Abstract:[Objective] The characteristics of runoff and sediment production on the slopes of mine dumps with different recovery periods in alpine regions were analyzed in order to provide scientific basis for the efficient and rational restoration of vegetation, as well as for improving the soil and water conservation efforts, on such mine dumps. [Methods] Seven dumps of the Delni copper mine in Machin County, Guoluo Xizang Autonomous Prefecture, Qinghai Province, with recovery periods ranging from 2 to 15 years, were selected as the research subjects. Runoff, sediment, and hydrodynamic characteristics of dump slopes with different recovery periods were determined through simulated rainfall tests, and their influencing factors were analysed. [Results] The runoff and sediment yield of the dump slopes in the study area were relatively complex and random. Large variations were observed in runoff and sediment yield per unit area with rainfall duration in the different recovery years. No significant relationship was observed between the cumulative runoff per unit area of dump slope and recovery period. The cumulative sediment per unit area and average volume diameter of the eroded sediment decreased with increasing recovery period. A significant power function relationship was observed between the average volume diameter of the eroded sediment and recovery period (p<0.05). The runoff generation period increased linearly with the recovery period (p<0.05). Laminar flow was the main runoff flow pattern at the dump slopes each year, and all patterns demonstrated tranquil flow. The Reynolds number and flow shear stress of runoff showed significant exponential and linear decreases, respectively, with an increase in the recovery period (p<0.05). No significant relationship was observed between the velocity and Froude number during the runoff and recovery periods. With increasing recovery period, the erosion and sediment-carrying capacity of runoff on the dump slope decreased. Significant positive correlations (p<0.05) were observed between the slope gradient and cumulative sediment per unit area, runoff velocity, and Reynolds number of the dump slope. [Conclusion] When applied to artificial vegetation restoration, the anti-erosion ability of dump slopes in alpine regions showed a positive trend with increasing recovery years. When vegetation regreening was incomplete, the impact of the slope gradient on runoff and sediment production characteristics, including the hydrodynamic characteristics, outweighed that of vegetation coverage.

Abstract:[Objective] This study aimed to optimise organic and inorganic mulches suitable for urban bare soil coverage and provide theoretical guidance for urban bare soil management. [Methods] Four types of organic ecological mulches (straw, mushroom residue, sawdust, and pine bark) and four types of inorganic ecological mulches (ceramsite, volcanic stone, perlite, and maifan stone) were used as research objects, and the indoor immersion method was used to compare the water retention effect of the organic and inorganic ecological mulches applied to urban bare soil. Several ecological mulches with good water retention effects were selected. [Results] ① The changing trends of the water-holding capacity and water absorption rate of the organic and inorganic ecological mulches were basically consistent. The water-holding capacity, water absorption rate, and soaking time of the two types of ecological mulches had significant logarithmic and power function relationships, respectively. ② The maximum water-holding capacity and effective storage capacity of the organic ecological mulches were generally higher than those of the inorganic ecological mulches. Among the four types of organic ecological mulches, sawdust and straw had the best (i.e., highest) water-holding capacity and effective storage capacity, followed by mushroom residue and pine bark. Among the four types of inorganic ecological mulches, volcanic rock, perlite, and ceramsite had the best water-holding capacity and effective retaining capacity, and maifan stone had the worst. [Conclusion] In the actual application of urban bare soil coverage, organic ecological mulches (sawdust and straw) and inorganic ecological mulches (volcanic stone, perlite, and ceramsite) with good water retention effects can be selected preferentially when various local natural environmental factors are fully considered.

Abstract:[Objective] We aimed to elucidate the process of runoff and sediment production on the upper and lower slopes of construction access roads under vegetation recovery conditions, reveal the impact of vegetation recovery on soil and water loss at the slope scale after the disturbance caused by the construction of access roads in an ecologically fragile subalpine forest and shrubland area of Southeastern Xizang Autonomous Region, in order to provide a theoretical basis for the prevention and control of soil and water loss and vegetation restoration after the disturbance caused by the construction road project. [Methods] Typical slopes under different vegetation recovery conditions after disturbances on the upper and lower slopes of construction access roads were selected for indoor simulated rainfall experiments. In this study, we investigated the processes of runoff and sediment production under four types of vegetation coverage (0%, 30%, 60%, and 90%), three slopes (15°, 30°, and 45°), and two rainfall intensities (30, 60 mm/h) after engineering disturbance to determine the impact of vegetation recovery in construction access roads on soil and water loss. [Results] ① After the engineering disturbance of the construction access roads, vegetation recovery on the bare upper and lower slopes effectively delayed the initial runoff time, and this effect became more pronounced with increasing vegetation coverage, especially on the upper slopes. ② When the vegetation coverage was within the range of 0 to 60%, the stable runoff rate on both the upper and lower slopes significantly decreased with increasing vegetation coverage, wherein the stable runoff rates under 60% and 90% vegetation coverage were similar. Compared with bare slopes, the benefits of runoff reduction under 60% and 90% vegetation coverage were 59%—75% and 58%—77% respectively, indicating that the critical vegetation coverage value for runoff reduction was 60%. ③ Sediment reduction benefits under 30% and 60% vegetation coverage reached 29%—82% and 86%—96% respectively. Below a vegetation coverage of 60%, the sediment reduction effect significantly increased with increasing coverage; beyond this critical threshold, even with increased coverage, the sediment reduction benefits showed slight change. ④ Under the same vegetation coverage, slope, and rainfall intensity conditions, the total runoff volume from the upper slopes formed by excavation was always higher than that from the lower slopes formed by filling, whereas the total sediment yield from the lower slopes was always higher than that from the upper slopes, indicating significant differences in soil erosion on the slope surface after the disturbance of the construction of access roads between the excavation and filling slopes. [Conclusion] For the prevention and control of soil and water loss in areas disturbed by the construction of access roads in Southeastern Xizang Autonomous Region, a vegetation recovery rate of 60% offers good control benefits and economic feasibility. When designing soil and water conservation measures, more emphasis should be placed on ‘controlling water’ for excavation slopes and ‘blocking sediment’ for filling slopes. Only by fully considering these differences can better soil and water conservation be achieved in disturbed areas on access roads.

Abstract:[Objective] The effects of water content, root content, and root arrangement on the shear strength of the root-soil composite were analyzed to reveal the reinforcement mechanism of Amorpha fruticosa root system on loess slopes, in order to provide a reference for the ecological protection of loess slopes and engineering practices for improving slope stability. [Methods] A shear test of the root-soil complex of A. fruticosa was conducted using a ZJ strain-controlled direct shear apparatus. This study analysed the effects of various water contents, root contents, and root distributions on the shear strength, with non-root soil serving as the control. Additionally, the FLAC 3D software was used to simulate the influence of the root distribution of A. fruticosa on the stability of the loess slope. [Results] ① The cohesion and internal friction angle of the shear strength index decreased with increase in water content. ② With an increase in root content, the shear strength exhibited different patterns under different water content levels. When the water content was 9.31%, the shear strength initially increased with an increase in root area ratio (RAR) but then decreased with further increase in RAR. At RAR was 0.15%, the shear strength reached its maximum value. However, when the water content was 15.65% and 17.44%, the shear strength in RAR. ③ The “卄” shape root arrangement can significantly improve the shear strength of the root soil complex. When the water content was 17.44%, the average shear strength of the root-soil composite increased by 31.81 kPa compared to the control. ④ Numerical simulation results indicated that both root length and the angle between the main root and vertical direction were positively correlated with stability. [Conclusion] The findings from laboratory tests and numerical simulations demonstrated that A. fruticosa can enhance the stability of loess slopes and that an interlaced planting pattern of A. fruticosa provides a more effective protective effect.

Abstract:[Objective] The species composition and diversity characteristics of different types of vegetation communities along with the correlation between plant community characteristics and soil moisture content in the Zhangye desert-oasis transition zone in Gansu Province were analysed, in order to provide a scientific basis for the evaluation of water and soil conservation benefits in the region. [Methods] Different types of desert vegetation were chosen, and the diversity of different types of vegetation community plants and soil moisture content at 0—120 cm were investigated and determined. [Results] ① There were six vegetation types in this area, and the vegetation structure was very simple, and the species composition was dominated by drought-tolerant and super-drought-tolerant small shrubs, semi-shrubs and herbs such as Reaumuria songarica, Sympegma regelii, Salsola passerina, Aristida adscensionis, and Bassia dasyphylla that were suitable for arid desert habitats. The plant community was a shrub and grass community with a relatively small species diversity index. ② The change of soil moisture in the vertical direction presented a “double peak”, and the soil humidity gradually increased from the surface layer to the deeper layers; it increased to the “first peak” at 20—40 cm, decreased to a lower level at 40—60 cm, and gradually increased at 60—120 cm, until to the “second peak” at 120 cm. ③ The vegetation height, density, and cover of each plant community increased with increasing soil moisture content. Vegetation height was significantly positively correlated with soil moisture in the soil layer of 40—120 cm, and the density and vegetation cover of herbaceous plants and shrubs were significantly positively correlated with soil moisture content in the layer where their root systems were mainly distributed. [Conclusion] In the desert oasis transition zone where the moisture content of the surface soil (0—20 cm) and deep soil (40—80 cm) was less than 2%, it is appropriate to plant arid shrubs such as R. songarica, S. regelii, Nitraria tangutorum and other herbaceous plants such as A. adscensionis, Salsola tragus, B. dasyphylla, Eragrostis pilosa and Artemisia scoparia. In the desert zones where the moisture content of the surface soil and the deep soil is more than 2%, it is appropriate to plant arid shrubs such as R. songarica and S. passerina and herbaceous plants such as Artemisia frigida, Artemisia xerophytica, and Carex duriuscula, which are capable of effectively promoting ecological recovery and reconstruction.

Abstract:[Objective] The structural characteristics of the near-surface airflow field and wind-sand flow under the disturbance of photovoltaic (PV) arrays in the Tengger Desert were analysed to assess the effect of PV arrays in preventing winds and fixing sands, in order to provide theoretical support for both the management of wind-sand disasters in desert areas and the sustainable development of ecological environments. [Methods] The vertical distribution of wind speed, wind velocity flow field, and wind-sand flow structure of PV arrays (front edge of electric panels, back edge of electric panels, and midline between arrays) and control points were assessed in the field using gradient wind speed observation equipment, and the airflow field and sand transport characteristics at different locations inside and outside a power plant were compared and analysed. [Results] (1) The overall wind speed inside the power station decreased, the average wind speed between arrays and along the back edge of the electric panel increased with height, and the average wind speed along the front edge of the electric panel decreased and then increased with height. (2) ① For the grass square observation section, the wind speed at the wind outlet in front of the electric panel increased significantly, and the wind speed along the wind inlet behind the electric panel and below 100 cm of the centre line between arrays decreased; ② For the wind erosion pit observation section, the wind speed of PV panels below 150 cm decreased, and the wind speed pulsation between arrays varied significantly; ③ For the gravel observation section, the relative rate of change of the wind speed and the pattern of the wind flow field were stable, and the wind speed along the back edge of the electric panel above 150 cm increased. The wind speed increased in the section above 150 cm behind the electric plate. The average wind protection effect occurred in the order of gravel > grass squares. (3) The order for sand transport was as follows: front edge of the electric plate > back edge of the electric plate > midline between the arrays; the reference point of the mobile sand dune (upwind) was saturated with λ (a characteristic value of the wind-sand flow structure) at the front edge of the electric plate, and unsaturated at the back edge of both the electric plate and λ between the arrays. [Conclusion] Compared with the mobile sand dune, the PV array perturbed the wind velocity flow field pattern, the wind velocity pulsation and turbulence degree changed, sand transport decreased significantly, and a sand fixation benefit was evident.

Abstract:[Objective] The application prospects of using landslide deposits as a new type of soil improvement material were explored, and the changes in soil nutrients after landslide deposit improvement were analysed in order to provide new approaches for local landslide deposit utilisation and purple soil rehabilitation. [Methods] Purple soil improved by landslide deposits was selected as the research object, and the quality of the improved soil was analysed using weighted grey correlation analysis. [Results] At the same fertility irrigation level, adding collapsed deposits significantly increased the nutrient content of topsoil (0—20 cm) compared to the blank control group (Y₀). The average total nitrogen content in this layer of soil increased by 3.26% to 10.60%, the average total phosphorus content increased by 10.61% to 43.33%, the average organic matter content increased by 9.14% to 24.12%, the average alkaline nitrogen content increased by 5.76% to 12.73%, the average effective phosphorus content increased by 24.75% to 46.22%, the average available potassium content increased by 16.21% to 28.96%, and the soil electrical conductivity (EC) increased by 11.32% to 27.41%. The different treatment schemes had no significant effect on soil pH value. Using the AHP grey correlation analysis evaluation model, a preliminary evaluation of the soil quality of each treatment group was conducted. Within the topsoil (0—20 cm), the grey correlation degree of each treatment group was ranked as follows: Y₂ 〔rock soil composite ratio (RSCR): 20%〕 > Y₃ (RSCR: 30%) > Y₄ (RSCR: 40%) > Y₁ (RSCR: 10%) > Y₀ (RSCR: 0%) > Y₅ (RSCR: 50%). The grey correlation degree of each treatment group within the deep soil range of 20—40 cm was ranked as follows: Y₅ > Y₄ > Y₃ > Y₂ > Y₁ > Y₀. [Conclusion] An appropriate proportion of composite treatment between landslide deposits and soil can improve the nutrient content of purple soil.

Abstract:[Objective] The biological mechanisms underlying the effect of shrub forest development on soil in the Hobq Desert was analyzed in order to provide theoretical support for the establishment of a reasonable and effective desert shelter forest system. [Methods] Soil from 0—10, 10—20 cm, and 20—30 cm soil layers in a Salix psammophila forest system with different forest ages (6, 12, and 15 years) in the Hobq Desert was collected in early July 2023. The main physical and chemical properties and enzyme activities of the soil were analysed to reveal the mechanism of vegetation restoration on soil in this area. [Results] ① The fine particle content increased gradually with increasing forest age, whereas the soil bulk density and pH value decreased. ② Soil nutrients and enzyme activity levels clearly indicated surface aggregation in the vertical direction. There were significant differences in soil nutrients and enzyme activity levels among the different S. psammophila forest ages (p<0.05). The soil alkali-hydrolysable nitrogen, available phosphorus, available potassium, alkaline phosphatase activity, and catalase activity in the 12-year S. psammophila forest were 316.4%, 420.3%, 134.6%, 164.5%, and 94.8% higher than those of bare sand, respectively. Organic carbon, urease activity, and invertase activity under 15-year S. psammophila were 186.2%, 145.3%, and 2 703.4% higher than those of CK, respectively. ③ Soil enzyme activity was closely related to soil alkali-hydrolysable nitrogen, available phosphorus, available potassium, and organic carbon in different forest age restoration stages. [Conclusion] The establishment of the S. psammophila shelter forest in the Hobq Desert significantly improved soil nutrient levels and enzyme activity.

Abstract:[Objective] The influence mechanism of soil water erosion on the patch distribution pattern of Stipa krylovii in a Xilamuren grassland was analysed in order to provide a theoretical basis for soil erosion control in this area. [Methods] Three distribution patterns (aggregation, uniform, and random distribution patterns) and two controls patterns (non-grazing and bare slope ) were set up by field investigation and the variance mean ratio method. Indoor simulated rainfall experiments with rainfall intensity of 30, 60, 90 mm/h, and 120 mm/h were conducted to quantify the sediment production and abortion processes on slopes with different distribution patterns. [Results] ① The distribution pattern of heavy grazing and no grazing was aggregation distribution pattern, the distribution pattern of moderate grazing was uniform distribution pattern, and the distribution pattern of light grazing was random distribution pattern. ② At 30 mm/h rainfall intensity, no runoff was produced, whereas at 60 mm/h rainfall intensity the runoff yield was in the order of bare slope ＞ aggregation distribution pattern＞ random distribution pattern＞ uniform distribution pattern＞ no grazing. For the rainfall intensity at 90 mm/h, the runoff yield was in the order of bare slope ＞ aggregate distribution pattern＞ uniform distribution pattern＞ random distribution pattern＞ no grazing. At 120 mm/h rainfall intensity, the runoff yield showed the order of bare slope ＞ aggregation distribution pattern＞ no grazing ＞ uniform distribution pattern＞ random distribution pattern. ③ At 30 mm/h, there was no sediment production. However, at 60 mm/h the sediment production rate was in the order of bare slope ＞ uniform distribution pattern＞ no grazing ＞ random distribution pattern＞ aggregation distribution pattern. The rainfall intensity at 90 mm/h resulted in sediment distribution in the order of bare slope ＞ aggregate distribution pattern＞ uniform distribution pattern＞ random distribution pattern＞ no grazing. Furthermore, at 120 mm/h rainfall intensity, the sediment distribution was in the order of bare slope ＞ no grazing ＞ aggregate distribution pattern＞ uniform distribution pattern＞ random distribution pattern. ④ At 120 mm/h rainfall intensity, the sediment reduction benefit of the random distribution pattern can be reduced by 88.76%, whereas at 90 mm/h rain intensity the flow reduction benefit of the non-grazing pattern can be reduced by 45.78%. [Conclusion] Grazing promoted the patching phenomenon of S. Krylovii, and soil water erosion intensified the formation of bare patches, which led to different distribution patterns of S. krylovii patches.

Abstract:[Objective] The dynamic characteristics of soil moisture in sandy arid lands were analysed to provide scientific support for desertification control. [Methods] Sandy land (mobile dunes, semi-fixed dunes, fixed dunes and shelter forest) in east of the Yellow River in Ningxia Hui Autonomous Region was selected as the research object. According to data from the positioning observation and automatic observation systems, the soil moisture distribution characteristics of sandy soils (0—150 cm depth) were analysed. [Results] ① Changes in soil moisture content in the different plots showed a consistent pattern with time. Changes in soil moisture content could be divided into three periods: the soil moisture accumulation period from April to May, the soil moisture consumption period from June to August, and the soil moisture stable period from September to November. ② The soil moisture content in the 0—10 cm topsoil layer was significantly different in the three periods, whereas the soil mositure content in the 40—150 cm soil layer did not differ significantly. ③ The topsoil (0—20 cm) was the active layer of soil moisture, 20—40 cm was the subactive layer, and 40—150 cm was the stable layer of soil moisture. ④ The soil moisture content between the different plots was as follows: moving dune > shelter forest (Salix matsudana, Populus bolleana, and Pinus sylvestris forest) > fixed dune (Hedysarum scoparium forest) > fixed dune (Calligonum mongolicum and Caragana korshinskii forest) > semi-fixed dune (C. mongolicum and C. korshinskii forest). ⑤ The soil moisture content in different terrain parts decreased from the slope bottom > slope middle > hill top. [Conclusion] The vertical distribution and stratification characteristics of soil moisture in the sandy arid lands in east of the Yellow River in Ningxia are clear. Changes in soil moisture content are not only affected by rainfall, vegetation type, and vegetation distribution patterns, but also by the microgeomorphology of the sand dunes.

Abstract:[Objective] The nutrient content and ecological stoichiometric characteristics of plants across various altitudinal gradients in fragile forest ecosystems in arid regions were analysed in order to provide scientific support for their nutrient management. [Methods] This study focused on the dominant plant species at five distinct altitudinal intervals, i.e. 1 730, 1 799, 2 025, 2 487, and 2 544 m in the Helan Mountains National Nature Reserve. The variations and correlations of carbon (C), nitrogen (N), and phosphorus (P) contents and stoichiometric features in leaves, fine roots, and soil along these gradients were analysed. [Results] ① Soil organic carbon (SOC) displayed a unimodal pattern with altitude, peaking at 2 487 m (42.92 g/kg). Soil total nitrogen (TN) levels at the three highest altitude sites (2 025, 2 487, 2 544 m) were significantly greater than those at the two lowest altitudes (1 730, 1 799 m), whereas total phosphorus (TP) remained relatively stable. The C∶P and N∶P initially increased and then decreased with increasing altitude. ② There was no significant change in leaf and fine root C across altitudes, but the P content increased with altitude. Fine root N content progressively declined with altitude, whereas leaf N exhibited a fluctuating trend. At high altitudes, the N∶P ratio in the leaves and fine roots was less than 14; however, at low altitudes, the ratio exceeded 16. ③ Nutrient concentrations in the leaves were significantly higher than those in the fine roots. ④ Correlation analyses revealed that C content in leaf positively correlated with SOC, TN, C∶P and N∶P in soil. In contrast, N content in leaf and fine root significantly decreased as SOC, TN, C∶P and N∶P in soil increased, and the relationship between leaf and fine root P and soil TP was not significant. [Conclusion] Plant growth at high and low altitudes is mainly limited by N and P, respectively. Leaves of dominant plant species at different altitudes exhibit higher nutrient contents than their fine roots, and variations in soil nutrient supply due to altitude influence the N, P and stoichiometric characteristics of plants in the Helan Mountains.

Abstract:[Objective] The anti-erosion and anti-scouring characteristics and factors influencing road and campus green spaces in Wenjiang District, Chengdu City were analysed in order o provide functional guidance for urban green space soil and water conservation and promote ecologically sustainable development. [Methods] The soil anti-erosion and anti-scouring properties of arbour + grass, arbour + bush, bush, bush + grass and grass in road and campus green spaces were characterised through field sampling and laboratory tests. [Results] The >5 mm soil water-stable aggregate content was highest in both roads (79.72%) and campus green spaces (39.23%). Total soil porosity, soil water content, and silt content were greater in campus green spaces than road green spaces (p<0.05). Mean weight diameter (MWD), geometric mean diameter (GMD), soil anti-erosion, water stability aggregate index, and anti-scouring were all higher in the road green space than in the campus green space (p<0.05). Specifically, the anti-erosion and anti-scouring of arbour + bush and bush + grass structures were better than that of the other vegetation structures, and the soil anti-scouring coefficient decreased with increasing landscape slope. Soil anti-erosion and-scouring were positively correlated with >5 mm soil water-stable aggregates, organic matter content, and soil clay particles, and negatively correlated with the percentage of aggregate destruction (PAD), unstable aggregate index (ELT) and <0.25 mm and 0.25～2 mm water-stable aggregates (p<0.01). [Conclusion] Arbour + bush and bush + grass had the best soil anti anti-erosion and-scouring effects on road green areas. Campus green space can reduce the risk of soil erosion by adjusting the vegetation structure, thereby enhancing the stress resistance and ornamental property.

Abstract:[Objective] The effects of short-duration high-intensity rainfall on runoff and sediment yield in a karst slope farmland were analysed to reveal the mechanism of soil erosion, in order provide a scientific basis for reducing it, and ensuring food production in karst slope farmlands. [Methods] Through simulated rainfall experiments, the effects of short-duration high-intensity rainfall on the runoff and sediment yields over a karst slope farmland were studied by taking a karst bare slope and a corn slope as research objects. [Results] ① Surface runoff and sediment yield moduli of both bare and corn slopes increased with the rise of the slope. At similar slopes, the surface runoff and sediment yield moduli of the corn slope were much less than those of the bare slope (p＜0.05). With the increase of rainfall duration, the surface runoff yield moduli of both bare and corn slopes increased first and then remained stable, while the surface sediment yield moduli increased first and then decreased. ② The runoff yield moduli of the respective subsurface runoffs of bare and corn slopes increased with the rise of the slope. At a similar slope, the runoff yield of respective subsurface runoffs in the corn slope was much less than that in the bare slope (p＜0.05), whereas when slope was 20°, the total runoff yield of the corn slope’s subsurface runoffs (15—25 cm) decreased by 62.59% compared with that of the bare slope. ③ When the slope was fixed, underground runoff and sediment yield moduli of the corn slope were much less than those of the bare slope (p＜0.05). With the increase of rainfall duration, the underground runoff yield moduli of both bare and corn slopes showed a trend of continuous increase, where their changes were basically consistent, while the underground sediment yield moduli showed a trend of first increasing and then decreasing and reached a maximum between 20 min and 30 min. ④ By comparing the correlations between the runoff and sediment yields of the bare and the corn slopes under different slopes, it was found that the correlations between the underground sediment yield and the surface runoff yield, underground runoff yield, and surface sediment yield were enhanced in the corn slope compared with the bare slope, whereas the correlations between the surface sediment yield and the surface and underground runoff yields were weakened. [Conclusion] Under high-intensity rainfall, corn slope can increase infiltration, which has the effect of blocking and inhibiting erosion, in which the surface and subsurface runoff moduli increase with the increase of the slope, the underground runoff moduli increase with the increase of the rainfall duration, and the sediment yield moduli increases first and then decreases.

Abstract:[Objective] The infiltration laws of slope soil bodies under short-duration heavy rainfall were investigated to reveal the causes and mechanisms of geological disasters in order to provide a scientific basis for the formation mechanism, early warning, and prediction of geological disasters in the region. [Methods] Regarding the shallow flow-type landslide event induced by heavy rainfall in Wuping area, Longyan City, Fujian Province, on May 26—27, 2022, an in-situ artificial rainfall infiltration test was conducted at the typical landslide site of the geological disaster area. Systematic observations using monitoring devices such as soil moisture meters, tensiometers, pore water pressure sensors, and rain gauges were conducted. At the same time, finite element software was used to simulate the rainwater infiltration process under different rainfall intensities to deepen the understanding of the infiltration law. [Results] The increase in volumetric water content of the soil was greater near the surface of the slope and decreased with increasing burial depth. The infiltration rate of the slope was fastest at the foot and middle of the slope and slowest at the top of the slope. Under the impact of short-term intense rainfall, the pore water pressure increased gradually, peaked, and then stabilised. Notably, the pore water pressure at a distance of 120 cm from the slope surface was higher than that at the other two depths. This may be attributed to the lower permeability of the soil layer at this location, which resulted in a relatively stable water level. The numerical simulation results reflected this pattern effectively. [Conclusion] The infiltration process of the slope soil is extremely complex in the case of short-duration heavy rainfall and plays a crucial role in triggering geological disasters. Its infiltration characteristics are comprehensively influenced by multiple factors such as rainfall intensity, soil layer depth, and permeability.

Abstract:[Objective] The influence of the soil water content on the rheological properties of the soil slurry was analysed to provide a scientific basis for understanding the flow law of the slurry and the prevention and control of mudflow in the Loess Plateau region. [Methods] Four main types of soil in the Loess Plateau were studied, and the effects of water content on the soil rheological properties were investigated using rheological oscillation shear tests. [Results] ① The storage modulus, loss modulus and shear stress of lou soil, cinnamon soil and dark loessial soil all decreased with the increase of soil water content (40%~80%). The shear stress reduced from 229.85, 193.38 and 96.46 Pa to 2.25, 2.65 and 2.32 Pa respectively. Under conditions of high water content (> 50%), the loess soil showed a strong strain overshoot. ② With increased shear strain, the storage modulus of the four types of soil slurry appeared in two plateau areas, showing a two-step yield phenomenon. With increased soil water content, the slurry changed from a two-step to a one-step yield. The first step of the yield was related to the destruction of the initial network structure, and the second step indicated that the slurry structure was completely destroyed. ③ When the soil moisture content was less than 50%, the fine soil particles increase the degree of flocculation by forming flocs, thus increasing the shear stress at the flow point of the soil slurry. When the moisture content was greater than 50%, the coarse particles in the soil increased the shear stress at the flow point by increasing the friction between the particles. [Conclusion] Soil rheological properties are not only related to soil properties but also significantly influenced by soil water content. Soils with a high fine particle content have a slurry that is more susceptible to flow under high-water-content conditions.

Abstract:[Objective] The interannual time-series patterns of water quantity changes and seasonal differences in wet, normal and dry in the Chaobai River basin upstream of the Miyun Reservoir were studied to provide decision support for efficient water utilisation and ecological water security in the Beijing-Tianjin-Hebei region. [Methods] Based on the collection of water quantity data and the analysis of the monthly wet, normal, and dry periods, the distance flatness percentage was used to explore the characteristics of water quantity changes in the Chaobai River basin and to derive the quantitative relationship between the wet, normal and dry periods of the basin and the amount of runoff water. [Results] From 2010 to 2021, the dry season of the Chaobai River basin was much longer than that of the wet and normal seasons, but the high water volume and its anomaly percentage showed an exponential growth trend every 1—2 years, indicating that the Chaobai River basin had more extreme climate characteristics in recent years. The wet period in the Chaobai River basin mainly occured from July to December, and the normal period of the basin was accompanied by a wet period. However, from 2010 to 2021, the normal periods of the Chaobai River basin only had a normal water period of 6—7 months, respectively, and the dry period covered most of the 12 years, and it was densely distributed in all periods except the wet dry period and the normal period. During all periods, the water volume of the Baihe River basin was higher than that of the Chaohe River basin, which may be attributed to the recharge of runoff by melting snow in spring. [Conclusion] The Chaobai River basin experienced an increase in extreme precipitation events from 2010 to 2021; however, the percentage of dry periods was much higher than that during the normal and wet periods. The relationship between the proportions of the three periods was the most important factor influencing the change in water quantity in this watershed.

Abstract:[Objective] The effects of soil physicochemical properties and enzyme activities on slopes under different restoration measures after disturbance from alpine wetland highway projects were analyzed in order to provide a theoretical reference for the screening of alpine wetland vegetation restoration models, soil erosion control, and improvement of the ecological environment. [Methods] We compared three slope treatments (natural succession, spraying grass planting, and turf cover) against the original undisturbed vegetation (the control). Soil physicochemical indexes and soil enzyme activities were measured, and their interrelationships and influencing factors were analyzed. [Results] ① All three restoration measures resulted in a significant increase (p＜0.05) in soil pH value and total potassium compared with the control. These restoration measures also resulted in a significant decrease (p＜0.05) in soil organic matter, total nitrogen, fine root biomass, and available potassium under the natural succession treatment, with minimum values of 15.16 (±0.15), 0.75 (±0.01), 0.60 (±0.27), and 65.00 (±4.5), respectively. The proportion of clay particles in the soil was significantly lower (p＜0.05) under the spraying grass planting and turf cover treatments. The richness indices of the spraying grass planting and natural succession treatments were significantly lower (p＜0.05) than observed for the control, with a minimum value of 1.29 (±0.02) under the natural succession treatment. Soil pH value, organic matter, total nitrogen, available potassium, fine root biomass, and richness index were higher for the two types of restoration measures (turf cover and spraying grass planting) than for natural selection. The richness indices for the two restoration measures were higher than for natural succession. ② Compared with natural succession, spraying grass planting and turf cover could better recover sucrase, urease, alkaline phosphatase, and catalase activity,, and even catalase activity could be recovered close to that of the control. The activities of the four enzymes were the smallest under natural succession conditions, which were 12.65±10.87,0.24±0.03,0.23±0.05 and 1.73±0.48, respectively. 0.48). ③ The correlations between the activities of the four enzymes and the physical and chemical properties of the soil were significant. Urease activity was the most sensitive to the physical and chemical properties of the soil, and was able to evaluate the soil quality of the slopes of the plateau wetland very well. [Conclusion] Compared with natural succession, spraying grass planting and turf cover can effectively improve soil physical and chemical properties and increase soil enzyme activity. Soil enzyme activity can be used as a sensitive indicator for evaluating the soil quality of slopes in plateau wetlands.

Abstract:[Objective] The capacity of a drainage ditch modified as a root channel wetland (ecological ditch) to purify aquaculture tail water was analysed in order to provide a scientific reference for circular aquaculture and pollution reduction in areas of large-scale aquaculture. [Methods] The study site was Koujia Lake Park, in Helan County, Ningxia Hui Autonomous Region, with an aquaculture area exceeding 500 hectares. We constructed experimental root channel wetlands on both sides of an original farmland drainage ditch to improve the purification capacity of the ditch. To evaluate the purification effect of this ecological ditch system on the tail water from large-scale aquaculture, we collected water samples in the ecological ditch in 2022 and 2023. [Results] In 2022, at the onset of its operation, the ecological ditch effectively purified phosphate, nitrite, and ammonia nitrogen in the aquaculture tail water, with the purification rate being 97.15%, 96.00%, and 59.65%, respectively. In 2023, the ecological ditch effectively purified the aquaculture tail water on a daily basis. The maximum purification rate for phosphate, nitrite, and ammonia nitrogen was 87.70%, 72.89%, and 83.15%, respectively. The concentration of ammonia nitrogen at the purification end of the system was less than 0.5 mg/L, reaching the Class Ⅱ standard of the ‘Surface Water Environmental Quality Standard’ (GB3838-2002). After shortening the purification distance by half, the ecological ditch still had a good purification effect on the aquaculture tail water, with no significant increase in the nutrient concentration at the ditch outlet (p＜0.05). [Conclusion] The construction of a root channel wetland around the drainage ditch could effectively purify the tail water generated in the daily aquaculture operations across a large-scale aquaculture area, and achieve water recycling.

Abstract:[Objective] The effects of surface photovoltaic (PV) power station on the structural characteristics of water quality and phytoplankton communities in subsidence ponds in the winter were investigated in order to provide data references for the application of surface PV in coal mining subsidence waters. [Methods] Water bodies and phytoplankton communities of column PV ponds, floating PV ponds, and non-PV ponds (comparison) were sampled and investigated, and the influencing factors were analysed using Pearson correlation and stepwise regression analyses. [Results] A total of 41 species of phytoplankton were identified in the column PV sinkhole pond, 40 species of phytoplankton in the floating PV sinkhole pond, and 47 species of phytoplankton in the pond without PV sinkholes; the diatom-green-algal type dominated the species. Compared with the control sinkhole ponds, the surface PV power plant effectively reduced the light intensity and lowered the levels of electrical conductivity, total dissolved solids, oxidation reduction potential, and ammonia nitrogen in the sinkhole ponds. Similarly, the floating PV power plants reduced the chemical oxygen demand, total nitrogen (TN), and total phosphorus contents in the water body. Additionally, the column PV power plant had lower levels of the above-mentioned indicators than the floating PV power plant. The number of phytoplankton species, density, and biomass in the floating PV and column PV sinking ponds were slightly lower than those in the control sinking ponds. The values for the Shannon-Wiener diversity index, Pielou homogeneity index, and Margalef richness index were ordered as follows: no PV pond > floating PV pond > column PV pond. [Conclusion] Surface PVs can help reduce the salinity of winter water bodies and maintain both the temperature of the water bodies and the content of dissolved oxygen. The above indices used for the column PV power station to improve its effect were better than those for the floating PV power station, and to a certain extent, the floating PV power station could improve eutrophic water bodies. Surface PVs can affect the structure of phytoplankton communities, and the effect of floating PVs on the phytoplankton of sunken water bodies is smaller than that of column PVs. Pearson and stepwise regression analyses revealed that the phytoplankton community diversity of column PV sunken ponds is mainly affected by water temperature (WT) and TN, while that of floating PV subsidence ponds are mainly affected by the WT. In summary, floating PV power station are more favourable for improving the water quality of subsidence ponds and have the least impact on the phytoplankton community structure.

Abstract:[Objective] The effects of mulching materials on the collection of faint rainfall and dew from soil moisture were analysed to provide a scientific basis to support their efficient utilisation in central arid belt of Ningxia Hui Aouonomous Region. [Methods] Three treatments were evaluated in the field experiment: ordinary polyethylene film mulch (T₁), high-density polyethylene film mulch (T₂) and polytetrafluoroethylene film mulch (T₃); bare ground (T₄) was used as the control. The slopes of the catchment surface were optimised, and the changes in soil moisture during faint rainfall and dew events were determined. [Results] ① The total multi-year single precipitation of less than 5 mm accounted for 29.8% of the annual precipitation in the study area, with an average annual dew of 31.68 mm, representing 13.2% of the average multi-year precipitation. ② The order of soil volumetric moisture content at depths of 5 and 15 cm in different ridge mulching modes was consistent, decreasing from polytetrafluoroethylene film mulching > ordinary polyethylene film mulching > high density polyethylene film mulching > bare ground. ③ The depth of influence of ridge mulching on soil moisture increased significantly when collecting faint rainfall, and was up to 15 cm for 2 mm precipitation, whereas it was only up to 5 cm in the bare ground control. ④ The effect of dew on soil moisture was mainly above 5 cm, and when the dew amount was 0.8 mm, the soil moisture of ordinary polyethylene film mulch, high-density polyethylene film mulch, polytetrafluoroethylene film mulch and bare soil increased by 0.6%, 1.6%, 4.0% and 0.2%, respectively. [Conclusion] We found significant differences in the effects of three mulching treatments to pool faint rainfall and dew to increase soil moisture, of which the polytetrafluoroethylene film mulch ridges pooled the best, with soil moisture content in the ridges being greatest.

Abstract:[Objective] The weathering degree and provenance of the Pisha sandstone from the Lower Jurassic Yan’an formation in Jungar, Inner Mongolia Autonomous Region was analysed in order to provide a basis for further research on the origins and epigenetic evolution of the Pisha sandstone, and the prevention and control of soil erosion. [Methods] We conducted field investigation and geochemical analyses, including major, trace, and rare earth element analyses, and calculated the chemical alteration index (CIA), plagioclase alteration index (PIA), light-to-heavy rare earth element ratio (LREE/HREE), and related trace and rare earth element relationships in the Pisha sandstone. [Results] ① The geochemical classification diagram showed that the Pisha sandstone in Jungar comprised shale, subarkose, and lithic sandstone facies. The Pisha sandstone was mainly composed of SiO₂ and Al₂O₃. The content of most of the major elements was lower than that in the average upper crust (UCC). The CIA value ranged from 64.95 to 86.57, with an average of 77.46. This was consistent with the characteristics of the Pisha sandstone from the Middle Triassic Ermaying Formation near the study area, reflecting a common history of rock weathering. ② The siltstone and mudstone facies had a higher trace element content than the sandstone facies, with Ba being the most abundant element, followed by Zr. The paleotemperature of the deposition of the Pisha sandstone was 10.67—22.78 ℃, with an average value of 17.68 ℃; the PIA value was 70.48—97.13, with an average of 89.76. ③ The rare earth element distribution pattern in the Pisha sandstone was consistent with that in the UCC, showing the characteristics of light rare earth enrichment, heavy rare earth depletion, and weak negative Eu anomalies. The total rare earth (∑REE), light-to-heavy rare earth ratio (LREE/HREE) and (La/Yb)_N values of the siltstone and mudstone facies were higher than those of the sandstone facies. This difference was mainly due to the attraction of most of the trace elements released by rock weathering during epigenetic processes by clay minerals, or due to hydraulic sorting. [Conclusion] The Pisha sandstone from the Lower Jurassic Yan’an Formation in Jungar, Inner Mongolia, consists of terrestrial clastic sedimentary rocks with a low compositional maturity and sorting, sourced from an area that had experienced moderate to strong chemical weathering. The Pisha sandstone formed under arid to semi-humid conditions. The rare earth element distribution pattern combined with the discrimination diagram of major and trace elements indicates that the Pisha sandstone from the Yan’an Formation originated from Hercynian-Indosinian granites in the Yinshan-Daqingshan area, in the Northern Ordos Basin.

Abstract:[Objective] The effects of different biochar additions on the physical and chemical properties of yellow loam soil, tobacco growth, yield, and output value were analysed in the Chongqing mountainous region to provide technical support for the application of biochar in soil conservation and tobacco production. [Methods] Flue-cured tobacco K326 was used as the experimental material. In 2022—2023, a completely random design was adopted for the tobacco field, and seven treatments of biochar addition were established based on the conventional film ridge cultivation and fertilisation methods. The seven biochar treatments were as follows: zero biochar addition (CK), 750 (T₅₀), 1 500 (T₁₀₀), 3 000 (T₂₀₀), 4 500 (T₃₀₀), 6 000 (T₄₀₀), and 7 500 kg/hm² (T₅₀₀) of biochar. During the study period, soil physical and chemical properties, tobacco agronomic traits, ground and aboveground dry matter, and yield and output values were measured. [Results] ① The application of biochar increased the soil porosity and capillary water capacity. The total porosity and capillary water capacity of soil treated with T₄₀₀ and T₅₀₀ were significantly higher than those treated with CK in the second year of the experiment. ② Compared with the CK treatment, biochar addition significantly increased the contents of available nitrogen, available phosphorus, and available potassium in the 0—20 cm soil profile, and T₃₀₀, T₄₀₀, and T₅₀₀ treatments significantly increased the organic matter content and pH value in the 0—20 cm soil profile, which could effectively alleviate soil acidification. ③ Compared with the CK treatment, the T₃₀₀, T₄₀₀, and T₅₀₀ treatments significantly promoted the growth and biomass accumulation of tobacco and significantly increased the yield and output value of tobacco leaves. Considering the input-output ratio, the T₄₀₀ treatment was optimal for improving the physical and chemical properties of soil, tobacco yield, and output value. [Conclusion] Adding suitable amounts of biochar to tobacco field soil can improve the physical and chemical properties of soil, increase soil cultivability, promote the growth, development, and dry matter accumulation of tobacco plants, and increase the yield and output value of tobacco leaves.

Abstract:[Objective] To provide a reference for the assessment of meteorological disaster risk and prevention of soil erosion, the spatial and temporal distribution characteristics of rainfall erosivity under different levels of rainfall in Jilin Province were analysed. [Methods] Daily rainfall data from 51 meteorological stations in Jilin Province from 1980 to 2022 were divided based on different rainfall magnitudes according to the rainfall grade. The daily rainfall erosivity calculation model proposed by Xie was adopted to calculate the rainfall erosivity, and the M-K mutation test, coefficient of variation, and climate tendency rate were used to analyse the spatial and temporal distributions of different grades of rainfall erosivity. [Results] ① The average annual erosive rainfall and rainfall erosivity in Jilin Province during 1980—2022 were 420.04 mm and 1 967.12 MJ·mm/(hm²·h), and the coefficients of variation were 0.27 and 0.2, respectively, both of which showed moderate variations. ② Different grades of rainfall erosivity showed an upward trend during 1980—2022. The torrential rain erosivity showed the largest increase of 57.7 MJ·mm/(hm²·h·10 a), whereas the moderate rainfall erosivity showed the smallest increase of 5.8 MJ·mm/(hm²·h·10 a). The contribution of heavy rain erosivity to the average annual rainfall erosivity was the largest at 36.68%. ③ The distribution of different grades of rainfall erosivity was uneven throughout the year. Moderate rainfall erosivity occurred throughout the year, whereas heavy rainfall erosivity only occurred from June to September. Moderate rainfall erosivity played a dominant role in the annual rainfall erosivity from October to May of the subsequent year. From June to September, the heavy and torrential rain erosivities gradually replaced the moderate rainfall erosivity and played a dominant role in the annual rainfall erosivity. ④ The spatial distributions of the average annual erosive rainfall, average annual rainfall erosivity, and different grades of rainfall erosivity were higher in the central and southern regions and lower in the East and West. [Conclusion] The regional characteristics of different grades of rainfall erosivity in Jilin Province were obvious, and the time and region with high probabilities of soil erosion caused by rainfall of different magnitudes were clearly distinguished; thus, meteorological disaster risk prevention and soil and water conservation prevention measures should be formulated according to the local conditions.

Abstract:[Objective] The morphological features of eroded gullies in rolling hill areas of black soil in Northeast China and temporal-scale variations in their morphology. were analysed in order to provide a scientific basis and empirical data to understand the development and evolution of erosional gullies in this area. [Methods] This study selected 61 typical gullies in Guofu Town, Baiquan County, China. Unmanned aerial vehicle technology was used to generate digital elevation models and manually interprets parameters such as gully length and width-to-depth ratio. Historical aerial imagery data were used to analyse the developmental changes and influencing factors of gullies. [Results] ① From 2003 to 2021, gully development in Baiquan County showed an overall intensification trend, with medium-sized gullies accounting for 60.66% of the total gullies. ② A significant variation was observed in gully morphology within the study area, with gully length, average cross-sectional area, and volume mainly distributed between 41.89—1 173 m, 11.23—440.69 m², and 895.38—107 686.57 m³, respectively. The overall shape parameter distribution was concentrated. ③ Gully length, area, and shape index exhibited a trend of increase followed by a decrease, with an average development rate of 9.64 m/a for length and 246.39 m²/a for area. The erosion gullys showed narrow and irregular shape. ④ Regression analysis revealed significant positive correlations between gully length and width, perimeter, and area (S), and significant relationships between top width and bottom width, perimeter, and S, with determination coefficients of 0.82, 0.23, and 0.58, respectively. However, gully depth showed a low correlation with erosion volume and S. [Conclusion] In typical areas of Baiquan County, the general trend in gully erosion has shown a relative slowdown compared with previous assessments, although gully erosion remains severe. Furthermore, there is an interrelationship among different morphological parameters, with gully length showing a close positive correlation with the area and perimeter of the eroded gullies.

Abstract:[Objective] The spatial and temporal patterns of vegetation cover and its driving forces in the Tingjiang River basin of the southern red soil erosion area， were scientifically evaluated to reveal the strength of the role of each driving factor in the spatial differentiation of vegetation cover and the mechanism of interaction in order to provide a scientific basis for the restoration of ecosystems and comprehensive control of soil erosion. [Methods] Based on the monthly scale MOD13Q1 (250 m) dataset for 20 years from 2000 to 2020, we used one-way linear regression and Pearson’s correlation analysis to explore the relationship between normalised difference vegetation index (NDVI) and time and incorporated natural and anthropogenic factors such as temperature, precipitation, and elevation, as well as the spatial and temporal dynamics of vegetation NDVI in the watershed using the geoprobe model. A geoprobe model was used to analyse the temporal and spatial changes in vegetation NDVI in the watershed. [Results] ① Temporally, the vegetation cover in the Tingjiang River basin showed a fluctuating upward trend from 2000 to 2020, with a growth rate of 7.11% and an average rate of increase of 0.002 2/year, indicating that the ecological environment of the region was stable and continuously improving. ② Spatially, the overall medium-high and high coverage was dominant, showing a spatial distribution pattern that was lower than the surrounding area in the middle of each district and county, with significant geographical differences; the NDVI improved area was 86.33%, which was much larger than the degraded area region. ③ The driving factor detection results were: precipitation ＞ elevation ＞ temperature ＞ GDP＞ population density ＞ land use type ＞ vegetation type ＞ slope ＞ soil type. [Conclusion] Temporal and spatial variations in vegetation cover within the Tingjiang River Basin were affected by both natural and anthropogenic factors. The explanatory power of the precipitation factor was 0.705, which was the main driving factor affecting the changes in vegetation cover in the study area. Elevation, temperature, and GDP were the secondary driving factors, with explanatory powers of 0.58 or more. The interactions (q) between the factors showed higher explanatory power than the single factors, mainly in the form of a complex relationship between the enhancement and nonlinear enhancement effects of the two factors.

Abstract:[Objective] The key ecological functional zone (KEFZ) of the Inner Mongolia Autonomous Region serves as a critical ecological barrier for the security of Northern China. The ecosystem type conversion and its impact on soil wind erosion was analysed in order to provide scientific reference for promoting ecological environment security and green development in this region. [Methods] The revised wind erosion equation (RWEQ) model based on land use, meteorology, and basic geographical information data was adopted to determine spatiotemporal changes in ecosystem structure and soil wind erosion in the KEFZ. This method revealed the impacts of ecosystem type changes on soil wind erosion. [Results] ① Substantial conversion between ecosystems in the KEFZ was observed, with a total area of change amounting to 6 019.59 km² from 2000 to 2022. The main transformations were between grasslands and deserts, and between cultivated land and forest-grassland ecosystems. The ecosystem tended to stabilise after 2015, with a reduction in the intensity of changes across various ecosystem types. ② The average soil wind erosion modulus in the KEFZ was 56.39 t/hm², with the erosion levels the highest in desert ecosystems, followed by grasslands, farmlands, and forests. Soil wind erosion was predominantly slight and light, mainly occurring in areas such as the Greater and Lesser Khingan Range forest ecological function area and the Horqin Grassland ecological function area. ③ The conversion between different types of ecosystems in the KEFZ resulted in a net reduction in soil wind erosion of 1.08×10⁸ t. Ecological restoration, land reclamation, grassland quality improvement, desertification control, and the expansion of construction land decreased soil wind erosion modulus by 0.11, 0.23, 0.66, 0.84 t/hm², and 0.68 t/hm², respectively. [Conclusion] Strengthening the consolidation of the effectiveness of ecological management in the KEFZ and avoiding the occurrence of and new land reclamation will be conducive to the comprehensive prevention and control of desertification and high-quality development in Inner Mongolia Autonomous Region.

Abstract:[Objective] The width, spacing, and system configuration mode of scientifically designed sand-control forest belts along the Hetian-Ruoqiang railway in areas prone to strong winds and sandstorms were analysed, in order to provide theoretical foundations for the configuration and construction of protective forest belts along the railway in sandy regions. [Methods] The configuration of a sand protection forest belt was studied using wind tunnel experiments and Haloxylon ammodendron and Calligonum mongolicum as forest tree models. [Results] When the protective forest belt spanned five rows and the gap between each belt was six times the height, a noticeable decrease in airflow was observed behind the second belt, with substantial attenuation continuing into the region behind the third sand-control forest belt. Notably, this attenuation remained consistent regardless of wind speed, highlighting its effective protective nature. Utilisation of these three forest belts resulted in enhanced protection. The protective area on the leeward side of the forest belt decreased as the wind speed increased. [Conclusion] The forest belt system employed the configuration modes of five protective forests to enhance the protective effect of the system against high wind speeds.

Abstract:[Objective] In order to provide references for promoting the development of breakthrough research methods and techniques for monitoring of gully erosion, the status quo, progress, and trends of the research technologies and methods for monitoring of gully erosion in the world from 1993 to 2022 were analysed and the development trend of the research technologies and methods were summarised. [Methods] A total of 376 English language research articles from the Web of Science were selected via a bibliometric approach using the CiteSpace software for knowledge map analysis. [Results] ① Research on gully erosion shows an upward trend during 1993—2022, with a rapid development after 2013, especially in 2020 (47 articles). ② China (20.25%) and the United States (10.44%) had the highest publication outputs among the main research countries. In terms of the citation frequency, the United Kingdom (70.85 times) and Belgium (72.89 times) had the highest citation frequencies. Among the top 10 influential research institutions in this field, there were four institutions from China (Chinese Academy of Sciences, Beijing Normal University, Northwest University of Agriculture and Forestry, and China West Normal University). The most influential author is Poesen Jean, with only one Chinese scholar in the top 10 in terms of publications. ③ Co-occurrence of keywords indicated that current research on gully erosion mainly focus on the spatiotemporal distribution and changes, influencing factors, and mechanisms of gully erosion. The diversity of techniques and methods had been gradually increasing, with 2D plane measurements being replaced by 3D volumetric measurements, and the integration of multi-technology had become a new trend in the field of gully erosion. [Conclusion] The development of techniques and methods for the study of gully erosion has a bright future, emphasizing the combined use of a variety of techniques to improve the accuracy of the measurements, which is conducive to the development of the discipline.

Abstract:[Objective] The level of coordination between green development and rural revitalisation in the Sichuan-Guizhou region and influencing factors were analysed in order to provide a scientific basis for promoting green development and rural revitalisation in the western regions of China, thus facilitating the coordinated development of both aspects. [Methods] This study focused on data from 30 cities and prefectures in the Sichuan-Guizhou region for the period 2011—2020. A comprehensive indicator system for green development and rural revitalisation was developed. Coupling coordination and Tobit models were employed to analyse the coupling coordination relationships between green development and rural revitalisation and influencing factors. Heterogeneity were conducted based on regional characteristics. [Results] ① The green development index in the Sichuan-Guizhou Province fluctuated slightly because of different policy influences; differences between regions were significant. The rural revitalisation index significantly increased after implementation of the rural revitalisation strategy, and differences between regions were relatively small. ② The coupling coordination level between green development and rural revitalisation in the Sichuan-Guizhou region showed an upward trend over time. ③ Considering the impact of economic, policy, and geographical factors on the level of coordination between green development and rural revitalisation in the region, all influencing factors, except for elevation, were significant and positive. ④ Educational development, scientific and technological innovation, traffic conditions, environmental regulations, terrain slope, and elevation had significant heterogeneity in different regions. [Conclusion] The Sichuan-Guizhou region should encourage and support economic development, take note of government influence, engage in industrial structure adjustment and upgrading, continuously improve levels of education and technological innovation, enhance transportation conditions, and address environmental regulations. Tailored approaches should be implemented to enhance coordination between green development and rural revitalisation based on local conditions.

Abstract:[Objective] The spatiotemporal characteristics of agricultural nonpoint source pollution in Shanxi Province during 2011—2022 were analysed and its development trends was predicted in order to provide a scientific reference for the prevention and control of agricultural non-point source pollution in the Shanxi Province. [Methods] The spatiotemporal characteristics of agricultural non-point source pollution in Shanxi Province were analysed using the pollution emission coefficient and equivalent pollution load methods, and an autoregressive integrated moving average (ARIMA) model was established to predict the development trend. [Results] ① In 2022, the agricultural non-point source pollution in Shanxi Province produced 4.74×10⁵ t of COD (chemical oxygen demand), 5 820 t of NH₃-N, 2.86×10⁴ t of total nitrogen (TN), and 4 180 t of total phosphorus (TP). The high-emission areas were located in Lvliang and Yuncheng City, and the low-emission areas were located in Taiyuan and Yangquan City. The equivalent pollution load was 3.95×10¹⁰ m³. The primary pollutant was TN, and the primary source of pollution was animal husbandry. ② From 2011—2022, the developmental trends of the four types of pollutants were consistent. All showed an increase in fluctuation, and the highest value for each pollutant was observed in 2022. The ranking of pollutants in each region was stable, with Yuncheng and Lvliang City always occupying important positions. TN has been the primary pollutant for 12 years, animal husbandry has been the source of the primary pollutant, and the proportion was still rising. ③ By determining model parameters, the ARIMA (1,1,2) model was established for the forecast. During the forecast period, agricultural non-point source pollution in Shanxi Province decreased slightly, and the development trend showed a steady increase. [Conclusion] It is necessary to strengthen the prevention and control of key agricultural pollution accounts and pollutants, reduce the discharge of agricultural nonpoint source pollution, and mitigate its rising trend.

Abstract:[Objective] The water and sediment changes in small and medium-sized rivers under the influence of human activities were analysed to provide scientific support for soil and water conservation and waterway water and sediment management in the watersheds. [Methods] The influence of landscape patterns on water and sediment changes in the basins was analysed based on water and sediment data and land use of the Nanliu and Qinjiang River basins from 1965 to 2021 using the landscape index, water-sediment mutation test, and other methods. [Results] ① Runoff and sediment transport in the Nanliu and Qinjiang River basins showed a gradual downward trend. The decreasing trend of sediment transport was more evident than that of runoff, and sudden change points in both runoff and sediment transport occurred in the 00s of the 21st century. ② The proportion of forestland in the Qinjiang River basin increased from 38% in 1990 to 41.6% in 2020, and the transfer area of cultivated land to forestland in the Nanliujiang River gradually increased. The policy of returning farmland to forests was effective, and the water-sediment change also showed a trend of gradual reduction. ③ The water-sediment changes in the two watersheds were negatively correlated with the degree of landscape fragmentation and positively correlated with the degree of patch aggregation. [Conclusion] In general, the land-use change within the Nanliu and Qinjiang River basins remained stable, and the water-sediment change was more obviously affected by land-use change; therefore, the relevant departments should strengthen the protection and management of eco-lands. Excessive interference of landscape patterns by human activities should be avoided, and landscape spatial configurations should be rationally planned to prevent soil erosion.

Abstract:[Objective] The spatiotemporal trends of surface water areas, evolution of surface water spatial patterns in typical wetlands, and imaging factors in the cities of the Beijing-Tianjin-Hebei region from 2000 to 2021 were analysed in order to provide scientific references for the protection, rational development, and utilisation of water resources in the region. [Methods] This study utilised the JRC global surface water dataset to identify surface water variations in Beijing-Tianjin-Hebei region from 2000 to 2021. We examined the spatiotemporal trends in surface water and morphological evolution within the Baiyangdian and Qilihai wetlands using morphological spatial pattern analysis (MSPA). Correlation analyses incorporating climatic and anthropogenic factors had identified the drivers of these spatiotemporal changes. [Results] ① During 2000—2021, from a temporal perspective, a notable decline occurred in the area of permanent water bodies across the Beijing-Tianjin-Hebei region, which was contrasted by a consistent increase in seasonal water bodies. In terms of spatial distribution, the reduction in surface water area was primarily concentrated in the metropolitan areas of Beijing, Tianjin, and Langfang City. Conversely, cities along the South-North Water Diversion central route, such as Handan, Xingtai, and Shijiazhuang City, experienced an increasing trend in surface water area, indicating a directional shift towards increased water resource availability. ② The surface water area of the core wetland of Baiyangdian gradually decreased from 2000 to 2005 and began to gradually increase after 2005. The core wetland area of Qilihai gradually decreased from 2000 to 2010 and gradually increased after 2010. ③ The maximum water body area in the southern cities of Beijing-Tianjin-Hebei was positively correlated with precipitation, whereas the eastern coastal cities were negatively correlated. This indicated an imbalance between human activities and natural recharge. A significant positive correlation was observed between water consumption and maximum surface water area in Beijing, Chengde, and Tangshan City, indicating a greater influence of cross-basin water transfer and ecological recharge. In contrast, Qinhuangdao and Tianjin City showed highly significant negative correlations, indicating that the over-exploitation of groundwater had a negative impact on surface water resources. [Conclusion] Changes in surface water area are significantly affected by climate and human activities. In the future, the Beijing-Tianjin-Hebei region should effectively protect surface water resources through inter-basin water transfers, water conservation campaigns, ecological restoration, and reduction of groundwater extraction to cope with the impacts of climate and human activities.

Abstract:[Objective] The characteristics and influencing factors of cultivated land changes in the Yellow River alluvial area of Southwest Shandong Province were analysed order to provide a scientific basis for regional cultivated land protection. [Methods] Using 2 m high-resolution remote sensing images and data from the ‘Heze statistical yearbook’, various methods including remote sensing interpretation, centre of gravity model, cold and hot spot analysis, and geographical detector were used to analyse land change characteristics and influencing factors of cultivated land in the Yellow River alluvial area of Southwest Shandong from 2019 to 2022. [Results] ① During 2019—2022, the arable land in the Yellow River alluvial area of Southwest Shandong Province accounts for more than 60% of the area, and there was annual cultivated land loss in the studied region, with a decreasing trend year by year. The arable land area in Yuncheng County decreased the most, reaching 18.28 km², and farmland dynamic attitude in Juancheng County changed the most, reaching -2.26%. The centre of gravity of cultivated land migrated to the Southwest and Northeast of Shandong Province. ② The outflow area of cultivated land was higher than that of the inflow area, and the main outflow and inflow directions were both construction and forest land. The area with the most concentrated cultivated land change was mainly distributed in the southern part of Caoxian County. ③ The single factors affecting the change in cultivated land were mainly rural employees (X₅); the two-factor interactive combination was mainly the intersection of the number of rural labour resources (X₄) and the per capita income of urban residents (X₆). [Conclusion] The loss of cultivated land in the Yellow River alluvial area of Southwest Shandong Province from 2019 to 2022 is the result of the comprehensive effect of multiple factors based on economic and social factors.

Abstract:[Objective] The spatial patterns and driving factors of the frequency of land-use dynamic transfer changes in Guizhou Province were analysed in order provide theoretical references for land survey work and related policies in the region. [Methods] Based on the land-use data of Guizhou Province from 2000 to 2020, the spatial and temporal distribution characteristics of the frequency of land-use change in Guizhou Province were analysed using land-use change frequency statistics, kernel density analysis, and spatial autocorrelation, and the influencing factors were studied using geographic probes. [Results] ① The area of land changed in the land use change frequency in Guizhou Province from 2000 to 2020 was only 2%, but the inputs of capital and manpower were relatively high; as a result, there was a relationship between the two inputs and discordance. ② The land that changed in land-use change frequency in Guizhou Province from 2000 to 2020 had significant spatial heterogeneity in spatial distribution. ③ The kernel density of changed land in Guizhou Province from 2000 to 2020 showed the distribution characteristic of “higher in the west and lower in the east”, with the distribution density of one land change being the largest and the distribution density of three land changes being the smallest. ④ In 2000 to 2020, both changed and unchanged land in Guizhou Province showed significant spatial agglomeration characteristics, with changed hotspots in areas such as, Hezhang, and Dafang and unchanged hotspots in areas such as Xianning and Congjiang area. ⑤ The results of the interaction detection of the driving factors of land-use change frequency in Guizhou Province from 2000 to 2020 showed that the interaction of slope and slope direction had the strongest explanatory power for the spatial variation in land-use change frequency in Guizhou Province. [Conclusion] An obvious spatial heterogeneity exists in the distribution of land-use change frequency in Guizhou Province. A mechanism to regulate the frequency of land-use change in Guizhou Province should be established to realise the effective use of social resources and reduce the financial burden on society.

Abstract:[Objective] As a unique mountainous ecological hot spot in Inner Mongolia Autonomous Region, the response relationship of land circulation and intensity to ecosystem service function was studied to provide theoretical basis for scientific allocation of land use pattern and ecological sustainable development in Daxinganling. [Methods] Based on five remote sensing images captured from 1990 to 2022, this study comprehensively applied the InVEST-CASA and four-quadrangle models to assess changes in five typical ecological service functions (habitat quality, carbon storage, water conservation, soil conservation, and the net primary productivity of vegetation) at the county scale. The correlation between the temporal and spatial evolution of land use intensity and ecosystem service function was studied. [Results] ① From 1990 to 2022, the land use pattern of the study area was stable, and farmland, grassland, and woodland (natural forest and plantation forest) were the main land types in the Daxinganling Mountains of Inner Mongolia. ② Ecosystem service function showed a trend of slower degradation in the north and lower degradation in the south, the habitat quality and soil conservation decreased annually, the water production and the net primary productivity of vegetation declined in a fluctuating manner, and the growth rate of carbon storage slowed down. ③ Owing to the change in the land use pattern and the increase in land use intensity, there was a negative correlation between the comprehensive value of ecosystem service function and land use intensity, and counties affected by this change were mainly distributed in the southeastern region of the study area. [Conclusion] There was evident spatial and temporal heterogeneity in ecosystem services in the Greater Khingan Mountains of Inner Mongolia, and rational optimization of land use patterns can effectively improve ecosystem services in this area.

Abstract:[Objective] The spatial distribution patterns and influencing processes of soil pH value in typical industrial and mining areas in the Southern Taihang Mountains were analyzed, to provide scientific support for soil environmental quality assessments and pollution prevention strategies in the complex environment of this area, comprising typical industrial and mining activities. [Methods] Studying the Manghe watershed in industrial and mining areas of the Southern Taihang Mountains, 121 topsoil (0—20 cm) and auxiliary samples were collected. “3S” technology, geostatistics, geographical detectors, and other model methods were comprehensively applied to study the spatial distribution characteristics and factors influencing topsoil pH value in the research area. [Results] The soil pH value in the study area ranged from 6.40 to 8.53, with a mean value of 7.82, which was lower than the background value of the Henan section of the Yellow River basin (8.46). Compared with previous studies, the average soil pH value decreased, indicating a trend of soil acidification. Soil pH value showed weak spatial variation and was significantly influenced by factors such as terrain. When the interval distance between sites was less than 1 905 m, the spatial distribution was continuous and exhibited strong spatial autocorrelation. The spatial interpolation effect of soil pH value based on empirical Bayesian Kriging was better, and the spatial distribution of soil pH value showed an increasing gradient from the central and western regions to the northeast and south. Low-value areas were mainly located in the valleys and piedmont plains in the central and western regions. The explanatory power of individual factors on pH value was unclear; however, the superposition of slope direction, land use, and other factors significantly enhanced the explanation of the spatial distribution of soil pH value in the watershed. [Conclusion] The superposition of multiple factors, such as natural conditions and human activities, were the main drivers explaining the spatial distribution of regional soil pH value and should be the focus of regional soil environmental assessments and pollution remediation efforts.

Abstract:[Objective] The factors and mechanisms influencing the evolution of groundwater flow fields were analysed to provide a theoretical basis for the sustainable utilisation of groundwater resources in the study area. [Methods] Using geostatistics, the projection pursuit regression technique, and other research methods, the impacts of precipitation changes and human activities on the evolution of groundwater systems in six basins in Shanxi Province were analysed. [Results] ① Precipitation showed a linear correlation with fluctuations in the groundwater levels. For every 100 mm increase in precipitation, the groundwater levels in the Taiyuan, Yuncheng, Datong, Xinzhou, Linfen, and Changzhi basins decreased by 0.45, 0.46, 0.20, 0.28, 0.22, 0.73 m respectively. ② Groundwater levels showed a linear correlation with the variations in groundwater storage. For every increase of 1.00×10⁸ m³ in groundwater overexploitation volume, the average groundwater levels in the Yuncheng, Taiyuan, Datong, Xinzhou, Linfen, and Changzhi basins decreased by 0.18, 0.36, 0.25, 0.55, 0.40, 2.0 m respectively. ③ The contributions of the different factors affecting groundwater resources vary significantly across different regions. Precipitation was the primary factor affecting the groundwater resources, with a contribution rate exceeding 40% in all areas. In the Yuncheng and Datong basins, land changes caused by cultivation were the second most influencing factor, with a contribution rate of 22.55%. In the Taiyuan, Xinzhou, Linfen, and Changzhi basins, land changes caused by construction were the second most influencing factor, with contribution rates of 19.12%, 17.57%, 16.56%, and 22.43%, respectively. [Conclusion] ① Artificial rainfall can be conducted in a timely manner to increase precipitation and groundwater recharge, thereby slowing the rate of groundwater level decline. ② In areas experiencing groundwater overextraction, groundwater extraction should be appropriately reduced and efforts should be made to increase the groundwater system storage capacity to gradually restore groundwater levels. ③ Effective measures should be taken to restrain the continuous decrease and rapid expansion of cultivated and construction lands, respectively, thereby reducing the impact of land change due to land use types on groundwater resources.

Abstract:[Objective] The study of river ecological water demand in the southern mountain area of Jinan City, Shandong Province based on ecohydrological variation characteristics was carried out to provide theoretical basis for regional water resources integrated management and ecological protection, strengthening ecological protection, and promoting sustainable development of the Yellow River basin. [Methods] The runoff data from Gushan station (Beidasha River) and Wohushan station (Yufu River) in the southern mountainous area of Jinan, located in the lower reaches of the Yellow River, were collected for the period 1979 to 2021. The study utilized the cumulative anomaly method, Mann-Kendall (M-K) test method, sliding T-test method, and double accumulation curve method to analyse abrupt changes in runoff. The IHA-RVA method was additionally used to examine variations in river runoff and ecological water demand. By comparing the rivers’ satisfaction with ecological water demand, this paper investigated key factors influencing the regional ecohydrology and variations in ecological water demand while proposing protective measures to ensure adequate supply within the study area. [Results] The runoff mutation points of Beidasha River and Yufu River were observed in 1996, and the overall hydrological alteration degrees were determined to be 72.75% and 69.42%, respectively, indicating significant alterations in both rivers. The annual ecological water demand of Beidasha River and Yufu River was 1.47×10⁶ m³ and 1.81×10⁶ m³, respectively. Overall, the monthly ecological water demand satisfaction of the Beidasha River and Yufu River was 32.35% and 60.42% on average, respectively. [Conclusion] The hydrological variation in the southern mountainous area of Jinan was found to be large before and after the mutation, and the overall satisfaction of the ecological water demand was relatively low. The ecological water demand of rivers may be guaranteed by strengthening the ecological regulation of rivers and improving the efficiency of water resource utilisation.

Abstract:[Objective] The topographic characteristics of abandoned farmland in mountainous areas were analysed in order to provide a scientific reference for regional land resource management and sustainable agricultural development. [Methods] Taking Wushan County of Chongqing City as the research area, this study used Landsat TM/ETM+/OLI and Sentinel-2 data on the Google Earth Engine (GEE) cloud platform and adopted decision tree and time series normalised difference vegetation index (NDVI) change detection methods. We extracted and analysed abandoned land information from the study area from 2017 to 2021. [Results] ① From the perspective of time series characteristics, the area of abandoned land in the study area showed an overall upward trend; the increase from 2017 to 2021 was 2 123.50 hm², with a growth rate of 19.61%, and the curve shape within the interval showed a “W” shaped characteristic. Spatially, abandoned land was regionally dispersed and locally concentrated. It was mainly distributed along the direction of the water system, significantly concentrated on both sides of the river, and surrounded by sloping farmlands. ② The abandoned land in the study area was distributed differently across different elevation and slope zones. The abandoned land was concentrated at elevations below 1 000 m and slopes within a range of 5°~20°. In areas with an elevation below 1 500 m, the area of abandoned land and rate of abandonment showed a pattern of “first increasing and then decreasing,” reaching the highest point in 2019; in areas with an elevation above 1 500 m, the area of abandoned land and the rate of abandonment showed a pattern of “first decreasing and then increasing” over time. The law of “increase” reached its lowest value in 2020. ③ The distribution index of abandoned land under different terrain levels was continuously decreasing, and the distribution index of terrain gradients 1 and 2 was greater than 1, indicating the dominant area of abandoned land. [Conclusion] The combination of a decision tree and NDVI time series change detection methods can accurately identify abandoned land with a recognition accuracy of 83.59%.

Abstract:[Objective] The spatio-temporal evolution and spatial differentiation of cultivated land pressure in the agro-pastoral ecotone of Northern China was analysed, in order to provide reference for the future strategic layout of food security development in this ecotone in Northern China. [Methods] The status of cultivated land resources in the northern agro-pastoral ecotone was analysed between 2000 and 2023 using the modified cultivated land pressure index mode. Thereafter, the study area was subdivided, and the spatiotemporal development trend of cultivated land pressure was analysed. The future change in cultivated land pressure was calculated using the prediction model, and corresponding countermeasures and suggestions were proposed. [Results] ① In general, the cultivated land pressure in the northern agro-pastoral ecotone increased, showing a “W” shape change in time series. The spatial pattern showed an “overall” alert and local stable situation, and the pressure centre of gravity migrated towards the southwest with time. ② The heterogeneity of regional cultivated land pressure showed a gradual trend of differentiation. Further, the heterogeneity was influenced by the development of regional functions and industrial structure and showed a gradual but evident trend in the time pattern. The spatial pattern distribution showed that the desertification area along the Great Wall was stable for a long time, the loess hilly gully area was gradually rising, and the Beijing-Tianjin-Hebei water conservation area was gently declining. In the next 7 years, the pressure of cultivated land in the northern agricultural and pastoral ecotone will show an overall increase, posing a certain threat to food security and regional development, which needs to be protected and paid attention to by relevant departments. [Conclusion] The cultivated land pressure in the northern agro-pastoral ecotone zone is on the rise in general, and the regional differences are gradually obvious. In the future, it is necessary to improve the land fertility and environmental political ability of the whole cultivated land, and carry out the compensation mechanism of cross-regional cultivated land protection.

Abstract:[Objective] To assess how farmers’ participation in soil conservation programs affects their welfare, to provide theoretical support for the sustainable development of regional soil conservation. [Methods] We selected counties involved in soil and water conservation projects within the Three Gorges Reservoir area and constructed a welfare evaluation index system based on capability theory. We explored how farmers’ participation in such projects affects their welfare using methods including propensity score matching, fuzzy comprehensive evaluation and quantile regression. [Results] ① After participating in soil and water conservation programs, the welfare indices of the farming and living environments were 0.523 and 0.614, respectively. The happiness index of resident farmers was high, and subjective well-being indices, such as income satisfaction, were above 0.5. ② A marked difference in welfare outcomes was identified between farmers that participated in soil and water conservation and those who did not, with the total fuzzy welfare index of participating farmers being greater than that of non-participating farmers. ③ Soil conservation projects comprehensively improved the welfare level of farmers from economic, social and ecological perspectives, with a welfare effect of 2.75%—2.80%. ④ The overall welfare level of farmers’ families increased with an increasing extent of their participation in soil and water conservation projects. The total welfare generated by farmers’ spontaneous soil conservation behaviours was greater than that generated by government-guided soil and water conservation initiatives, although government-guided welfare was more significant in terms of crop yield and farming environments. Cultivated land area was the main factor affecting farmers’ participation in soil conservation welfare. [Conclusion] The promotion and training of soil conservation interventions should be strengthened, and regional characteristics should be considered when implementing soil and water conservation measures, so as to improve farmers’ participation in such projects and ensure that more farmers benefit from these conservation measures.

Abstract:[Objective] The sources, migration characteristics, and influencing factors of non-point source pollution in orchards were analysed in order to provide theoretical support for scientifically aid in preventing and controlling non-point source pollution from orchards and improving the quality of soil and water environments. [Methods] Based on the latest research results (both domestically and abroad), the source, migration characteristics, and influencing factors of pollution by nitrogen, phosphorus, heavy metals, and pesticides in orchards were analysed. Existing research deficiencies were analysed and future research directions were proposed. [Results] ① The application intensities of nitrogen fertiliser in orchards 〔565—1 071.2 kg/(hm²·a)〕 and loss coefficients of nitrogen and phosphorus were generally higher than those in farmland. Nitrogen and phosphorus accumulated easily at the bottom of the orchard slope, and their spatial variabilities in soil were higher than those in the farmland and tea gardens. ② When the orchards were not irrigated by sewage and industrial activities were absent, fertilisers, pesticides, and traffic activities were the main sources of heavy metals in the orchard soil, and the migration ranges of heavy metals in the soil profile were approximately 0.005—0.8 m. ③ The dosages of benzimidazole and pyrethroid pesticides in orchards were approximately 40—4 050 and 60—150 g/hm², respectively. After application, weakly adsorbed pesticides were significantly affected by short-term rainfall, whereas moderately adsorbed pesticides were affected by rainfall and evaporation. The pesticide content in the river showed a seasonal correlation with rainfall. ④ To control non-point source pollution in orchards, the treatment of initial runoff must be prioritised to effectively intercept the sediment. Planting grasses under fruit trees can reduce runoff by 7.1%—98.7%, control sediments by 15.7%—99.8%, intercept nitrogen and phosphorus by 4.6%—98.5 and 15.3%—96.6%, respectively, and reduce heavy metals by 18.8%—90.1%. ⑤ The migration characteristics of non-point source pollution from orchards were consistent with the temporal and spatial distributions of rainfall. In particular, 20% of the surface runoff produced more than 50% of the pollution load. Under extreme rainfall, the runoff coefficients and loss loads of nitrogen and phosphorus in orchards were 2.6 and 11.5 fold higher than those under normal rainfall. Rainfall volume and intensity were the main factors affecting the migration of heavy metals and pesticides. Under rainfall with long duration and moderate intensity, heavy metals and pesticides were more likely to infiltrate and migrate downstream. [Conclusion] The management of orchards in China is still in its infancy. In the future, the migration laws of non-point source pollution, such as nitrogen, phosphorus, heavy metals and pesticides, under the influence of complex factors must be explored, the spatiotemporal scope and degree of non-point source pollution should be accurately identified, and the loss of non-point source pollution should be effectively reduced to ensure the quality of fruits, improve the ecological benefits of orchards, and reduce environmental risks.

Abstract:[Objective] The spatial and temporal evolution and driving factors of agricultural land allocation efficiency were analyzed in order to provide theoretical support and scientific reference for the practice of the all-encompassing approach to food, the effective utilization of agricultural resources and the high-quality development of agriculture. [Methods] The article was based on the concept of the all-encompassing approach to food. Using a three-stage data envelopment analysis (DEA) model, Dagum’s Gini coefficient, kernel density estimation and panel Tobit regression, the article measures the allocation efficiency of agricultural land in 30 provinces in China from 2004 to 2022, and analyzed the characteristics of the spatial and temporal evolution and the driving factors. [Results] The overall level of agricultural land allocation efficiency in China was high and stable, and after removing the effects of environmental factors and random errors, the spatial characteristics of allocation efficiency were reversed, and eventually showed a decreasing trend of central-northeastern-eastern-western; and the overall differences between regions showed a fluctuating upward trend, with hypervariable density dominating the overall differences; There was some spatial polarization phenomenon in all regions; urbanization rate, ecological governance, agricultural technology progress had a significant positive effect on the allocation efficiency of agricultural land, rural road facilities and residents’ food and nutritional needs had a significant negative effect, and the effect of financial support for agriculture was not significant. [Conclusion] We should correctly understand and exert the influence of food consumption structure on the allocation of agricultural land, deeply implement the practice of green ecological agriculture, and realize the organic combination of the government and the market, so as to improve the efficiency of agricultural land allocation in all aspects.

Abstract:[Objective] China’s soil erosion management has shifted from “comprehensive management, key management” to a new stage of “systematic management, overcome difficulties and challenges”. The concept and criterias of systematic management with mountains, waters, forests, farmlands, lakes, grasses and sands， and its relationship with soil and water conservation were analyzed, to provide references for enriching the theoretical system of soil and water conservation in the new period. Therefore, to lead high-quality development of soil and water conservation. [Methods] On the basis of long-term theoretical exploration and practical verification, the development process of the concept of mountains, rivers, forests, farmlands, lakes, grasses and sands systematic management has been organised, and its connotation, objectives, and practical guidelines have been elaborated. [Results] A comprehensive management technology route with small watersheds as a unit, formed by summarising and improving the long-term practice of soil and water loss management, is the simplest practical embodiment of the systematic thought of the life community in mountains, rivers, forests, farmlands, lakes, grasses, and sands. The systematicness of the integrated management of small watersheds is mainly reflected by six aspects: systematic coordination of governance objects, systematic integration of the overall layout, systematic coordination of governance measures, multi-benefit balance of governance effectiveness, multi-sectoral synergy of implementation and management, and multi-agent participation in shared governance. Specific initiatives based on the concept of systematic governance that need to be followed for the high-quality development of soil and water conservation include: using systematic thinking to understand the connotation and requirements for the high-quality development of soil and water conservation; accurately diagnosing the controlling elements of mountains, rivers, forests, farmlands, lakes, grasses and sands systems; constructing a multi-level, all-round, three-dimensional prevention and control system for mountains, rivers, forests, farmlands, lakes, grasses, and sands; and constructing a complete soil and water conservation management and technical guarantee system. [Conclusion] During the new period, the concept of systematic management of mountains, rivers, forests, farmlands, lakes, grasses, and sands should be completely and accurately understood and fully implemented, and new paths, modes, and mechanisms should be evaluated to enhance the level of academic research on soil and water conservation and effectiveness of governance as a whole. Simultaneously, comprehensive and systematic planning and management of farmland, water conservancy, animal husbandry, forestry, production, and construction activities should be conducted in combination with regional specific conditions to promote the high-quality development of soil and water conservation.