slope, aspect, altitude, and catchment area were extracted and analyzed for their effects on the morphological changes and development characteristics of gullies on sloping farmland, using drone aerial photography techniques to generate digital elevation models and based on data sources such as remote sensing images in the study area. [Results] ① The length, area, and volume of the erosion gullies in the study area showed a significant correlation with factors such as slope, altitude, and catchment area. Except for gully length, the correlation between gully morphological parameters and influencing factors ranked from large to small (i.e., catchment area > slope > altitude). ② Gully length variation and shape index showed a gradual decrease with increasing slope, reaching the maximum value within the range between 0° and 2°. Gully depth increased with increasing slope, peaking at 4° to 5°; significant variations were observed in gully development on sunny and semi-sunny slopes, with the most rapid development occurring on southwest-facing slopes. The average gully length and shape index in the study area showed a trend of first increasing and then decreasing with increasing altitude, reaching a peak in the range of 230—240 m. ③ Larger catchment areas corresponded to larger gully morphological parameters and more intense gully development. When the catchment area was within the range of >20 hm², the variations in gully length and gully bank area reached their peak values. ④ A multivariate regression model constructed with gully morphological parameters and influencing factors showed a high degree of fit. The fitting coefficients for gully length, area, and volume were 0.73, 0.47, and 0.16, respectively. [Conclusion] The development of erosion gullies in typical areas of Baiquan County is significantly influenced by slope, aspect, catchment area, and altitude. It is recommended to prioritize erosion control measures for gullies located on slopes between 2° and 3°, facing southeast, at altitudes of 230—240 m, and with catchment areas exceeding 20 hm².

Abstract:[Objective] The effects of culture media containing different contents of Salix psammophila, a kind of ecological products, on the quality of Stropharia rugosoannulata were explored to provide a scientific basis for the cultivation of S. psammophila at Yulin sand area in Shaanxi Province. [Methods] Using S. psammophila branches and wheat straw as the main raw materials, four cultivation material formulas with varying S. psammophila contents were set up. The effects of different S. psammophila cultivation substrate ratios on the yield, morphological characteristics, nutritional components, and mineral and heavy metal contents of S. rugosoannulata were studied, and the experimental results were comprehensively analyzed using gray relational analysis. [Results] ① When using S. psammophila branches and wheat straw to cultivate S. rugosoannulata, the yield of S. rugosoannulata increased with increasing S. psammophila content. The pure S. psammophila sawdust added quicklime (X₁) formula performed the best, with a yield of 7.42 kg/m², which was 4.33 kg/m² higher than that of the control (CK) group, and a biotransformation rate of 49.5%. Simultaneously, the protein content (41.5%) and mushroom shape index (0.81) in the X₁ formula were 4.06% and 0.14% higher, respectively, than those in the CK group. ② Using the gray correlation method to comprehensively analyze the yield, nutritional value, mineral content, and heavy metal content, the weighted correlation between pure S. psammophila shavings and the ideal sequence was determined to be the highest at 0.818. [Conclusion] The fermented S. psammophila could be used as a cultivation material for S. rugosoannulata, that is, the problem of S. psammophila branches can be solved by cultivating S. rugosoannulata, providing new ideas for the utilization of S. psammophila resources in sandy areas.

Abstract:[Objective] The quantitative characteristics of plant communities and their influencing factors under different slope positions in the Loess Plateau were investigated, so as to provide a scientific reference for the theoretical understanding of plant community construction mechanisms within the slope-gully system and for the practical guidance on the design of artificially plant communities restoration. [Methods] The study examines the composition, diversity, stability, and distribution patterns of dominant plants across five slope positions-sunny gully, sunny hill, hilltop, shady hill, and shady gully-within the forest-steppe zone of the loess hilly region under natural conditions. The structural equation model of environmental factors, soil erosion intensity, and plant diversity and stability was constructed to explore the main ecological factors affecting the construction of plant communities in different slope positions. [Results] ① In the forest-steppe zone of the loess hilly region, the sunny gully and sunny hill slopes exhibit a two-layer vertical structure predominantly composed of perennial herbs and shrubs, with dominant plants showing a dispersed distribution pattern. The hilltop had a single-layer vertical structure, mainly comprising annual and perennial herbs, where plants demonstrate a highly clustered distribution. The shady gully slope community had a three-layer vertical structure, with plants also showing a clustered distribution pattern. ② The shady gully slope had the highest species diversity, richness, and stability, whereas the sunny hill slope exhibited the lowest richness and diversity, with significant reductions of 18.4% and 26.5%, respectively, compared to the shady gully slope. The hilltop plant community showed the least stability, with an index of only 29. ③ The common key factors influencing community characteristics across different slope positions were soil erosion intensity and soil moisture. However, soil bulk density on the sunny gully slope, organic matter on the sunny and shady hill slopes, and light intensity on the hilltop and shady gully slope were the distinguishing ecological factors affecting plant community structure, stability, and diversity. [Conclusion] Vegetation restoration strategies should be tailored to the specific slope positions in the forest-steppe zone of the loess hilly region. The “fertile island” effect formed by perennial shrubs on the sunny gully slope could improve surface conditions, while micro-topographic modifications on the sunny hill slope could reduce soil erosion. On the hilltop, the introduction of drought-tolerant plants could enhance plant community structure. The shady hill and gully slopes do not require the construction of an excessively complex plant community structure, so as not to cause the degradation of the herbaceous layer under the artificial forest owing to insufficient light.

Abstract:[Objective] The rainfall regimes and their effects on runoff and sediment yield in the small watershed of the upper reaches of Dawen River were studied, in order to provided a theoretical basis for the predicting and early warning of flood control and soil erosion in the mountainous and hilly areas of Central and Southern Shandong Province. [Methods] The Culai Mountain watershed in the upper reaches of the Dawen River was selected as the study area. K-means clustering and multiple linear regression analysis were employed to examine different types of rainfall and their impacts on sediment yield using rainfall, runoff, and sediment yield data from 2021 to 2023. [Results] The rainfall in this basin can be divided into four types, categorized as follows: type Ⅰ features small amounts of precipitation with low intensity, type Ⅱ features medium amounts of precipitation with moderate intensity, type Ⅲ features heavy amounts of precipitation with high intensity, and type Ⅳ features extra heavy amounts of precipitation with moderate intensity. Rainfall in types Ⅲ and Ⅳ was the main source of runoff and sediment yield in this basin. [Conclusion] The Culai Mountain watershed mainly experiences light rainfall with low intensity, yet the frequency of rainstorms remains relatively high. Affected by the mountainous terrain, the Ⅳ type rainfall was significant sources of regional floods and debris flows. Rainfall Precipitation amount is the primary influencing factor for runoff and sediment production in this basin.

Abstract:[Objective] The characteristics of cultivated land changes around large cities were studied to provide a key basis for realizing the sustainable utilization of cultivated land resources and high-quality development of national space in the concentrated expansion areas of cities. [Methods] Three typical large cities in the upper, middle, and lower sections of the Yangtze River economic belt (Chengdu, Wuhan and Shanghai City) were selected as examples. Based on a land-use transfer matrix and a framework for analyzing the intensity of land-use change, it elaborated on the intensity and stability characteristics of cultivated land change around the three big cities over a long period and explored the synergistic mechanism between urban sprawl and the protection of high-quality cultivated land. [Results] ① The total area of cultivated land around the three major cities decreased continuously between 1990 and 2020, with the loss of high-quality cultivated land and the pressure to replenish cultivated land, and the loss of cultivated land in the middle of the period was the most serious. Wuhan City achieved a balance between occupation and compensation for cultivated land during the late stage. ② The big cities in the Yangtze River economic belt showed rapid land-use changes between 1990 and 2020, and only Chengdu City showed slow changes in the early period. ③ The transfer out of cultivated land and the transfer in of construction land around the big cities in the Yangtze River economic belt had been active between 1990 and 2020, whereas the transfer in of cultivated land had remained stable; the transfer out of construction land in Chengdu and Wuhan City began to be active after 2010. ④ The conversion process of cultivated land to construction land around the big cities in the Yangtze River economic belt between 1990 and 2020 showed a stable tendency systematic conversion pattern, and the transfer in of construction land mainly originated from cultivated land. [Conclusion] In the future, it will be necessary to scientifically formulate a rigid and elastic combination of cultivated land control strategies, realize the multifunctional protection of cultivated land from the perspective of regional ecological security, and establish a diversified cultivated land protection incentive system around the large cities of the Yangtze River economic belt.

Abstract:[Objective] The adaptive siting and layout characteristics of rural settlements in the aquatic environment and the ecological wisdom they contain from the perspective of water-related place names were analyzed to provide theoretical references and inspiration for safety and resilience planning and sustainable development of contemporary rural settlements in the context of climate change. [Methods] Settlement types were classified according to water-related names. Combining textual and spatial analyses, spatial autocorrelation, kernel density estimation, and the SCS-CN hydrological model were comprehensively applied to analyze the adaptive siting and layout characteristics of rural settlements in South Henan Province. [Results] ① The naming of rural settlements in South Henan presents significant aquatic environment orientation, and there is a certain corroborative relationship between place names and spatial patterns. ② The spatial distribution of various types of water-related settlements is significantly clustered and spatially heterogeneous, with a high degree of dependence on the unique water environment. ③ In the macro-level of adaptive siting to the water environment, rural settlements in South Henan have a strong preference for near-water siting and consideration of rain and flood risk. ④ Under the comprehensive influence of the aquatic environment, the adaptive layout features such as site utilization with storage and drainage, village layout to avoid rain and flood, and environmental transformation with consideration of defense have been formed. [Conclusion] The naming of the rural settlements in the Southern Henan region has strong water-related features, and the siting and layout fully embodies the ecological wisdom of water environment adaptation, which tends to benefit from and avoid harm, as well as low technology and ecology. In the future, the concept of water environment adaptation planning can be inherited by watersheds, town and village systems, and facilities.

Abstract:[Objective] The effects of soil erosion and sedimentation on the form, concentration, and enrichment of heavy metals were explored, and the mechanism of the influence of soil erosion and sedimentation on the form, concentration and enrichment of heavy metals were studied, in order to provide a scientific basis for the prevention and control of soil heavy metal pollution in river basins. [Methods] Based on relevant domestic and foreign studies about the influence of erosion-deposition on soil heavy metals, CiteSpace and VOSveiwer software were used to study the knowledge map of the influence of soil heavy metals during erosion-deposition and the relevant research results were systematically analyzed. [Results] ① The research on erosion-sedimentation and heavy metals has shown an upward trend in the past 30 years, increasing rapidly from 2017 to 2023, and geochemical characteristics, ecological risk assessment, source analysis, migration, and transformation are the hot spots in the research area. ② During the erosion process, rainfall promoted the transformation of heavy metals from a granular state to a dissolved state, runoff led to the spatial differentiation of soil heavy metal content, and soil aggregate and clay content in the sedimentary environment affected the distribution and enrichment of heavy metals. ③ Organic matter has dual effects on heavy metals: it can adsorb free heavy metal ions and reduce the exchange state content of heavy metals in soil. In addition, it can also have complexation with heavy metals and increase the organic binding state content of heavy metals. ④ The pH value has a significant effect on the transformation of heavy metal forms. Under acidic conditions, the complexation and precipitation of heavy metal ions are promoted. In contrast, under alkaline conditions, the positive charge on the surface of soil particles repels the positive charge carried by heavy metal ions, thus affecting the adsorption of heavy metal ions on the surface of soil particles. ⑤ Soil water affects the reduction and release of heavy metals. The higher the soil water, the greater the solubility of heavy metals, but excessive water will lead to insufficient oxygen and reduce the REDOX potential (Eh). The change of Eh directly affects the stability of iron and manganese oxides and sulfides in soil, causing changes in heavy metal concentration. [Conclusion] The occurrence forms, concentration changes, and enrichment characteristics of soil heavy metals during the erosion-deposition process are affected by various environmental factors, showing significant differences from erosion area to sedimentary area. Future studies should focus on the development of new technologies and new methods for monitoring the dynamic evolution of heavy metals during the erosion-deposition process. To provide more accurate strategies for the prevention and control of soil heavy metal pollution, a study on the internal relation mechanism of the occurrence form, concentration change, and enrichment characteristics of heavy metals during the erosion-sedimentation process and interaction effects of different factors on heavy metals during erosion-deposition should be conducted.

Abstract:[Objective] The temporal and spatial variation characteristics and the factors affecting the water conservation function in Gansu Province were studied to provide a reference and basis for regional water resources management decision-making and water conservation function recovery. [Methods] The dynamic changes in water conservation on the temporal and spatial scale in Gansu Province from 2001 to 2023 were evaluated quantitatively using the InVEST model, and the influencing factors of the water conservation function were analyzed using the geographic detector. [Results] ① The average water conservation in Gansu Province from 2001 to 2023 was 9.24 mm, and the water conservation fluctuated little during different periods. The change in water conservation was consistent with the precipitation and water yield, showing an upward and then a downward trend. ② From 2001 to 2023, the average water conservation capacity of different land use types in Gansu Province was ranked as cultivated, grass, forest, urban construction, unused land, and water area. ③ Precipitation was the most important driver for the change of water conservation in Gansu Province, and the interactions between precipitation and evapotranspiration, land use type, and elevation had the most significant influence on the spatial difference of the water conservation service function in Gansu Province. [Conclusion] The overall distribution pattern of water conservation in the Gansu Province was lower in the northwest and higher in the southeast. The change in water conservation function was mainly influenced by climate factors and human activities.

Abstract:[Objective] The temporal and spatial variations in the soil and water conservation service functions in Hunan Province were explored, in order to provide a scientific basis for evaluating these functions and formulating a regional ecological management plan. [Methods] Three factors of net primary productivity (NPP) of vegetation, digital elevation model elevation, and soil texture distribution were selected, and the spatial and temporal distribution characteristics of soil and water conservation service functions in Hunan Province were studied based on ArcGIS for the years 2000, 2005, 2010, 2015, and 2020 using the NPP quantitative index evaluation model. [Results] ① From 2000 to 2020, the average net primary productivity of vegetation in Hunan Province ranged from 4.39 to 334.52 g/(m²·a) (calculated by C), showing an upward trend over time. Spatially, the average net primary productivity was higher in the middle and decreasing towards the edges. The elevation varied from -12 to 2,081 m, exhibiting a trend of being high in the west and low in the east, with significant fluctuations in the west and relatively gentle terrain in the east. The slope ranged from 3.3° to 76.7°, showing a trend of being higher in the west and lower in the east. The soil erodibility values ranged from 0.011 to 1.411, indicating that soil erodibility tends to be low in the middle and high towards the edges, spreading and improving from the central area to surrounding regions. ② From 2000 to 2020, the amount of soil and water conservation in Hunan Province ranged from 8.75 to 185.97 t/hm², demonstrating an upward trend over time, primarily in general important and important regions. The area of general important region showed a downward trend over time, while the area of important region showed an upward trend, and the area of extremely important regions exhibited a downward trend. The service function of soil and water conservation transitioned from generally important and extremely important regions to important regions over time. [Conclusion] The increase in net primary productivity of vegetation is the primary reason for the enhancement of soil and water conservation service functions.

Abstract:[Objective] The coupling coordination relationship between economic development quality and ecological resilience, and its dynamic evolution form process were explored, and the coordination role and response mechanism of economic development and ecological protection were clarified, so as to provide theoretical reference for efficient resource allocation and urban-rural integrated development in land border areas. [Methods] The coupled coordination model and kernel density estimation were used to measure and depict the coupling relationship and distribution pattern between economic development quality and ecological resilience. Finally, the P-VAR model was employed to elaborate and verify the interactive response relationship between the two systems. [Results] ① From 2000 to 2020, the coupling coordination degree between economic development quality and ecological resilience in border areas ranged from 0.183 4 to 0.272 8, showing an “initial decline followed by an increase” evolutionary characteristic. The coupling coordination degree of each border area gradually evolved from a unimodal shape to a bimodal manifestation. ② The pulse response of ecological resilience to the quality of economic development in the northern, northwestern of China, and Xizang border areas was negatively impacted, while the pulse response of ecological resilience to the quality of economic development in the northeast, northwest, and southwest border areas of China was positively impacted. ③ The contribution rate of the quality of economic development to ecological resilience in border areas is gradually increasing, while the contribution rate of ecological resilience to the quality of economic development was gradually decreasing. The contribution rate of the interactive response between the two systems in the northwest border area was higher than that in other border areas of China. [Conclusion] There are significant regional differences in the coupling, coordination and interaction of economic development quality and ecological resilience in China’s land border areas, so it is beneficial to promote the sustainable use of economic elements and ensure the ecological security of land space in China’s land border areas.

Abstract:[Objective] The balance and sustainable status of water resources supply and demand in seven river basins in China were examined aiming to provide a reference for the future development of integrated management and scientific allocation of water resources. [Methods] Using the water resources ecological footprint method, this study examined the water resources ecological footprint and ecological carrying capacity of seven river basins in China between 2014 and 2022. The status of water resource sustainability was revealed by using the sustainability evaluation index based on water resources’ ecological footprint. [Results] ① The per capita ecological footprint of water resources in China’s seven major river basins showed a downward trend, among which Songhua River, Yangtze River, Pearl River, and Haihe River accounted for 82.86%, 33.32%, 19.87%, and 12.38% of agricultural water, industrial water, domestic water, and ecological water, respectively. ② The highest per capita carrying capacity was that of the Pearl River at 19.89 hm²/person, whereas the lowest was only 0.03 hm²/person for the Haihe River. Affected by climate anomalies, the ecological carrying capacity of water resources in each basin oscillated considerably from 2020 to 2022. ③ During the study period, the Yangtze, Pearl, and Songhua rivers had a total water resources ecological surplus, with the Pearl River having the largest water resources ecological surplus of 18.21 hm²/person in 2016. The Huaihe and Liaohe rivers went from a water resources ecological deficit to a surplus. The Yellow and Haihe rivers had a water resources ecological deficit, with the Yellow River having the largest water resources ecological deficit of -0.62 hm²/person in 2015. ④ The indicators of sustainable development of water resources implied that the Yellow and Haihe rivers were under greater ecological pressure from water resources and in a state of unsustainable water resources throughout the year, whereas the Pearl River had poor water resource coordination and overall low water use efficiency. [Conclusion] Currently, the balance between the supply and demand of water resources in the Yangtze, Pearl, Songhua, Huaihe, and Liaohe rivers is maintained, whereas the demand of the Yellow and Haihe rivers is always greater than the supply. In the future, water resources planning schemes at the national and basin levels should be established to promote rational utilization of water resources and support sustainable economic and social development in the basin.

Abstract:[Objective] The changes of vegetation net primary production (NPP) and its response to climate factors were quantitatively analyzed to provide scientific reference for assessing the role of urban carbon sequestration under different climate conditions and improving urban ecosystem carbon sequestration. [Methods] Based on GEE (Google Earth Engine), the NPP of Tianjin City during 2001—2022 was calculated, and the spatial and temporal variation pattern of NPP was analyzed by Slope trend analysis, F-test, barycentric migration model, standard deviation ellipse model, and other methods. Multi-factor sensitivity analysis and correlation coefficient evaluation were used to quantitatively evaluate the NPP response characteristics under temperature, precipitation, and wind-speed changes. [Results] ① The average annual vegetation NPP in Tianjin City showed an increasing trend of fluctuation, and the fluctuation range was 53.46—96.54 g/(m²·a) (calculated by C); ② The vegetation NPP of Tianjin City is higher in the north and lower in the south, and higher in the west and lower in the east. The center of gravity is concentrated in the central region, and it gradually moved to the south during 2001—2022. ③ The response of vegetation NPP to climate factors in Tianjin City has a significant lag time of 1 month for temperature and precipitation and 3 months for wind speed. [Conclusion] The variation of NPP in Tianjin City has great spatiotemporal heterogeneity and is affected by temperature, precipitation, and wind speed, with a lag effect of 1—3 months in response to climate factors.

Abstract:[Objective] Taking Ma’anshan City of Anhui Province, a resource-based city in transition, as the research object, the influence of urban expansion on the habitat quality of this city was studied, aiming at providing reference for realizing regional sustainable development. [Methods] Based on the Globe Land30 data in 2000, 2010 and 2020, the urban land expansion was studied by means of center of gravity analysis and standard deviation ellipse, and the habitat quality of Ma’anshan City was calculated. In addition, the PLUS model was used to simulate land use change under different scenarios to analyze the impact of urban expansion on habitat quality change. [Results] ① From 2000 to 2020, the construction land and water areas increased significantly in Ma’anshan City, while the areas of other land types decreased. ② Over the same period, habitat quality in Ma’anshan City showed a downward trend, with lower habitat quality in the central plain and higher quality in the eastern and western regions. These results indicate that the spatial distribution of habitat quality is closely related to topography, land use types, and the intensity of human activities. ③ Under three scenarios-natural development, economic development, and ecological protection-the habitat quality indices for Ma’anshan City were 0.448, 0.451, and 0.459, respectively, indicating habitat quality degradation in all scenarios. [Conclusion] Urban expansion has led to a decline in habitat quality in Ma’anshan City. The ecological protection scenario yielded the highest habitat quality index, suggesting it is the most favorable development trend.

Abstract:[Objective] The spatiotemporal variation characteristics of vegetation net primary productivity (NPP) and their influencing factors were explored in Altay region of Xinjiang, China, and the adjacent area of Mongolia to provide a reference for cross-border regional ecological protection and sustainable development. [Methods] Regression analysis was used to reveal the spatiotemporal changes in vegetation NPP in Altay region adjacent to China and Mongolia, while correlation analysis and geographical detectors were applied to explore the main influencing factors of vegetation NPP in the cross-border area. [Results] ① From 2001 to 2021, the vegetation NPP in Altay region of Xinjiang, China, showed a slight decreasing trend of 5.49 g/(m²·10 a) (calculated by carbon), while the vegetation NPP in the western part of Mongolia showed a significant increasing trend of 27.06 g/(m²·10 a, p<0.05). ② Temperature (0.49, p<0.05) and precipitation (0.31, p<0.05) were the main factors affecting vegetation NPP in Altay region of Xinjiang, China, and the western part of Mongolia, respectively. ③ The interaction between temperature and land use type had the strongest explanatory power for vegetation NPP in Altay region of Xinjiang, China (0.68, p<0.05), while the interaction between precipitation and land use type had the strongest explanatory power for vegetation NPP in the western part of Mongolia (0.37, p<0.05). [Conclusion] From 2001 to 2021, the vegetation NPP in Altay region of China had been declining yearly, while the vegetation NPP in the western part of Mongolia had been increasing yearly. The interactive drivers of temperature, precipitation, and land use types are the main influences on vegetation NPP in both the Altay region of China and the western part of Mongolia.

Abstract:[Objective] The changes in net primary productivity (NPP) under forest management and drought disturbance in natural forest areas of Heilongjiang, Jilin, and Liaoning provinces were compared and analyzed, in order to provide scientific support for responding to climate change and achieving sustainable forest management in Northeast China. [Methods] Based on the forest NPP remote-sensing data and land use data of the three northeastern provinces from 2000 to 2022, combined with the vegetation transfer matrix, the net increment of forest NPP under the forest management strategy was obtained. In addition, based on the standardized precipitation evapotranspiration index (SPEI) from 2000 to 2022, combined with the NPP anomaly index and Pearson correlation analysis, quantitative analysis of the effects of severe drought on forest NPP in three provinces of Northeast China was conducted. [Results] ① The average annual growth rate of forest NPP in the three northeastern provinces from 2000 to 2022 was 1.54%, and the spatial distribution of NPP varied significantly. The NPP average of forest area Ⅲ was the highest, and the NPP growth trend of forest areas Ⅰ and Ⅱ was more significant. Over the past 23 years, drought in the three northeastern provinces had been mitigated, and the area of severe drought zone had gradually shrunk from a large area in the west during 2000—2002 and moved north to the northwest of Heilongjiang Province in 2008. ② As forest management continues, the increase of forest area and the conversion of low NPP vegetation to high NPP vegetation over the past 23 years in the forested areas of the three northeastern provinces were the important reasons for the growth of forest NPP at the site by 15.20 Tg (calculated by carbon), with the highest percentage of increase in the area of deciduous broadleaved forests, which amounted to 43.29%. ③ Forest NPP and SPEI for the three northeastern provinces showed a significant positive correlation (R=0.60, p<0.01) and also showed a highly significant positive correlation (p<0.01) in forest areas Ⅰ (R=0.57) and Ⅱ (R=0.79), where forest NPP decreased with drought. Heavy drought decreased forest NPP in the three northeastern provinces by 11.09 Tg during 23 years. [Conclusion] Drought disturbance under climate change and forest management affected forest NPP both negatively and positively in the three northeastern provinces, but the latter was greater than the former, and forest NPP increased. Among them, the sensitivity to drought was much higher in the Greater and Lesser Khingan Mountains forests than in the Changbai Mountain forests.

Abstract:[Objective] A logical system of “connotation interpretation, identification and evaluation, and regulation and resolution” of land use conflicts was constructed to explore the spatial types and pattern conflicts in Yancheng City, Jiangsu Province from 2010 to 2022 and to provide references for the optimization of territorial spatial layout and marine ecological environment protection. [Methods] Taking Yancheng City as an example, the spatial type and pattern conflict index were constructed based on the scale characteristics of conflicts and the landscape ecology model based on the land profit data for 2010, 2015, and 2022, respectively, to identify the spatial units and intensities of land use conflicts at the three scales of Yancheng City: City, district or county, and grid. It also revealed the conflict of interest in the social and economic background, putting forward the regulation and optimization measures. [Results] ① Owing to the strict protection of ecological space, spatial development would mainly occupy agricultural space. Coastal areas and counties would present more complex conflicts of interest due to the promotion of coastal economic development strategy and ecological protection. ② The spatial pattern conflicts in Yancheng City from 2010 to 2022 were mainly found in the western inland region and the coastal land of Dafeng District, which were related to the high ecological risk of land use change driven by lake wetland protection and coastal economic development. ③ The Yancheng City should focus on coordinating the main contradictions between economic development and basic farmland protection, and there was a need to standardize the conflict of interests on land use for the smooth promotion of coastal economic development strategy. [Conclusion] From 2010 to 2022, the ecological space of Yancheng City had been controlled strictly. The pressure of cultivated land protection in the city was relatively larger, and the contradiction of coastal development was relatively complicated. The conflict between economic development and agricultural protection should be solved in the whole city, and the conflict between port economy, aquaculture development and beach wetland protection should be coordinated in the coastal area.

Abstract:[Objective] The stages and regional differences in the industrial ecological level of the Hohhot-Baotou-Ordos-Yulin urban agglomeration were measured to understand the shortcomings of the industrial ecological level and formulate more scientific countermeasures and suggestions for the development of the urban agglomeration. [Methods] The evaluation index of industrial ecology was constructed by considering the following two aspects: industrial economic system and ecological environment system. The entropy method was employed to measure the level of industrial ecology in each city of the Hohhot-Baotou-Ordos-Yulin urban agglomeration from 2012 to 2021. The coupling coordination model was then used to analyze the degree of coupling and coordination between the industrial economic system and the ecological environment system in urban agglomeration. Finally, the fixed-effect model was utilized to analyze the influencing factors. [Results] ① From 2012 to 2021, the overall level of industrial ecology in the cities affected by Hohhot-Baotou-Ordos-Yulin urban agglomeration showed a fluctuating upward trend, and from the perspective of the average level for prefectures and cities, the development of industrial ecology level was unbalanced. ② From 2012 to 2021, the coupling degree of the industrial economic system and the ecological environment system of each city in the urban agglomerations was in the advanced coupling stage of dynamic change. The degree of coordination between cities had improved to varying degrees, but it was still poorly coordinated. In addition, the rate of development of coupling coordination was slow. ③ By analyzing the influencing factors of industrial ecology using the fixed-effect model, the results showed that the levels of economic development, opening to the outside world, technological innovation, comprehensive utilization of waste, and government regulation and control had a significant positive effect on the level of industrial ecology, whereas the industrial structure had a significant inhibitory effect on the level of industrial ecology. [Conclusion] The level of industrial ecology and coupling coordination degree of Hohhot-Baotou-Ordos-Yulin urban agglomeration requires significant enhancement. It is necessary to optimize the industrial structure and cultivate a diversified industrial system; promote circular development and improve the level of waste utilization; increase investment in innovation and enhance social innovation capabilities. Meanwhile, goveronment departments should actively participate, and give full play to the role of supervision.

Abstract:[Objective] The ecological performance of the Yellow River basin in Shanxi Province was evaluated to provide theoretical support and a decision-making basis for sustainable development of the region. [Methods] Using the Yellow River basin in Shanxi Province as the research area, a theoretical framework was constructed based on the “pressure-state-response” model, and the spatial-temporal interaction of ecological performance from 2010 to 2020 was evaluated using InVEST, SFA, and the coupling coordination degree. According to the current situation and spatial distribution characteristics of the ecological performance level, ecological performance optimization zoning was conducted from bottom to top. [Results] ① From 2010 to 2020, the ecosystem services index of the Yellow River basin in Shanxi Province increased by 2.27%, and the spatial distribution was “north-south, high and low,” forming a double-core pattern mainly in the Lüliang Mountains and Taiyue-Zhongtiao Mountains. ② From 2010 to 2020, the ecological efficiency of the Yellow River basin in Shanxi Province increased by 43.48%, and the spatial distribution was “lower in the center and higher in the periphery.” ③ From 2010 to 2020, the ecological performance of the Yellow River basin in Shanxi Province increased by 35.29%, with a spatial distribution of “lower in the center and higher in the periphery.” ④ Based on the characteristics of spatial differentiation of ecological performance, the study area was divided into ecological performance remodeling, ecological performance improvement, ecological performance buffer, ecological performance enhancement, and ecological performance conservation areas, and the targeted ecological performance improvement paths were proposed. [Conclusion] The ecological performance of the Yellow River basin in Shanxi Province is generally poor and is still in the primary stage of high-quality development. In future, it will be necessary to explore new paths and support points suitable for a high degree of coordination between ecological protection and economic development in the region.

Abstract:[Objective] The spatiotemporal evolution characteristics of ecosystem carbon storage and habitat quality and the main driving factors of spatial differentiation in Hebei Province were explored to provide a more reliable reference basis for improving regional carbon sequestration capacity and ecological environment governance. [Methods] Based on the land-use transfer matrix, the status of land-use change in Hebei Province from 2000 to 2020 was analyzed. The PLUS-InVEST-Geodector model was used to estimate the carbon storage and habitat quality of the ecosystem in Hebei Province from 2000 to 2030, and the spatio-temporal changes and driving factors were also analyzed. The change pattern of its spatial and temporal changes and driving factors were analyzed. [Results] ① The carbon stock in Hebei province decreased by 13.45 Tg (calculated by carbon) from 2000 to 2020, and the areas with decreasing carbon stock were mostly concentrated in the Bashang Plateau area, the North China Plain, and the southeastern hilly areas. ② In 2030, the carbon stock under the natural development scenario will decrease by 6.37 Tg compared with that in 2020. The carbon stock under the economic development scenario will decrease by 21.73 Tg, and that under the sustainable development scenario will increase by 3.65 Tg. ③ The habitat quality index showed a gradual downward trend over time from 2000 to 2020. The main land categories of lowest and lower grade habitat quality were construction land and cropland, while that of higher and highest grade habitat quality were grassland and forest land. ④ The habitat quality index of Hebei Province in 2030 varies under different scenarios, with sustainable development (0.463 9) > natural development (0.454 2) > economic development (0.450 0). ⑤ The strongest explanatory factors for the spatial variations in carbon stock and habitat quality were slope and elevation. [Conclusion] Carbon stock and habitat quality were affected by both natural geographic factors and socioeconomic factors. The land use pattern under the sustainable development scenario can help to improve the carbon stock and habitat quality of the ecosystem in Hebei Province.

Abstract:[Objective] The characteristics of carbon emissions from cultivated land use and their decoupling relationship with grain yield were investigated to provide a scientific basis for coordinating the reduction of carbon emissions from cultivated land use and grain security in the North China Plain. [Methods] Based on data from 45 cities in Shandong, Hebei, and Henan provinces in the North China Plain from 2001 to 2021, the spatial and temporal evolution and influencing factors of carbon emissions from cultivated land use and the decoupling relationship between these emissions and grain yield were analyzed using the carbon emission coefficient method, spatial autocorrelation analysis, spatial Durbin model, and Tapio decoupling model. [Results] ① From 2001 to 2021, the total carbon emissions from cultivated land use in the three provinces of the North China Plain exhibited an inverted U-shaped pattern, with fertilizer as the main carbon source, accounting for 51.67% of the total emissions. The total carbon emissions from cultivated land use in Shandong and Henan provinces were higher than those in Hebei Province, and the carbon emission structure differed among the three provinces. ② Spatially, the carbon emissions from cultivated land use in the three provinces of the North China Plain generally shifted from a high-carbon stage to a low-carbon stage, with notable differences in carbon emission levels among different cities. ③ The carbon emissions from cultivated land use generally showed positive spatial agglomeration characteristics, and the degree of agglomeration tended to strengthen, with spatial coherence expanding in high-high type clustering areas, while low-low type clustering areas were more dispersed. ④ The agricultural economic level, rural electricity consumption, and fertilizer application intensity had positive effects on carbon emissions from cultivated land use, while the urbanization level had negative effects. The urbanization level and rural electricity consumption had positive spatial spillover effects, while the agricultural economic level had negative spatial spillover effects. ⑤ The decoupling state between carbon emissions from cultivated land use and grain yield shifted from mainly weak decoupling with expansive negative decoupling to mainly strong decoupling with recessive decoupling. [Conclusion] Organic fertilizers and precise fertilization techniques should be encouraged to use; emission reduction measures should be formulated according to the different carbon emission structures of each province; the adaptability of grain varieties should be enhanced, and inter-regional coordination and interaction should be strengthened.

Abstract:[Objective] The changes of soil biomes and organic matter in typical forest park areas of Eastern Zhejiang Province were studied to lay a foundation for improving soil structure and increasing soil organic matter content in this area. [Methods] Detecting aggregate (0.25—2 mm), micro aggregate (0.053—0.25 mm), big aggregate (>2 mm), and powder clay (<0.053 mm) in the content of organic carbon, microbial biomass carbon and nitrogen content, the influence of soil aggregate stability, and microbes using wet sieving method under different land utilization way of forest land, orchard, vegetable land, and waste land to provide a scientific basis for formation pattern and regulation of soil organic carbon pool. [Results] ① The results showed that the distribution trend of the components of the aggregates of different soil particle sizes was consistent under different land-use patterns. The mean weight diameter (MWDS) and geometric mean diameter (GMD) of 0—10 cm soil under different land use ways were higher than those of the 10—20 cm soil layer. The MWDS and GMD of both types of soil were roughly characterized by forest land > wasteland > orchard > vegetable land; forest land and wasteland showed no significant difference (p>0.05), and neither did orchards and vegetable land (p>0.05); this demonstrates the influence of different ways of land use on soil aggregate stability, mainly in the surface soil. ② For soils under different land-use patterns, each grain size trend of organic carbon content is consistent, and the basic performance is big aggregate > micro aggregate > middle aggregate > powder and clay; for the 0—10 cm soil layer, each particle’s size distribution of organic carbon content was higher than that of 10—20 cm soil layer, and the organic carbon content of forest land > wasteland > orchard > vegetable land for the 0—10 cm and 10—20 cm soil is significantly higher than that of forest land and wasteland orchards and vegetable land (p<0.05), whereas orchards and vegetable land show no significant difference (p>0.05). ③ Soils under different land-use patterns of each particle size of microbial biomass carbon and nitrogen variation trend are consistent, and the basic performance is big aggregate > micro aggregate > middle aggregate > powder and clay; for the 0—10 cm soil layer, the soil’s microbial biomass carbon and nitrogen content were higher than those of the 10—20 cm soil layer, and the microbial biomass carbon and nitrogen content of 0—10 cm and 10—20 cm soil is generally characterized by forest land > wasteland > orchard > vegetable land, significantly higher than that of forest land and wasteland orchards and vegetable land (p<0.05), whereas orchards and vegetable land show no significant difference (p>0.05). [Conclusion] Overall, the organic carbon, microbial biomass carbon, and nitrogen of the forest land and wasteland aggregate were higher than those of the orchard and vegetable land; thus, forest land and wasteland were more conducive to the accumulation of soil organic carbon and could promote soil carbon sequestration.

Abstract:[Objective] The temporal and spatial evolution patterns of regional agricultural carbon budgets and carbon emission fairness were investigated, in order to provide scientific references for formulating differentiated emission reduction and carbon sequestration strategies. [Methods] Based on the agricultural statistical data of Shaanxi Province from 2000 to 2020, this study estimated the carbon budget of cultivated land in the province for 21 consecutive years using the carbon emission coefficient method. A carbon emission fairness evaluation model was constructed to analyze the carbon-emission fairness of cultivated land in Shaanxi Province from two aspects: ecological carrying capacity and economic efficiency coefficient. [Results] ① The total carbon emission of cultivated land in Shaanxi Province increased first and then decreased during 2000—2020, and the carbon emission intensity increased by 48.15%, with chemical fertilizers as the main source of carbon emissions. ② The total carbon absorption continued to rise, with an average annual growth rate of carbon absorption intensity of 13.67%, in which vegetables having the highest contribution to carbon absorption. ③ Both carbon emissions and carbon absorption showed a high distribution pattern in Central Shaanxi Province and a low one in Northern and Southern Shaanxi, with the ecological carrying capacity of cultivated land carbon emissions being Southern Shaanxi > Central Shaanxi > Northern Shaanxi and the agricultural economic efficiency being Southern Shaanxi > Northern Shaanxi > Central Shaanxi. The results of carbon emission fairness cluster analysis showed that Southern Shaanxi and Xi’an shared the pressure of carbon emission reduction of cultivated land for other regions of Shaanxi Province to a certain extent, while Tongchuan City, Baoji City, Yulin City, and Weinan City regions increased the pressure of carbon emission reduction of cultivated land. [Conclusion] The dynamics and fairness of cultivated land carbon budget in Shaanxi Province vary greatly among different regions; thus, differentiated emission reduction strategies should be developed and improved according to different regional conditions.

Abstract:[Objective] The characteristics of water supply and demand for major crops in Yan’an City were investigated to provide references for the water requirements of crops and the structure of crop planting in the region. [Methods] Based on daily meteorological observation data from meteorological stations in the Yan’an City (from 2000 to 2020), the FAO-56 formula and crop coefficient method were used to study the characteristics of water requirements, effective precipitation, and irrigation water demand during the growth period of major crops (spring maize, spring millet, potatoes, and winter wheat) in the region. [Results] From 2000 to 2020, spring maize in the Yan’an City had the highest water requirement and effective precipitation during the mid-growing stage, which were 247.85 mm and 68.34 mm, respectively, with a water deficit increasing at a rate of 6.61 mm per decade. Potatoes also had the highest water requirement and effective precipitation during the mid-growing stage, which were 288.83 mm and 89.53 mm, respectively, with a water deficit increasing at a rate of 5.75 mm per decade. Meanwhile, spring millet had the highest water requirement and effective precipitation during the mid-growing stage, which were 248.29 mm and 71.68 mm, respectively, with a water deficit decreasing at a rate of -7.0 mm per decade. Winter wheat had the highest water requirement during the rapid development stage, at 192.98 mm, with effective precipitation peaking in the early growth stage at 31.14 mm; the water deficit increased at a rate of 9.94 mm per decade. This indicates that even when effective precipitation reaches its peak, water demand for crop growth remains deficient. [Conclusion] The planting area of spring maize should be reduced, and that of spring millet and potatoes should be expanded, to improve the structure of crop planting. Additionally, increasing on-farm water collection measures can enhance the efficiency of rainwater resource utilization, ensuring sustainable development of food production in the Yan’an City.