Abstract:[Objective] The mechanism on how bryophytes influence water infiltration in the soil surface layer following a short period of heavy precipitation was studied in order to provide data support for the use of bryophytes to control soil erosion in rocky desert areas. [Methods] We measured soil water infiltration in a laboratory study using a one-dimensional soil column covered with Hypnum plumaeforme, Anomodon viticulosus, Weisia controversa, or Bryum coronatum after a short period of 20 mm of precipitation. We used the classical Horton infiltration model and Singh’s entropy infiltration equation to simulate water infiltration, and compared the differences in soil water infiltration. [Results] ① The initial, stable, and mean infiltration rates and the cumulative infiltration amount for the bryophyte-cover treatments were all greater than observed for the bare soil treatment (p＜0.05). The four infiltration characteristic values were 0.718 cm/min, 0.279 cm/min, 0.180 cm/min, and 19.575 cm, respectively, for the Bryum coronatum treatment, which had the slowest infiltration rate, and the respective values were 7.65%, 8.56%, 11.90% and 3.75% greater than those observed for the bare soil treatment. The reason that the bryophyte-cover treatments increased water infiltration was that the bryophytes prevented the production of a physical crust on the soil surface. This effect was greater than the effect of the bryophyte layer to intercept and prevent water infiltration. ② The four bryophytes produced different effects to promote or impede water infiltration during the infiltration process, resulting in significant differences in water infiltration eigenvalues (p＜0.05). Infiltration characteristics were negatively correlated with rhizoid density, rhizoid length, and saturated water absorption rate of bryophytes, and positively correlated with bryophyte roughness, but the correlation was small. ③ The classical Horton infiltration model was more suitable for simulating the soil water infiltration process of bryophyte-covered soil. The Philip model was more suitable for simulating bare soil water infiltration. If the accuracy requirement is not high and a simple model is desired, Singh’s entropy infiltration equation can be used as well as the E-Kostiakov infiltration model. [Conclusion] Bryophytes covering the soil surface layer increased water infiltration following a short period of intense precipitation of 20 mm, which was mainly due to the presence of bryophytes impeding the formation of physical crusting of the soil surface layer.

Abstract:[Objective] The impacts on soil saturated hydraulic conductivity that occur because of differences in root and soil properties between combinations of grasses and shrubs having different root configurations were studied, and an empirical equation for estimating soil saturated hydraulic conductivity was established by comprehensively considering root and soil properties in order to provide a theoretical reference for the establishment of hydrological models appropriate for conditions following vegetation restoration on the Loess Plateau. [Methods] Plots of grass-shrub mixtures having different root system configurations were used: Agropyron cristatum and Caragana korshinskii, and Artemisia gmelinii and Caragana korshinskii. Saturated hydraulic conductivity was measured by the double-ring knife method. [Results] The influence of sample grass-shrub mixture type and soil depth on soil saturated hydraulic conductivity was significant, and their factor contribution rates on soil saturated hydraulic conductivity were 26% and 52%, respectively. The soil saturated hydraulic conductivity of the tap-root grass Artemisia gmelinii and Caragana korshinskii mixture was greater than that of the fibrous root grass Agropyron cristatum and Caragana korshinskii mixture. Soil saturated hydraulic conductivity of different plots declined with increasing soil depth. Root length density, soil aggregates, and soil bulk density better simulated soil saturated hydraulic conductivity, with a fitting accuracy (R²) reaching 0.86. [Conclusion] The combination of a taproot grass and a shrub had a higher saturated hydraulic conductivity than observed for the combination of fibrous root grasses and shrubs. Root length density, soil aggregates, and soil bulk density were the main factors affecting saturated hydraulic conductivity.

Abstract:[Objective] The influence of dry vegetation cover on the structure of wind-blown sand flow under the action of sand-carrying wind of S105 in Inner Mongolia Autonomous Region was studied in order to provide a theoretical reference for the prevention of soil wind erosion on both sides of a grassland highway. [Methods] Sediment transport rates were measured at 0%, 20%, 40%, and 50% vegetation cover levels by wind-tunnel simulation tests. [Results] Under the action of sand-carrying wind, the sediment transport rate decreased as dry vegetation cover increased, and the height of the maximum sediment transport rate rose as cover increased. When vegetation cover was 0%, the sediment transport rate decreased exponentially as height increased. As vegetation cover increased to 20%, 40%, and 50%, the sediment transport rate decreased, then increased, then decreased, and then tended to be flat as height concurrently increased. These results can be described by a polynomial function below 85 mm height and by an exponential function above 85 mm height. Total sediment discharge decreased as vegetation coverage incrased, and the maximum anti-wind erosion efficiency was 65.73%. [Conclusion] Dry vegetation cover significantly affected the structure of surface wind-blown sand flow, which can weaken the erosion force of sand-carrying wind. Dry vegetation cover is an effective means of inhibiting wind erosion and desertification of surface soil along highways.

Abstract:[Objective] The physical and chemical properties and water characteristics of substrates under different eroded microhabitats were studied to provide a theoretical basis for understanding the driving and limiting mechanisms of vegetation settlement and restoration, and to provide scientific references for the practice of vegetation reconstruction in early abandoned mining areas in the North China. [Methods] The mechanical composition, bulk density, capillary porosity, pH value, electrical conductivity, and moisture characteristics of bare slopes, rills, shallow gullies, and deposit bodies were studied, and the relationships between them were analyzed. [Results] Particle size matrices varied among different eroded microhabitats, and there were differences among different soil layers. The bulk density of the substrates in different eroded microhabitats followed the order of shallow gully>rill>bare slope>deposit body, while capillary pore size followed the order of deposit body>bare slope>shallow gully>rill. There were no significant differences in the pH value of different eroded microhabitats, but there were differences in the changes in different soil layers. Electrical conductivity followed the order of deposit body>bare slope>shallow gully>rill, and was higher in the 10—20 cm soil layer than in the 0—10 cm soil layer. The matrix moisture content and capillary water capacity of different eroded microhabitats followed the order of deposit body>bare slope>shallow gully>rill. The matrix moisture content and capillary water capacity of the bare slope and the shallow gully were the lowest on the upper slope, while they were lowest for the rill on the middle slope. [Conclusion] The substrate moisture characteristics of weathered gangue dumps were significantly affected by bulk density and capillary porosity. There were relatively more sand and medium-coarse grain particles in bare slopes and deposit bodies of weathered gangue dumps, and the moisture characteristics were superior. Bare slopes and deposit bodies can provide a safe habitat for vegetation settlement and restoration.

Abstract:[Objective] The slope vegetation restoration effect and dominant ecological factors in the working area of DG hydropower station in Xizang Autonomous Region were studied in order to provide a theoretical basis and technical support to increase the success rate of vegetation restoration, control soil erosion, and improve the ecological environment in the work area. [Methods] Five different types of slope (slag accumulation, soil, soil/rock mixed, rock, and concrete) were taken as the research objects, and the relative soil water content, air temperature, slope and slope aspect were selected as ecological factors. After in-situ monitoring, sampling and analyzing the entropy-weight method was used to calculate the weight scores of vegetation characteristics (species diversity, species richness, and vegetation coverage) and soil fertility (organic matter, available phosphorus, available nitrogen, and available potassium). Then the comprehensive-evaluation method was used to calculate the comprehensive score that was then combined with the range analysis to select the most dominant ecological factor. [Results] The highest comprehensive score of vegetation restoration (10.000 0) was obtained for the slag accumulation slope and the soil slope, and the effect of vegetation restoration was the best for these two slopes. The comprehensive score of vegetation restoration for the concrete slope was only 5.369 0, and the effect of vegetation restoration was poor. Different types of slope had different effects on vegetation restoration because of different ecological factors. The impact of ecological factors followed the order of relative soil water content＞slope＞air temperature＞slope aspect for the soil/rock mixed slope; relative soil water content＞air temperature＞slope＞slope aspect for the rock slope; relative soil water content＞slope aspect＞slope＞air temperature for the soil slope, concrete slope, and slag accumulation slope. Hence, relative soil water content was the most dominant ecological factor for all slopes. [Conclusion] The main ecological factor affecting slope vegetation restoration in the working area of DG hydropower station in Xizang Autonomous Region is soil relative humidity. There are great differences in the combination of optimal ecological factors for vegetation restoration in different types of slopes, among which the relative soil water content and slope of soil-rock mixed slope, rock slope, soil slope, concrete slope and residue accumulation body slope are the same, and the differences are mainly reflected in slope aspect and air temperature.

Abstract:[Objective] The influences of porous sand-fixing bricks layout on wind field characteristics, windbreak effect and sand-fixing were studied in order to provide a theoretical basis for the selection of new windbreak and sand-fixing materials. [Methods] The wind pressure distribution and the fluctuation of average wind pressure coefficient of a grid sand barrier and a gradient determinant sand barrier under wind conditions were explored by wind tunnel experiment. It was compared and analyzed emphatically for wind speed, windbreak efficiency, and sand accumulation for the two different types of sand barrier under sand storm. [Results] The average wind pressure coefficient inside the grid sand barrier was negative compared with the gradient determinant sand barrier, and the vortex generated by the internal wind circulation made it more stable under pressure. The average wind speed attenuation rate behind the grid sand barrier was higher than that behind the gradient determinant sand barrier. The windbreak efficiency first increased and then decreased with the increases of height along the height divection of sand barrier in barrier height. At 10 cm height, the windbreak efficiency of the grid sand barrier was 64.3%, which was 4.2% higher than that of gradient determinant sand barrier. The total sand deposition rates in the first row and the second row of the grid sand barrier were 1.14 and 1.66, respectively, times higher than that of the gradient determinant sand barrier. The amount of sand deposited behind the grid sand barrier and the deposition range behind the grid sand barrier were smaller than those values observed for the gradient determinant sand barrier. [Conclusion] The grid sand barrier had a significant attenuation effect on wind flow, and the sand resistance rate was higher than that of the gradient determinant sand barrier. Sand particles mainly settled inside the grid sand barrier, and its windbreak effect was better than observed for the gradient determinant sand barrier. The grid sand barrier was, therefore, judged to be the optimal sand barrier layout.

Abstract:[Objective] The changes in herbaceous plant diversity and the factors influencing those changes after revegetation at a gully head were studied in order to provide a relevant foundation for the assessment of the benefits of soil and water conservation in the loess tableland. [Methods] Herbaceous plant diversity at a gully head was measured and soil property indexes related to the topsoil (0—10 cm and 10—25 cm) were determined by selecting grassland gully heads with vegetation restoration periods of 5, 13, 18, and 22 years in the Baicao Tableland. Farmland was used as the control. [Results] The Patrick richness index initially increased with increasing number of vegetation restoration years, and then stabilized. The Shannon-Wiener index showed a continuously increasing trend, and the Shannon-Wiener index values in 18 and 22 years of vegetation restoration were greater than at 13 years of restoration. However, the differences were not significantly different. The Pielou evenness index exhibited a fluctuating trend of increasing, and then decreasing, then increasing again, reaching a maximum value (0.89) in 22 years of recovery. The soil bulk density in both the 0—10 cm and 10—25 cm layers reached a minimum value in 22 years of recovery, with significant decreases of 13.1% and 17.8%, respectively, compared with values observed for farmland (p＜0.05). The soil organic matter content, water-stable aggregate content, mean weight diameter of aggregates, and saturated hydraulic conductivity in the 0—10 cm and 10—25 cm layers significantly increased with increasing number of vegetation restoration years, and soil factors between the two soil layers demonstrated significant differences at each restoration year. Correlation analysis indicated a negative correlation between herbaceous plant diversity indicators and soil bulk density, and a significant positive correlation (p＜0.05) with soil organic matter content, water-stable aggregate content, mean weight diameter of aggregates, and saturated hydraulic conductivity. Redundancy analysis revealed that soil aggregate content was an important factor in explaining herbaceous plant diversity variation. [Conclusion] Vegetation restoration could significantly increase herbaceous plant diversity, and could play an important role in improving soil properties at a gully head in the loess tableland.

Abstract:[Objective] The soil quality changes caused by land from hill citting in Beishan Mountain in Lanzhou City were assessed in order to provide a scientific basis and suggestions for land-cutting and land-reclamation projects and ecological benefit evaluation in this area. [Methods] We selected four land use types for evaluation: original cultivated land, forest land, grassland, and newly reclaimed land created by mountain cutting in Beishan Mountain of Chengguan District, Lanzhou City. We collected soil physical properties, chemical properties, and root biomass samples. We screened the minimum data set based on principal component analysis (PCA), and evaluated the soil quality of Beishan Mountain through the soil quality index. [Results] ① Based on the principal component analysis of the full data set of soil quality (including 12 physical and chemical indicators), a minimum data set consisting of bulk density, available phosphorus, available potassium, total nitrogen, and pH value was constructed. ② Soil quality index for the four land use types followed the order of cultivated land＞forest land＞newly reclaimed land＞grassland. Hill cutting significantly affected soil water conservation, organic matter accumulation, total nitrogen, available potassium, etc. ③ The correlation coefficient between the minimum data set and the full data set was 0.66, and the minimum data set better evaluated soil quality (p＜0.01). [Conclusion] Cultivated land and forest land in Beishan Mountain had better soil quality than grassland and newly reclaimed land. Water holding capacity and nutrient accumulation capacity of newly reclaimed land was lower than that of cultivated land and forest land, which is a key area for future vegetation restoration and reconstruction. Land cutting on mountains should take place on grasslands as far as possible, and attentions should be given to the protection of original cultivated land and forest land.

Abstract:[Objective] The effects of plant fiber sand barriers, cattle and sheep dung barriers, and sand barriers comprised of cattle and sheep dung combined with plant fiber were studied in order to create effective sand barriers for the restoration of desertified grassland in the alpine area at Maqu County, Gansu Province. [Methods] Sand barriers made of plant fiber, cattle and sheep dung, and cattle and sheep dung combined with plant fiber were installed in the alpine area at Maqu County. Plant and soil characteristics in the grassland before and after installing the sand barriers were compared. [Results] ① Sand barriers made of cattle and sheep dung, and made of cattle and sheep dung combined with plant fiber produced good effects with regard to vegetation restoration. The average plant community cover grew from 7.28% to 48.21% and 58.29%, respectively, and the number of species increased from 4 to 11. Plants grew taller, increasing from an average of 6.67 cm to 35.17 cm and 30.70 cm, respectively. Average plant dry weight increased from 4.46 g/m² to 81.17 g/m² and 80.70 g/m², respectively. The plant dieback rate dropped from 9.55% to 7.0% and 6.80%, respectively; ② Cattle and sheep dung sand barriers as well as cattle and sheep dung sand barriers combined with plant fiber greatly boosted soil nutrients at the 5 cm depth. Total nitrogen increased from 0.154 g/kg to 0.370 g/kg and 0.491 g/kg, respectively. Soil alkaline hydrolyzed nitrogen rose from 4.78 mg/kg to 13.99 mg/kg and 19.78 mg/kg, respectively. Available phosphorus increased from 1.64 mg/kg to 5.54 mg/kg and 6.20 mg/kg, respectively. Available potassium increased from 21.07 mg/kg to 55.37 mg/kg and 56.90 mg/kg, respectively. [Conclusion] Considering the vegetation restoration effects, costs, and degradation factors, cattle and sheep dung sand barriers are the ideal technique for vegetation restoration of desertified grassland in alpine area of Maqu County.

Abstract:[Objective] The effects of soil texture reconstruction on soil hydraulic properties in the Shanxi-Shaanxi-Inner Mongolia region, and the improvement effect of different amounts of arsenic sandstone on sandy loess were studied, in order to providing theoretical basis for the restoration work of sandy land in the region. [Methods] Pisha sandstone and sandy loess were combined in different ratios, and the saturated water conductivity, soil water characteristic curve, available soil water-holding capacity, and other indexes were measured. [Results] ① As the proportion of Pisha sandstone increased (0%~100%), the content of sand particles (0.05~2 mm) in the reconstructed soil decreased by 8.1%~33.5%, while the content of silt particles (0.002~0.05 mm) and clay particles (＜0.002 mm) increased by 5.2%~21.0% and 2.9%~12.5%, respectively. When the content of Pisha sandstone in the reconstructed soil reached 75%, the reconstructed soil texture changed from sandy loam to loam. The K_s value of the reconstructed soil at 10 ℃ was 4.07×10^-6 m/s, which is similar to the K_s value of a typical Huangmian soil under natural field conditions; ② The effects of Pisha sandstone content on the soil water characteristic curve occurred primarily in the range of high suction. When the ratio of sandy loess to Pisha sandstone was 25∶75, the soil water-holding capacity was the largest among seven ratio treatments; ③ The soil water retention capacity of reconstructed soil tended to increase as the proportion of Pisha sandstone increased. Saturated water content (θ_s) and residual water content (θ_r) values also increased. [Conclusion] The available soil water-holding capacity of the reconstituted soil was greater than observed for the other treatments when the ratio of sandy loess to Pisha sandstone was 25∶75 (soil bulk density was 1.41 g/cm³). This ratio is recommended as an optimal soil reconstruction method for this region.

Abstract:[Objective] The spatial distribution characteristics of surface soil particles under different vegetation patterns at Pisha sandstone area in tipical area in Ordos City, Inner Mongolia Autonoous Region, and the sorting and transportation mechanisms of water erosion for soil particles were studied in order to provide a theoretical basis for the restoration of the ecological environment in this area. [Methods] The study was conducted with in-situ monitoring of field runoff plots. The effects of different vegetation patterns on the spatial distribution of surface soil particles on Pisha sandstone slopes under natural rainfall conditions were determined by combining three-dimensional laser scanning and geostatistics. [Results] ① The uniformly distributed vegetation pattern effectively inhibited runoff and sediment production on the slope. The erosion area, average runoff, and average sediment volume were 5.35%, 63.16%, and 76.47%, respectively, lower than observed for the bare slope. ② Under the uniformly distributed vegetation pattern, the contents of soil clay and silt particles were 1.3% and 2.2%, respectively, greater after rain than before rain, and sand content was 3.2% lower. The content of sand particles increased after rain by 5.8% and 15.3% in the randomly distributed and aggregated vegetation patterns respectively, resulting in a coarsening of soil texture. ③ Different vegetation patterns were the main factors causing the spatial variation of soil particles. The uniformly distributed and randomly distributed vegetation patterns increased the nugget coefficients of silt and sand particles after rainfall, and decreased the spatial autocorrelation. The aggregated vegetation pattern decreased the nugget coefficients of clay and silt particles from 95.06% and 83.89% to 0.07% and 0.06%, showing a strong spatial autocorrelation. [Conclusion] A uniformly distributed vegetation pattern produced suitable soil and water conservation benefits on an arsenic sandstone slope, significantly reducing runoff and sediment production and inhibiting soil coarsening.

Abstract:[Objective] The effects of humic acid on seed germination and seedling growth of Haloxylon ammodendron seeds under NaCl stress were studied in order to provide technical supports for ecological restoration in arid mining areas. [Methods] Germination and seedling growth of Haloxylon ammodendron seeds were measured under five NaCl stress concentrations and five humic acid additions. [Results] Application of humic acid at appropriate levels significantly increased seed germination rate, alleviated salt stress during the seed germination, increased the growth of primary roots, and reduced seedling damage caused by salt stress. Under 1.0 mol/L NaCl, humic acid at 700 mg/kg produced the best alleviating effect. For this treatment, germination rate, germination potential, root length, fresh mass of young roots, and dry mass of young roots were 10%, 11.12%, 1.77 cm, 4.84 mg, and 4.03 mg, respectively, greater than observed for the control treatment. [Conclusion] Humic acid can be used as a regulator of seed germination and seedling growth in the ecological restoration of arid mining areas. Humic acid has good potential for use as a regulator of saline soils in arid mining areas.

Abstract:[Objective] The effects of ryegrass growth on the physical properties and shear resistance of a mixed substrate were studied in order to provide a scientific basis for the rapid restoration of coal gangue hill vegetation and for the prevention of soil erosion. [Methods] The physical structure of gangue is poor and the nutrient content is low. Ryegrass was planted in pots to which phosphogypsum and mycorrhizal residue were added to determine the effect of ryegrass growth on the physical properties and shear resistance of a mixed substrate. [Results] ① The addition of different proportions of phosphogypsum and mycorrhizal slag significantly increased the growth of ryegrass. Height, aboveground dry biomass, root weight density, and chlorophyll content of ryegrass on the mixed coal gangue substrate consisting of 20% phosphogypsum and 10% mycorrhizal slag had the best effect, followed by the mixed substrate consisting of 10% phosphogypsum and 10% mycorrhizal slag. ② The addition of phosphogypsum and slag significantly increased the aeration and water-holding capacity of the gangue mixed substrate in which the natural water content, total porosity, capillary porosity, and non-capillary porosity of the gangue mixed substrate with 20% phosphogypsum and 10% slag were increased by 18.88%, 14.18%, 13.12%, and 18.08%, respectively, and the bulk density was decreased by 24.76% compared with the respective values observed for the gangue mixed substrate with only 10% slag. ③ The shear strength of the gangue mixed substrate with 20% phosphogypsum and 10% mycorrhizal slag increased by 71.71%, and the cohesion and internal friction angle increased by 102.84% and 45.05%, respectively, compared with the mixed substrate having only 10% mycorrhizal slag. [Conclusion] The coal gangue mixed substrate with ryegrass root complex having 20% phosphogypsum and 10% mycorrhizal residue had the greatest shear resistance and was beneficial for controlling soil erosion in coal gangue hills.

Abstract:[Objective] The effects of restoration years on plant diversity and soil chemical characteristics of alpine metal mine dumps were studied in order to provide scientific guidances for further exploring the plant succession trends and optimizing the plant restoration process of alpine mine dumps. [Methods] The study was conducted at the Delny copper mine, Guoluo Xizang Autonomous Prefecture, Qinghai Province. Plant species composition and diversity and soil chemical properties of ten alpine metal mine dump slopes varying in recovery years (1—12 years) were measured by quadrat survey and soil chemical analysis. Relationships between four α plant diversity indexes (Patrick richness index, etc.), eight soil chemical property indexes (total nitrogen, etc.) and number of recovery years were determined. [Results] The number of families, genera, and species of plants at the dump sites increased with increasing number of recovery years due to the continuous invasion of natural plants. There were differences in plant species composition and community characteristics of the dumps in different years. The Patrick richness index increased as a power function as number of recovery years increased. The Shannon-Wiener diversity index, Simpson diversity index, and Pielou evenness index initially increased with increasing recovery year, and then decreased, and all indexes changed with time following quadratic relationships. The contents of total nitrogen, total phosphorus, total potassium, alkaline hydrolysis nitrogen, and rapidly available phosphorus initially increased with increasing number of recovery years, and then decreased. The contents of rapidly available potassium and organic matter increased as a power function as number of recovery years increased. pH value decreased as number of recovery years increased. The four α plant diversity indexes were positively correlated with the contents of soil total nitrogen, total phosphorus, total potassium, alkaline hydrolysis nitrogen, rapidly available potassium, and organic matter, but negatively correlated with the contents of rapidly available phosphorus and with the pH values. [Conclusion] When the recovery period was 12 years, the plants in the dump area were still in the successional development stage and had not yet reached a stable state. There was an obvious interaction between plant succession and soil nutrients. It is suggested that high nitrogen, high phosphorus and low potassium slow release compound fertilizer should be used for plant restoration in mine dumps.

Abstract:[Objective] The objective of this study was to determine the impact of the combined application of PAM (polyacrylamide) and humic acid on the vertical infiltration characteristics of purple soil in order to provide theoretical references for water and soil conservation, soil improvement, water regulation, and efficient utilization of agricultural water resources in the purple soil region of western Sichuan. [Methods] An indoor soil column simulation experiment was conducted with one check treatment (CK, no mixing), three PAM application levels (PAM-1: 1%, PAM-3: 3%, PAM-5: 5%), and two humic acid application levels (HA-1: 0.1%, HA-5: 0.5%). Infiltration rate, cumulative infiltration volume, and wetting peak transport distance were measured and the variation characteristics were analyzed. The infiltration process was simulated and analyzed using infiltration models. [Results] Compared with CK, the other treatments effectively reduced water infiltration rate, and the infiltration rate gradually decreased with increasing application rate. Under the same cumulative infiltration amount, the infiltration time of each treatment (except H₁P₁) was greater than that of CK, among which H₁P₃ and H₂P₃ were 14.7 times and six times, respectively, the infiltration time of CK. H₁P₁ had an infiltration time that was 25% less than CK. Within 220 min, the wetting peak transport distances in all treatments were lower than that of CK, with the lowest wetting peak transport distance (4.98 cm) in H₁P₃, which was significantly shorter (57.67%) than that of CK. Model applicability followed the order of general empirical formula＞Kostiakov formula＞Horton formula＞Philip formula. However, the steady permeability rate (f_s) of the general empirical formula deviated from the measured values. [Conclusion] PAM mixed with humic acid can effectively decrease infiltration rate, reduce cumulative infiltration, and slow down the transport distance of the wetting peak. The infiltration reduction effect became more evident with increasing application amount. The optimal treatment was H₁S₃ (humic acid 0.1 g/g and PAM 3 g/g. Compared with other formulas, the Kostiakov formula was more suitable for describing the soil water infiltration process in the study area.

Abstract:[Objective] The water chemical characteristics and irrigation suitability evaluation of surface water body in areas around Yuelu Mountain in Xiangjiang River basin were analyzed in order to provide theoretical support for ecological environment protection and scientific decision-making of integrated water resources management in this area. [Methods] The study was conducted in the area around Yuelu Mountain. Water samples of precipitation, mountainous creek water, and Xiangjiang River water were collected from December 2020 to November 2021. The water chemical characteristics and factors influencing each water body were analyzed by using Piper diagram, Gibbs diagram, end-member diagram, etc. [Results] The main anions and cations of precipitation were Ca²⁺, K⁺, SO^2-₄, and NO^-₃, with no obvious water chemical type. The main anions and cations of mountainous creek water were Ca²⁺ and NO^-₃, and the water chemical types were Cl-Ca·Mg and Cl-Ca. The main anions and cations of Xiangjiang River water were Ca²⁺ and HCO^-₃, and the water chemical type was HCO₃-Ca. Mountainous creek water was primarily influenced by atmospheric precipitation and carbonate rock weathering, whereas Xiangjiang River water was more influenced by carbonate rock weathering. [Conclusion] Na⁺%, SAR, and RSC indexes, and the USSL diagram and Wilcox diagram results were good. The mountainous creek water and Xiangjiang River water in the areas around Yuelu Mountain are suitable for irrigation and are not prone to salt or alkali damage.

Abstract:[Objective] The water use characteristics of plants and their responses to environmental changes in a tunnel construction area at the eastern margin of Qinghai-Xizang Plateau were studied in order to provide a reference for soil and water conservation in this ecologically fragile region influenced by both nature and human activity. [Methods] The δ²H and δ¹⁸O values of xylem water of typical plants and potential water sources in different months from 2020 to 2021 in a tunnel construction area with an altitude of 3 230 m were measured. The MixSIAR model was used to calculate the proportion of plants absorbing water from each potential water source. The proportional similarity index (PS index) between every two plants was calculated to compare the water competition relationship between different species. [Results] Shallow soil water (0—40 cm) was the main water source for Festuca rubra, Picea likiangensis var. balfouriana, and Quercus spinosa. Populus szechuanica mainly absorbed middle and deep (40—200 cm) soil water. The uptake proportions from shallow soil water by plants in August and October 2021 were significantly lower than during the same period in 2020. For P. likiangensis var. balfouriana, there were significant positive and negative correlations (p＜0.05) between soil water utilization ratio and soil water content in the 0—40 cm and 40—80 cm layers, respectively. The water competition relationships between P. szechuanica and the other three plants in October 2020 were weak, with the PS index ranging from 0.19 to 0.54. [Conclusion] Changes in soil moisture content and external temperature were the main factors influencing the variation of vegetation water use strategy at the eastern margin of the Qinghai-Xizang Plateau, and the importance of these two factors varied among different species. Loss of soil and soil water due to tunnel construction resulted in a decrease in soil water content after tunnel construction. The contribution of shallow soil water to plants was lower after tunnel construction than before tunnel construction. Therefore, the impact of tunnel construction on soil water and vegetation adaptation mechanisms in ecologically fragile areas needs to be of concern.

Abstract:[Objective] The infiltration characteristics of urban green space runoff and the infiltration parameters for sponge facilities were studied in order to provide theoretical support for the construction of sponge facilities in built-up urban green space areas. [Methods] Taking Nanchang City, Jiangxi Province as a case area. Soil characteristic parameters were calculated by particle size distribution (PSD) and the soil-plant-air-water (SPAW) model. The Horton infiltration equations were fitted to single-ring infiltration field measurements of infiltration rate using Matlab to obtain the initial and stable infiltration rates and the attenuation coefficient. Soil water tension and unsaturated hydraulic conductivity were estimated by HYPROP2 and HYPROP-data evaluation software (HYPROP-DES). [Results] The stable infiltration rate was basically reached the stage of stable infiltration 5—10 min after the start of on-site infiltration, and most of the observed stable infiltration rates were less than 100 mm/h. The infiltration process was greatly affected by differences in hydrological soil groups and human disturbance. It took about seven days after full saturation for the infiltration rate of the soil to recover to the initial state. Based on the RECARGA model, a technical route for green space sponge facility reconstruction under the concept of sponge city was constructed. [Conclusion] The three methods can be used to deduce the process of urban green space soil infiltration and can improve the design accuracy of key parameters of sponge facilities. Initial water content and site factors need to be considered in the process of model calculations.

Abstract:[Objective] The changes in ecological environmental quality in the Taiyuan urban agglomeration from 2002 to 2021 were studied in order to provide scientific recommendations for sustainable urban development and green transformation. [Methods] We used the GEE platform, MODIS images, and principal component analysis to construct the ecological remote sensing index (RSEI) by coupling greenness, humidity, heat, and dryness. The spatial properties of ecological quality changes in the Taiyuan urban agglomeration were studied by using combining stability analysis and spatial autocorrelation analysis. The influence of various factors on RSEI was quantified by geographic detectors. [Results] The contribution rate of the first principal component was greater than 75% in all years, indicating that RSEI values extracted based on the first principal component could comprehensively characterize the ecological environmental quality in the study area. The ecological environmental quality of the Taiyuan urban agglomeration showed an overall upward trend from 2002 to 2021, increasing from 0.433 to 0.488, with a growth rate of about 0.0029/yr. The ecological improvement area accounted for 17.1%, mainly located in Lanxian County and Jingle County in the northwest. There was obvious spatial autocorrelation in the change of ecological environmental quality in the study area, and the Moran’s I index was 0.729. The high-high and low-low aggregation areas basically coincided with the ecological improvement and degradation areas, respectively. The ecological environmental quality of the Taiyuan urban agglomeration was significantly correlated with the climatic factors of relative humidity, air temperature, and potential evapotranspiration. [Conclusion] The ecological environmental quality of the Taiyuan urban agglomeration has improved from 2002 to 2021, and the vegetation coverage and urban expansion factors have had great impacts. RSEI can effectively monitor changes in the ecological environmental quality in the study area.

Abstract:[Objective] The soil erosion under different conservation engineering measures was precisely predicted in order to provide a technical and theoretical basis for formulating appropriate conservation measures in Northwest Liaoning Province. [Methods] We used experimental plot data from 2011 to 2021 that included maximum precipitation intensity in 30 and 60 minutes (I₃₀ and I₆₀), precipitation duration (T), and precipitation (P) to construct a long short-term memory neural network model (LSTM) to predict soil erosion under three different water-and-soil conservation measures (horizontal trough, fruit tree terrace, terrace). Results from the LSTM model were compared with the results of three classical machine learning models, i.e., artificial neural networks (BP), random forest (RF), and support vector machine (SVM). [Results] ① The impacts of I₃₀, I₆₀, T, and P on soil erosion were different for the three different conservation conditions, but in general, I₃₀, I₆₀, and T had significant impacted on soil erosion. ② The normal relative mean square error (NRMSE) of the BP model under the three different water-and-soil conservation measures were all greater than 0.2. ③ Compared with the RF and SVM models, the LSTM model decreased NRMSE by 0.04~0.08, 0.02~0.08, and 0.05~0.08 under the three different water-and-soil conservation measures, respectively. ④ The LSTM model based on only two input features (I₃₀ and T) had a similar accuracy with the LSTM model based on four input features in predicting soil erosion. [Conclusion] The LSTM model was used to predict the soil erosion amount based on the maximum 30 min rainfall intensity and rainfall duration, and the prediction accuracy was higher than other traditional models. This shows that the LSTM model can be popularized and applied in the accurate simulation of soil erosion and the determination of soil and water conservation measures in similar areas.

Abstract:[Objective] The value change and radiation effect of the regional aquatic ecosystem service function were analyzed in order to provide a scientific basis for sustainable development of regional water resources and ecological compensation of a river basin. [Methods] ArcGIS software was used to extract land use data for Luoyang City, Henan Province from 2000 to 2020 in order to obtain the area of water type. The emergy method was used to quantify and analyze the changes of aquatic ecosystem service functions, and the functional radiation was analyzed by the break point model. [Results] From 2000 to 2020 (in five-year time steps), the total emergy values of aquatic ecosystem services at Luoyang City were 8.01×10²¹ sej， 1.29×10²² sej， 1.27×10²² sej， 1.29×10²² sej， and 1.31×10²² sej, respectively, with a general increasing trend. Among these emergy values, the focus of service composition had shifted from supply function to cultural function. In this system, biodiversity protection, aquatic product production, water resource supply, water resource regulation, and leisure and entertainment functions were dominant. Leisure and entertainment functions have become core functions. In addition, the main transfer areas of the aquatic ecosystem service function in Luoyang City were Songxian County and Luoning County, with total outward transfer values of 3.10×10²⁰ sej and 3.21×10²⁰ sej, respectively. The main transfer areas were Luanchuan County, Yiyang County, Yichuan County, and Ruyang County. [Conclusion] Greater attention will need to be given to ecological protection of water, increasing support and guidance for regional tourism, and reasonably carrying out ecological compensation in areas similar to Luoyang City to promote the coordinated development of the economy, society, and ecology in various regions.

Abstract:[Objective] The changes in the soil conservation function of the ecosystem of Shenfu-Dongsheng mining area from 2000 to 2020, and the present situation and existing problems of the ecosystem function in the mining area were studied. The ways to improve the ecological function of construction projects concentrated in semi-arid areas were summarized. The results will provide a reference for guiding the coordinated development of ecology and economy at production and construction project areas in semi-arid areas. [Methods] The Chinese soil loss equation (CSLE) and a wind erosion model were used to calculate soil conservation under water erosion and wind erosion based on grid cells in Shenfu-Dongsheng mining area during different periods (2000, 2010, and 2020). The spatial and temporal changes of soil conservation for different land use types, different vegetation coverages, and different mines were determined. [Results] ① Potential soil erosion in Shenfu-Dongsheng mining area was 3.76×10⁶ t/a. The amount of soil conservation increased from 2.30×10⁶ t in 2000 to 3.17×10⁶ t in 2010. The amount of wind erosion reduction in the mining ecosystem increased significantly. ② The area of cultivated land, sandy land, and bare land in the mining area decreased continuously from 2000 to 2020, while the area of gardens and grassland increased continuously, and the soil conservation of gardens and grassland increased from 1.80×10⁶ t/a to 2.78×10⁶ t/a. ③ Vegetation in the mining area changed from low coverage to medium-high coverage. Soil conservation of medium and medium-high coverage forestlands accounted for 67.12% of the total soil conservation of the mining ecosystem in 2020. ④ The soil conservation capacity of different mines with different degrees of governance significantly increased. [Conclusion] The soil conservation function in Shenfu-Dongsheng mining area increased significantly from 2000 to 2020. Production and construction projects in semi-arid areas can improve the ecological environment through the use of effective ecological measures, and achieve a win-win situation between economic development and ecological improvement by exploring ways to realize an ecological economy.

Abstract:[Objective] The adaptability and landscape application effects of rainwater garden plants were studied using a multi-index from a biodiversity perspective in order to provide a scientific reference for the optimal allocation of rainwater garden plant communities in Beijing City. [Methods] A field investigation was conducted to analyze and understand the diversity characteristics of rain garden plant communities. Quantitative analysis was used to construct a landscape evaluation model of rain garden plant communities to classify and evaluate 15 typical rain garden plant communities. [Results] ① There were 45 species of rain garden plants belonging to 43 genera and 20 families in Beijing sponge city pilot area. The dominant plant families were mainly Compositae, Gramineae, Liliaceae, Crassulaceae, etc. There was little difference in the index values of different plots in the pilot area, the richness of herbaceous plants was similar, and the concentration of plant species was consistent in the investigated plots. ② The comprehensive evaluation of the rain garden plant community landscape in the pilot area was at a high level, and the evaluation of the rain garden plant community landscape was significantly higher than that of road rain garden plant community landscape. Due to the influence of the pollution in surface runoff in the region causing differences in plant growth, the plant community structure was different at different sites. [Conclusion] In the future, it will be necessary to strengthen regular monitoring and evaluation of constructed rain garden plant communities, screen out dominant species, and summarize the stable plant community allocation patterns and maintenance management methods in order to provide a reference for the selection and configuration of rain garden plants in Beijing City.

Abstract:[Objective] Soil disintegration characteristics around the Huangdeng hydropower station reservoir on the Lancang River were studied in order to provide a basis for the prevention and control of soil erosion around the reservoir, reduce the sediment entering the reservoir, and provide a reference for soil and water conservation and ecological restoration in the Three Rivers parallel flow area. [Methods] We used a combination of field survey sampling and laboratory experiments to determine the disintegration rate and physicochemical properties of five typical soils around the reservoir, and to analyze the correlation between soil disintegration rate and soil properties. [Results] Soil disintegration (ranging from strong to weak) was observed to follow the order of red soil, yellow brown soil, siltation soil (top), siltation soil (bottom), and purple soil. Under the saturated soil condition, the ratio of average disintegration rates was 8.76∶5.65∶5.24∶4.29∶1. Soil disintegration was closely related to the soil liquid plastic limit, mechanical composition, porosity, and other properties; There was a significant negative correlation between the average soil disintegration rate and both soil silt and liquid plastic limit. A significant positive correlation was observed between soil disintegration rate and both the content of soil coarse sand and porosity. When the initial moisture content (ω₀) was high, soil disintegration rate was significantly negatively correlated with soil organic matter, hydrolytic nitrogen, available phosphorus, and total nitrogen. The linear equations between soil disintegration rate and total nitrogen, silt, and liquid plastic limit for the five soil types in the saturated state had a high fit degree (R²>0.9). [Conclusion] When ω₀ was saturated for red soil, yellow brown soil, siltation soil, and purple soil, soil total nitrogen content, silt content, and liquid plastic limit can be used to predict soil disintegration. Forests and grasslands should be established and maintained or engineering measures should be implemented to treat the red soil and yellow brown soil around Huangdeng power station reservoir. Suitable water-zone plants should be planted on siltation soil. Measures should be taken to strengthen the protection of purple soil so that it is suitable for agriculture and forests. Taking these measures will provide more agricultural and forestry land resources for rural revitalization in the reservoir area.

Abstract:[Objective] An ecological security pattern with regional characteristics was constructed in order to provide a scientific reference for the protection of the ecological environment and the construction and zoning management of ecological security patterns at the county level. [Methods] Referring to the Guide for Delimitation of Ecological Protection Red Lines, we selected four indicators for quantitative evaluation of ecology at Yongchun County in Fujian Province: soil and water conservation, water conservation, biodiversity protection, and forestry protection. The minimum cumulative resistance (MCR) model and the gravity model were used to build the wildlife corridor, evaluate the importance of the corridor by grades, extract ecological nodes, and construct the ecological security pattern of Yongchun County. [Results] A total of 11 ecological source areas were identified in Yongchun County, with a total area of 64.8 km², accounting for 4.45% of the total area. Fifty-five ecological corridors and 27 ecological nodes were constructed, including 25 important corridors and 30 secondary corridors that were concentrated in the central and eastern regions with a reticular distribution. [Conclusion] According to the results of ecological source identification and corridor division, an ecological security pattern framework for Yongchun County was constructed, with source as the core, corridor as the network, and ecological nodes as the focus. The interaction intensities between ecological source areas were obviously different. The distribution densities of source areas and the stability of the wildlife corridor in the central region were greater than in the western region, and should be regarded as key protection areas.

Abstract:[Objective] The temporal and spatial variation characteristics of cultivated land types and their influencing factors were studied in order to provide a theoretical basis for policy-making regarding cultivated land protection, sustainable agricultural development, and soil and water conservation in this region. [Methods] The study was conducted for Laiyang City in Shandong Province. High-resolution remote sensing data from 2019 to 2021 were combined with field observations in order to divide cultivated land types into five categories: irrigated land, arid flat land, arid sloping land, arid terrace land, and abandoned land. We determined the spatio-temporal distribution and variation of different types of cultivated land and their influencing factors, and identified the variable regions by using dynamic change degree, land use transfer matrix, and geographic detector. [Results] ① Cultivated land of Laiyang City accounted for 54.44% of the total land area, with an overall distribution pattern of more cultivated land in the southern and western areas of the city, and less in the northern and eastern areas of the city. Arid terrace land accounted for 61.19% of the total cultivated land area, which was followed by irrigated land, arid flat land, and arid sloping land. Abandoned land accounted for only 0.33% of the total cultivated land area. ② The analysis of single factor detector showed that landform type, slope, and soil type were the three main factors affecting the distribution of cultivated land type, and the (q values) were all above 0.3 when the factors interacted with each other. ③ From 2019 to 2021, the net rate of cultivated land conversion was -0.25%. The total area decreased 4.73 km², mainly due to conversion of arid terrace land, arid sloping land, arid flat land, and irrigated land to construction land. This conversion mostly occurred in the urban area located in the low hilly area with a slope of less than 5° and a brown soil type. [Conclusion] The mainly cultivated land type is dry terraced field. Cultivated land distributed in low hilly area with gentle slopes (representing cultivated land with good quality) is easy to change. As the area continues to decrease, the protection measures of high-quality cultivated land should be strengthened.

Abstract:[Objective] The construction method for an urban ecological network based on morphological spatial pattern analysis (MSPA) and ecological protection importance evaluation were studied in order to provide a scientific reference for the planning and construction of urban ecological network. [Methods] The importance of ecological protection at Mudanjiang City, Heilongjiang Province was evaluated using the topological superposition of MSPA analysis results, and the birth source area was comprehensively obtained. We used the minimum resistance model to extract potential ecological corridors in the study area, and combined them with gravity models for importance classification. We optimized the ecological network structure from three aspects: source supplement, corridor supplement, and stepping stone supplement. [Results] ① The MSPA analysis results showed that the core area of Mudanjiang City had the highest proportion of landscape types (accounting for 87.41%) and that forest land was the main landscape type. ② There were 10 main ecological sources and six secondary ecological sources at Mudanjiang City. ③ There were 16 potential important ecological corridors and 104 general ecological corridors at Mudanjiang City. ④ Ecological network closure (α index) before optimization was 0.53, and 0.66 after optimization. Number of network connections (γ index) was 0.69 before optimization, and 0.77 after optimization. Line point rate (β index) was 2.0 before optimization, and 2.26 after optimization. [Conclusion] The application of the comprehensive MSPA analysis method and the ecological protection importance evaluation method in ecological network construction can help improve the structure and functionality of the ecological network.

Abstract:[Obiective] The spatial distribution pattern of waterfowl ecological corridors in Dongguan City, Guangdong Province were studied in order to provide a realistic basis for its ecological restoration.[Methods] We considered waterfowl as the key species of Dongguan City. The research was carried out by using the minimal cumulative resistance (MCR) model, the centrality principle of habitat and connection, and the circuit theory based on water data and resistance surface composition data of Dongguan City. [Results] A total of 26 ecological corridors with a total length of 259.91 km were constructed in Dongguan City, of which six, fifteen, and five were important, more important and generally important ecological corridors respectively, and the important and general ecological corridors were centrally distributed, while the more important ecological corridors were dispersed. The spatial locations of the key obstacles were characterized as areas with serious anthropogenic disturbances. [Conclusion] In the perspective of spatial layout of ecological corridors, the main purpose is to optimize the urban background conditions and maintain the balance of the entire urban ecological space. In the perspective of corridor connectivity enhancement, it is suggested to give full play to the self-generated ecological function of the corridor as a guide to ensure the continuity of the overall corridor network space. In terms of restoration of obstacles, the intensity of human activities should be reduced to alleviate the obstruction of waterbirds passing through the corridor.

Abstract:[Objective] The mechanism underlying the spatial and temporal variation characteristics of regional forest cover was studied by using the source-sink landscape principle in order to provide a basis for decision-making regarding forest resource conservation. [Methods] We collected datasets of land use/cover change (LUCC), digital elevation model (DEM), and road traffic in Fujian Province for 2010 and 2020, and identified landscapes (i.e., source landscapes and sink landscapes) that either promoted or prevented/delayed forest loss. The comprehensive location-weighted landscape contrast index (LCI') was calculated by integrating three landscape spatial elements (elevation, slope, and distance). The spatial pattern change of forest loss in Fujian Province was systematically determined at the provincial and city scales. [Results] At the provincial scale, LCI' was 0.117 and 0.152 in 2010 and 2020, respectively. The source landscape contributed more to forest loss, and the most influential of the spatial elements of the landscape was distance, followed by slope and elevation. There were differences in calculated LCI' at the city scale, with relatively small LCI' in Nanping, Sanming, and Longyan (＜0) and large LCI' in Fuzhou, Putian, Xiamen, Quanzhou, and Zhangzhou (＞0). The LCI' of all cities in Fujian Province in 2020 had increased slightly since 2010, with Fuzhou having the largest increase (0.070) and a more dramatic forest loss relative to other cities. [Conclusion] There have been different degrees of forest loss in various regions of Fujian Province during the last decade. The LCI' combined the landscape pattern with process, and effectively reflected changes in forest spatial patterns in Fujian Province from 2010 to 2020.

Abstract:[Objective] An assessment framework for ecological security evaluation of natural resources was constructed to further analyze its evolution law in response to urbanization, in order to provie references for regional territorial space optimization and ecological civilization construction. [Methods] Based on the correlation between ecosystem health and ecosystem services, an ecological security framework based on “contribution, vigor, organization and resilience” was constructed. By using the InVEST model, landscape indices, and the Delphi method to evaluate the ecological security of Wuhan City in 2000 and 2021, the temporal and spatial evolution of ecological security was also analyzed. [Results] ① The ecological security index of Wuhan City was 0.394 4 in 2000 and 0.374 5 in 2021. Ecological security level showed a spatial distribution pattern of “low in the middle and high in the surrounding area”. The ecological security level of the Huangpi District was the highest. ② From 2000 to 2021, the overall ecological security of Wuhan City showed a downward trend. The declining areas were mainly located in a ring along the edge of the central urban area. The distribution of the “low security” area tended to gradually expand from the central core area. The transition of areas from “medium ecological safety” to “low ecological safety” and from “high ecological security” to “medium ecological safety” was widespread. [Conclusion] Urban expansion has resulted in declining ecological security of natural resources. Therefore, territorial space planning should be further strengthened, including punishments for illegal occupation of ecological land and strengthening the protection of ecological space.

Abstract:[Objective] The evolution characteristics and driving capacity of ecological zones in the middle and lower reaches of the Hanjiang River basin were studied in order to provide a scientific basis for the sustainable development of the water ecological environment of this region. [Methods] We used the InVEST model, clustering, and correlation analysis to conduct a multi-year analysis of ecosystem service changes and zoning characteristics based on water environment-related ecosystem services, and to study the association characteristics of ecosystem services and environmental variables within each ecological zoning transfer area. [Results] ① In 2010, 2015, and 2020, the dominant ecological zoning areas were the third, third, and second category areas, respectively, with area shares of 70.54%, 72.92%, and 45.53%. The second category areas had greater water content and soil conservation intensity than the third category areas. ② Correlation analysis showed that rainfall changes were significantly correlated with changes in water conservation and soil conservation intensity. Changes in the areas of agricultural land and construction land for each land use type were significantly correlated with changes in ecosystem services. ③ Regarding the contribution rate of explanatory variables in the areas where ecological zoning shifts occurred, the areas with larger explanatory rates of rainfall changes were mainly located in the central and southern parts of the study area, and the areas with larger explanatory rates of land use changes were mainly located in the western and northwestern parts of the study area. [Conclusion] Rainfall changes had a greater impact on ecosystem services and ecological zoning changes than land use changes. By identifying the key drivers of ecological zoning changes, the stability of ecosystems can be enhanced in the future with targeted optimization of land use type layout or construction of green and gray infrastructure.

Abstract:[Objective] The objective of this study was to determine the efficiency of land and water resource allocation in grain production of China and its influencing factors in order to provide theoretical support for ensuring food security. [Methods] Using the DEA model, taking 30 provinces (cities) as samples from 2005 to 2020, an empirical analysis of land and water resource allocation of Chinese grain production was carried out and analyzed. [Results] In the time series, the allocation efficiency of land and water resources showed a fluctuating growth. From the perspective of provinces and cities, the economic utility coefficients of Henan and Jilin Province were both 1, and DEA had a good effect. In the grain production of Anhui, Gansu, and Ningxia, the efficiency of land and water resource allocation was significantly improved by 1%. The four provinces of Chongqing, Zhejiang, Qinghai, and Guangxi all showed significant declines; In terms of spatial distribution, the distribution efficiency of land and water resources in this area was as follows: Northeast, East China, Central China, West China. Among them, Henan and Jilin had the highest soil resource utilization efficiency, and Qinghai had the lowest soil utilization efficiency. [Conclusion] The Tobit regression results indicated that agricultural land transfer significantly affected the efficiency of land and water resource allocation in grain production and is conducive to improving resource allocation efficiency.

Abstract:[Objective] The impacts of precipitation on the groundwater preservation capacity for agricultural regions in North China were studied in order to provide a theoretical basis for the sustainable use of groundwater resources in this region. [Methods] We established a theoretical system for evaluating groundwater preservation capacity (F) and determined the influence of precipitation changes on F value in agricultural regions of North China using methods such as geoscience statistics and correlation analysis. [Results] ① The spatial distribution of F value changed dramatically as precipitation changed. The multi-year average and wet years were dominated by the “basic guarantee” distribution, while the dry years were dominated by the “difficult to guarantee” distribution; ② As precipitation changed, the frequency of F value also varied in different locations. In the Yanshan Plain and the Taihang-Hebei Plain, when the precipitation frequency was greater than 75% and 50%, respectively, the F value was less than 0.5; in the Taihang-Henan Plain, when the precipitation frequency was less than 75%, the F value was greater than 1.0; in the Central Henan Plain, when the precipitation frequency was less than 50%, the F value increased to 1.0; in the Central Shandong Plain and Littoral Plain, when the precipitation frequency was less than 25%, the F value was greater than 0.5; in the Central Hebei Plain, there were only a few years where the F value was greater than 0.5. [Conclusions] Precipitation is an important factor that affects groundwater preservation capacity. For areas that can be “highly preserved” even during normal and dry years, the scale of agricultural planting can be appropriately expanded to ensure ample food production. However, for areas that are “difficult to preserve” and have “lower preservation” capacity during wet years, the scale of agricultural planting should be appropriately reduced to alleviate the pressure of groundwater overexploitation.

Abstract:[Objective] The utilization efficiency of land and water resources in the Huaihe River basin was evaluated to clarify the degree of coupling and coordination between the two and their spatial differentiation characteristics, in order to provide a theoretical reference for improving the utilization efficiency of land and water resources and promoting the benign and coordinated development of land and water resources in the basin. [Methods] The Super-SBM model was used to measure the land and water resource utilization efficiencies of 30 cities in the Huaihe River basin. The coupling coordination degree model was constructed to discuss the coordinated development of the two. The standard deviation ellipse and the Dagum Gini coefficient method were used to analyze the spatial deviation degree and spatial differentiation source of the coupled coordination degree. [Results] ① During the study period, the utilization efficiency of land and water resources in the Huaihe River basin showed a fluctuating upward trend, and the spatial heterogeneity was significant. ② From 2011 to 2014, the degree of coupling and coordination between the two factors was in the barely coordinated stage. From 2015 to 2020, the degree of coupling and coordination was basically in the primary coordination and intermediate coordination stage, both of which were dominated by the lag of water resource utilization efficiency. A spatial pattern of “higher in the east and west, and lower in the middle” was gradually presented. ③ The coupling and coordination degree of land and water resource utilization efficiency in the northwest and southeast cities of the Huaihe River basin increased rapidly, and there was a phenomenon of strong and weak alternation. ④ The overall difference of the coupling coordination degree between the two showed a downward trend, and the spatial differentiation mainly came from the hypervariable density, followed by regional differentiation. [Conclusion] The utilization efficiencies of urban land resources and water resources in the Huaihe River basin were not high, and the coupling coordination degree was also low. Cities should strengthen the efficient and intensive use of water and land resources, improve the coupling coordination degree between the two, and provide a decision-making basis for the implementation of differentiated resource development strategies in various regions.

Abstract:[Objective] The spatiotemporal changes and correlations between landscape ecology risks and ecosystem service values in the Hanjiang eco-economic belt were studied in order to provide a theoretical basis for regional ecological security and sustainable development of the ecosystem and support for the optimization of landscape pattern and rational allocation of land resources. [Methods] We evaluated the ecological risk and ecosystem service value of landscape in the Hanjiang eco-economic belt based on an ecosystem service value equivalence table. We determined the internal relationship between these parameters, and the spatiotemporal variation law of landscape ecological risk and ecosystem service value. [Results] ① Landscape fragmentation gradually increased, and the landscape ecological risk slightly increased in the Hanjiang eco-economic belt from 1990 to 2020. A spatial pattern of “low risk in the upstream, high risk accompanied with low risk in the midstream, and high risk in the downstream” was observed. ② The ecosystem service value showed a slight increase from 1990 to 2020 of 8.66 billion yuan, with an annual growth rate of 0.06%. Regulation service accounted for 66.8% of the increase and support service accounted for 22.2%. A spatial pattern of “medium-high values in the upstream mountainous area, medium-high and low values in the middle reaches, and low values in the downstream” was observed. ③ Changes in ecosystem service value and ecological risk were negatively correlated. Low ecosystem service value was associated with high ecological risk, while high ecosystem service value was associated with low ecological risk. The significance of the correlations decreased before 2005 and increased after 2005. [Conclusion] Greater attention should be given to the system integrity of the Hanjiang eco-economic belt, and organic coordinated development within the basin should be strengthened. Additionally, greater attention should given to protecting biodiversity in the upstream region and to strengthening the control of ecological space use in the downstream region so as to comprehensively improve the ecosystem service value of the economic belt.

Abstract:[Objective] The structure and sustainability of livelihood factors and their coupling coordination under different grazing intensities were studied in order to provide a scientific basis for optimizing the livelihood strategies of farming households, increasing their economic income, and realizing rural revitalization. [Methods] Taking the typical district of loess hilly area as an example, based on the sustainable livelihood framework, constructing the evaluation index system from multiple livelihood elements, combining the survey data of farmers and mathematical modeling, a comprehensive study was conducted on the sustainability of livelihoods of farmers with different grazing intensities and their coupled and coordinated development. [Results] ① Grazing intensity enhanced the sustainability of farmers’ livelihood capital, but there were significant differences in the effects on the sustainability of livelihood environment, livelihood strategies, and livelihood outcomes. ② Livelihood sustainability was highest under moderate grazing intensity, and livelihood capital, livelihood environment, livelihood strategy, and livelihood outcome sustainability increased by 37.86%, 3.83%, 9.92% and 30.45%, respectively, compared with non-grazing farmers. ③ The coupling coordination development characteristics followed the order of moderately grazing farmers ＞ lightly grazing farmers ＞ heavily grazing farmers ＞ non-grazing farmers. Farmers’ livelihood coupling degree was higher than the coordination degree, indicating that the livelihood system of grazing farmers in the loess hilly region had a strong inter-role intensity, and that good coupling and synergistic development within the system had not yet formed. Therefore, it will still be necessary to further strengthen the transformation and upgrading of farmers’ livelihoods to improve their livelihood sustainability in the future. [Conclusion] Moderate grazing can increase livelihood capital and optimize livelihood strategy for farming households in the loess hilly region, and increase the livelihood sustainability and economic income of farming households.

Abstract:[Objective] The ecosystem service value of different land use types at Anjiagou watershed in Dingxi City, Gansu Province was quantitatively determined in hilly and gully regions of the Yellow River basin from 2005 to 2020, and the temporal and spatial variation patterns were studied in order to provide a scientific reference for optimizing land use structure and sustainable utilization of land resources in this area. [Methods] Soil and water conservation ecosystem service values were quantitatively analyzed by using the opportunity cost and the shadow engineering method in the Anjiagou watershed from 2005 to 2020. Land use types included artificial grassland, wheat fields, sea buckthorn land, Chinese pine land, closed land, and barren land. [Results] ① Ecosystem service values continuously increased from 2005 to 2020 for all land use types except for wheat fields. ② The average value of soil and water conservation ecosystem service for artificial grassland, wheat fields, sea buckthorn land, Chinese pine land, closed land, and barren land was 5.82×10⁵, 4.49×10⁵, 6.99×10⁵，6.73×10⁵, 5.34×10⁵, and 4.68×10⁵ yuan/(km²·ha) respectively. The order of the rasult was sea buckthorn land＞Chinese pine land＞artificial grassland＞barren land＞closed land＞wheat fields. However, there were significant differences among different land use types. ③ The annual growth rate of ecosystem service value increase was greatest for artificial grassland (9.82%), followed by closed land and barren land (8.52% and 6.84%, respectively), and lowest for Chinese pine land (2.12%). However, there was no obvious trend in wheat fields with years. [Conclusion] Sea buckthorn land and Chinese pine land accounted for 21% and 20%, respectively, of the soil and water conservation ecosystem service value, followed by artificial grassland (17%). Wheat fields accounted for the least amount of ecosystem service value (13%). Closed land and barren land had intermediate values (15% and 14%, respectively). Therefore, the key to controlling soil and water loss in hilly and gully regions of the Yellow River basin is to maintain and improve the quality of forest land and grasslands.

Abstract:[Objective] The adaptation relationship and the changing trends between total water consumption and total GDP, water consumption of three industries and GDP of corresponding industries in Jiangxi Province and its 11 prefecture-level cities from 2015 to 2020 were studied, revealing the reasons for the adaptation differences, and providing scientific basis for the coordination of water resource utilization and economic development in the region. [Methods] Industrial water consumption and industrial GDP data were used with the Tapio model in this study. [Results] Total water use and total GDP of Jiangxi Province were both in a state of adaptation from 2015 to 2020, showing a trend pattern of “strong adaption—expanded adaption—strong adaptation”. The degree of adaptation exhibited a spatial distribution pattern of northwest ＞ south ＞ central and east. Agricultural water consumption and GDP of the primary industry showed a trend pattern of “adaptation—coupling—adaptation”, while the adaptation relationship for each city fluctuated. Except for the expansionary adaptation between industrial water consumption and GDP for the secondary industry in the province in 2018—2019, there was a strong adaptation relationship in other periods, and all cities reached a strong adaptation state in 2017—2018. The tertiary industry of the entire province was in a state of expansionary adaptation and positive coupling from 2015 to 2020. Except during the pandemic period in 2020, the adaptation of most cities was better than that of agriculture from 2015 to 2019. On the whole, the degree of adaptation between industrial water consumption and industrial GDP in Jiangxi Province followed the order of industry ＞ tertiary industry ＞ agriculture. [Conclusion] The main reasons for the change in the adaptation relationship between water use and economic development were precipitation, economic level, policy measures, industrial structure, technological progress, construction of water conservation facilities, etc. Countermeasures, such as developing special industries according to local conditions, determining production with water, and promoting transformation and upgrading of industrial structure, have been proposed to help promote sustainable development in Jiangxi Province.

Abstract:[Objective] Biomechanical properties of plants are an important part of studies dealing with the use of plants for soil and water conservation because of the important role plants play in soil stabilization, water conservation, and water flow and sediment retention. The objective of this paper was to search the CNKI and Web of Science databases to find literature related to plant biomechanical properties in order to highlight the current status and development trend of biomechanical properties of plants related to soil and water conservation. [Methods] Citespace and VOSviewer were used to visualize the annual number of published papers, highly cited journals, primary research countries, primary research authors, keywords, etc. [Results] The number of publications on the biomechanical properties plants in the field of soil and water conservation was low during 1990—2010. After 2010, there was a significant increase in the number of both domestic and foreign publications. The United States ranked first in the number of papers published; China ranked third in the number of papers published. The international influence of research results needs to be improved. Four major research teams led by Hu Xiasong, Ge Rile, Liu Jing, and Chen Lihua have been formed domestically, but no authoritative large team has been formed internationally. [Conclusion] Domestic research has mainly focused on the analysis of biomechanical properties of desert plants and slope plants, placing emphasis on the influence of plant biomechanical properties on windbreak and soil-fixing effects. International research has been more diversified, with studies conducted on the role of root reinforcement of slopes, the windbreak and erosion resistance role of desert pioneer plants, and the role of aquatic plants in wave attenuation.

Abstract:[Objective] The characteristics of cultivated land ecological supply and demand were analyzed in order to provide theoretical surpport for ensuring the sustainable supply of ecological functions of cultivated land and to maintain regional food security and ecological safety. [Methods] The study was conducted at Liaohe River basin in Jilin Province. and improves the ecological footprint model. Based on the productive-living-ecological functions of cultivated land, the production function footprint, living function footprint, and ecological function footprint of cultivated land were integrated, the ecological footprint model was improved, and the difference between cultivated land ecological supply and demand in the study area was clarified. [Results] ① The productive, living and ecological function footprints of cultivated land differed greatly at Liaohe River basin, among which the living function footprint of cultivated land was the largest and the ecological function footprint is the smallest. ② Cultivated land use was in a state of significant ecological surplus at Liaohe River basin, with the overall characteristics of “county (city) surplus and district deficit”. The production function deficit of cultivated land was the main cause of the ecological deficit of cultivated land. ③ The cultivated land ecological supply and demand were significantly unbalanced in space at Liaohe River basin, and the overall spatial variation was characterized as “surplus in the north and deficit in the south, with gradual progression”. [Conclusion] The ecological footprint model based on the productive-living-ecological functions of cultivated land was conducive to a more comprehensive exploration of the cultivated land ecological supply and demand. Based on the multifunctional nature of cultivated land, human occupation and consumption of cultivated land resources varied significantly, and the establishment of ecological compensation mechanisms for cultivated land in watersheds should fully take into account their spatial variation characteristics.

Abstract:[Objective] The spatial and temporal variation characteristics of vegetation cover in Yan’an City and its relationship with climate change and human activities were studied in order to provide scientific support for the evaluation of eco-environmental benefits and eco-environmental construction in this area. [Methods] Linear trend analysis, correlation analysis, and residual analysis of MODIS-NDVI and meteorological data were used to determine the spatio-temporal characteristics and influencing factors of vegetation cover change in Yan’an City from 2000 to 2020. The effects of different factors on vegetation cover change and the interaction among them were analyzed by geographic detector. [Results] ① During the past 21 years, NDVI in Yan’an City showed an overall upward trend with a growth rate of 10%/10 yr, which was faster than the average growth rate of vegetation coverage in the Three-North Shelterbelt System. ② The vegetation cover in Yan’an City had been optimized, with 99.64% of the area showing improvement, of which 97.85% was significantly improved, and the proportion of the area showing degradation was very small. ③ Influenced by the distribution of water and heat, Yan’an City exhibited a vegetation distribution pattern of “high in the east and low in the west, high in the south and low in the north”. ④ The correlation coefficient between NDVI and precipitation was significantly larger than the correlation coefficient between NDVI and temperature in this area. The correlation coefficient between NDVI and temperature ranged from -0.60 to 0.70, and the positive correlation area accounted for 47.52% of the total area. The correlation coefficient between NDVI and precipitation ranged from -0.23 to 0.91, and the positive correlation area accounted for 99.62% of the total area. ⑤ The effective implementation of the policy of returning farmland to forest and grass in Yan’an City was the most significant factor in improving vegetation cover, followed by the role of precipitation. The roles of temperature and physical geography were smaller. [Conclusion] Yan’an City is a central city in the hinterland of the Loess Plateau. Vegetation cover there was influenced by climate and human activities. Ecological construction in the future will require knowledge based on the resource availability of different regions, with reasonable participation of human factors, and the use of corresponding control and compensation measures according to local conditions, with a view to achieving the effect of continuous increases in NDVI in Yan’an City and further enhancement of the ecological benefits of Yan’an City.

Abstract:[Objetive] The characteristics and driving mechanisms of spatial and temporal changes in the ecological vulnerability of the Songnen Plain from 1980 to 2020 were studied in order to provide a scientific basis for ecosystem management and sustainable development in the region. [Methods] From the perspective of natural factors and human factors, the “pressure-state-response” (PSR) model was used to build an evaluation index system. Principal component analysis was combined with the Moran’I index. [Results] ① The ecological vulnerability of the Songnen Plain was dominated by extreme, severe, and moderate vulnerabilities, accounting for 81.72% of the total vulnerability. The overall level of ecological vulnerability showed an upward trend before 2000, and the overall level of ecological vulnerability declined after 2000. ② The ecological vulnerability of the Songnen Plain was dominated by light (62.19%) and moderate (91.30%) vulnerability changes. ③ Changes in ecological vulnerability were due to conversions between grasslands, waters, unused land, construction land, and cultivated land. ④ Spatial autocorrelation existed in ecological vulnerability, and low-low aggregation was mainly located in the forestland area in the western part of the study area. [Conclusion] The ecological vulnerability of Songnen Plain during the past 40 years generally showed a fluctuating and decreasing trend. The spatial ecological vulnerability gradually increased from east to west. Natural factors such as temperature and precipitation, and human factors such as land use had a great impact on ecological vulnerability.

Abstract:[Objective] The land use change and its driving forces at Tongliao City of Inner Mongolia Autonomous Region were analyzed in order to provide a scientific basis for economic construction and sustainable development of land at Tongliao City. [Methods] Based on eight periods of land use data and statistical yearbook data for Tongliao City from 1980 to 2020, land use dynamic attitude, land use degree, land use transfer matrix, and principal component analysis were used to determine the characteristics and driving forces of land use change at Tongliao City. [Results] Land use at Tongliao City was mainly classified as cultivated land and grassland from 1980 to 2020. The total area of cultivated land increased by 3037 km², with an overall increase of 20.48%, while the total area of grassland decreased by 2922 km², with an overall decrease of 10.40%. The area of construction land increased continuously during the past 40 years, and its single land use dynamic attitude was the largest. The comprehensive index of land use degree was at a medium and low level. The change rate of the comprehensive index was positive during the study period, indicating a period of generally increasing development. Grassland was mainly converted to cultivated land, forest land, construction land, and unused land during the study period. The socio-economic drivers of land use change at Tongliao City were dominated by the level of economic development, agricultural development, social affluence, and industrial structure, followed by population. Average annual temperature and annual precipitation were the main climatic factors influencing land use change. [Conclusion] There was obvious heterogeneity in the area devoted to different classifications of land use at Tongliao City from 1980 to 2020. The speed of land use change tended to be stable. The level of land use continued to increase, land use conversion became more frequent, and socio-economic and climatic factors had a significant positive effect on land use change, thereby continuously promoting economic construction and sustainable development of land in the region as a whole.

Abstract:[Objective] The spatial and temporal distribution of water yield at Yunlong Reservoir basin (one of the sources of drinking water in Kunming) from 2001 to 2020 was studied in order to provide a scientific basis for the sustainable development of a water yield service function, and for constructing an ecological compensation mechanism and ecological protection policies. [Methods] We used the InVEST model and the ArcGIS spatial geographic analysis tool to determine the spatial and temporal changes of water yield. The factors influencing these changes were compared and analyzed by multi-scenario analysis and the difference comparison method. [Results] ① The water yield of Yunlong Reservoir basin showed seasonal distribution characteristics, mostly concentrated in summer. From 2001 to 2020, the water yield of Yunlong Reservoir basin initially decreased and then increased. The average water yield per unit area in the three study phases were 495 mm, 278 mm, and 364 mm, respectively. ② Water production gradually increased spatially from southwest to northeast, with high values located in the northeast and low values in the middle. ③ The contribution rates of land use change, precipitation, and potential evapotranspiration to water yield change at Yunlong Reservoir basin from 2001 to 2020 were 1.93%, 85.66%, and 12.41%, respectively. [Conclusion] Climate was the dominant factor affecting water yield changes at Yunlong Reservoir basin, and changes in land use type had the smallest impact on water yield. The annual water yield of forest land was the highest among the land use types. In the future, efforts should be made at Yunlong Reservoir basin to reduce the waste heat released to the atmosphere by human production activities and life, to strengthen the construction and protection of water conservation forests, and to reduce the negative impacts of human activities on climate which are the results of changing the underlying surface properties.

Abstract:[Objective] The habitat quality of the urban agglomeration in the lower reaches of the Yellow River, and the relevant influencing factors were studied in order to provide a reference for ecological protection and quality development in the region. [Methods] The InVest model was used to analyze the evolution characteristics of regional habitat quality based on land use data from 2005 to 2020. The agglomeration effect of habitat quality was analyzed through spatial analysis. Influencing factors of habitat quality were determined using GeoDetector. [Results] ① From 2005 to 2020, the overall habitat quality of urban agglomeration in the Lower Yellow River basin was low, with an average value index of 0.402 2. During this period, habitat quality initially decreased and then increased. ② Spatial autocorrelation analysis showed that habitat quality was highly correlated, showing a polarized clustering pattern. Habitat quality showed a cluster of high values (H-H) in the western and northern parts of the Central Plains urban agglomeration and the central part of the Shandong Peninsula urban agglomeration, and a cluster of low values (L-L) in cities with more prominent economic development in the urban agglomeration, such as Zhengzhou and Qingdao City. ③ The results of the GeoDetector analysis showed that land use was the main factor influencing habitat quality of urban agglomeration in the Lower Yellow River basin, and that the interaction between different factors was stronger than the influence of individual factors on habitat quality. [Conclusion] Regions of urban agglomeration in the Lower Yellow River basin with high habitat quality should continue to protect the ecological environment, while regions with low habitat quality should strictly control land exploitation and the expansion of construction land, and improve land use efficiency.

Abstract:[Objective] The spatiotemporal changes of different grades of sloping farmland, the soil conservation effects of different sloping farmland types, and the impact of returning farmland to forest or grassland on sloping farmland and soil conservation at the source area of Weihe River were studied in order to provide a scientific basis for the rational planning and utilization of different sloping farmland resources. [Methods] Land use and topographic data at the source area of Weihe River from 1990 to 2020 were analyzed by superposition analysis, farmland dynamic attitude, land use transfer matrix, and the Chinese soil loss equation. [Results] ① During 1990 to 2020, the area of cultivated land increased slowly, then decreased sharply, and then decreased slowly, with a net decrease of 321.03 km². Steep slope cultivated land and gentle slope cultivated land were the main types of cultivated land change. ② The temporal and spatial changes of cultivated land were mainly characterized by a small increase in cultivated land from 1990 to 2000, mainly located in Zhangxian County and Minxian County. With the implementation of the grain for green project (GGP), 279.80 km² of sloping land were transformed into forest and grassland, in which the conversion of cultivated land to grassland was mainly located in Tongwei and Longxi counties, while the conversion of cultivated land to forest land was mainly located in Longxi and Minxian counties. ③ The reclamation of forest and grassland at the source area of Weihe River from 1990 to 2000 reduced soil conservation by 5.52×10⁴ t, while returning farmland to forest and grassland increased soil conservation by 2.21×10⁶ t from 2000 to 2020. The transformation of sloping land with greater than 15° slope could affect changes in soil conservation. [Conclusion] The implementation of GGP has achieved remarkable results at the source area of Weihe River. The area of farmland conversion on steep slopes was the largest from 2000 to 2010. The soil conservation effect on steep slopes was the largest on abandoned land. Steeply sloping farmland will be the main target during the new round of returning farmland.

Abstract:[Objective] The spatiotemporal pattern of soil conservation was studied and the protection vacancy areas were identified in order to provide references for regional development planning and ecological protection. [Methods] The study was conducted with data from Ganzhou City of Jiangxi Province. We used the integrated RUSLE model, the InVEST model, other ecological evaluation methods, hot spot analysis, overlay analysis, and other analysis tools combined with protection vacancy theory to analyze the space-time evolution characteristics of soil and water conservation from 2000 to 2020. We compared the existing protection areas, and identified potential priority protection areas. [Results] ① The spatial distribution of soil conservation services in Ganzhou City generally showed higher in the surrounding areas, and lower in the middle area, The most important areas were concentrated in the Luoxiao Mountains, Jiulian Mountains, Wuyi Mountains, and Yushan Mountains, with an average annual total soil conservation of 8.46×10⁸ t. ② The spatial characteristics of the water conservation function were also generally characterized by higher in surrounding areas, and lower in middle area. The most important areas were concentrated in the upper reaches of Meijiang River basin, Pingjiang River basin, Beiling River basin, Youjiang River basin, and Taojiang River basin, as well as Wuyi Mountains to the east of Mianjiang River basin and Xiangshui River Basin. The water conservation depth averaged over many years was 213.48 mm. ③ The areas with significant soil and water conservation functions in Ganzhou City had strong spatial correlations. Compared with the existing natural reserves, the protection vacancy area was 6 155.54 hm². There were several obvious areas with no protection around them that were located in the north of Xingguo County, the northeast of Shicheng County, the northwest and southeast of Ruijin City, and the middle of Quannan County, the southeast of Anyuan County, and the west of Xunwu County. [Conclusion] Climate factors, land use changes, and topographic and geomorphic conditions were important factors affecting the spatial and temporal differentiation of soil and water conservation functions in Ganzhou City. Ecological protection and restoration strategies should be adopted for the protection of vacant areas and functionally degraded areas.