Abstract:[Objective] The soil erosion of topsoil in agricultural forestry production in Loess Plateau was researched in order to provide scientific basis for the selection and allocation of tree species in ecological restoration in this area and its similar areas.[Methods] The shear mechanical properties of topsoil under four different vegetation community types including poplar + Caragana korshinskii mixed forest, poplar pure forest, Pinus tabulaeformis evergreen coniferous forest and C. korshinskii shrub pure forest were studied, and the influence of soil moisture content on its mechanical properties was analyzed.[Results] In the range of 2.5%~12.5% of the water content of the test topsoil, the shear strength and adhesion of the surface soil were increased with the increase of soil moisture content in 4 different vegetation types and bare ground, indicating that the increase of soil moisture played a positive role in improving the anti-erodibility of soil surface in a certain range. The shear strength and adhesion values of topsoil under 4 different vegetation community types were significantly larger than those of bare land, which indicated that the soil and water conservation measures had improved surface soil structure, thus improving the anti-erodibility of the surface soil. There was no significant change in friction angle of surface soil with the increase of water content in the range of 2.5%~12.5%.[Conclusion] The shear strength and cohesion of the topsoil under the mixed forest of lime + poplar were the greatest among the four different vegetation community types, which also explained the superiority of mixed forest in forest and grass measures of soil and water conservation.

Abstract:[Objective] The erodibility of topsoil on purple soil sloping farmlands in the Three Gorges reservoir area was investigated in order to provide a basis for spatial allocation design of soil conservation measures.[Methods] Two different kinds of purple soil sloping farmlands with soil bunds, horizontal ditch were selected, and topsoil was collected to determine the particle composition and organic matter content. Then the soil erodibility index was calculated by the environmental policy-integrated climate (EPIC) model, as to compare the particle composition, organic matter content and erodibility of the topsoil on purple soil sloping farmlands with different soil conservations.[Results] ① The content of silty particle in the topsoil of purple soil sloping farmlands was higher, and ranged from 45.78% to 76.29%, while the content of clay particle was relatively lower, ranged from 6.05% to 10.58%. At the slope scale, silty particle content at the lower slope of the upper field was significantly higher than that at the uphill position of the adjacent downhill plot, while sandy particle content was the opposite. At the field plot scale, sandy particle content was higher in the upper slope, and silty particle content and clay particle content were both higher in the middle and lower slope. ② The content of soil organic matter in topsoil on purple soil sloping farmlands ranged from 0.61% to 1.48%. At the slope scale, the organic matter content in topsoil of the lower slope of the upper field was significantly higher than that in the upper slope of the adjacent downhill plot. At the field plot scale, the organic matter content in the topsoil was mainly concentrated in the middle and lower slope. ③ The erodibility K value of topsoil on purple soil sloping farmlands was ranged from 0.043 8 to 0.059 2. At the slope scale, the erodibility K value at the upper slope of the lower slope of ridge and horizontal gully farmland was 16.55% and 6.30% lower than that at the lower slope of the adjacent upper field, respectively. At the field plot scale, the erodibility K value was higher in the middle and lower slope. The highest value occurred at the 3/4 of the slope. The erodibility K value of topsoil was positively related to silty particle content (p<0.01), while negatively related to sandy particle content (p<0.01).[Conclusion] The anti-erosion capability of topsoil on purple soil sloping farmlands in the Three Gorges reservoir area is weak. Both soil bund and horizontal ditch have good soil conservation effects on purple soil sloping farmlands, which play an important role in improving the capability of soil anti-erosion.

Abstract:[Objective] This study investigated the rainfall, runoff, land use changes during the period of 1995-2016 in the upper reaches of Sancha river basin, the water source area of the Qianzhong hydraulic project. The impacts of land use change on runoff were explored in order to provide a reference for predicting future changes of the water resources in the basin and the allocation of water resources in Qianzhong hydraulic project.[Methods] The relationship between rainfall and runoff was analyzed by conventional linear regression and result simulation. The impact of land use change on runoff was studied by using the land use dynamic change index and transfer matrix.[Results] The rainfall and runoff in the upper reaches of Sancha river watershed fluctuated and declined during the past 20 years, and the evolution processes could be divided into two stages:1995-2010 (stageⅠ) rainfall and runoff showed a downward trend. 2010-2016 (stageⅡ) rainfall and runoff showed a downward trend, but the decline of runoff was greater than rainfall. Since 1995, the land use change in the basin was obvious. The area of grassland and woodland increased by 5.33% and 3.63%, respectively. The cultivated land decreased by 6.92%. The dominant changes in land use types were conversion from cultivated land to forestland, grassland and construction land. In addition to the impact of rainfall, land use change was the major factor affecting the continuous decline of runoff. During the period of 2010-2016, the area of grassland and woodland increased by 19.93% and 5.25%, while the cultivated land and unused land decreased by 13.93% and 87.97%, respectively, indicating that land use change was the main reason for the significant decrease in runoff. In addition, the construction of Pingzhai reservoir in the Qianzhong water control project had an important impact on the reduction of runoff to a certain extent.[Conclusion] Land use change in the upper reaches of the Sancha River was closely related to the changes of runoff, which reduced watershed runoff.

Abstract:[Objective] The soil enzyme activities in different artificial forage in the Loess Plateau was researched in order to provide a scientific basis for improving the stability of artificial vegetation and soil fertility on the Loess forage.[Methods] Seven grasslands planted 3 years including Poa crymophila, Elymus nutans, Uraria crinite, Elytrigia intermedia, Medicago sativa, Astragalus adsurgens, Onobrychis viciaefolia, were selected as the research objects. Soil samples were taken from 0-5 cm and 5-10 cm soil layers in March, June, September and December, to investigate the activity of urease, sucrose enzyme, alkaline phosphatase and catalase.[Results] The activity of urease, sucrose enzyme, alkaline phosphatase in 0-5 cm layer was higher than that in 5-10 cm layer, but there was no significant difference in the activities of catalase between the two soil layers. The activity of urease, sucrose enzyme, and alkaline phosphatase in June was higher than that in March, September and December, but the activity of catalase was not significant different. The activity of soil enzyme in M. sativa was the highest, while the lowest in A. adsurgens. The interaction of soil depth and season had a significant effect on the activities of four enzymes(p<0.01). Herbage variety and season showed significant interaction on the activity of the urease, sucrose enzyme and phosphatase.[Conclusion] The soil enzyme activities of different grasslands in the Loess Plateau changed seasonally, and planting artificial forage could effectively improve soil enzyme activities and soil fertility conditions.

Abstract:[Objective] The variation of vegetation community and soil nutrients in artificial grassland was studied and the long-term successional mechanism of artificial grasslands was explored in order to provide theoretical basis for the near-natural restoration of degraded alpine meadow (wetland).[Methods] The vegetation communities and soil nutrients of artificial grassland with different planting years (3, 11 and 17 years) were investigated in Maqin County of Qinghai Province, the source region of the Yellow River. Random forest analysis was used to determine the variation of vegetation community and soil nutrient characteristics of artificial grassland under different restoration years.[Results] The coverage of dominant species Elymus nutans decreased with the increase of restoration years, while the total coverage, biological crust coverage, weed coverage and reproductive branch number showed an inverted "V" shape of variation. The Cyperaceae coverage and species richness increased gradually with the increase of restoration years. The coverage of Cyperaceae in 17 years artificial grassland was 10 times of that in 3 and 11 years. The total nitrogen, total potassium, available nitrogen, available potassium and organic matter in soil increased with the increase of restoration years. The soil pH value tended to be neutral with the increase of restoration years. The greatest differences among vegetation with different restoration years was the soil total nitrogen content, with the average accuracy degraded about 25.71. Followed by the organic matter content, the average accuracy degraded about 18.55. The differences of total potassium content and Pielou index among vegetation with different restoration years were the smallest, and the average index degraded was less than 5.[Conclusion] The vegetation community structure and soil nutrient of artificial grassland with 17 years restoration are gradually recovering, but the soil total nitrogen and organic matter content of the artificial grassland is only half of the original alpine meadow soil, and it will take a long time for the soil nutrient to recover completely.

Abstract:[Objective] The influences of flooding on the growth and plant diversity of typical riparian forest communities in the desert was quantitatively analyzed in order to provide a theoretical basis for improving the scientific water replenishment plan and the efficient use of ecological water in arid area.[Methods] Data were obtained from vegetation surveys in the upper and middle reaches of the Tarim River from 2016 to 2018. The impacts of flooding were analyzed using the Pielou index, Shannon-Wiener index, Simpson index and important values.[Results] After flooding for 2 years, 11 new plants were found in the upper and middle reaches of the Tarim River, mainly Populus euphratica, Tamarix chinensis, hygrophilous plant and annual herb. The density of P. euphratica increased by 0.72 plants/m², with a growth rate of 855.9%. The new branch length of T. chinensis increased by 41.8 cm, and the growth rate was 71.58%. The growth of P. euphratica was significantly improved as the occurrence of good quality P. euphratica increased by 0.11 plants/m² with a growth rate of 32%. With the increase of the distance from ecological gate, the density of P. euphratica forest showed a tendency of decrease, and the aging of the forest became more prominent. The species diversity under the forest showed a tendency of decrease with the increase of the flooding distance. Within 300 m from the ecological gate, the seedlings of P. euphratica, T. chinensis and the hygrophilous one year or perennial herb became the dominant species (the important values were 0.243, 0.195 and 0.248, respectively). When the distance was greater than 300 m, the dominant species were gradually replaced by perennial herbs of T. chinensis and drought-tolerant herbs. The annual herb, P. euphratica and T. chinensis disappeared at 450 m away from the ecological gate.[Conclusion] Flooding irrigation enhanced the regeneration ability of plant communities and species diversity in desert riparian forests. In order to maintain the current ecological improvement trend, the flood irrigation project needs to be continued.

Abstract:[Objective] The community composition, diversity, dynamic characteristic and vertical distribution of soil mesofauna was investigated in order to reflect the soil environment and provide the reference for exploring the suitable farming methods in the black soil area.[Methods] Soil mesofauna was isolated by modified tullgren method, the community structure and distribution characteristics of soil mesofauna under different tillage methods were analyzed and compared.[Results] A total of 3 749 soil mesofauna were collected from the study plots, belonging to 47 groups. Among which, Quadroppiidae and Isotomidae were the dominant groups in the experimental area. Under the three tillage methods, the number of soil mesofauna in the 0-10 cm soil layer accounted for 71% of the total number of individuals, and the vertical distribution had obvious surface aggregation. The number of soil mesofauna was the highest(1 671) under deep pine(DP)treatment, and the number of groups was the largest under CK treatment (41). The diversity index and richness index of soil mesofauna under CK treatment were the highest (2.81 and 3.81 respectively). The dominance index of soil mesofauna under deep pine (DP) treatment was the highest, which was 0.15. The total osmotic amount of soil infiltration under different tillage methods was deep pine(DP) > check(CK) > no-tillage(NT); The soil moisture and soil temperature were DP > NT > CK deep pine > no-tillage > check; The soil bulk density was no-tillage(NT) > check (CK)> deep pine(DP). There was a significant positive correlation between the individual number of soil mesofauna and soil bulk density (p<0.05). The abundance index of soil mesofauna was positively correlated with soil organic matter (p<0.05). There was a significant positive correlation between the evenness index of soil mesofauna and the total soil permeability (p<0.01).[Conclusion] The farming methods have obvious influence on the community structure of soil mesofauna, and significantly improve the number of soil mesofauna individuals after deep pine tillage, which can effectively improve the soil environment and is more beneficial to the survival and reproduction of soil mesofauna than no-tillage and traditional tillage.

Abstract:[Objective] The changes of soil water and salt under different intercropping patterns of Lycium chinense in saline-alkali soil were researched in order to provide scientific basis for the improvement and utilization of saline-alkali land.[Methods] Four treatments of L. chinense intercropping with Medicago sativa, Brassica napus, Suaeda glauca and L. chinense monoculture were set up to analyze soil water and salt changes and soil salt balance under different intercropping modes.[Results] The soil moisture content of each treatment in the 0-60 cm soil layer showed that the intercropping M. sativa(13.67%) > intercropping B. napus (13.02%)> intercropping S. glauca(12.22%) > control(11.86%), and it was not obvious in the 60-100 cm soil layer. Compared with the control, the soil salinity of intercropping M. sativa, intercropping B. napus and intercropping S. glauca decreased by 6.91, 5.82 and 2.21 g/kg in the 0-40 cm soil layer, respectively. Soil desalination rates of intercropping M. sativa, intercropping B. napus and intercropping S. glauca and CK were 40.38%, 26.52%, 9.00% and -60.66% in 0-100 cm soil layer, respectively. Except for control, the soil of other treatments was all desalinated.[Conclusion] Different intercropping patterns of saline-alkali mantle can effectively increase soil water content, reduce soil salinity, and improve saline-alkali land.

Abstract:[Objective] The soil water dissipation features between purple soil and yellow soil at different temperatures were compared, in order to provide a basis for field management of soil water in the purple soil area.[Methods] The topsoil on purple soil and yellow soil farmland were collected to observe the process of water dissipation at three different temperatures (20, 30 and 40℃) conditions, and the evaporation amount and evaporation rate, average evaporation rate and cumulative evaporation amount were then calculated.[Results] ① The evaporation amount, the evaporation rate, the average evaporation rate and the cumulative evaporation amount of purple soil and yellow soil were ranked as 40℃ > 30℃ > 20℃, however, the significant difference only occurred in the incremental stage of soil water evaporation(p<0.05). ② Under the three different temperature conditions, the evaporation amount, the evaporation rate and the average evaporation rate of purple soil and yellow soil increased first and then decreased, and finally tended to be stable. In contrast, the cumulative evaporation amount of purple soil was less than that of yellow soil, and the difference increased with time. ③ The cumulative evaporation amount of soil water changed rapidly at first and then slowly.[Conclusion] The dissipation processes of purple soil and yellow soil are greatly affected by the drying temperature, and the differences occur at the same temperature, especially at the stage of high water content.

Abstract:[Objective] This study explored the characteristics of soil temperature changes in farmlands of Mollisol region in Northeast China in order to provide basic data for quantifying the degree of freeze-thaw action and its impacts on soil erosion.[Methods] Based on the data of soil temperature in 2 m soil profile and air temperature from November to next April in 2015-2018 at the typical farmland in Binzhou River basin of Heilongjiang Province, we analyzed the characteristics of soil temperature variation and its responses to air temperature changes during freeze-thaw processes and freeze-thaw times in plough layer in farmlands.[Results] The soil temperature increased with the increase of soil depth from November to next February, while declined with the increase of soil depth when the soil was completely melted. The maximum frozen depth was 80 cm in farmlands of the research region. Meanwhile, there was a significant positive correlation between soil temperature in 0-60 cm depth and air temperature, and this correlation decreased with the increase of soil depth. In contrast, soil temperature under 80 cm depth was negatively correlated with air temperature.[Conclusion] There was a unidirectional freezing and bidirectional thawing in the study area. The freeze-thaw action mainly occurred at 0-20 cm in the topsoil layer of farmland, both maxinum freeze-thaw cycle times were 12 and 7, respectively, which provided the scientific basis for the design of simulated Mollisol freeze-thaw cycle experiments.

Abstract:[Objective] The formation conditions and spatial-temporal evolution of chair shaped soil landslide in the Three Gorges reservoir region were studied in order to provide the theoretical support for landslide monitoring and warning.[Methods] Taking Baijiabao and Bazimen landslides, the typical chair shaped soil landslide in the Three Gorges Reservoir area as examples, the formation conditions of these landslides were analyzed and compared with typical landslides in the Three Gorges Reservoir area. The spatial and temporal evolution of the landslides were analyzed based on the topographic and geomorphic characteristics of Xiangxi river basin.[Results] The formation conditions of chair shaped soil landslides were obviously different from other typical landslides in the Three Gorges reservoir region, and the formation of such landslides in Xiangxi river basin was obviously affected by valley topography.[Conclusion] The formation of chair shaped soil landslide is influenced by factors such as lithological conditions, sliding surface morphology and stratigraphic state. The chair shaped soil landslide in Xiangxi river basin is gradually formed with the evolution of the valley.

Abstract:[Objective] The surface water quality after the comprehensive treatment of tailless manganese ore at the mud field in Guzhang County in Hu'nan Province was studied in order to provide the basis for the pollution control of heavy metals in the study area.[Methods] The pH value, Mn, Pb, Hg, As, Cu, Cd, Cr⁶⁺, chemical oxygen demand (COD) and NH₄⁺-N in the samples were determined. The water environment quality was evaluated by comprehensive pollution assessment and health risk assessment methods.[Results] ① The Mn content from sampling points S₃(upstream of culvert exit), S₄(downstream of Hengyuan Mining) and S₅(end of mud fiold river) exceeded the class Ⅲ standard of the Environmental Quality Standard for Surface Water (GB 3838-2002). ②As effected by the discharged wastewater from Zhang's manganese industry, the comprehensive pollution index of water environment ranged as S₃(upstream of culvert exit) > S₄(downstream of Hengyuan Mining) > S₅(end of mud fiold river) > S₁(upstream of manganese slag reservoir) > S₂(culvert exit). ③The results of health risk assessment showed that the total health risks (RT) of the S₁ to S₅ sampling point were 7.73×10^-6, 1.19×10^-5, 4.23×10^-5, 2.64×10^-5, 2.40×10^-5, respectively, all of which not exceeded the maximum acceptable risk level of International Commission on Radiological Protection(5.0×10^-5).[Conclusion] The total health risk of water environment is mainly derived from non-carcinogenic substances. Reducing Pb and Cu in the water environment can effectively control the total health risks caused by drinking water. Overall, the implementation of the comprehensive management of the tailing-free manganese mine at mud field in Guzhang County has achieved the target, and the water environment quality has basically reached the standard.

Abstract:[Objective] The characteristics of the permeability anisotropy of the South Jinghe tableland were analyzed, and the disaster-pregnant mechanism of landslides was discussed in order to provide guidance for disaster prevention and control of rainwater infiltration landslides in the loess distribution area.[Methods] Through field investigation and infiltration test, the infiltration characteristics of fractured soil and different soil layers in this area were analyzed.[Results] The permeability coefficient of fractured soil was much higher than that of homogeneous soil. Comparison of permeability coefficients of different soil layers showed that the permeability coefficient of Malan loess was the largest due to large and medium porosity and joint fracture development, while the permeability coefficient of the paleosol was the smallest.[Conclusion] The soil in South Jinghe tableland has significant permeability anisotropy. The mechanism of water-fissure disaster-forming has become a malignant disastrous chain model in this area.

Abstract:[Objective] The effects of water stress on water consumption and yield of wine grapes were studied in order to provide a scientific basis for water-saving and efficient irrigation of wine grapes in Hexi desert oasis region.[Methods] Two water stress levels of mild (65% field capacity, FC) and moderate (55% FC) were set in the five growth stages of wine grapes (germination, shoot growth, flowering, fruit enlargement and coloring mature stage), respectively, with the lowest limit of 75% FC as a control. The effects of water stress on water consumption intensity, yield and water use efficiency of wine grapes were studied from 2015 to 2016.[Results] ① Water stress at every growth stage of wine grapes significantly affected (reduced) the daily water consumption intensity of grapes, and the effect of water stress in short growth stage (such as germination, shoot growth, flowering stage) could be automatically eliminated after rehydration, while the effect of water stress in long growth period (fruit enlargement and coloring mature stage) was persistent across the year, and it was difficult to recover in a short time after rehydration. ② The yield of mild water stress at germination stage reached the maximum in the two experimental years, it was up to 14 868, 15 306 kg/hm², respectively, and the water use efficiency also reached the highest (2.77, 2.96 kg/m³). The water use efficiency of mild water stress at coloring maturity stage could be improved without no obvious yield reduction. The moderate water stress at shoot growth, flowering and fruit expansion stage could significantly reduce grapes yield, and the reduction rate reached to 39%~49% under water stress at fruit expansion stage.[Conclusion] The growth period and duration of water stress have important effects on water consumption intensity of grapes. Long-term water stress have a continuous effect on water consumption of wine grapes across the year. Mild water stress at germination or coloring maturity stage, and adequate water supply at other growth stages are the efficient irrigation modes for wine grapes in Hexi desert oasis region.

Abstract:[Objective] The effects of single root pulling strength on the shear strength of slope soil were investigated, and the effect of root on the shear strength of slope soil was quantitatively analyzed in order to provide a basis for evaluating the shear strength of slope soil strengthened by plant roots.[Methods] The root-soil complex of 2-year-old Hypericum acmosepalum was studied. The indoor single-strand pull test and the root-soil composite shear test were conducted to obtain the tensile strength of the root system. The relationship between the root tensile strength and the cohesion force of the root-soil composite was analyzed.[Results] There was a negative power function relationship between the tensile strength and root diameter of H. acmosepalum, and the correlation coefficient was greater than 0.92. The root pullout displacement and tensile force were positively correlated with root diameter, and there was also a significant positive correlation between the pullout displacement and tensile force. The tensile strength was negatively correlated with root diameter, the pullout displacement and the pullout force, and the cohesive force of the root-soil composite increased by 17.25%~94.76%, compared with that of the rootless soil. The cohesion and cohesion growth rates were positively correlated with root-soil area ratio and root-soil volume ratio.[Conclusion] The pullout characteristics of the H. acmosepalum root have a significant influence on the shear strength of the slope soil, and the evaluation indexes of the shear resistance of the slope soil are closely related to the changes of the root pullout characteristics.

Abstract:[Objective] The tensile strength tests were carried out of the main roots and lateral roots of four shrub species in the loess area of Northeast Qinghai-Tibet Plateau, and the relationship between mechanical properties of main roots and lateral roots was discussed, which provided a reference for investigating the mechanical mechanism of plant roots in stabilizing soils and slopes.[Methods] The drainage area of Changlinggou in Xining Basin was selected as the studying area, and the tensile force, tensile strength, Young's modulus were measured by laboratory single root tensile test of four three-year-old shrub species(Caragana korshinskii, Lycium chinense, Nitraria tangutorum and Sarcozygium xanthoxylon).Then the relationship between root diameter, tensile force, tensile strength and Young's modulus of main roots and lateral roots of four species was further analyzed.[Results] The tensile forces of main roots of C. korshinskii, L. chinense, N. tangutorum and S. xanthoxylon were 28.45, 13.21, 11.01 and 7.35 times of lateral roots, the tensile strengths of main roots were 0.67, 1.17, 0.68 and 1.22 times of lateral roots, and the Young's moduluses of main roots were 2.00, 2.39, 2.82 and 2.48 times of lateral roots, respectively.[Conclusion] The tensile forces of main roots were significantly higher than lateral roots for four shrub species. The tensile strengths of main roots of C. korshinskii and N. tangutorum were lower than lateral roots, while the tensile strengths of main roots of L. chinense and S. xanthoxylon were higher than lateral roots. The Young's moduluses of main roots were significantly higher than lateral roots for four species, it showed that the main roots were not easy to deform in comparison with the lateral roots, and the contribution of main roots to the stability of the shallow slope is significantly higher than lateral roots.

Abstract:[Objective] The monitoring and evaluation of the ecological effect of soil and water conservation in the open-pit coal mine project were conducted in order to determine the protection effect and the feasibility of the soil and water conservation measures.[Methods] With the actual monitoring data, we took Xiwan open-pit coal mine in Shaanxi Province and coal preparation plant project as an example in this study. The evaluation index system was established in terms of soil and water conservation and vegetation recovery. The index weight was determined by Delphy method and the comprehensive evaluation model was established by linear weighted sum method to calculate the value of ecological effect of soil and water conservation in different periods of the project construction.[Results] The results showed that the value of ecological effect of operation period (0.683) > trial operation period (0.344) > early construction period (0.213). Since the implementation of the project, the total area of soil and water erosion has decreased from 426.71 hm² to 376.63 hm², the vegetation coverage has increased from 20.20% to 27.18%, the interception runoff has increased by 7 530 m³, and the soil conservation has increased by 6.90×10⁴ t.[Conclusion] Xiwan open-pit coal mine in Shenyu Mining area of Shaanxi Province has got good control effect and ecological effect by implementing soil and water conservation engineering and plant protection system designed by soil and water conservation scheme.

Abstract:[Objective] In order to provide reference for similar water transfer projects, the configuration pattern and effects of soil and water conservation measures in inverted siphon project were discussed.[Methods] According to the field investigation and documentary data of the inverted siphon project in Zhengzhou City section of the middle route of the South to North Water Transfer Project in He'nan Province, the layout of soil and water conservation measures in three main construction periods was determined, the configuration pattern of soil and water conservation measures in the inverted siphon project was constructed, and the effect after implementation was analyzed and evaluated according to the field survey data and photos.[Results] Taking the inverted siphon project of Zhengzhou City section as an example, soil and water conservation measures were determined based on the project layout, natural conditions, construction technology and the characteristics of soil erosion in different periods:① Surface soil should be peeled off before construction, together with temporary soil heaping, centralized stacking, blocking, covering or sowing with grass seeds; ② Temporary iron fences, interception and drainage ditches should be set up in the construction area; ③ Cut off drainage and anti-seepage furrow should be installed on the excavated slope and the tarpaulin should be timely covered; ④ Ecological landscape areas should be set up from the dam to the protection area; ⑤ Drainage ditches, frame planting grass slope protection and triangular small green space should be set up in the gradual transition sections on both sides of the inlet and outlet; ⑥ Landscaping, drainage and sand sinking measures should be set up in the operation management area, and permeable bricks should be laid in parking lots; ⑦ A leisure ecological park built on the top of the siphon become an allocation model of soil and water conservation measures in the inverted siphon project, which has achieved good results after implementation.[Conclusion] The inverted siphon project is not only an important part of water diversion project, but also a kind of cross building with the largest number in the first phase of the middle route of the South to North Water Transfer Project. The reasonable layout of engineering, plant and temporary measures according to the location and the construction of soil and water conservation measure system will certainly achieve better results on soil and water conservation and greatly improve the ecological environment, and provide a reference for similar projects to compile scientific, economic, safe and feasible scheme.

Abstract:[Objective] This paper reveals the characteristics of soil and water conservation measures in different stages of the Loess Plateau in order to provide theoretical basis for key measures and main strategies of soil and water loss control.[Methods] Based on the data of different soil and water conservation measures from 1954 to 2015 in the loess hilly and gully region, we analyzed the changes of the key measures of soil and water conservation, such as terrace, afforestation, grass planting, closure treatment and silt dam.[Results] The application area of the key measures of soil and water conservation increased with the growing governance years, and the fastest increase rate was the measure of afforestation. The incremental proportion of various soil and water conservation measures was relatively stable over the years. The maximum incremental proportion of woodland was 58%, and closed treatment area gradually increased while terrace area gradually decreased. The number of silt dams increased firstly and then decreased.[Conclusion] The temporal and spatial variation pattern of soil and water conservation measures is related to the guiding principle of national policies and the governance requirement of local governance in the loess hilly and gully region. Afforestation is the most important soil and water conservation measure in the region, and closure and protection has become the development trend of vegetation restoration in the Loess Plateau.

Abstract:[Objective] The impact of water storage variation on the local ecological environment and economic construction in the Horqin sandy land was studied in order to provide reference for the protection and sustainable utilization of local water resources.[Methods] Using gravity recovery and climate experiment(GRACE) Release-05 data from July 2003 to December 2010 provided by center for space research(CSR), the long-time series of terrestrial water reserves in Horqin sandy land were retrieved by using the filtering method combining the decorrelation filter with the Gauss smoothing filter (smooth radius 300) and the scaling factor method. The result was compared with the Climate Prediction Center(CPC) hydrological model inversion. Based on soil moisture content changes calculated by GLDAS hydrological model, the temporal and spatial variation of ground water storage was retrieved. This result was preliminarily verified by monitoring well data and feed water information.[Results] The reduction rates of terrestrial water storage and ground water storage were 13.2±2.6 and 13.5±1.9 mm/a, respectively from July 2003 to Decomber 2010.[Conclusion] Drought and agricultural irrigation are one of the important reasons leading to the decrease of surface water and groundwater level in Horqin sandy land.

Abstract:[Objective] The feasibility of improving saline-alkali soil with different additive proportion of garbage enzymes fermentation product of fruit and vegetable waste was explored in order to provide theoretical and practical basis for the sustainable development of agriculture in Inner Mongolia.[Methods] The garbage enzymes and water were diluted by volume ratios of 1:200 (GE₁), 1:500 (GE₂) and 1:800 (GE₃). The effects on key soil chemical properties (pH value, EC and ESP) and soil nutrient status (organic matter, hydrolytic nitrogen, available P, available K and DOC) were studied by soil culture experiments.[Results] The application of appropriate garbage enzymes dilution ratio could reduce soil salinity and increase soil nutrient content. When the garbage enzymes dilution ratio was GE₃, the soil pH and alkalinity (ESP) were reduced by 17.51% and 38.42%, respectively; the electric conductivity(EC) value was significantly reduced by 42.50%, the soil organic matter and available K content increased significantly by 56.54% and 79.76%, respectively, and the soil available N and available P content decreased by 6.52% and 8.48%, soil DOC increased by 34.28%.[Conclusion] In this experiment, with the GE₃ ratio of garbage enzymes for improving saline-alkali soil, and according PCA analysis, we found that pH value, EC and available K were the characteristic indicators of garbage enzymes for the improvement of saline-alkaline soil.

Abstract:[Objective] The slope protection and reinforcement effect of ecological slope protection model consisting of Cynodon dactylon and bamboo lattice as the main material on the slope of ion-absorbed rare earth mines by in-situ leaching were explored in order to provide a new idea for the stope slope control technology of rare earth mines in Southern Jiangxi Province.[Methods] Root-soil composite systems of C. dactylon and rare earth mineral sandy clay were used as the research object. The influences of root amount and water content on shearing strength were analyzed by direct shear tests. The effect of ecological slope protection mode of "bamboo lattice+C. dactylon" slope stability was analyzed by two-dimensional finite element method. The support parameters of spacing, length and diameter of bamboo piles were optimized by visual analysis method of orthogonal experiment.[Results] Plant roots could significantly enhance soil cohesion, but had little effect on internal friction angle. When root weight reached 0.5% or more, the shear strength of root-soil composite decreased, there was an optima root content. Root system had the most significant effect on soil reinforcement under 25% water content. The ecological slope protection model could significantly enhance the stability of slope. When the length of the bamboo pile was 3 m, the spacing was 2.5 m and the diameter was 8 cm, the protection effect was the best.[Conclusion] The reinforcement effect of C. dactylon root systems is different under different water content and root amount. The ecological slope protection mode of "bamboo lattice+C. dactylon" can effectively prevent the slippage of shallow soil of slope.

Abstract:[Objective] The effects of wetland plant species, plant coverage and treatment time on the purification of antibiotic-containing livestock waste water were investigated in order to provide the basis for utilization of wetland plant floating beds technology to efficiently remove pollutants and antibiotics from livestock waste water.[Methods] Plant floating beds were constructed using Brachiaria mutica and Cyperus malaccensis Lam. var. brevifolius, respectively. Three different plant coverage areas (20%, 40% and 60%) were set for each plant bed. The purification effects of plant floating beds on chemical oxygen demand (COD), nitrogen, phosphorus and sulfadiazine (SDZ) were monitored at different treatment times.[Results] The water quality was improved with the treatment time:pH value became neutral, dissolved oxygen (DO) content and oxidation reduction potential (ORP) increased, and the concentrations of COD, nutrients and SDZ decreased. Plant species had no significant effect on water pH value, DO, ORP and COD, but had significant effect on water nutrient removal. B. mutica performed better in the removal of ammonia nitrogen (NH₃-N), total nitrogen (TN) and total phosphorus (TP) than C. malaccensis Lam. var. brevifolius, but no significant difference was found in terms of SDZ removal between the two plant species. In general, plant beds with 60% coverage area was more conducive to the removal of pollutants in water, but was not conducive to DO diffusion.[Conclusion] The floating beds constructed by B. mutica with 60% plant coverage had the best removal efficiencies. After 47 days of operation, the floating bed simultaneously removed 88% of the COD, 97% NH₃-N, 89% TN, 94% TP and 43% of the SDZ in the wastewater.

Abstract:[Objective] The ecological restoration effects of cultivated land on grain yield and soil heavy metal content were explored in order to provide a certain basis for the decision-making of cultivated land sustainable utilization.[Methods] Taking Tianjin City as a case study, a system dynamics model of cultivated land ecological restoration (CLERSD) was constructed by using system dynamics method. Six scenarios were set under of three strategies:green development, sustainable development and ecological restoration strategy. The deployment of cultivated land and ecological land in Tianjin City from 2016 to 2030 was simulated under different land use patterns.[Results] In the green development strategy, although increasing the use of chemical fertilizer and pesticide could increase grain yield in a short time, it was not beneficial in the long term, and more cultivated land would need ecological restoration because of damage. In the strategy of sustainable development, increasing investment could increase grain production and promoted sustainable agricultural development. Increasing sewage irrigation could meet the demand of crop growth water in the short term, but it would lead to the increase of cadmium content, as a result, more arable land would need to be converted to ecological land. In the strategy of ecological restoration, planting the plants with strong metal enrichment ability could rehabilitated the damaged cultivated land in a relatively short time, and reduced the content of heavy metals in soil and increased the area of cultivated land.[Conclusion] In agricultural production, it is possible to maintain food security and sustainable green development of agriculture by changing the input of pesticides, fertilizers and capital investment, reducing sewage irrigation and ecological restoration of cultivated land.

Abstract:[Objective] For solving the problems of drought and nutrients loss caused by soil erosion, a series of studies on water and fertilizer saving were conducted in order to expound the effects of water pad on fertilizer and water saving and its application prospect.[Methods] Compared to the conventional method of mixing water absorbing polymer (WAP) with soils, WAP was used to make water pad to obtain a better water and fertilizer saving effect.[Results] Under the same watering condition, the application of water pad could reduce water loss by 65%, and reduce nitrogen, phosphorus and potassium nutrients loss by more than 89%. Pot experiment showed that under drought stress condition, the application of water pad could increase corn yield by 155%. Field experiment showed that under natural rainfall condition, the application of water pad could increase corn yield by 26%, and increase sugarcane yield by 10.5%, and the sugar degree increaed. In addition, with the application of water pad, nitrogen, phosphorus and potassium nutrients loss decreased, while nutrients absorption increased.[Conclusion] A serial of experiments indicate that water pad can increase crop yields, quality and nutrient uptake.

Abstract:[Objective] The sand blocking and windproof effects of high-parallel reed sand-barriers along the Korla-Golmud railway were investigated, and whether the high-parallel reed sand barrier can meet the engineering needs of wind and sand resistance was judged, in order to provide a scientific basis for sand-wind disaster prevention.[Methods] The sand blocking rate test and gradient wind monitoring of the high-parallel reed sand-barriers were conducted in the test section along the line. Numerical simulation calculations were used to analyze the flow field distribution characteristics and sand control laws of high-parallel reed sand-barriers.[Results] ① The sand-blocking rate of single-channel reed sand barrier was 93.85%. Multiple sand barriers were usually set along the railway line. The sand flow was basically cleared after passing through multiple sand barriers. ② Under the action of single reed sand barrier, the velocity distribution around the barrier was obvious, and the deceleration zone formed behind the barrier was more uniform and there was no eddy current zone. The porosity of reed sand barrier was 36.5%.The weakening impact zone of the reed sand barrier on the inflow was mainly within the range of 3.5H(H=200 cm) before the barrier and 17H after the barrier. The mean weakening capacity for the incoming flow was 29.7% and the maximum value was 48%. ③ When the wind speed exceed 6 m/s, the sand particles were mainly distributed within the 0.2H range before the reed sand barrier, and the sand flux decreased sharply after the sand flow passed through the sand barrier.[Conclusion] Through the field experiment and numerical simulation, the law of sand control of high-parallel reed sand-barrier is revealed. The high-parallel reed sand-barrier has excellent sand control capacity similar to the net sand barrier and can be used along the railway.

Abstract:[Objective] This study aims at discussing the harmlessness treatment and maturity safety of waste vegetable leaves with microbial agent, in order to solve the problems of environmental pollution during fermentation, and improve the porosity, ventilation and temperature of fermentation reactor.[Methods] Waste vegetable leaves were used as raw materials, corn straw and cow dung were used as auxiliary materials, and methods such as adjusting the carbon-nitrogen ratio of fermentation raw materials, types of microbial inoculum, moisture and temperature of fermentation stack were adopted.[Results] The optimal ratio of microbial fermentation raw materials for waste vegetable leaves was optimized, and the weight ratio of waste vegetable leaves, corn stalks, cow dung and fermenting agent was 100:4:2:0.25. A set of evaluation system for microbial fermentation maturity index of waste vegetable leaves was established. The temperature of the fermentation reactor was ≥ 50℃, lasts for 3~5 days, pH value was ≤ 8.0, conductivity was ≥ 2.0 mS/cm, E₄/E₆ ratio was ≤ 2.5, C/N ratio was < 20, and germination index GI was >80. The nutrients and safety limit indexes of total nitrogen, organic matter, alkali nitrogen and available potassium of the fermentation products were in line with industry standards.[Conclusion] The pH value, electrical conductivity, E₄/E₆, C/N, GI and other physicochemical and biological indicators of the product of microbial fermentation in the waste cabbage leaves all meet the requirements of the fertility and safety limits of vegetable cultivation matrix.

Abstract:[Objective] Due to the serious heavy metal lead pollution in the farmland around the rare earth mining area in Southern Jiangxi Province, we aim to study the migration and transformation of heavy metal lead in the farmland soil in this area in order to provide a basis for lead pollution control in mining area.[Methods] The leaching amount of heavy metal lead was observed by simulated acid rain leaching experiment, and the experimental results were analyzed by response surface methodology.[Results] As the leaching amount of lead increased with time, it showed two stages of rapid and slow decline. With the decrease of pH value, the leaching amount of lead increased first and then decreased with the increasing of leaching intensity. When the concentration of exogenous lead increased, the leaching amount increased with the decrease of pH value and the increase of leaching intensity. Response surface software was used to fit the experimental data by multiple regression. The pH value and concentration of lead in culture were significant in the interaction term.[Conclusion] The degree of lead pollution was positively correlated with the release of lead. The pH value of acid rain had an important influence on the release of lead in contaminated farmland.

Abstract:[Objective] The impacts of different forage species and biochar application on soil moisture were studied in order to provide a scientific support for ecological restoration and soil improvement in karst rocky desertification areas.[Methods] The pot experiment was conducted with Paspalum thunbergii, Lolium perenne and Dolichos lablab and with the soils mixed with biochar, and the soil moisture content was periodically determined.[Results] There were significant differences in soil water holding capacity and soil saturated hydraulic conductivity among P. thunbergii, L. perenne and D. lablab, with the order as follows:P. thunbergii > L. perenne > D. lablab. After applying 5% biochar, the soil water content of P. thunbergii, L. perenne and D. lablab increased to certain degrees on rainy or dry days of spring and summer, and the soil water holding capacity and saturated hydraulic conductivity of planting grass significantly increased, and the order was also P. thunbergii > L. perenne > D. lablab.[Conclusion] Biochar application obviously improved soil water holding capacity, which was beneficial to pasture growth.

Abstract:[Objective] The economic benefits of optimum fertilization of nitrogen, phosphorus, potassium and zinc of licorice in sierozem of the desert region area of Gansu Corridor were studied in order to provide technical support for the sustainable development of licorice industry.[Methods] A field experiment was carried out to study the economic benefits of optimum fertilization of nitrogen, phosphorus, potassium and zinc in sierozem of Sanbao Town, Minle County, Zhangye City, Gansu Province.[Results] With the increase of the fertilization of nitrogen, phosphorus, potassium and zinc, the fresh root yield of licorice was increased, but the increased amount of licorice under per 1 kg fertilization was decreased. The marginal yield and value of licorice were decreased, and the marginal profit showed a negative value eventually. In the desert region area of Gansu Corridor, the optimum application rate of nitrogen, phosphorus, potassium and zinc was 0.46, 0.26, 0.16 and 0.02 t/hm², and the theoretical yield of fresh root at the optimum application rates were 12.81, 13.35, 13.06, 12.76 t/hm².[Conclusion] Sierozem has the low content of nitrogen, phosphorus, potassium and zinc, the application of nitrogen, phosphorus, potassium and zinc to licorice can increase the yield obviously, however, the fertilizer amount with the highest yield is not the optimum fertilization of economic benefits. The best fertilization amount is necessarily lower than that.

Abstract:[Objective] The effects of different management measures on water conservation capacity of litter layer of natural secondary forest were studied, and the management measures that are most conducive to improving the water source conservation capacity of litter layer are determined in order to provide theoretical basis and reference for the healthy management of natural secondary forest in this area.[Methods] Field measurement and indoor immersion method were used to analyze the change of water storage index in the litter layer, and to analyze the effects of five different kinds of management measures. The plots without management measures were set as the control, the water conservation of the stand was adopted, and the water conservation indicators were evaluated.[Results] ① After the transformation measures, the accumulation of litter was higher than that of the unmodified stands, and the amount of litter accumulated after 4 years was increased by 27%~39% compared with that before the transformation. ② After the implementation of the management measures, the growth rate of the maximum water holding capacity of the 2 a litter layer was 4.61%~9.30%, and the growth rate of 2 a to 4 a after the transformation was 6.31%~7.66%. ③ After 2-year and 4-yearr transformation, the natural water holding capacity of litter was:introduction of shrubs > closure of hills for afforestation > squash selective cutting > strip clear cutting > tending and thinning > unreconstructed. The growth rate after the 2-year transformation was 0.61%~29.68%, while the growth rate after the 4-year transformation was 1.82%~31.91%. ④ After the transformation, the effective growth rate of the litter layer after 2 years was 3.67%~8.08%, and the growth rate after 2-4 years was 4.51%~5.95%.[Conclusion] The water storage index of the litter layer in the forest with the implementation of management measures was higher than that in the unreformed forest stand. The management measures of shrubs introduced had the most obvious influence on the water storage capacity of litter.

Abstract:[Objective] The ecological vulnerabilities of six counties and districts in Haidong City, Qinghai Province were quantitatively studied in order to alleviate poverty in high-cold and poverty-stricken mountainous areas, improve awareness of environment protection and provide basis for the implementation of national "precise poverty alleviation" policy.[Methods] The evaluation index system of ecological vulnerability in high-cold and poverty-stricken mountainous area was constructed from three dimensions of economic development, social development and the ecological environment. The index system was quantitatively analyzed and evaluated by the gray correlation method of entropy weight.[Results] The ecological vulnerability in Huzhu County was 0.850 1, which belonged to the slight vulnerability. The ecological vulnerability in Ping'an District was 0.712 8, belonging to light vulnerability level. The ecological vulnerability in Salar Autonomous County of Xunhua was 0.557 3, belonging to moderate vulnerability level. The vulnerabilities of ecological in Ledu, Minhe and Hualong, were less than 0.45, belonging to severe vulnerability level. The vulnerabilities of the six counties and districts in Haidong City were ranked as:Huzhu County > Ping'an District > Salar Autonomous County of Xunhua > Hualong County > Minhe County > Ledu County.[Conclusion] The ecological environment and the resource endowment not only seriously restrict the development of the social economy, but also have a remarkable impact on the ecological vulnerability.

Abstract:[Objective] The differences of sponge city construction between the north and the south part of China were compared in order to find out the suitable way for the construction of sponge city in the north part of China via a case study in Shenyang City, Liaoning Province.[Methods] Remote sensing interpretation, spatial analysis and field interview were used to analyze of the issues in sponge city construction in Shenyang City from 4 aspects:the precipitation and the characters of urban underlying surface, the utility of sponge projects, the cost-benefit of sponge projects and the public awareness and participation.[Results] There were four main issues in the construction of sponge city in Shenyang City:increasing impervious surface, mismatching between sponge projects and urban waterlogging areas, high costs and low benefits of sponge projects and low public participation.[Conclusion] Sponge city should be constructed in coordination with the civil engineering, and it should play a role in promoting the construction of national central city, attracting the inflow of human resources, increasing wealth and stimulating investment. Therefore, it is necessary to improve the participation of public in sponge city construction, use different methods to governance the suburban and center areas, and ensure the sustainability of public private partnerhip(PPP) madel in sponge city construction.

Abstract:[Objective] The spatial pattern of flood control in flood detention area was discussed in order to provide a reference for the decision-making in flood control.[Methods] This paper elaborated the basic principles and constituent elements of village flood control, and analyzed the main functions of each spatial element of village flood control by spatial typology method.[Results] The village flood control space in Nihewa flood detention area was mainly composed of cofferdam, pond, ditch and dam. Various patterns had been formed to meet the needs of different terrain environments in engineering practice. Six different kinds of combination modes were refined, including block, storage, dredging, block & storage, storage & dredging, block & block & storage, and illustrated with local actual cases.[Conclusion] The spatial pattern of village flood control in flood detention area has a great impact on the effectiveness of flood control work, and the detailed management of village flood control facilities is helpful to improve flood control capacity.

Abstract:[Objective] Landslide hazard zoning research in Yan'an City of Shaanxi Province was carried out in order to provide a scientific basis for regional landslide prevention and reduction in Yan'an City and the Loess Plateau region.[Methods] Starting with the triggering factors of landslides in Yan'an City, and coupling with field survey, we established regional risk assessment model for shallow landslide using SINMAP model. We analyzed the risk areas of regional landslide, and quantitatively evaluated the migration and transformation of the landslide area under different rainfall conditions.[Results] With the increase of rainfall intensity from 5 mm/h to 200 mm/h, the proportions in the unstable region increased by 6.48% and 6.44% and the proportions in the stable region were always the highest, with an average of 46.79% and 51.33%. Meanwhile, potential unstable region may be transformed into unstable and very unstable region; area proportions varies between 5.04% and 17.31% and landslide proportions varies between 5.14% and 15.43%.[Conclusion] With an increase in rainfall, surface shallow soil moisture and humidity area increased, and extended to the ridge and gentler slopes unit. The transition from stable region to unstable region is taking place in the region.

Abstract:[Objective] The important role of ecological security land use pattern in maintaining regional ecosystem balance was explored in order to provide a basis for the development and decision-making of Shoucheng Nature Reserve in Guangxi Zhuang Autonomous region.[Methods] Based on the theory of landscape security pattern and MCR model, GIS platform and Fragstats 4.2 software was adopted, human-computer interactive remote sensing image interpretation method was used to obtain the land use type data of Shoucheng Nature Reserve in 2013 and 2017. The evolution of landscape pattern and the construction of security pattern were studied in Shoucheng Nature Reserve.[Results] The spatial distribution of land use patches in Shoucheng Nature Reserve tended to be scattered, the fragmentation of patches increased, and the shape of patch edge tended to be complex. Land use for human activities in 2013 and 2017 was divided into four types:development core area, development transition area, development adjustment area and development restricted area. Accordingly, the corresponding suggestions and optimization schemes for different types of human activity land were proposed.[Conclusion] Human activities have an important impact on the landscape change of Shoucheng Nature Reserve. The areas of human activities show an increasing trend in the development core area, the transition area and the optimization area, but a decreasing trend in the most ecologically functional restricted area.

Abstract:[Objective] The temporal and spatial variation of ecological risks in Tuojiang River Basin based on the value of ecological services was explored in order to provide a basis for ecological risk management and control in the area.[Methods] By using ArcGIS, GeoDa, GS⁺ and Conefor Sensinode software, taking Tuojiang River basin as the study area, based on the land use data derived from remote sensing images in 2000, 2005, 2010 and 2015, the ecological service value in the study area was calculated, then the calculation method of ecological risk was improved, and the evaluation index system of ecological risk based on ecological service value was constructed. The spatial autocorrelation analysis and statistical analysis methods were then used to investigate the spatio-temporal variation of ecological risk in Tuojiang River basin in the rapid urbanization areas.[Results] ① The dynamic change of land use in Tuojiang River basin was remarkable. The main land types were conversion of arable land to construction land and forestland to arable land. ② The total value of ecological services in Tuojiang River basin increased firstly and then decreased, and the contribution of farmland and forestland to the value of ecological services was the greatest. ③ The ecological risk value showed an increasing trend. The ecological risk level was shifted from low and medium ecological risk to medium ecological risk, and the area of medium ecological risk increased significantly. ④ The variation of the ecological risk level distribution in the study area was great. The high risk and relative high risk areas were mainly distributed in the north of the study area, while the medium and lower risk areas were mainly distributed in the middle and south of the study area. The overall ecological risk was greater in the north than in the south.[Conclusion] Land use change have an important impact on the value of ecological services, which in turn will have an impact on the ecological risk of the Tuojiang River basin.

Abstract:[Objective] The impacts of heavy rainfall caused by typhoon on rainfall erosivity were explored in order to provide a theoretical basis for the prediction, prevention and control of soil erosion.[Methods] Based on the hourly rainfall erosivity model, the temporal and spatial distribution of rainfall erosivity during typhoon Mangosteen landing in Guangdong Province in 2018 was calculated.[Results] ① The rainfall erosivity in Guangdong Province was related to the typhoon path. On the 15th, September 2018, the rainfall erosivity was the highest in the eastern part of Guangdong Province, while the largest rainfall erosivity in the west was occurred on the 16th and 17th; ② Rainfall erosivity in Guangdong Province tended to be centered arond Yangchun City and decreases to both sides during typhoon Mangosteen, especially in Northern and Eastern Guangdong Province; ③The stations with large rainfall also showed a large rainfall erosivity, but it was not a one-to-one correspondence. Rain strength and rainfall kinetic energy were also important factors affecting rainfall erosivity.[Conclusion] The heavy rainfall caused by typhoon affected the distribution of rainfall erosivity in Guangdong Province from 15th to 17th September 2018, and the path of typhoon movement determined the magnitude of rainfall erosivity.

Abstract:[Objective] The objectives of the study were to analyze the overall spatial distribution characteristics of the ecological vulnerability of Dalian City and identify the sensitivity characteristics of the evaluation index system.[Methods] We constructed an urban ecological vulnerability index system based on sensitivity-recovery-pressure model (SRP), and the one-at-a-time method (OAT) was used to estimate the sensitivity of results under uncertainty of index weights.[Results] The vulnerability of Dalian City was classified into five levels:extreme vulnerability, high vulnerability, moderate vulnerability, light vulnerability and slight vulnerability, with an area proportion of 4.17%, 22.97%, 41.00%, 23.69%, and 8.16%, respectively. The areas with the highest vulnerability distributed in the city center and the east area of Ganjingzi District, while areas with the lowest vulnerability distributed in the northern part of Dalian and the junction of Ganjingzi District and Lushun District. The soil organic carbon showed the greatest impact on the evaluation results. The maximum absolute average change rate and the maximum pixel change rate was 11.49% and 17.27%, respectively.[Conclusion] The overall ecological vulnerability of Dalian City is at a moderate vulnerability level. The weight of soil organic carbon index should be carefully considered to reduce the uncertainty of evaluation results.

Abstract:[Objective] The land use performance and its diagnose obstacle factors were evaluated in order to provide references for ecological civilization construction and land resource management in Guiyang City.[Methods] The land use performance evaluation index system of Guiyang City was constructed from four aspects:land use economic performance, social performance, ecological performance and fair performance. The improved technique for order preference by similarity to an ideal solution(TOPSIS) model and obstacle degree model were used to evaluate the land use situation of Guiyang City from 2006 to 2015. Performance evaluation and obstacle factors were used for diagnosis.[Results] ① The land use performance of Guiyang City showed a steady upward trend in fluctuations, and the performance level improved from poor to high quality. ② The performance of the four criteria levels improved as a whole, but there were differences in growth patterns, among which, social performance and ecological performance have the fastest growth rate,while the economic performance and fair performance have entered the intermediate level relatively late. ③ Economic performance and social performance were two major factors affecting land use performance. ④ From the obstacles of the indicator factor, the main obstacles affecting the land use performance of Guiyang City in the future would be urban per capital disposable income, ecological management area, average employment, house price income ratio and Engels coefficient.[Conclusion] The improved TOPSIS model combined with the obstacle degree model can objectively and truly reflect the change of land use performance and the existing performance obstacles in Guiyang City.

Abstract:[Objective] The distribution of carbon, nitrogen and phosphorous in soils under different grassland types and the relationships between different nutrients in Northern Tibet was explored in order to provide a theoretical basis for grassland protection and evaluation.[Methods] Soil samples of different grassland types in Northern Tibet were collected by s-shaped soil sampling method, and the carbon, nitrogen and phosphorus content of the soil was measured by test. Variance analysis and correlation analysis were conducted based on SPSS.[Results] The organic carbon in ridge alpine meadow, alpine shrub meadow and hillside alpine meadow was mainly affected by elevation. The organic carbon increased with elevation while decreased with soil depth. The organic carbon was significantly correlated with total nitrogen, and the correlation coefficient was 0.968(p<0.01). The total nitrogen and organic matter had the same trend in different grassland types. Except alpine swamp meadow, the distribution pattern of available nitrogen and total nitrogen were the same that in other grassland types. There was a significantly positive correlated between available nitrogen and total nitrogen, and the correlation coefficient was 0.439 (p<0.05). Rapidly available phosphorus was significantly positive correlated with total phosphorus, and the correlation coefficient was 0.442. The total phosphorus content was affected by grazing, but the effect of grazing on available nutrients was more obvious.[Conclusion] The carbon, nitrogen and phosphorous of different grassland in Northern Tibet shows a regular change, grassland degradation has a certain correlation with grazing intensity.

Abstract:[Objective] There is a coupling and coordinating relationship between rational land use and urbanization development. This paper studied the coupling and coordinating degree, the relative development degree and the influence of each index on the coordination degree of land use efficiency and urbanization level in Hohhot-Baotou-Ordos region from 2006 to 2015, in order to provide decision-making basis for sustainable land use and urbanization development in Hohhot-Baotou-Ordos region.[Methods] The coordination relationship and influence degree between land use benefit and urbanization were evaluated based on coupling coordination modeland grey correlation model.[Results] ① The land use benefit and urbanization level have steadily increased in Hohhot-Baotou-Ordos region. The biggest increase one was Hohhot, whose value was 0.373 8 and 0.362 6, respectively. ② The benefit of land use efficiency lagged behind the level of urbanization in Hohhot City. The benefit of land use synchronized with the level of urbanization in Baotou City. The level of urbanization lagged behind the benefit of land use in Ordos City during the period from 2010 to 2014. ③ The coupling degree was at a high level, and the coordination degree was from weak to strong in the whole research region.[Conclusion] The overall coordination between land use efficiecny and urbanization was developing well in Hohhot-Baotou-Ordos region. However, according to the current condition of coordination, urban socialization construction should be improved and land use should be reasonably planned, so as to promote the quality coordination condition between land use and urbanization.

Abstract:[Objective] The relationship between land use and cover change and urban heat island effects and the influencing factors was explored in order to provide a scientific theoretical basis for the sustainable development of ecological environment in Huzhou City, Zhejiang Province.[Methods] The remote sensing images of Landsat TM and Landsat OIL in 2000, 2005, 2010 and 2015 in Huzhou City were collected. Land use was classified and surface temperature were inversed based on GIS and RS technologies. The LUCC was analyzed based on the development and gravity center shift of land use types, and the relationship between LUCC and urban heat island effect was explored by principal component analysis.[Results] ① In the past 15 years, the construction land area of Huzhou City accounted for 50% of the total area, while the area of cultivated land decreased significantly. The center of construction land in Wuxing District was shifted to the southwest, while the center of construction land in Nanxun District was shifted to the northeast. ② With the gradual increase of surface temperature in Huzhou City, the highest temperature in 2015 reached 38.6℃, and the area of high temperature zone was also expanding. ③ The continuous development of construction land was responsible for the wide expansion of high temperature areas, and the urban water system was conducive to alleviating the increase of urban underlying surface temperature. ④ The load in the first principal component of Huzhou City in the past 15 years had a great influence on the surface temperature change, and the load factor was located in the land use type.[Conclusion] The land use has entered a period of slow change in Huzhou City, the construction land area is increasing, the surface temperature is rising, and the main load factors affecting surface temperature changes are related to land use types.

Abstract:[Objective] The environmental risk of dangerous goods transportation in sensitive water environment section of the Qinghai-Tibet expressway was analyzed in order to make the corresponding prevention and the emergency countermeasures.[Methods] Based on the identification of the water environment sensitive section along Qinghai-Tibet expressway, the environment risk of the dangerous goods transportation was predicted by probability estimation method.[Results] The length of the water environment sensitive section was 477.48 km, accounting for 42.77% of the total length of the Qinghai-Tibet expressway. Among them, the high sensitive section was 89.52 km, the medium sensitive section was 221.49 km and the low sensitive section was 166.47 km. The traffic accident probability of dangerous goods transportation vehicles on Qinghai-Tibet expressway in the forecast year was low, with the average probability of 0.162 5~1.176 0 t/a. The risk of environmental pollution in dangerous goods transportation accidents could be ranked as:medium sensitive section > high sensitive section > general section > low sensitive section. By improving the road pollution prevention and the emergency measures as well as the management and monitoring of the dangerous goods transport vehicles, the environmental pollution risk caused by the dangerous goods transport accidents could be effectively reduced.[Conclusion] The water environment sensitive section of Qinghai-Tibet expressway accounts for a major part of the studied road. Pollution prevention measures and emergency measures can effectively reduce the environmental risks of dangerous goods transportation on Qinghai-Tibet expressway.

Abstract:[目的]为把握复合指纹示踪方法发展动态，为黄土高原泥沙来源研究提供建议。[方法]综述了复合指纹示踪方法的理论基础，对各指纹因子（物理示踪剂、核素、地化元素、磁性、有机质、碳氮稳定同位素、孢粉、生物标志物）的发展进程、模型算法、不确定分析等进行了详细论述。[结果]黄土高原地区在利用指纹因子的时空差异性来研究侵蚀区泥沙的来源，定量描述侵蚀过程的发展等方面已取得一系列成果。[结论]复合指纹示踪泥沙来源技术在黄土高原地区以探讨指纹因子应用研究为主，在混合模型矫正、多方法比较、指纹因子守恒等方面还需要进一步加强研究。

Abstract:[Objective] In the context of ecological civilization construction and the world's first-rate universities and first-rate discipline("double first-rate") construction in the new era, the talent training and teaching reform of soil and water conservation discipline were explored in order to improve the teaching quality of soil and water conservation discipline and to cultivate high-level talents who can serve the local ecological environment construction and social and economic development.[Methods] Taking Guizhou University as an example, we analyzed the tasks faced by the development of soil and water conservation discipline in the new era, and discussed issues such as the goal, requirements and teaching reforms of talent cultivation.[Results] A goal of "based on Guizhou Province, facing the southwest region of China, serving the construction of ecological civilization and striving for world's first-rate" was proposed. The specific requirements of talent cultivation at different levels of bachelors-masters-doctors were analyzed from three aspects including:ability, quality and knowledge.[Conclusion] In the new era, the discipline of soil and water conservation needs to start with teaching reform measures such as optimizing curriculum system, improving teaching methods, enriching practical links and paying attention to international talent cultivation, so as to improve the knowledge system, the teaching quality, ability level and international competitiveness of talent training for ecological civilization construction of soil and water conservation, and to cultivate the first-rate talents of "thick foundation, strong ability and high quality" to serve the construction of ecological civilization of soil and water conservation.

Abstract:[Objective] This paper aims to investigate the spatio-temporal changes in the patterns of cultivated land use in China and its 31 provinces (excluding Hong Kong, Macao and Taiwan) from 2009 to 2015 so as to provide a scientific reference for promoting China's cultivated land protection policy and regional sustainable development.[Methods] The methods of grain supply-demand balance and ecological footprint analysis were employed to account for the cultivated land budget based on food safety and ecological security. In addition, the safe operating space for cultivated land utilization in China was discussed based on the China's ecological redline policy and the planetary boundaries framework.[Results] The budget of supply and demand of China's cultivated land was generally in disequilibrium, with surplus in central and northeast of China and deficit in southeast of China. From the perspective of ecological footprint, the cultivated land use in China was in deficit. The provinces with high deficit coefficient were mainly located in the central and eastern regions of densely populated and economically developed provinces, while a few surplus provinces were mainly distributed in south and southwest of China. Following the planetary boundaries framework arguing that the maximum permissible percentage of global land cover converted to cropland was estimated at 15%, together with China's redline of cultivated land protection, the safe operating space for cultivated land use in China could be ranging from 1.20×10⁸ hm² to 1.44×10⁸ hm².[Conclusion] More attentions need to be paid on the determination and variation of safe range for cultivated land at multiple scales. The food safety and ecological security could assist decision makers in developing regional-specific policies for sustainable use of cultivated land.

Abstract:[Objective] The research aims to investigate soil erosion in Pakistan in order to provide scientific basis for the prevention and control of soil erosion in Pakistan and for the understanding of the ecological environment status in Pan-Third Pole.[Methods] The Pothohar Plateau in Northern Pakistan was selected as the representative area of soil erosion in the country. Along the route of Muree-Islamabad-Rawalpindi-Gucer Khan-Jagwar-Bowen, 15 investigation units (12 small watersheds and 3 rectangular areas) were selected to investigate the types and characteristics of soil erosion, land use types and soil and water conservation measures from April 16 to 20, 2019.[Results] The overall soil erosion of woodland and grassland was relatively light with sheet erosion as the main type. Soil erosion mainly occurred in construction land. Gully erosion was caused by rainfall and runoff on excavated slopes, dump slopes, roadside slopes and brick factory platforms. Due to overgrazing, gravity erosion and gully erosion occurred in some natural hillsides. The average soil erosion modulus of the 15 investigation units was 51.40~1 338.91 t/(km·a).[Conclusion] The soil erosion in Pothohar Plateau mainly occurred in construction land. The soil erosion caused by development and construction projects should be supervised and controlled. Meanwhile, matching soil erosion prevention measures should be developed through science experiments. The Muree region in the north is an important water conservation area in Pakistan, which requires rational planning and approval of a large number of construction projects to prevent the intensifying of soil erosion and the deterioration of water quality and ecological environment. The research and control on headwater erosion in gully region should be strengthened to protect farmland and ensure food security. It is necessary to strengthen the collection of basic data on soil erosion, and to study the mechanism and process of soil erosion at different scales in order to protect the land resources in Pakistan.

Abstract:[Objective] The objectives of this paper were to review and synthesizes the research programs which were conducted in the field of change of forest vegetation and the evolution of soil erosion in Southeast Asia, and to discuss the effectiveness of improved conservation practices on managing soil erosion and sediment yield at catchment scale.[Methods] The forest vegetation change countermeasures at different spatial and temporal scales were analyzed according to data from countries in Southeast Asia. This paper focused on an extensive range of methodologies at different spatial and temporal scales. The research area was the region selected for the implementation of watershed management in Thailand. The efficacy and practicality of passive and active erosion control strategies were expounded.[Results] ① Forest loss in Southeast Asia had remained at high levels during the period from 2000 to 2005, accumulating to an annual deforestation rate of about 2.76×10⁶ ha. However, forest cover has increased in the recent years due to the establishment of forest plantations. ② Southeast Asian haze was a large-scale air pollution problem that occurs regularly. The haze was largely caused by illegal agricultural fires. ③ Soil erosion control strategies for manage soil erosion in Southeast Asia include alley cropping, contouring, strip cropping, grass barriers, conservation tillage, minimum tillage and hedgerow inter-cropping. Despite the role of conservation practices being well established in reducing water runoff at the plot scale, extrapolation to a large scale, it has been less understood and verified. The potential impact of soil conservation on yield may be a key factor that affects the value of soil conservation investments.[Conclusion] The challenge of forest vegetation change in Southeast Asia is real and urgent. Regional prevention and control mechanisms should be constructed to decrease forest fire and haze. To decrease soil erosion, we should keep a sustainable forestry and sustain terrestrial biodiversity. Selection of appropriate soil conservation methods for low income smallholder farmers is critical to reduce the rate of soil erosion as well as to increase crop productivity.