Abstract:[Objective] The dynamic changes and causes of vegetation coverage and wind erosion at the edge of the reservoir in arid sandstorm region were analyzed in order to provide a basis for the prevention and control of sandstorm hazards in the reservoir area.[Methods] Taking Qiaozi reservoir at Guazhou County, Gansu Province as a study area, landsat images of the edge of Qiaozi reservoir was collected, and the pixel dichotomy model was used to calculate the vegetation coverage in the arid sandstorm area. Both qualitative and quantitative methods were used to evaluate the changes of vegetation edge and wind erosion.[Results] The annual average values of vegetation coverage in 2006, 2011, and 2018 were 0.15, 0.13, and 0.35, respectively. The vegetation at the edge of the reservoir decreased first and then increased, and tended to grow away from the reservoir, and the change of vegetation coverage from 2006 to 2011 was higher than that from 2011-2018. The severe erosion area still accounted for a large proportion (>50%).[Conclusion] In addition to climate, the reduction of groundwater recharge, the decrease of water level, the expansion of oasis beyond ecological load, unreasonable planting, inadequate farming methods and animal husbandry development have accelerated natural vegetation degradation and local erosion. The adoption of grassland enclosure, sand fixation and afforestation and other management and restoration measures have delayed this process to a certain extent. It is suggested that ecological water diversion, groundwater replenishment, development of water-saving agriculture, reclamation and grazing prohibition, adjustment of industrial structure, restoration of vegetation and other rescue measures as well as prevention, protection and control measures should be taken to maintain the lasting stability of the oasis.

Abstract:[Objective] The process of slope runoff and sediment yield and its influencing factors of different types of biological soil crust were clarified in order to provide theoretical basis for evaluating soil and water conservation function of biological soil crust.[Methods] The common cyanobacterial crust and moss crust in the Loess Plateau region were selected as the research objects, to systematically study the effects of crust types and destruction on runoff and sediment yield under the condition of rainfall.[Results] ① The coverage of biocrusts could significantly enhance the cohesion of soil surface. Soil surface cohesion of cyanobacterial crust and moss crust were 1.52 and 1.25 times higher than that on bare land (4.53 kPa), respectively. After the biocrusts were destroyed, the soil cohesion of soil surface was still higher than that of bare land, which was 1.22 and 1.10 times of that of bare land, respectively. ② Biocrusts could increase slope runoff and inhibited slope sediment yield. Compared with bare soil condition, cyanobacterial crust and moss crust increased the total runoff by 21.64% and 55.75% respectively, and decreased the sediment yield by 94.06% and 89.24% respectively. After the biorusts were destroyed, it could still promote runoff and inhibit sediment yield. The runoff was increased by 58.76% and 59.66%, and the sediment yield was decreased by 16.18% and 29.45%. ③ With the increase of cumulative runoff, the increasing rate of cumulative sediment yield from large to small was as follows:bare land > cyanobacterial crust removal > moss crust removal > moss crust coverage > cyanobacterial crust coverage. Cohesion was an effective indicator of biological crust to inhibit soil erosion. With the increase of cohesion, the sediment yield decreased linearly (R²=0.66).[Conclusion] By increasing the biological soil crust coverage and prevent the biological crust from being damages, its function of soil and water conservation could be maximized.

Abstract:[Objective] In order to guide local afforestation and promote efficient use of water resources, the green water flow of the typical artificial forest of Robinia pseudoacacia, Platycladus orientalis and Pinus tabulaeformis was studied in the loess gully region.[Methods] The applicability of Granger model in typical artificial forest land in Nanxiaohegou sub-basin was evaluated. Then combined with the measured green water of low efficiency, the high and low efficiency green water in each forest was separated. And based on the separation results, we analyzed and summarized the characteristics of high and low efficiency green water changes in various forest land during the rain free period and their relationships with solar radiation, leaf area index, and soil moisture content.[Results] ① The Granger model has good applicability in various forest lands, and its Nash efficiency coefficient was above 0.67 and 0.52 in the regular period and verification period. ② In each forest land, the change of high efficiency green water in different hydrological years was Platycladus orientalis (45.93%) > Pinus tabulaeformis(28.81%) > Robinia pseudoacacia (6.11%). The change of low efficiency green water is Pinus tabulaeformis (52.73%) > Platycladus orientalis (34.97%) > Robinia pseudoacacia (21.16%). And the change of green water flow was Platycladus orientalis (21.13%) > Robinia pseudoacacia (12.37%) > Chinese pine (0.50%). Robinia pseudoacacia, Platycladus orientalis and Pinus tabulaeformis forest land with 10 cm relative water content less than 50% were 90.1%, 56.8%, 64.0% during dry year, and 68.4%, 70.1%, 71.2% during extremely dry year; 20 cm relative water content less than 50% are 90.1%, 61.0%, 60.1%, and 80.0%, 66.7%, 50.5%.[Conclusion] ① Platycladus orientalis was the most sensitive tree species for water. ② Different hydrological years have a greater impact on the high efficiency green water (45.93%) of Platycladus orientalis than the low-efficiency green water (34.97%), and the opposite was true for Robinia pseudoacacia and Pinus tabulaeformis. ③ Solar radiation had the greatest impact on the low efficiency green water in Platycladus orientalis, and the greatest impact on the high efficiency green water in the Robinia pseudoacacia forest. The low efficiency green water of Robinia pseudoacacia and Pinus tabulaeformis decreased with the increase of leaf area index while the high efficiency green water increased. The high-efficiency green water of Platycladus orientalis was less affected by the leaf area index. The three forest land was in a state of moderate water shortage during most of the experiment period.

Abstract:[Objective] The anti-erosion effects of corn on slope farmland was studied in order to provide a theoretical basis for the prevention and control of soil erosion on slope farmland in the Loess Plateau region.[Methods] An outdoor artificial simulated rain test was conducted to analyze the effects of corn on the runoff and sediment production and erosion process on slope farmland at five different growth stages, such as seedling stage, early jointing stage, mid-joint stage, late jointing stage, and tasseling stage.[Results] ① With the growth of crops, the resistance of corn to runoff and sediment yield increased, this effect was the weakest in the seedling stage and the strongest in the tasseling stage. Compared with bare land, the average runoff and sediment yield of corn plot decreased by 48.5% and 73.7% respectively. The sediment reduction effect of corn in different growth stages was better than that of runoff reduction effect. ② The process of runoff and sediment yield showed a continuous fluctuation trend. Corn crops delyaed the initial time of runoff and sediment yield, and the average runoff and sediment yield decreased in stable runoff and sediment yield stage. When rainfall intensity increased from 40 mm/h to 80 mm/h, the increase rate of runoff and sediment yield was more than 100%, the runoff coefficient and sediment concentration increased, and the erosion process became more severe. ③ There was a good exponential correlation between leaf area index and soil loss ratio of corn slope at different growth stages. The leaf area index could be used to estimate the soil loss ratio of corn slope in different growth periods, which laid a foundation for estimating annual vegetation cover and management factor C value.[Conclusion] With the growth of corn, the anti-erosion effect of corn is enhanced, but the erosion is serious at seedling stage and early jointing stage, auxiliary measures should be taken to prevent soil and water erosion. The increase of rainfall intensity makes the erosion and sediment yield more serious under various underlying surface conditions.

Abstract:[Objective] The effects of different tourism disturbance intensity on litter and soil water-holding capacity in the scenic area were explored in order to provide some reference for scenic area management measures and ecological environment improvement.[Methods] The Huangshui National Forest Park was selected as experimental object and the changes of litter and soil water-holding capacity were analyzed under four treatments:undisturbed area, light disturbed area, moderate disturbed area and severe disturbed area.[Results] With the increase of tourism disturbance intensity, the litter and soil water-holding capacity were decreased significantly, while the soil bulk density was increased significantly (p<0.05). Compared with undisturbed area, the total accumulation of litter, decomposed litter and semi-decomposed litter were decreased by 55.30%, 57.47% and 49.19% respectively (p<0.05); the maximum water-holding rate, maximum interception rate, effective interception rate, the maximum water-holding capacity, maximum interception capacity and effective interception capacity of undifferentiated litter were decreased significantly by 19.83%, 24.83%, 20.22%, 57.89%, 56.67% and 62.35%, respectively, but the semi-decomposed litter were significantly decreased by 30.01%, 33.21%, 37.48%, 69.90%, 70.94% and 72.77%, respectively. The soil bulk density of scenic spot under serve disturbance intensity was significantly increased by 97.33%, while the soil porosity, soil capillary porosity, soil non-capillary porosity, soil maximum water-holding capacity, soil capillary water capacity, soil non-capillary water capacity, soil initial infiltration rate, soil stable infiltration rate, soil average infiltration rate and soil total infiltration were significantly decreased by 26.57%, 8.83%, 17.74%, 38.64%, 42.98%, 32.13%, 67.01%, 65.23%, 64.22% and 44.01% (p<0.05), respectively.[Conclusion] Tourism disturbance decreased the hydrological regulation function of the scenic area ecosystem by reducing the litter, especially the semi-decomposed litter and the soil water-holding capacity.

Abstract:[Objective] The relationship between temperature dynamics of biological soil crusts (biocrusts) and soil moisture on silty loam in the loess hilly region of China was clarified in order to provide scientific basis for further understanding the function of biocrusts.[Methods] A field monitoring experiment was conducted in the abandoned farmland in Wuqi County, Shaanxi Province from January 1 st, 2016 to December 31 st, 2018.[Results] ① Soil temperature of biocrusts had obvious dynamic within a year. During the observation period, the highest temperature of biocrusts layer occurred in June with an average temperature of 27.1℃, the highest temperature of 5 cm soil under biocrusts layer was 22.7℃ in July. The lowest temperature of biocrusts layer and 5 cm soil in January were -1.7℃ and -1.4℃, respectively. ② The diurnal dynamics of soil temperature in the biocrusts layer and 5 cm soil were changed in a sinusoidal curve throughout the year. The maximum diurnal temperature range appeared in June, and biocrusts layer and 5 cm soil were 32.0℃ and 17.2℃, respectively. The minimum diurnal temperature range of biocrusts layer was 17.3℃ in October, while 5 cm soil was 8.5℃ in January. ③ The soil temperature of biocrusts throughout the year was significantly positively correlated with air temperature, the soil temperature of biocrusts from March to October was significantly negatively correlated with soil moisture, and the soil temperature of biocrusts from November to December was significantly positively correlated with soil moisture. ④ The increase of soil water content (SWC) in January and July resulted in a decrease in diurnal temperature range of biocrusts layer and 5 cm soil.[Conclusion] The soil temperature of biocrusts on silty loam in the loess hilly region of China was closely related to the soil moisture, and the influence of soil moisture on the soil temperature of biocrusts was different in different months.

Abstract:[Objective] The spatial distribution and effects of soil nutrients in the agro-forestry system in sandy land were explored in order to provide scientific basis for the sustainable management of the agroforestry system from a perspective of soil nutrients in the region of Northwest Liaoning.[Methods] Soils in apple-peanut intercropping, peanut monoculture, and apple monoculture were sampled to determine and analyze soil nutrients contents in the range of 0-60 cm and 0-300 cm horizontal distance.[Results] Total organic matter and available potassium were extremely deficient, the total nitrogen and available nitrogen were very deficient, total phosphorus was deficient, and the available phosphorus content was medium in the intercropping system of sandy land. In the horizontal direction of the intercropping system, the intense competition sites for total organic matter, total N and total P for apple trees and peanut plants were located in the fruit tree zone, and the intense competition sites for available nutrients of N, P and K were located in the near fruit trees. In the vertical direction, all nutrients showed surface aggregation. The competition of organic matter and available phosphorus in the intercropping system was mainly located in the deep soil layer, and the competition of total phosphorus and available potassium was mainly located in the top soil layer. There was a cooperative effect on total nitrogen and available nitrogen, and the effect in soil of surface layer was more obvious. Compared to peanut monoculture and apple monoculture, the contents of available potassium and available phosphorus in the intercropping system showed a negative effect.[Conclusion] Soil nutrients in the apple-peanut intercropping system were poor. Organic fertilizers and phosphate fertilizers are recommended to be applied in the fruit tree zone, and potassium fertilizer should be applied in the crop area so as to reduce nutrient competition and improve nutrient effect.

Abstract:[Objective] The effects of abandoned farmland, planting spring-sown crops and mixed sowing of legume and herbal grass on soil salinity were analyzed in order to provide scientific support for the prevention and control of soil salinization by using biological measures in irrigated areas along the Yellow River in Gansu Province.[Methods] Bare land (CK), Triticum aestivum and mixed grass (Elymus nutans×Medicago sativa) were employed to conduct treatments. Indicators related to vegetation and micro-environment and topsoil (0-5 cm) moisture and salinity were measured to analyze the relationship between vegetation characteristic index and salt content.[Results] The salinity of topsoil in bare land showed a W-shaped curve pattern throughout the year, with three peaks occurring in early spring, late summer and late autumn. The salinity in wheat land showed a U-shaped trend with the peak in early spring and late autumn. The salinity in mixed grass land was only higher in the early spring. By the end of autumn (October), the salinity of topsoil in wheat field was 18.4% higher than that in bare land, while in grassland, was 55.9% lower than that in bare land. Compared with that in the March of two consecutive years, soil salinity in bare and wheat fields increased by 23.7% and 14.8% respectively, while in pasture field, decreased by 28.2%. There were extremely significant negative correlation between vegetation characteristics and salinity (p<0.01), among them, the negative correlation between vegetation coverage and salinity was the strongest (up to -0.916). With the increase of vegetation coverage, height, and biomass by 1%, 1 cm and 1 g/m², the soil salinity would reduced by 0.031, 0.139 and 0.014 g/kg.[Conclusion] Abandoned farmland and short growing period of spring-sown crops are easy to cause salt accumulation of topsoil and soil secondary salinization in irrigated areas along the Yellow River in Gansu Province, while mixed planting legume and grass with long growth period can effectively reduce topsoil salinity and prevent soil salinization.

Abstract:[Objective] The effects of silver-black double-color film mulching on the physical and chemical properties of soil and the growth and yield of cassava were studied in order to provide the theoretical and technical basis for the application of silver-black double-color film mulching on cassava.[Methods] The effects of silver-black double-color plastic film mulching, black plastic film mulching, white plastic film mulching and no plastic film mulching on soil physical and chemical properties and cassava yield were studied based on DPS 7.05 and Excel 2003.[Results] Compared with black film mulching, white mulching and no mulching, the water holding capacity by soil mulched with silver-black plastic film was increased by 18.34%, 15.49% and 49.95%, respectively; the solid volume ratio of soil decreased by 4.87%, 15.18% and 15.25%, respectively; the proportion of soil vapor phase increased by 2.24%, 2.43% and 8.13%; the proportion of soil liquid phase increased by 2.4%, 2.45% and 6.83%; and the content of soil available nitrogen increased by 20.94 mg/kg, 21.64 mg/kg and 27.22 mg/kg respectively. Similarly, the content of available phosphorus in soil increased by 18.19, 19.39 mg/kg and 41.29 mg/kg respectively; the content of available potassium in soil increased by 21.77, 22.30 mg/kg and 28.16 mg/kg respectively; and the root tuber yield of cassava increased by 10.49%, 17.75% and 30.93% respectively. The yield of starch increased by 11.18%, 19.55% and 34.70%, respectively.[Conclusion] Silver-black double-color plastic film mulching can significantly enhance soil water holding capacity, adjust the three-phase ratio of soil, improve soil physical and chemical properties, promote soil nutrient efficiency, increase soil available nutrient content, promote cassava growth, and increase cassava yield.

Abstract:[Objective] The characteristics of soil nutrient changes after gully control and land consolidation were investigated in order to improve the land consolidation methods, take the proper cultivation management measures and increase the nutrient utilization efficiency of the loess hilly and gully region.[Methods] Taking the typical land-consolidation project in Yan'an City, Shaanxi Province as the research object, soil samples at different locations of the gullies before and at 2, 3 a and 6 a after the consolidation were collected, and the change characteristics of soil organic matter, total nitrogen, available phosphorus and available potassium were analyzed based on the statistical analysis method. The comprehensive evaluation of soil nutrients was performed by matter-element model.[Results] ① The soil nutrient level in the study area was generally low, except for the available potassium. The variation of soil nutrients in the gully was relatively large, belonging to moderate degree of variation. After the land consolidation, the variation coefficient of soil nutrients tended to decrease. ② Soil organic matter content decreased at first and then increased with the increase of project implementation within 6 years after the gully consolidation, and the content of soil organic carbon was lower than that before consolidation. Soil total nitrogen and available phosphorus increased at first and then decreased, which was higher than those before years. Soil available potassium decreased continuously after consolidation. ③ Three years after the land consolidation, the soil nutrient evaluation level in the study area returned to the level before remediation, and had the potential to continue to improve.[Conclusion] Compared with slope land consolidation, soil nutrients could recover faster following the gully land consolidation in the loess hilly and gully region. According to the variation characteristics of soil nutrients in different locations, the grain yield could be increased through adjusting the spatial layout of crops and implementing different management strategies.

Abstract:[Objective] The effects of contour reverse-slope steps on the water use efficiency and yield of maize crops in sloping land were explored in order to provide scientific basis for crop cultivation in sloping land in Yunnan Province.[Methods] Maize (Yunrui 668) was used as test material. Two sloping farmland plots with contour reverse-slope (2^# and 3^#, CR) and 1 undisturbed control plot (1^#, CK) were set up in the field experiment. The maize growth index, net photosynthetic rate, transpiration rate, water use efficiency and crop yield were measured by field monitoring method to investigate the effects of contour reverse-slope order on maize growth and photosynthetic characteristics.[Results] The effect of contour reverse-slope measure on the ear height of maize and stem diameter was not significan, while the promotion effect on the height of maize plant was the most significant, with an increase of 27.9%. The leaf area index (LAI) of the contour reverse-slope sample plot was significantly higher than that of the undisturbed slope land, with LAI as high as 5.01~5.78. After the grouting stage, relatively high LAI could be maintained, while the LAI of the CK group was ranged from 3.78 to 4.79, which decreased rapidly. The net photosynthetic rate, stomatal conductance, WUE_L (instantaneous water use efficiency) and water use efficiency of maize leaves under the contour reverse-slope was higher than that of sloping land. Maize yield increased by 9.6% and 13.8%, respectively, compared with sloping farm land.[Conclusion] In the slope cultivated land area in Yunnan Province, by increasing soil moisture and soil water storage, the contour reverse-slope measure can promote photosynthesis of leaves and physiological status, which lays a physiological foundation for dry matter production of maize and improves the crop yield. Under the condition of natural rainfall, when the slope was 15°, the contour reverse-slope measure has the best promotion effect on WUE of photosynthetic characteristics and yield promotion of maize.

Abstract:[Objective] The new urbanization level of Jiangxi Province was analyzed based on the impervious surface data, the pattern and trend of the new urbanization development in cities were studied in order to provide scientific support for the development of the new urbanization of Jiangxi Province.[Methods] By constructing a comprehensive index system according to population, economic and social development, urban space, the new urbanization level of each city in Jiangxi Province was analyzed during the period from 1988 to 2017, and then based on the data of urban impervious surface, the correlation changes between new urbanization level and impervious surface in different stages were studied, and a linear relationship model between them were built.[Results] Over the past 30 years, the urban impervious surface expanded significantly, and it presented a spatial pattern of "high-slightly high-middle-slightly low-low" density circle distribution. The level of new-type urbanization in Jiangxi Province exhibited a general trend of "high in the north and low in the south". The regional development of urbanization was uneven. The year of 2006 marked an abrupt change point of new-type urbanization level growth. Before and after the abrupt change point, the correlation between new-type urbanization level and impervious surface was different. The R² value of linear fitting between the impervious surface and the new-type urbanization were both above 0.9, which showed that the data of impervious surface could better reflect the new urbanization level of each city.[Conclusion] There is a strong correlation between the impervious surface and the new-type urbanization level, so the new-type urbanization level of each city can be well reflected by using the impervious surface data, it may finally help to analyze the development trend of urbanization and promote regional urbanization research.

Abstract:[Objective] The relationship between the root tensile properties and its responses to their chemical contents was discussed in order to enrich the mechanical properties of soil consolidation by root system and provide theoretical support for ecological restoration and plant protection in mining areas.[Methods] The tensile of straight roots and lateral roots of Artemisia ordosica in the Shendong coal mine area with diameters from 1~4 mm were measured with TY8000 servo power machine, and measure the contents of cellulose, hemicellulose and lignin of each diameter grade.[Results] ① The anti-tension force of straight roots and lateral roots of Artemisia ordosica were positively correlated with the diameter as a power function, the anti-tension strengths and Young modulus were negatively correlated with root diameter as a power function. ② The contents of cellulose hemicellulose and lignin of straight roots and lateral roots present a significant difference,the average chemical content is:hemicellulose (31.69%,32.18%) > lignin (28.42%,25.30%) > cellulose (15.50%,15.35%). ③ The contents of cellulose of straight roots were negatively correlated with the diameter,the hemicellulose content and lignin content of straight roots were positively correlated with the diameter, the contents of cellulose of lateral roots were negatively correlated with the diameter, the hemicellulose content and lignin content was unchanged with the diameter. ④ The anti-tension strengths and Young modulus of straight roots present a positively correlated with the contents of cellulose (p<0.01), but present a negatively correlation with hemicellulose content and lignin content (p<0.01). The anti-tension strengths and Young modulus of lateral roots present a positively correlated with the contents of cellulose (p<0.01), but not with hemicellulose content and lignin content.[Conclusion] The root tensile properties of Artemisia ordosica have a certain correlation with the chemical contents, the contents of cellulose is key factors affecting the mechanical properties of the root materials of shrubs.

Abstract:[Objective] The variation of the erosion depth of debris flow solid mater, and the relationship between the corresponding scouring rate and different influencing factors were explored in order to provide reference for debris flow prediction and prevention engineering design.[Methods] According to the principle of the laser rangefinder, the variation of the erosion depth of debris flow solid matter over time and the relationship between the corresponding erosion rate and different influencing factors were explored, including the incoming flow, hydraulic radius, and gully bed longitudinal slope and the content of fine particles.[Results] The scour rate showed an exponential relationship with the hydraulic radius, a positive correlation with the incoming flow, and an exponential relationship with the energy slope gradient. If the solid matter was uniformly scoured, the scouring rate had a linear positive correlation with residual shear force. For the solid matter with a relatively low initial moisture content, the scouring rate increased slightly with the increase of the content of fine particles.[Conclusion] Under the condition of thin runoff, the energy slope gradient had a greater influence on the erosion rate, compared to the hydraulic radius.

Abstract:[Objective] The main driving factors affecting soil fungal communities in the main maize production areas were explored in order to provide theoretical basis for the restoration of soil quality in Jilin Province.[Methods] Jilin Province was divided into the humid mountainous area in the east, the semi-humid plain area in the middle and the semi-arid plain area in the west, according to the ecological environment and climate factors. Soils of maize planting area in these three regions was taken as the main research object. The composition of soil fungal community was analyzed by high-throughput sequencing technology, and canonical correspondence analysis were employed to further analyze the effect of chemical properties, enzyme activity characteristics of soils and environmental factors on fungal communities.[Results] The differences in chemical properties and enzyme activities among the three ecological regions were significant. There was no significant difference in fungal diversity, and the abundance of fungi decreased gradually from west to east. Ascomycota and Basidiomycota were the dominant fungal groups in phylum levels, and the Ascomycota group in the western semi-arid plain was significantly higher than that in the central semi-humid plain area. In contrast, Basidiomycota had an opposite trend. Sordariomycetes was the dominant class, showing a increasing trend from east to west, Guehomyces was the dominant genus, which was showing as follows:central planting area > Western planting area > Eastern planting area.[Conclusion] Accumulated temperature, frost-free period and annual average temperature are the main climatic driving factors that influence the change of dominant groups of soil fungi, and soil pH value is the main driving factor of soil chemical properties.

Abstract:[Objective] The evolution of ecological environment at Jiaozuo City, He'nan Province in the past 20 years was studied in order to provide reference for the transformation of other resource exhausted cities.[Methods] The data of five Landsat image data are selected, which included images in 2000,2006,2009,2014 and 2019. The index system including four indicators of green degree, humidity, temperature and dryness, and a evaluation model of remote sensing ecological index (RSEI) was established by principal component analysis, which could evaluate quantitatively the ecological environment quality of Jiaozuo City.[Results] ① From 2000 to 2014, the ecological environment of Jiaozuo City can be presented by shape of an inverted "U", and the quality of ecological environment rose in the next five years. ② The slow urbanization process and the transformation of industrial structure from the secondary industry to the tertiary industry have improved the ecological environment quality of Jiaozuo City. ③ In the regression analysis, the importance of the four selected indicators on the ecological environment in Jiaozuo City was:dryness > humidity > greenness > heat.[Conclusion] Remote sensing ecological index can effectively monitor and evaluate the ecological environment quality of resource exhausted cities.

Abstract:[Objective] The applicability and uncertainty of HSPF model in tropical coastal basins was explored in order to provide scientific reference for the application of HSPF model in different basins and regions.[Methods] Taking the Sanya river basin located in the tropical coastal region as a study area, a HSPF model was established, and the flow from 2017 to 2019 was selected to calibrate and verify the model. The sensitivity of 8 parameters in the hydrological process was analyzed by Morris screening method, and compared with the relative sensitivity of parameters in different watersheds studied at home and abroad. Meanwhile, the uncertainty of the model under different rainfall conditions were analyzed by MC-LHS method.[Results] The HSPF model could simulate the actual hydrological process in the study area very well. The NSE of the periodic and validation period was 0.93 and 0.98 respectively, and the R_e was 0.87% and 0.21%, respectively. Among which, base groundwater recession was the most sensitive parameter, while the influence of lower zone evapotranspiration parameter and proportion of groundwater flow into deep was almost negligible.[Conclusion] The relative sensitivity of the parameters reflected the spatial differences. The uncertainty of model simulation is significantly correlated with rainfall, the greater the rainfall is, the greater the uncertainty and confidence interval of the model simulation are, and the more unstable the model is.

Abstract:[Objective] The best suitable areas, suitable crops, and the effect difference between degradable and water-permeable mulching film were studied in order to provide theoretical guidance for the application of degradable and water-permeable mulching film.[Methods] The field researches on degradable mulch and water-permeable mulch were collected through the search of literatures, and a meta-analysis was performed based on these studies.[Results] The yield and WUE of all crops covered by degradable mulching film were significantly higher than that of no mulching; compared with ordinary mulching film, the degradable mulching film reduced the yield of corn and increased the yield of cotton, and there were no difference to other crops. The yield was lower than ordinary mulching film when the rainfall was less than 500 mm, while the rainfall was higher than 500 mm, there was no significant difference in yield. The yield and WUE of corn, wheat, millet and sorghum covered with water-permeable plastic film were significantly higher than those without mulching; compared with ordinary plastic film, the yield and WUE of corn and millet covered with water-permeable plastic film were higher than those of ordinary plastic film, especially in the millet which showed a significant increase in yield. Compared with ordinary mulching film, water-permeable mulching film had a significant increase effect in production in areas where the rainfall was less than 500 mm, and there was no difference above 500 mm. The soil temperature of the degradable mulching film in the late growth period was lower than that of the ordinary mulching film, while the temperature increase effect of the water-permeable mulching film at low temperature was better than that at high temperature, and the temperature of whole the growth period was more suitable for crop needs.[Conclusion] At present, degradable mulching film can basically replace ordinary mulching film on short-growth crops with rainfall greater than 500 mm, but it is risky to apply it on long growth period crops in areas with low rainfall; and water-permeable mulching film should be prioritized when rainfall is less than 500 mm in short growth period crop.

Abstract:[Objective] The prediction and optimization of the landscape pattern evolution in Yanhe River basin of loess hilly-gully region were studied in order to provide support for the construction and management of the ecological environment in this region theoretically.[Methods] Taking Yanchang County of Shaanxi Province in the lower reaches of Yanhe River basin as an example, based on the analysis of landscape pattern index over the years, the evolution of landscape pattern in Yanchang County was simulated by CA-Markov method, so as to analyze the landscape-change intensity and direction from the perspective of human disturbance. The landscape security pattern was established and hierarchical management and control measures were proposed.[Results] ① The division index of the landscape pattern in Yanchang County increased by 2.1% from 2008 to 2017, and the largest patch index decreased by 32.4%. ② In the coming 10 years, the forest landscape was expected to decrease by 18.5%, and the grassland was expected to increase by 13.1%. ③ The extreme,medium and mild ecological degradation areas in the study area accounted for 0.3%, 23.3%, and 48.4% of the total area, respectively. The landscape security pattern included 9 core ecological corridor and 21 general corridor. Human disturbance could represent the landscape resistance.[Conclusion] The implementation of hierarchical management and control, and the construction of landscape security pattern are of great significance for preventing the deterioration of the ecological environment in Yanchang County.

Abstract:[Objective] The performance of rural water environment governance was studied in order to provide theoretical supports for optimizing rural water environment governance.[Methods] The rural water environment management performance was assessed based on the satisfaction survey of farmers, by using 551 samples from Jiayu, Tianmen and Gong'an of Hubei Province. Based on the conception of "process-result", the influencing factors of rural water environment governance performancewere explored, from the dimensions of "process" and "result". Agent variable and instrumental variable methods were employed to solve the potential endogenous problems in the econometric model.[Results] ①In the overall satisfaction evaluation of the current rural water environment treatment, most respondents rated it as "moderate", accounting for 36.30%, and only 3.27% of respondents considered it as "very satisfied"; ② Among the variables of process performance, the centralized collection and transportation of domestic waste, improvement of village dry toilet, treatment of crop straw, renovation of domestic waste facilities, riverway renovation, professional staff, publicity of water environment management, public participation and renovation of domestic sewage pipe network had significant influences on the performance of rural water environment governance; ③ For the variables of results performance, the water quality of ditches and ponds also had significant impacts on the performance of rural water environment governance.[Conclusion] In the context of the implementation of the rural revitalization strategy, it is an important path to enhance the rural water environment by reinforcing river ecological reestablishment, speeding up the laying of rural sewage pipeline network, and strengthening the group management of professional personnel, as well as smoothing the channels.

Abstract:[Objective] The risk and loss of landslides in Hunan Province was evaluated to enrich the theories and methods of landslide prevention in Hunan Province in order to provide a scientific basis for reducing landslide disasters in this area.[Methods] Based on GIS technology and analytic hierarchy process (AHP), with the support of DEM, remote sensing, meteorology, lithology, seismic points and other data, the risk assessment of landslides in Hunan Province was evaluated from two aspects:risk assessment and vulnerability assessment.[Results] ① Most of the landslide risk grades in Hunan Province are in the middle and low risk grades, and a few of them are at high risk level. The medium risk level is the most, accounting for 31.31% of the whole province. The rest are low, moderate, relative high, and high risk levels, accounting for 24.92%, 22.09%, 13.88% and 7.79%, respectively. ② From the perspective of spatial pattern, the characters of the overall risk grade distribution are low in the northeast and southwest, while high in the southeast and middle.③ The loss level of Hunan Province is generally low in west and high in east, with middle in moderate and uneven distribution locally.[Conclusion] The landslide disaster in Hunan Province should be managed from two aspects of prevention and control, according to the common types of landslide in prefecture-level cities in Hunan Province, targeted regional different prevention and control plan should be formulated.

Abstract:[Objective] The impacts of the process of land use evolution on ecosystem service value in Jilin Province were analyzed and predicted in order to provide theoretical basis for the formulation of ecological environment protection and improvement policies and strategies in Jilin Province.[Methods] Based on the land use data of Jilin Province in 2000, 2010 and 2017, the CA-Markov model was used to simulate and predict the land use pattern in 2024, and InVEST model was used to analyze the change of ecosystem service value and the spatial-temporal evolution characteristics of habitat quality in Jilin Province from 2000 to 2024.[Results] ① From 2000 to 2024, the area of cultivated land, grassland and construction land increased continuously, while the area of woodland, water area and unused land decreased. ② From 2000 to 2024, the total value of ecosystem services showed a downward trend, among which forest ecosystem services value was the largest, and hydrological and climate regulation were the main ecological service functions. ③ The spatial distribution of habitat quality in Jilin Province was low in the central and western regions and high in the east. The quality of the habitat is deteriorating continuously, and the degradation is serious around the city and along the main river basins.[Conclusion] The habitat quality in the central and western regions of Jilin Province has declined seriously, thus, more attention should be paid on the protection and rational utilization of city surrounding zones and water systems.

Abstract:[Objective] Carbon emission and its influencing factors of farmers' agricultural production was studied in order to comprehensively and rationally understand the issue of agricultural carbon emissions and promote the development of low-carbon and sustainable agricultural.[Methods] We selected Huangpi District, Jiangxia District, and Ezhou City of Wuhan City, Hubei Province as the research areas to investigate the status of farmer's agricultural production carbon emissions, calculate carbon emissions from agricultural production, analyze the structural characteristics of carbon emissions from agricultural production, and finally analyze the influencing factors of carbon emissions intensity using the semi-logarithmic regression model.[Results] ①In terms of crop structure, the total carbon emission of rice cultivation was the largest, while the carbon emission intensity of lotus root was the largest. ② In terms of carbon emission sources, chemical fertilizers were the main cause of carbon emissions, followed by input from human activities. ③ In terms of the influencing factors of carbon emission intensity, the age of farmers, the number of years of farming, the proportion of average annual agricultural income, the area of arable land, land quality, participation in agricultural technology training, and the village cadres showed significant negative impacts on the intensity of carbon emission from agricultural production.[Conclusion] Technological advancement should be emphasized to promote the low-carbon development of agriculture, agricultural production subsidies should be increased, moderate scale cultivation should be advocated, and farmers' awareness of farmland protection and agricultural technology training should be strengthened.

Abstract:[Objective] The landscape pattern and its vulnerability of urban wetland were investigated in order to provide a scientific basis for urban wetland protection and sustainable development.[Methods] Based on the high-resolution WorldView-3 remote sensing images, the distribution information of landscape types was extracted, and the landscape spatial structure indicators including landscape diversity index, patch density and number of patches were selected, and the spatial pattern and heterogeneity of landscape composition as well as the landscape vulnerability were evaluated by using geographic information system technology and theory of landscape ecology in the Datong wetland of Huainan City in Anhui Province. Based on the landscape sensitivity and fitness indexes, the landscape vulnerability assessment model was constructed to evaluate the landscape vulnerability of Datong urban wetlands.[Results] ① The landscapes in Datong wetland with balanced area scale were dominated by arbor, water, and bare land. ② The landscapes were interlaced in space and formed a distinct "network structure", among which, the water, bare land, and Metasequoia glyptostroboides were continuously distributed, while the others were highly fragmented and heterogeneous. ③ The vulnerability of landscape pattern was dominated by low vulnerability, showing significant positive spatial autocorrelation and spatial aggregation pattern. The main "high-high" value aggregation areas and vulnerability hot spots were mainly distributed in eastern bare land. The "low-low" value agglomeration area and vulnerability cold spots were mainly distributed in the water body area. ④ Landscape vulnerability was consistent with vegetation coverage and landscape pattern complexity, that was, the higher the vegetation coverage and the greater the interlace of spatial distribution, the less vulnerable it was.[Conclusion] The landscape types in the Datong wetland mainly include arbor, water bodies, and bare land. The vulnerability of the landscape is mainly low, and shows a significant spatial agglomeration pattern. It has spatial consistency with the vegetation coverage and the complexity of the landscape pattern.

Abstract:[Objective] The effects of different amount of soil conditioner on soil chemical properties and rice growth in saline alkali soil were studied in order to provide reference for saline alkali soil improvement and rice planting in Northern Shaanxi Province.[Methods] Taking rice in saline alkali soil of Dingbian County in Northern Shaanxi Province as the research object, the field experiment was carried out with different soil conditioner application rates (1 000, 1 500, 2 000 kg/hm²).[Results] ① With the increase of soil conditioner dosage, the pH value and total water soluble salt content of 0-40 cm soil in each treatment were decreased significantly, and the reduction range of each treatment was 0.89%~5.02% and 6.78%~13.56%, respectively. ② After adding soil conditioner, the content of soil organic matter increased significantly, while there was no significant change in the content of total nitrogen, available phosphorus and available potassium. ③ When the amount of soil conditioner was 1 500 kg/hm² and 2 000 kg/hm², the tiller number and plant height of rice were significantly increased. ④ When the application amount of soil conditioner was 1 000~2 000 kg/hm², the rice yield was increased by 5.49%~24.77% compared with control group.[Conclusion] Considering the yield and benefit of rice, the suitable rate of soil conditioner is 1 500 kg/hm² for rice planting.

Abstract:[Objective] The effects of vegetation types on the leaching and migration of Fe/Mn in coal gangue dumps under natural vegetation restoration were discussed in order to provide a scientific basis for the ecological environment management and ecological restoration of coal gangue dumps in coal mining areas.[Methods] The surface runoff of the coal gangue yard under different vegetation conditions in the abandoned coal mine area of central Guizhou Province was sampled and analyzed. At the same time, pot experiment was carried out by transplanting Masson pine, Betula luminifera and reed growing on coal gangue yard, and the samples of matrix permeate water were collected.[Results] The content of Fe or Mn in the infiltrated water of coal gangue substrates, and in the surface runoff water of coal gangue pile site grown with Masson pine, Betula luminifera and reed was significantly lower than that of gangue without plant growth. After natural recovery vegetation at coal gangue pile site, the decrease rates of Fe and Mn contents in surface runoff water were 45.27%~85.60% and 60.17%~90.13% respectively, the order of vegetation effects was Pinus massoniana young forest > Broadleaf young forest > reed grass. The sediment content of surface runoff water in the gangue pile sites grown with Pinus massoniana young forest, broad-leaved tree young forest, and reed-like grass was reduced by 40.18%, 30.67%, and 27.91%, respectively, compared with that of gangue without plant growth, and the migration of mineral particulate Fe and Mn in coal gangue was also decreased significantly.[Conclusion] Natural vegetation restoration can significantly reduce migration of Fe and Mn from the coal gangue yard to the water and improve the surface water quality in abandoned coal mines. The environmental effect of plant growth on reducing the migration of Fe from coal gangue to water was greater than that of Mn, especially the growth of Pinus massoniana.

Abstract:[Objective] The spatial distribution of soil moisture and the determination of representative sample points under the infiltration irrigation system of plastic film mulching in semi-arid area was studied in order to provide scientific support for orchard water management in semi-arid area.[Methods] Taking the 4-year-old red plum apricot trees under the infiltration irrigation system of mulching rainwater in Pengbao Town, Yuanzhou District, Guyuan City, Ningxia Hui Autonomous Region as the research objects, based on the analysis of soil water distribution characteristics and time stability, the measuring points which could represent the soil profile moisture content around fruit trees were determined by mathematical statistics method, and the relationship between soil water content and representative sampling points were constructed in order to reduce the number and cost of monitoring points.[Results] ① The vertical and radial distribution characteristics of soil moisture were basically the same, the water content first increased and then decreased with the increase of soil depth and diameter distance.The variation coefficient of vertical soil moisture gradually decreased from 30 cm of the first infiltration point to the top, then increased and then decreased. The farther the radial soil moisture was from the infiltration irrigation device, the smaller the variation coefficient was. ② Through time stability, one sample was selected as the representative sample point in humid area. Trough the correlation and cluster analysis of the relationship between the vertical measurement points where the sample was located, it was concluded that the soil moisture content of the 3 representive monitoring points can represent the water content of the whole 0-60 cm depth profile. And verified by the measured data, the water content error was within ±5%.[Conclusion] The distribution characteristics of soil water content in all directions are basically the same. The 3 monitoring points are representative samples of the whole 0-60 cm depth profile.

Abstract:[Objective] The origin, formation process and characteristics of the "8·20" debris flow at Xiazhuang gully, Wenchuan, Sichuan Province in 2019 was explored in order to provide a scientific reference for the prevention and early warning of debris flow disasters in the region.[Methods] Based on field surveys and remote sensing images, debris flow source supply conditions, debris flow formation, erosion transport and river blockage process were analyzed. And FLO-2D model was used to analyze the extent of Xiazhuang debris flow blockage under different rainfall intensities.[Results] After the earthquake, part of the debris flow in the debris flow basin continued to erode the source of the channel, resulted in the accumulation of gully material source. Runoff formed by short-duration heavy rainfall continuously eroded the gully material source and formed a channel-initiated debris flow. A large amount of debris from the "8·20" debris flow in Xiazhuang gully was transported out of the ditch, and formed a dammed body with a length of 280 m along the river and a maximum width of 110 m across the river. The blocking mode of the river was full blockage of the dam. Under the frequency of 5-year rainfall, the material source would stay in the channel without blocking the river. Under the frequency of 20-year rainfall, the debris flow basically would block the Zagunao river and form a blocking phenomenon. Under the frequency of rainfall once in 50 years, the debris flow would completely block the Zagunao river and form a dammed lake.[Conclusion] Xiazhuang gully and Zagunao river intersect vertically, and the diversion dam of a hydropower station is built at the mouth of the gully, which is easy to form the phenomenon of dam blocking. During the flood season, when the rainfall intensity is high, debris flows may still cause river blockage. In the future, the prevention and control of debris flows need to strengthen flood prevention and early warning and other disaster reduction measures.

Abstract:[Objective] The resilience level of He'nan Province after flood disasters was studied in order to provide decision-making basis for flood control and disaster reduction planning and emergency capacity construction.[Methods] He'nan Province, where flood disasters occurred frequencely, was chosen as the study area. The key influencing factors of flood disaster resilience were identified based on the literature review, and the evaluation index system and model were built from four dimensions of society, economy, nature and technology. The relative weight of each index was determined using the analytic hierarchy process (AHP) method, and the flood resilience level of each city in He'nan Province was calculated using the comprehensive index method. The evaluation results were mapped using ArcGIS software.[Results] ① The resilience level of flood disasters in He'nan Province presented a certain spatial distribution pattern. In general, there was a decreased trend from the northwest to southeast. ② Among six cities, Zhengzhou and Jiyuan City were rated as level Ⅲ, which belonged to the high resilience area. Other cities, such as Nanyang and Xinyang were rated as level Ⅰ, which belonged to the low resilience area. The remaining cities were rated as level Ⅱ, which belonged to the middle resilience area. ③ The percentages of the areas with low, middle and high resilience levels in He'nan Province accounted for 42.58%, 35.11% and 22.31% of the total area, respectively.[Conclusion] The resilience of flood disasters in He'nan Province is in the low and middle level, which has a certain influence on regional sustainable development.

Abstract:[Objective] The impacts of ecological restoration in the middle reaches of Yellow River on water resources were studied in order to provide a scientific basis for the eco-environment protection and high-quality development of the basin.[Methods] Based on the GIMMS NDVI, ET, soil moisture, surface runoff and other hydrology data, the study used trend analysis and double cumulative curve methods to analyze the spatial and temporal characteristics of the evapotranspiration, soil water and surface runoff in the middle reaches of Yellow River, before and after ecological restoration.[Results] From 1982 to 2018, the fractional vegetation cover of the middle reaches of Yellow River increased by 29.72%. As the fractional vegetation cover increased by 1%, the evapotranspiration increased by 3~4 mm. In the ecological restoration area, the decline rate of soil moisture was 0.001 3% per year. The average runoff was decreasing from 1961 to 2018, and human activities represented by ecological restoration played an important role in the decline of runoff.[Conclusion] Due to the climate warming and drying and ecological restoration, there is a serious shortage of water resources in the middle reaches of Yellow River. People should consider water resources comprehensively, reduce human interference, and focus on natural vegetation restoration in the follow-up ecological restoration.

Abstract:[Objective] The habitat quality of the high-efficiency eco-economic zone in Yellow River delta (YRD) was studied in order to reveal the impact of human activities on the ecological environment of the region and provide references for the ecological protection and development of the YRD.[Methods] Based on the land use data of the YRD in 2000, 2010 and 2018, the InVEST model, land use degree index and bivariate space autocorrelation model were used to analyze the spatial-temporal evolution characteristics of habitat quality and its correlation with land use change.[Results] ① Cultivated land and wetland were the main land use types of YRD. Construction land and wetland increased continuously. The main change direction was from cultivated land, grassland and unused land to wetland and construction land. ② The habitat quality of the YRD was above medium level on the whole. Medium, medium-high and high grades areas accounted for more than 82%, and the habitat quality kept improving. However, the habitat quality showed a "mid-course reduction and two-end growth" trend, in which the habitat quality of medium-low, medium and medium-high decreased while the habitat quality of high and low increased continuously. ③ The habitat quality of the YRD showed a significant spatial heterogeneity. The habitat quality of coastal and along the Yellow River areas dominated by wetland was higher, while that of construction land and cultivated land distribution area was lower. ④ There was a significant negative correlation between land use degree and habitat quality, and the correlation was increasing.[Conclusion] The connectivity protection should be strengthened for the high-grade habitat in YRD, and green space construction shuold be strengthened for the built-up areas with serious habitat degradation to improve the habitat quality.

Abstract:[Objective] The suitability of ecological-living-industrial spaces in the Southwestern Guangxi-Beibu Gulf region was evaluated in order to provide a reference for the complex transitional geographic space to achieve the ecological-living-industrial and land-sea coordination, and to provide theory for scientifically delineating the spatial layout of the land.[Methods] The spatial suitability evaluation index system of ecological-living-industrial in Southwestern Guangxi-Beibu Gulf region was constructed. The coefficient of variation method was used to determine the index weights, and the evaluation results were analyzed by ArcGIS technology.[Results] ① The industrial and ecological suitability in the transitional and complex geographic spatial distribution characteristics of the karst and Beibu Gulf region in Southwest Guangxi Zhuang Autonomous Region showed "mutual-differences". From karst to coastal areas, the production space suitability increased gradually, but the ecological space suitability decreased gradually. ② The suitability of living space in karst area was generally weaker than that of Beibu Gulf region. ③ In the suitability evaluation of composite space, the proportion of compound space dominated by ecological space was the highest (accounting for nearly 1/2), followed by production space sand the living space. ④ The proportion of marine ecological-living-industrial suitability in descending order was production-ecology-production and living, and there was a conflict between coastal marine ecological space and terrestrial production and living space.[Conclusion] The suitability of ecology and production space is mainly restricted by natural conditions, and the suitability of living space is mainly affected by administrative location. There is a game between ecological protection and social and economic development in coastal zone.

Abstract:[Objective] The spatial and temporal evolution and formation mechanism of ecological land was studied in order to provide scientific reference for maintaining regional ecological balance and ensuring the construction of ecological civilization.[Methods] The land use change amplitude, Lorentz curve, Gini coefficient, regression analysis and GIS technology were used to comprehensively analyze the spatial-temporal evolution characteristics of ecological land in Fuxian Lake basin from 2010 to 2018, and discuss its formation mechanism.[Results] ① The main types of ecological land use in Fuxian Lake basin were cultivated land, forest land, water area and water conservancy facilities. In the past 8 years, the area of arable land, woodland, grassland, garden land and other land decreased by 5.15, 1.94, 0.81, 0.19 and 1.40 km², respectively, while the area of water and water conservancy facilities increased by 0.03 km². ② The spatial distribution of various ecological land in the river basin was quite different, the spatial distribution of cultivated land and forest land was relatively uniform. The Lorentz curve was relatively close to the absolute uniform line, and the Gini coefficient was 0~0.25. The distribution of grassland, garden land, water area and water conservancy facilities, unused land were relatively concentrated. The Lorentz curve was more concave, and the Gini coefficient was mostly above 0.5. The uneven spatial distribution of ecological land has strengthened. ③ From the perspective of driving mechanism, the main driving factors that driving the temporal and spatial changes of ecological land in the river basin were population density, urbanization level, policy, distance to major roads, distance to waters, and distance to urban built-up areas.[Conclusion] During the study period, the temporal and spatial changes of the ecological land in Fuxian Lake basin were significant, which is the result of the synergistic effect of various factors, such as natural conditions, socio-economic conditions and spatial location conditions.

Abstract:[Objective] The spatial-temporal change of land use and its driving mechanism in Dongjiang River basin from 1990 to 2018 was analyzed in order to provide support for the land us optimization.[Methods] Four evaluation indexes of land use, principal component analysis and grey relation analysis methods were employed to investigate the land use change and its driving mechanism.[Results] ① From 1990 to 2018, the land use types were mainly forest and farmland, the area of construction land continue to increase, while the area of other land use types decreased. The cultivated land and forest land were the main transferring sources of the construction land. ② The comprehensive land use index of the river basin increased year by year with an annual rate of 0.038, which indicated that the land use was in an upward developing trend. ③ Rapid economic development, population growth, social affluence, and agricultural development were the main driving forces of land use change, while the effects of various driving factors on land use change were different.[Conclusion] From 1990 to 2018, the land use structure of Dongjiang River basin was continuously optimized, while the land use agglomeration was constantly increasing. With the development of the Guangdong-Hongkong-Macao greater bay area, land development and utilization activities will be more frequent within the basin area.

Abstract:[Objective] The interaction between urbanization system and water resource system was studied in order to provide a scientific basis for the correct evaluation of the coupling and coordination relationship between urbanization and water resources, and to provide decision reference for promote the coordinated development of regional population, resources, economy and ecological environment.[Methods] Apply coupling and coordination research achievement, the urbanization evaluation index system was established from three aspects of population urbanization, land urbanization and social urbanization build. Water resource evaluation index system was established from water resources levels, water resource stress and water resource management, and then the coupling and coordination evaluation index system about urbanization and water resources was established. Based on the relevant data from 2008 to 2017, the coupling degree development index and coordinated development degree between urbanization and water resources in Yunnan Province was quantitatively calculated. According to the classification of coordinated development types, the coordinated development types and comparison types in Yunnan Province during the study period were divided, and the coordination status was evaluated. At the same time, with the support of GIS technology, taking 2008 and 2017 as the time points, the spatial pattern characteristics and spatial pattern of variation characteristics between urbanization and water resources in different cities (states) in Yunnan Province were studied.[Results] ① From the characteristics of time series, the coordinated development of urbanization and water resources experienced two phases, namely, run-in phase and coordination phase.② The urbanization lag had shifted to water resources lag since 2013 in Yunnan Province. ③ From the feature of spatial pattern, the spatial pattern with Kunming City as the center gradually changed from the central "coordination" to the edge "disorder".[Conclusion] There is a high degree of interdependence between urbanization and water resources in Yunnan Province. The coordinated development and overall development trend is good, but the spatial difference of the coordinated development types is significant. The process of urbanization has promoted the efficiency of water resources, at the same time, the improvement of support of water resources for economic and social development effectively promoted the process of urbanization.

Abstract:[Objective] Based on the scale of network unit, the regional land use evolution and its ecosystem service value response characteristics from 1990 to 2019 were studied in order to provide decision-making basis for ecosystem protection and land spatial planning in rapid urbanization area represented by Gongyi City.[Methods] Based on the interpretation data of land use from 1990 to 2019 and the modified ESV equivalent at the grid scale, the ecosystem service value was estimated at Gongyi City, He'nan Province, and its spatial auto-correlation characteristics were discussed.[Results] ① During the study period, the growth rate of construction land in Gongyi City was the highest, on the contrary, the water area and shrubbery decreased significantly, with a decline of -45.17% and -10.09% respectively. In terms of land type transfer, the area of water and cultivated land was the most, and the main transfer out types were cultivated land and construction land. ② The value of ecosystem services showed a fluctuating downward trend, with a total decrease of 3.485 billion yuan in the past 30 years. Water area, arbor forest and cultivated land were the main components of ESV in Gongyi City. From the perspective of change characteristics, ESV in water area decreased significantly, with a total decrease of 3 554.9 million yuan. The regulation services dominated by hydrological regulation and climate regulation played a leading role in the composition of regional ESV, and its loss rate in the past 30 years was at a high level. ③ Spatial exploratory analysis showed that ESV had declined significantly in recent 30 years, and the negative effects of regional urbanization process on ecosystem were significant. The changes of high and low value areas of ESV in the north were mainly water area, cultivated land and construction land, while those in the south were mainly forestland and high coverage grassland, which were relatively stable. In 1990, the higher ESV areas were concentrated along the Yellow River, Yiluo River and Fuxi Mountain in the south, while the areas with lower ESV were mainly Gongyi City and the areas with relatively flat terrains in the east and the west. After 2000, the areas with higher ESV were rapidly reduced and mostly concentrated along the Yellow River. During 2000-2010, the low value ESV area in the main urban area gradually spread under the influence of rapid urban expansion. The low value concentration area of ESV had been formed in the urban area and the west and east oriented two belt areas of Gongyi City-Zhitian Town-Huiguo Town and Gongyi City-Zhulin Town-Mihe Town.[Conclusion] The expansion of construction land in Gongyi City is intensified, which leads to the continuous decline of regional ecosystem, and the spatial distribution is closely related to the development of human society and economy.

Abstract:[Objective] The temporal and spatial variation characteristics of rainfall erosivity in mountainous areas of Hebei Province were studied in order to provide a scientific basis for the formulation and implementation of soil erosion control measures in this area.[Methods] The rainfall erosivity in mountainous areas of Hebei Province from 2000 to 2018 was analyzed by using temporal variation analysis and spatial distribution analysis.[Results] At the temporal scale, the annual rainfall erosivity of Yanshan Mountain showed a fluctuating upward trend, with a main period of 11 years, and a sudden change occurred in 2009. The spring and autumn showed a fluctuating downward trend. The main periods were 8 and 11 years, respectively. Abrupt changes occurred in the autumn in 2001, and the summer showed an upward trend of fluctuations. The main cycle was 9 years, and the sudden change occurred in 2010. The annual rainfall erosivity of the Taihang Mountains showed a fluctuating downward trend, with the main cycle of being 6 years and no sudden changes. The summer and autumn showed a fluctuating upward trend, the main periods were 8 and 10 years, respectively, and there were no mutation points. The spring showed a downward trend of fluctuations, the main period was 8 years, and a sudden change occurred in 2006. At the spatial scale, the average annual rainfall erosivity range was 1 063.39~5 127.44 MJ·mm/(hm²·h). Average annual and summer rainfall erosivity increased first, then decreased, then increased from west to east in the Yanshan Mountain area, and gradually decreased from south to north in the Taihang Mountain area. The distribution of rainfall erosivity in the two seasons was relatively variable.[Conclusion] Through the analysis of rainfall erosivity in mountainous areas of Hebei Province, it is concluded that summer soil erosion is the most serious, especially in some areas of Yanshan mountainous area.

Abstract:[Objective] The ecological security pattern and its influencing factors were studied in order to provide basis and reference for the construction of ecological security in Zhejiang Province, and ensure the overall economic, social and ecological development of the Yangtze River Economic Zone.[Methods] Based on the economic, social and environmental data and the "pressure-state-response (PSR)"" ecological safety evaluation index system, the spatial-temporal evolution characteristics of ecological security pattern in Zhejiang Province from 2009 to 2018 were analyzed by entropy method. The key factors that revealing the impact of key factors on ecological security were extracted by combining the PSR sub-index and factor analysis method.[Results] ① From 2009 to 2018, the comprehensive eco-security index (ESI) of Zhejiang Province fluctuated slightly. ② From the perspective of space, the ESI of Zhejiang Province has reached the early warning state, showing a spatial pattern of changing from "high in the south and low in the north" to "High in the north and low in the south". ③ From the perspective of time nodes, the best year for ecological security of Zhejiang Province was 2016 (0.123), while the worst year was 2011 (0.077), which were in a relatively safe state and a critical security state respectively. ④ Urbanization, economic development, social development, industrial development and resource condition were the important factors affecting the ecological security pattern in Zhejiang Province.[Conclusion] National and regional planning and policies impact the ecological safety index of Zhejiang Province significantly. In order to fully guarantee the ecological safety and healthy development of Zhejiang Province, it is necessary to continuously increase investment in ecological safety construction, promote the co-administration of five kinds of water, promote intelligent and green manufacturing industry, cultivate a number of typical demonstration sites of ecological civilization in ancient villages and characteristic towns, and improve the ecological environment quality.

Abstract:[Objective] The temporal and spatial changes and driving forces of vegetation coverage in Hami Oasis in the past 30 years were analyzed in order to provide theoretical reference for the sustainable and healthy development of oasis in this area.[Methods] Based on the 4 images of 1988, 1998, 2008 and 2018, the vegetation coverage extracted from the AFRI_SWIR2 index was calculated using the pixel binary model. The vegetation coverage of Hami Oasis was analyzed using the dynamic index and the vegetation coverage transfer matrix. Then, 8 influencing factors were detected by the geographic detector, to explore the driving factors of the vegetation coverage of Hami Oasis.[Results] In the past 30 years, the area of Hami Oasis increased from 214 km² in 1988 to 632.1 km² in 2018, with increase range of 195%. The development speed was relatively fast, but the level of vegetation coverage in the oasis was low. At the same time, the main expansion area was in the northwest and southeast regions. The development stage was defined as follows:1988-1998 was the low-strength stable period, 1998-2008 was the period of extreme expansion, and 2008-2018 was the high-strength stable period.[Conclusion] The change of land use type is the direct cause of the change of vegetation coverage in Hami Oasis. At the same time, in the past 30 years, the influence of human factors on vegetation coverage of Hami Oasis is much higher than natural factors.

Abstract:[Objective] The formation mechanism of the group flash flood/debris flow disasters in Ganluo County of Sichuan Province in 2019 was analyzed in order to provide a reference for the prevention and mitigation of flash flood/debris flow disasters in mountainous areas.[Methods] Based on the field investigation of the group flash flood/debris flow disasters in Ganluo County in 2019, combined with relevant images and rainfall data, the influencing factors and formation mechanism of flash flood/debris flow disasters were analyzed.[Results] The flash flood/debris flow disasters in Ganluo County were mainly caused by short-term heavy rainfall, in addition, there were abundant solid resources and favorable landform conditions in the area. The flash flood/debris flow disasters were the production of the interaction between flood and solid materials. The flash flood/debris flow movement was affected by terrain and some engineering facilities. Meanwhile, the flash flood/debris flow squeezed the main channel or even blocked the channel, thus leading to more disasters.[Conclusion] Based on the formation mechanism and disaster-causing characteristics of flash flood/debris flow disasters in Ganluo County, the disaster control measures shuld be based on strengthening ecological restoration and soil and water conservation in disaster-stricken areas, and combining engineering prevention and ecological control.

Abstract:[Objective] The characteristics and driving factors of spatial variation of land use in Jilin Province were analyzed in order to provide scientific basis for sustainable development of land use and ecological environment construction.[Methods] Based on the land use data of Jilin Province in 1990 and 2018, the location index, diversification index, information entropy and equilibrium degree of land use were calculated. Combined with Moran index, the spatial auto-correlation was explored to analyze the land use spatial differentiation characteristics in Jilin Province.[Results] ① From 1990 to 2018, the characteristics of land use in Jilin Province generally maintained a double dominance of forest and cultivated land, the double dominance of cultivated land in the west and the central part were relatively increased, the double dominance of water area were disappeared, and the double dominance of cultivated land in Changchun City in the central part was developed. ② The land use diversification index, information entropy and equilibrium index of Jilin Province kept high in the west and low in the east, but those three indexes showed an overall trend of decline in other areas, except for the main urban area of Changchun City. Both the diversity index and the information entropy had positive global auto-correlation. The high-high pattern aggregation area was in the western region of Jilin Province, and the aggregation area was shrinking. The aggregation area of low-low pattern was generally stable. ③ Natural environmental factors (temperature, precipitation) had a relatively significant impact on the spatial differentiation of land use.[Conclusion] The land use change in Jilin Province has obvious spatial differentiation characteristics, and natural environmental and social and economic factors are the main driving factors.

Abstract:[Objective] The temporal and spatial variations of the water ecological characteristics of Guangxi Zhuang Autonomous Region in recent 10 years, and the driving factors of the water ecological footprint changes were studied in order to provide reference for the rational development, utilization and management of water resources of Guangxi Zhuang Autonomous Region or similar regions.[Methods] Based on the water resources consumption ecological footprint, water resources ecological carrying capacity and water ecological capacity indexes in the ecological footprint model, the temporal and spatial variations of the water ecological characteristics in the study area from 2008 to 2017 were analyzed. LMDI model was used to analyze the driving factors of the ecological footprint changes and the contribution rate of each prefecture-level city in the key driving factor.[Results] ① The ecological footprint of water resources per capita presented an overall downward trend, with an average decline rate of -0.017 4 hm²/(person·year). The water resources ecological carrying capacity and water resources ecological capacity showed a fluctuating upward trend, with the average rising rate of 0.324 6 hm²/(person·year) and 0.342 1 hm²/(person·year) respectively. All of them showed a certain differences and imbalances in space. ② Economic effect and population effect were the first and second factors to promote the growth of the water ecological footprint in the study area, contributing efficiency of 191.8% and 25.38% respectively. Technical effect and structural effect were the first and second factors restraining the water ecological footprint growth, with contributing efficiency of -238.0% and -79.18% respectively. ③ Nanning City and Guilin City contributed the most to reduce the water resources consumption ecological footprint in terms of structural effect and technical effect.[Conclusion] The ecological capacity of water resources in Guangxi Zhuang Autonomous Region was in an ecological surplus state. However, great differences existed among different cities in urban development and planning, so countermeasures should be taken according to local conditions.

Abstract:[Objective] The land use situation and its terrain gradient distribution pattern in the alpine canyon area was analyzed to clarify the functional zoning in order to provide references for the sustainable use of land resources in similar areas.[Methods] Taking Lushui City of Yunnan Province as an example, the distribution and change characteristics of land use on the terrain gradient were analyzed by using terrain niche index and distribution index in the alpine canyon area.[Results] ① The land use of Lushui City had a significant dominant distribution characteristic. From 2000 to 2018, the proportion of woodland as the dominant land use type increased from 77.50% to 84.49%. Construction land also increased rapidly, from 2 804.49 hm² to 4 785.65 hm². Unused land, arable land, and grassland gradually converted to woodland, and the area decreased by 14 368.38, 5 171.68, and 4 049.54 hm², respectively. The water area was stable around 900 hm². ② The hierarchical differences in terrain gradient in the land use pattern of Lushui City were remarkable. Woodlands showed a dominant position in the entire terrain gradient. Water, construction land, and arable land were widely distributed in low and middle terrain niche index area. The dominant area of the grassland was in the medium terrain niche index area with a high slope but low elevation. Unused land dominated in the high terrain niche index area. ③ Based on terrain differentiation laws, Lushui City could be divided into 4 major functional areas:river valley intensive development area, steep slope comprehensive treatment area, mid-alpine ecological promotion area, and mountaintop ecological closed area.[Conclusion] The land use in the alpine canyon area has formed a unique multi-level distribution pattern on the terrain gradient, with the potential for zoning development, and should be corresponding to different land-use development strategies.

Abstract:[Objective] The temporal and spatial evolution characteristics of land use and ecological service value (ESV) in the urban agglomeration on the northern slope of Tianshan Mountains were studied in order to provide theoretical guidance for the improvement of ecological service functions and the construction of ecological landscape in this area.[Methods] Based on the land use data of the urban agglomeration on the northern slope of the Tianshan Mountains in 2000, 2010, and 2018, the characteristics of the land use dynamics and the ecological service value of the urban agglomeration on the northern slope of the Tianshan Mountains were analyzed using remote sensing and spatial statistical analysis methods. The landscape index model was used to explore the landscape pattern changes of the urban agglomeration on the northern slope of Tianshan Mountain.[Results] ① The main types of land used in the urban agglomeration on the northern slope of Tianshan Mountains were unused land and grassland. The dynamic change of land use for construction land was the largest. The land use transfer mainly occurred from grassland to cultivated land, cultivated land and unused land. And the transfer from grass land to cultivated land and construction land was the most prominent. ② The total amount of ESV in the study area in the past 20 years decreased from 141.176 billion yuan to 140.017 billion yuan, with a total loss of 1.059 billion yuan. The overall trend was declining, and grassland had the most ESV loss. ③ The ESV of the study area presented a spatial pattern of high in the northwest and middle, and low in the north and southeast. the ESV landscape pattern of the study area changed significantly from 2000 to 2018, and the landscape pattern of the low, medium and high ESV density areas was characterized by fragmentation and heterogeneity in the early stage of the study, and the homogeneity of agglomeration in the later stage.[Conclusion] The ecological environment of the urban agglomeration on the northern slope of the Tianshan Mountains is deteriorating. For different grades of ESV areas, different measures need to be taken to improve the ecological service value of the study area, reduce the damage to the ecological environment caused by the development of the urban agglomeration, and promote the construction of ecological landscape.