Abstract:[Objective] The grain size distributions and erosibilities of sandy soils in Northwestern Shanxi Province were studied to provide basic data and scientific evidence for rational utilization of land and effective prevention to control wind erosion.[Methods] We studied 0-20 cm surface soils of different land use patterns in Northwestern Shanxi Province by extracting all types of potential erosive particles. Land use included abandoned land, corn field, artificial forest and bare land.[Results] ① Soil particle size of sandy land in northwest of Shanxi Province were mainly composed of very fine sand (0.125~0.063 mm) and silty sand (0.063~0.002 mm), which were more than 70% of the total sand. ② The silty sand contents of abandoned land, corn land and artificial forest were 52.86%,48.81% and 43.52% respectively. Bare land has a high fine sand content of 45.64%. ③ The contents of erodible particle (0.25~0.056 mm) of the four land types increased in the following order:abandoned land (47.18%) < corn field (49.67%) < artificial forest (55.83%) < bare land (68.80%).[Conclusion] Different land use patterns would affect soil particles' grain size distributions and make changes in soil properties. Eventually these changes would lead to different soil wind erosion possibility. Bare land was the main field which should pay more attention to prevent wind erosion. Protection measures such as surface cover should be taken to reduce wind erosion.

Abstract:[Objective] In order to investigate the rainfall infiltration process in fractured deposits, this study focuses on the variation of volume moisture content, matric suction, pore pressure and other changes in soil slope under rainfall conditions, as well as the migration low of wetting, which will provide theoretical support for the instability mechanism of rain-induced overburden slope.[Methods] The indoor model tests of two types of different structural soil deposits were carried out.[Results] The wetting fronts in the homogeneous accumulations were uniformly moving downward, the pore pressure and water content decreased and the matric suction increased when the wetting fronts reach the measuring points. The change of top slope were affected obviously by rainfall while the bottom showed a cumulative effect. The fissures constituted the dominant channel for rainwater infiltration and there was a transient saturated zone at the bottom of the fissures. The wetting fronts produced a strong depressions in this area that form a percolation "funnel" that causes the wetting fronts to reach its bottom in advance.[Conclusion] The rainfall infiltration processes are in the sequence of complete infiltration→slow infiltration→stable infiltration→saturated infiltration for homogeneous model and in the sequence of complete infiltration→local strongly infiltration→compensation accelerated infiltration→horizontal lateral infiltration for fracture model.

Abstract:[Objective] The effects of different materials covering urban bare soil were studied to provide the guidance and basis in theory for urban bare soil amendment and ecological beautification.[Methods] The bare soil with different types of coverings, including wood chips, garden waste, pebbles, ceramsite, organic mulching mats, mulching with two layers(upper garden waste, lower garden waste compost), were designed, and the bare soil without mulch was control. Soil physical and chemical properties were measured after one year.[Results] In general, all mulching treatments could affect soil physical and chemical properties in different soil layers. The effects on the layer of 0-10 cm were stronger than on the layer of 10-20 cm. However, the effects would be gradually weakened as extended time. Soil moisture could be improved by the treatments of pebbles and ceramsite. Soil bulk density was reduced and soil porosity was increased by the treatments of wood chips and mulching with two layers. The treatments of mulching with two layers and garden waste could also significantly reduce soil pH value. Organic mulching materials could increase soil organic matter and available nutrients in both layers. The effects of the mulching with two layers and the garden wastes were better than that of other treatment. Soil content of available nitrogen, available phosphorus and available potassium of with mulching with two layers and the garden wastes were 56.63%, 85.73%, 224.52% and 48.66%, 63.11%, 25.00% greater than in bare soil without mulch. The continuity of nutrient supply was better for the treatment of the mulching with two layers and the organic pad.[Conclusion] The treatment of mulching with two layers was the better choice to amend bare soil in cities. It is of realistic popularization significance in the construction of sponge city and green city.

Abstract:The effects of drying-wetting cycles on the mechanical properties and meso-mechanism of the hydrophilic polyurethane material(W-OH) solidified Pisha sandstone were conducted to provide scientific basis for the study of W-OH consolidation amending Pisha sandstone and its durability. W-OH was used to consolidate the Pisha sandstone in this study. Macroscopic mechanical properties of the W-OH solidified Pisha sandstone were tested by unconfined compression experiment and triaxial compression experiment. To obtain the meso-mechanism, SEM, EDS and weighing methods were used to analyze the microstructure, elements, and quality losses of the sample after drying-wetting cycles. The results showed that unconfined compressive strength, elastic modulus, and cohesion of the W-OH solidified Pisha sandstone increased after drying-wetting cycles of 1~3 times. During drying-wetting cycles of 3~9 times, the mechanical strength of the W-OH solidified Pisha sandstone decreased. the rest solidified W-OH with high cohesive forces remained on the surface of the Pisha sandstone particles and the mechanical strength tended to be stable after drying-wetting cycles 9 times. The internal friction angle varied with fluctuation from 1 to 9 time drying-wetting cycles and stabilized after 9 times. The W-OH loss in the solidified soil samples was evaluated by the carbon element analysis and mass loss analysis. The solidified W-OH gradually decreased during drying-wetting cycles of 1~9 times and became stable after 9 times, which proved meso-mechanism of macroscopic mechanical properties above-mentioned and provided theoretical basis for long-term characteristics of W-OH consolidated Pisha sandstone. The results of this study suggest that the mechanical properties of W-OH solidified Pisha sandstone after 9 drying-wetting cycles can be considered as the long-term mechanical properties of this material.

Abstract:[Objective] The effects of drought stress on the seed germination and seedling growth of Sibiraea angustata was investigated in order to provide reference for wild species domestication and population recovery.[Methods] To study the swellingrate, germination percentage, germination potential, germination index, vigor index, seed drought germination index and seedling growth in Sibiraea angustata under different concentrations of polyethylene glycol(PEG-6000) treatments.[Results] With the intensification of the stress level, the absorption process of the seeds of narrow leaves Sibiraea angustata showed three stages:rapid water absorption period, slow rising period and water absorption period, and the germination rate, germination potential, germination index, vigor index and seed drought-resistance germination index, seedling height and root length, and the seedling weight were negatively correlated with the stress intensity. When the polyethylene glycol concentration reached 30%, the germination of seed was inhibited completely. On the other hand, seed germination and emergence, and 50% of the time delay were decreased with the increase of stress intensity. Among them, the most stringent stage is emergence stage, seed emergence process of environmental was more sensitive, and drought capability is weak.[Conclusion] Drought stress significantly inhibited the seed germination and seedling growth, it also suggested that water is one of the dominant factor for the formation of seed germination and seedling growth. Therefore, planting Sibiraea angustata in the arid areas requires consideration of water supply.

Abstract:[Objective] The effects of water & soil conservation measures on the reductions of runoff and sediment were researched in Changting County of Fujian province in order to provide scientific basis for soil erosion control in the southern red soil erosion area.[Methods] In the soil and water conservation science and education park in Changting County, Fujian Povince, seven soil and water conservation measures were set, the efficiencies in runoff and sediment reduction under four kinds of rainfall with respect to intensity and type were experimented and analyzed. Method of K-mean clustering was used.[Results] ① ZG(platform+fruittree) and MWS(Pinus massoniam pure trees) were the most significant in the reduction of water loss. BC(full slope planting+sowing grass) and ZG had the most significant effect on the reduction of sediment. ② There was a significant positive correlation between runoff and rainfall. There were no significant difference in the amounts of runoff and sediment among different rainfall intensities. Runoff were significantly correlated with vegetation coverage. ③ Under the same rain pattern, the effect of different water conservation measures on reducing flow and sediment was remarkable.[Conclusion] The difference of annual runoff between the plots treated with conservation measures and the control plot was very significant. The sediment reduction rate was less affected by rainfall type. The sediment quantity of runoff was significantly correlated with vegetation coverage and soil organic matter.

Abstract:[Objective] The characteristics of polychlorinated biphenyls(PCBs) pollution of surface sediments in Dongping Lake were studied in order to provide the scientific basis for pollution control and risk assessment.[Methods] PCB28,PCB52,PCB101,PCB118,PCB153,PCB138 and PCB180 in 16 different surface sediments samples were monitored in Dongping Lake in July 2015. GC-ECD was used to determine the concents of PCBs. Ecological risk assessment of PCBs in surface sediments of Dongping Lake was conducted by EPA method.[Results] The total content of PCBs was in the range of nd~605.9 ng/kg, the mean value was 126 ng/kg, and standard deviation was 153. In terms of spatial distribution, its order was:the central of the lake area(184.5 ng/kg) > entrance of lake area(149.9 ng/kg) > the southwest of the lake area(101.4 ng/kg) > the northern of the lake area(46.7 ng/kg). PCBs homologues were mainly composed of PCB7(66.72%) in the study area. Compared with other xregions sediments, PCBs in surface sediments of Dongping Lake were at a lower level. The ecological risk assessment of polychlorinated biphenyls(PCBs) in surface sediments of Dongping Lake using Regulations the United States Environmental Protection Agency(EPA), the probability of biological toxicity was much less than 10%.[Conclusion] Due to influence of hydrological factors, there was a decreasing trend of spatial distribution from the entrance of the Dawen River to the northwest direction of the PCBs in the surface sediments of Dongping Lake. The concentration of PCBs in sediments has no serious effect on the environmental safety of water, and it has no toxic effect on most benthic organism.

Abstract:[Objective] The key natural factors affecting the distribution of landslide disasters induced by mountain torrent in the Xiangxi catchment, which represents the Sichuan-Hubei fold mountain area inner Eastern Three Gorges Area, was studied in order to provide scientific support for the regional prevention and control of the mountain torrent and geologic disasters. Besides, the performance of Geodetector model was also discussed.[Methods] The quantitative relationships between the regional torrent-landslide distributed pattern in disaster-prone mountain and its main natural impact factors was analyzed based on field investigation, GIS, general statistic method and Geodetector.[Results] The stepwise regression analysis indicated that the main five factors, i.e., lithology frangibility, fault range, NDVI, extreme value of storm and lithology hard degree can totally explain 80.6% of the variation of the pattern, and the contributions of them were 28.6%, 19.8%, 18.9%, 16.4% and 16.3%, respectively. The Geodetector analysis indicated that the main factors were lithology frangibility, fault range, NDVI, soil erodibility and lithology hard degree, their contributions were 24.5%, 20.9%, 18.3%, 16.3% and 14.8%, respectively. The interactions between lithology frangibility and the two vaiables of NDVI and slope, can explained 68.8% and 62.0% of the pattern, respectively.[Conclusion] The regional mountain torrent-landslide disaster pattern were mainly controlled by lithology, fault and vegetation cover. The harder the rock was, and the farther from the fault, and the higher cover level of vegetation, the less the mountain torrent-landslide developed. The Geodetector is suitable for the nonlinear geographical phenomenon in general. However, the linear characteristic of independent variable is ignored in this method, and naturally the repeatability among the variables cannot be distinguished. Therefore, the classic statistical method should be combined for understanding the results comprehensively.

Abstract:[Objective] The distribution characteristics of soil organic carbon (SOC) content and density (SOCD) in typical forests of Bailongjiang region were studied in order to provide a scientific basis for further promoting multi-objective forest management.[Methods] Field investigation, sampling and laboratory test were used.[Results] ① The mean SOC content of artificial spruce forest was (32.5±21.82) g/kg, and SOCD was (13.85±6.98) kg/m² in the soil depth of 0-60 cm. ② The density of soil is significantly different in the different soil depths, and the content of soil organic matter, total N, total P, total K, effective P and K in five forest types showed a trend of decline with the increase of soil depth. ③ Content of soil in 0-60 cm layer was positively correlated with natural water content, total N, total K and effective K, while it had a significantly negative correlation with soil density. SOCD showed a consistent correlation with physicochemical properties of soil.[Conclusion] The content and density of SOC in the different forest types are affected by many factors in the study area. Under the influence of those factors such as stand structure, soil physical and chemical characteristics, and tree characteristics, the content and density of SOC showed a significant difference between the different forest types.

Abstract:[Objective] The objective of this paper was to analyze the characteristics and influencing factors of phosphorus adsorption on surface sediment of small shallow lake, and provide decision basis for eutrophication control and ecological environment restoration of small shallow lake.[Methods] Adsorption characteristics of phosphorus on surface sediments samples taken from Kongmu Lake was determined by adsorption kinetics and isothermal adsorption, and the adsorption behavior of phosphorus at different pH values was determined by calculation formula of phosphorus adsorption capacity.[Results] Adsorption kinetics of phosphorus on the surface sediments was divided into two stage:the rapid adsorption stage occurred in 0~1 h, while the slow adsorption stage occurred in 1~3 h. Adsorption isotherm curves was fitted into Langmuir model, Freundlich model and D-R model under high concentration conditions, while fitted into Linear equation under low concentration conditions. Under acidic or neutral environmental conditions, surface sediments has better phosphorus adsorption effect.[Conclusion] The surface sediments from small, eutrophic shallow lake has the trend to release phosphorus into the overlying water. The amount of phosphate in overlying water and sediments will affect the adsorption characteristics and dynamic equilibrium of phosphorus in surface sediments.

Abstract:[Objective] The effects of the geometric characteristics of the shrub root on pulling force is studied in order to provides a theoretical reference for the selection of plant species and the full utilization of plant value.[Methods] Taking photinia fraseri as an example, the outdoor pull-out test of photinia fraseri root system was carried out to study the interaction between root and soil in different water gradients, root form, secondary side root and so on.[Results] The maximum pulling force of the Y-type root system and horizontal root system decreased logarithmically and exponentially with increasing moisture content. However, the maximum pulling force of the main direct root system increased first and then decreased with the increase of water content,and the optimum moisture content was about 17.5%. The maximum pulling force of the Y-type root system increased with the increase of the root system angle. The activation time of the root system increased first and then increased with the increase of the angle of the root system. It was most easily activated when the angle was 75°. The maximum tensile force of the Y-type root system and the main direct root system increased linearly with the increase of the number of secondary lateral roots, but the increase of the maximum tensile force of the main direct root system was greater than that of the Y-type root system. The drawing curve was drawn hardened when the water content was 10%, 20% and 25%,and the drawing curve was a pull-softening type when the water content was 15%. When the horizontal root system and the Y-type root system were in the water-bearing rate of 15% and 17.5%, the drawing curve was drawn hardened, and when the water content was 20%,22.5% and 25%, the drawing curve was a pull-softening type. Through the comparison of the effects of different root system slopes, the mechanical of the multi-form root vegetation slope was evaluated, which had a theoretical guiding effect on ecological protection.[Conclusion] Root morphology and water content are the key factors affecting the pullout force of roots. The more complex the root morphology, the greater the pulling force. As the water content increases, the drawing curve gradually changes from hardening to softening.

Abstract:[Objective] The water environment quality and its controls in drainage ditches from Ningxia Irrigation area were observed in order to provide theoretial reference for the comprehensive control of water pollution of drainage ditches.[Methods] We collected water environmental data of drainage ditch during 2009-2015 and prefectural socio-economic data. The permanganate index, chemical oxygen demand, ammonia nitrogen, total phosphorus, biochemical oxygen demand, volatile phenols, fluoride, cyanide, and sulfides were selected to evaluate the comprehensive water pollution. Correlation analysis and grey correlation analysis were used to analyze the impact of socio-economic indexes on the water quality.[Results] The water quality of Nangan ditch was gradually improved, while Yinxingan and Qingshui ditchs deteriorated rapidly, and others remained stable and sound. The water quality was highly related to socio-economic indexes. The correlation coefficient(r) was 0.998 for chemical fertilizers utilization with water quality in Zhonggan ditch, and 0.983 for total industrial effluent discharge in Nangan ditch; the correlation between Yongergan ditch and agricultural water consumption was as high as 0.793 41, the correlation degree between Nangan ditch and discharges of total industrial wastewater discharge was as high as 0.75 569, respectively.[Conclusion] The water quality of drainage ditches was greatly affected by agricultural non-point source pollution and industrial waste water. On the prefectural level, the order of correlations between the comprehensive pollution and socio-economic indexes was Wuzhong City, Yinchuan City, Zhongwei City and Shizuishan City. There is a good consistency between the results of correlation analysis and grey correlation analysis. The combination of the two analyses was performed to exploring the main controls for water quality. Generally, agricultural production was the dominant driver for water pollution in Yinchuan City and Shizuishan City, while industrial production was dominant in Wuzhong City and Zhongwei City. Moreover, agricultural non-point source pollution caused by agricultural production has a greater adverse effect on water quality than industrial wastewater produced by industrial production.

Abstract:[Objective] The objective of the study was to elucidate the effects of representative artificial vegetation types on soil glomalin-related soil protein (GRSP) and aggregate stability, and to evaluate the relationship between the latter two factors on the Loess Plateau in Western Shanxi Province in order to provide basic data for artificial vegetation restoration project.[Methods] Four representative artificial vegetation types, Medicago sativa, Robinia pseudoacacia, Platycladus orientalis, and Juglans regia, were selected in the Sanchuan River Basin, western Shanxi Province, with a cropland as the control. Soil samples were taken from a depth of 0-100 cm to analyze the distribution differences of easily extractable-GRSP(EE-GRSP), total-GRSP (T-GRSP), soil organic carbon (SOC), and aggregate stability among different vegetation types. The relationship between these parameters were evaluated by Pearson analysis.[Results] The EE-GRSP and T-GRSP concentrations and the EE-GRSP/T-GRSP ratio significantly differed in the 0-30 cm surface soil across different vegetation types, with the highest and lowest values being found in the J. regia and M. sativa plots, respectively. Both the EE-GRSP/SOC and T-GRSP/SOC ratios always increased with the increase of soil depth, having ranges of 1.78~6.77 and 4.07~19.11, respectively. The EE-GRSP/SOC and T-GRSP/SOC increased in the P. orientalis (39.67% and 36.62%) and M. sativa (39.25% and 46.70%) plots as compared with the ones in cropland, while they decreased in the J. regia plot (31.07% and 36.93%). Mean weight diameter was positively correlated with T-GRSP and SOC (p<0.05) and negatively correlated with EE-GRSP/SOC (p<0.05).[Conclusion] Different artificial vegetation types considerably influenced GRSP components in the surface soil. Soil aggregate stability was not only related to the concentration of soil GRSP components, but also to their contribution to SOC.

Abstract:[Objective] The influence of soil moisture content and dry bulk density on the shear strength of soil in the study area was explored and an empirical formula was established in order to provide a theoretical basis for improving the stability of the slope and protecting the soil and water environment.[Methods] Three typical forest stands (evergreen broadleaved forest, coniferous and broad-leaved mixed forest, shrub-grass forest)was sampled in Fengyang Mountain Nature Reserve, Zhejiang Province. Remolded soil direct shear experiment was conducted to analyze the effect of different classification of moisture content (25%, 27%, 29%, 31%, 33%) and dry bulk density (0.8, 0.9, 1.0, 1.1, 1.2 g/cm) on the shear strength parameters (the internal frictional angle φ and cohesive force c).[Results] ① There were a significant positive correlation between cohesive force and dry bulk density, and a significant negative correlation between cohesive force and moisture content. There was a significant positive correlation between the internal frictional angle and the dry bulk density. ② The soil cohesive force decreased with the increase of moisture content, and increased with the increase of dry bulk density, it had obvious regularity; with the increase of dry bulk density, the internal frictional angle had a tendency of obvious increase, which in the case of high compactness, the internal frictional angle was always large. In relate to the cohesive force, the internal frictional angle was less affected by the moisture content. With the increase of the moisture content, the characteristics of non-linear decrease in shrub-grassland forests and coniferous and broad-leaved mixed forest were showed. In the evergreen broad-leaved forest, there was a trend of increasing first and then decreasing, considering the occurrence of optimal moisture content. ③ At the same moisture content, the dry bulk density had an enhanced effect on the cohesive force of the three types of soils. The logarithm of cohesion and the dry density showed a positive linear correlation. We consider the combined effects of moisture content and dry bulk density, add the influence coefficient β, and establish an empirical formula, respectively.[Conclusion] The logarithm of cohesive force and moisture content were significantly negatively correlated with each other, and there was a significant positive correlation with dry bulk density and cohesive force. Soil dry bulk density had a significant effect on soil internal frictional angle, and moisture content had no significant effect on internal frictional angle.

Abstract:[Objective] The soil erosion situation was evaluated in the Zhifanggou watershed of Northern Shaanxi Province in order to provides scientific basis and theoretical support for the adjustment and optimization of unreasonable land use patterns and the rational arrangement of soil and water conservation control measures in the watershed.[Methods] The present study amended the parameters of Chinese soil loss equation(CSLE) and calculated soil erosion intensity based on the data of monthly rainfall, DEM, soil type, and land use from 2005 to 2016 in the Zhifanggou watershed at Ansai County of Northern Shaanxi Province using ArcGIS. The linkages between land use change, slope degree and soil erosion intensity were also analyzed. Based on the aforementioned results, we put forward suggestions for the management of soil and water loss in this area.[Results] Soil erosion intensity differed greatly among different slope zones in the investigated area. Farmlands with 15°~25° slope in the watershed were sensitive to soil erosion. Forestland, farmland and grassland dominated the Zhifanggou watershed. The area of farmland decreased continuously and that of forestland and grassland increased gradually. Since the project of Grain for Green initiated, the area that subjected to soil erosion, and the erosion intensity were both decreased. There was a close association between land use change and soil erosion intensity, characterized by higher erosion intensity in farmland and lower density in forestland and grassland. These results indicated that increasing the forestland and grassland and decreasing the farmland could be favorable for the reduction of soil erosion.[Conclusion] Spatial distribution of soil erosion in the study area was dominantly determined by the land use types and slope degree. Soil and water loss management should focus on the slope land with degree of 15°~25°.

Abstract:[Objective] The effect of particle sizes of super absorbent ploymer on soil moisture and flue-cured tobacco(Nicotiana tabacum) growth was studied in order to provide scientific support for improving soil moisture and flue-cured tobacco growth in Qinba Mountain area.[Methods] The experiment took no super absorbent polymer application as control, powder (particle size < 0.18 mm), fine granularity (particle size 0.18~2.25 mm) and granularity(particle size 2.25~3.25 mm) of potassium polyacrylate super absorbent ploymer as the research materials in yellow brown soil of Qinba Mountain area, the effects of different particle sizes of potassium polyacrylate super absorbent ploymer on soil moisture, soil bulk density and flue-cured tobacco growth, flue-cured tobacco quality and flue-cured tobacco economic properties were investigated.[Results] The soil moisture of 0-40 cm soil layer were increased and the soil bulk density of 0-40 cm soil layer were reduced by potassium polyacrylate super absorbent ploymer with different particle sizes in different growing stages of flue-cured tobacco, but there was no significant effect on soil moisture under 40 cm soil layer. Among different particle sizes of potassium polyacrylate super absorbent ploymer, fine granularity potassium polyacrylate super absorbent ploymer had great influence on soil moisture and soil bulk density. Potassium polyacrylate super absorbent ploymer with different particle sizes could promote root growth, stem growth and leaf growth of flue-cured tobacco, increase tobacco yield and tobacco output value, and reduce the proportion of inferior tobacco, and fine granularity potassium polyacrylate super absorbent ploymer had a great effect on the largest leaf growth, root growth, tobacco yield and tobacco output value, but powder potassium polyacrylate super absorbent ploymer has a great influence on the proportion of superior tobacco.[Conclusion] Potassium polyacrylate super absorbent ploymer with different particle sizes improved the quality of flue-cured tobacco, and the fine granularity potassium polyacrylate super absorbent ploymer had great influence on levels of nicotine, total nitrogen, potassium and chlorine of tobacco, and the powder potassium polyacrylate super absorbent ploymer had a great influence on the total sugar and reducing sugar levels of tobacco. Fine granularity potassium polyacrylate super absorbent ploymer should be used in yellow brown soil in Qinba Mountain area in tobacco fields.

Abstract:[Objective] The land use change and ecological environment effect in Xuzhou City were studied in order to provide theoretical support and reference basis for rational land planning and balance of regional economy and ecological environment.[Methods] The dynamic changes of land use types and spatial pattern evolution of land use in downtown Xuzhou City were investigated based on the analysis of land use transfer matrix and overlay. The ecological environmental effects of land-use changes were analyzed using NDVI and regional ecological environmental quality index.[Results] The Kappa coefficient of multi-source remote sensing data was higher than 0.90 based on results of classification and regression tree (CART). The area of cultivated land was greatly reduced, and construction land was increasing rapidly. Much suburb area has been converted into building land. During the period of 2004-2016, the low value zone of NDVI in Xuzhou City gradually expanded, but the ecological environment quality increased from 0.323 to 0.360, and then decreased to 0.320.[Conclusion] From 2004 to 2016, the urban expansion of Xuzhou City resulted in less farmland and intensified landscape fragmentation, but the acreage of greenbelt increased during the urban construction process and the overall ecological environment quality improved slightly. It is suggested to further strengthen the reasonable planning of urban landscape pattern and reduce the negative impact of urbanization on the ecological environment.

Abstract:[Objective] Soil particle composition and fractal dimension was observed in reclaimed soils in order to provide scientific evidences for restoring and improving ecological function of mined soils in wind-sandy area.[Methods] We compared the soil particle composition and its fractal dimension characteristics under three vegetation types and unreclaimed substrates in Daliuta coal mine based on fractal theory.[Results] ① Soil in this wind-sandy area was predominantly fine sand, with the remainder mainly comprised of medium sand at arbor forest, shrubbery and bare sand, while comprised of very fine sand at grassland sites. The effect of vegetation type on soil fine particles varied with soil layers. The content of clay and silt in 0-30 cm of reclaimed soils was significantly higher than that in bare sandy land. ② Fractal dimension of soil particles was 1.306~2.490, and the average value was as follows:grassland (2.425) > shrubbery (2.300) > arbor forest (1.626) > bare sand land (1.550). Changes in fractal dimension were layer-dependent. There is no significant difference between grassland and shrubbery in all soil layers. However, the fractal dimension of grassland and shrubbery is significant higher than that of arbor forest and bare sand land. ③ Fractal dimension is tightly related to soil particle composition, but not to soil moisture and soil organic matter. We found a significantly positive relationship with the clay and silt content, and a negative relationship with the coarse sand content.[Conclusion] It is a quite difference in soil particle composition and fractal dimension between vegetation types. Grassland and shrubbery land could promote the soil grain refinement which can be adopted to reverse the mined environment.

Abstract:[Objective] In order to provide a calculation basis for the standard of soil and water conservation compensation fees for oil and gas projects, the values of water and soil conservation function loss due to oilfield road pressure and hardening during production period were quantitatively evaluated.[Methods] The ecological service value evaluation method was used to estimate the loss value of the soil and water conservation function of oilfield by calculating the model of the oilfield in Zhidan County of Shaanxi Province. According to this method, the value of soil and water conservation function is equal to the sum values of holding soil, water conservation, carbon fixation and oxygen supply, air purification, wind and sand fixation, and biodiversity maintenance.[Results] Roads in oilfield can reduce the value of the soil and water conservation function, the average annual loss of soil and water conservation function of each well reached 1 827 yuan. According to 30%~50%, usual proportion of the road area to total area of oil field, the average annual loss of soil and water conservation function of each well was 3 654~6 090 yuan higher than the current standard which is not more than 2 800 yuan.[Conclusions] It is reasonable and feasible for the current method of soil and water conservation compensation to be collected according to the year and the standard of collection(no more than 2 800 yuan per well).

Abstract:[Objective] The possible mass movement distance resulted from the instability of the abandoned dreg sites was studied for life and property security and environmental protection.[Methods] In accordance with the summarized historical data about 1 032 samples from soil accumulation, landslide mass and volcanic fluids, 882 effective data were selected by statistical analysis, and two models with regard to site selection were proposed.[Results] The corresponding safe distance for waste rock and soil accumulation in the different scales was calculated by the historical frequency. The 2.78, 5.88 and 14.29 times of its distance corresponding to the waste rock and soil accumulation were suggested for 5, 4 and 1 class abandoned dreg sites. And the 7.14 times of its distance corresponding to the waste rock and soil accumulation was suggested for 2 and 3 class abandoned dreg sites. The numerical prediction method with a highly application for loess accumulation was proposed to determine the safe distance by the theoretical modification and evaluation of the existed experience models, considering the mass scale, landform and rock classification.[Conclusion] The historical frequency method with a simple procedure can be widely used and accepted. The numerical prediction method has higher precision with iterative computation.

Abstract:[Objective] The farmland works planning and design under water storage pit irrigation is studied to solve the problems of future promotion and application, in order to lay the foundation for promoting large-scale and industrialized development of water storage pit irrigation in hilly regions.[Methods] Taking the water-saving irrigation demonstration garden in Taigu County, Shanxi Province as an example, water storage pit irrigation farmland works planning and design was carried on, by reference to micro-irrigation projects and low-pressure pipeline irrigation projects.[Results] Parallel rainwater harvesting ditches were adopted in land leveling. Each tree was allocated 4 pits, the water storage pits were 40 cm deep. The pit diameter was 30 cm, under the detention capacity of rainfall runoff standard of 24 hours maximum rainstorm volume occurred every 5 years. Every pit was decorated with a baseplate, a solid wall and a head cover as a whole. The annular grooves were 20 cm deep, 30 cm wide, with a radius of 50 cm. The pipe network included three levels:main pipes, branch pipes and laterals, made of polyethylene. The annular four-outlets lateral was around the tree; the calculation methods for the pipe diameters, lengths, and import working heads and the determination method for the working system were provided.[Conclusion] The planning and design of land leveling technology, water storage design and layout technology, and low-pressure pipeline system design technology can meet the special demand of water storage pit irrigation in hilly regions.

Abstract:[Objective] The applicability of different types of foaming agents and different bubble preparation methods in the preparation of foamed mixture lightweight soil of sludge(FMLSS) was studied in order to provide reference for environmental protection and utilization of river sludge.[Methods] From the micro and macro perspectives, different channels of silt and bubble mixed soil were investigated. The microscopic characteristics of different mixed soil of river silt and bubble was compared, and the influences of different microstructural characteristics on the physical and mechanical properties of various river silt mixed soil was anayzed.[Results] ① The microstructural differences of different types of river silt and bubble mixed soil were significantly affected by the amount of air bubbles and were less adffected by cement content. ② When the amount of air bubble was constant, the bubble would be burst seriously by hydrogen peroxide(H type), and the prepared soil with mixed river silt and bubble by hydrogen peroxide contained a small amount of big atmospheric pores and the distribution was uneven. Under the same density, the air pore content of H type river silt and bubble mixed soil was more, and the quality of the mud-bubble mixing soil was worse. ③ The distribution of FMLSS micro pores made by compound foaming agent(F type) and anionic foaming agent K₁₂A(K type) were better. But the pore size of F type foaming agent was small and the distribution was uniform and good strength and deformation characteristics were shown.[Conclusion] The first foaming process is better than the later foaming process. The F type foaming agent has better applicability in the preparation of foamed mixture lightweight soil using of river sludge.

Abstract:[Objective] The applicability of HBV model to the runoff sequence simulation of Fuchun River basin was investigated, and the critical disaster-causing surface rainfall of the water level at all levels of the basin was determined through the relationship between water level and runoff in order to provide a service product for the storm disaster risk warning and evaluation and an important basis for the production scheduling of Fuchunjiang Reservoir.[Methods] Taking Fuchunjiang hydropower station as a study area, the meteorological data and HBV hydrological model of the study area were applied.[Results] ① Application of the HBV hydrological model in simulating Fuchunjiang river basin runoff, in a sequence of regular rate and validation period, showed an agreement between the simulated and measured distributions of runoff process. There also was a good relationship between the runoff peak area and live distribution of heavy precipitation. Besides, the mean relative error between the simulated and measured flood peak is less than 5%, indicated a good performance carried out by the calibrated HBV model in the study area. ② Based on the response relationships among the precipitation, runoff, and water level, the warning water level of reservoir and critical surface rainfall could be determined.[Conclusion] The HBV hydrological model performed well to a certain degree in the study area. The reservoir can make a scientific regulation in water level according to the forecast information of rainfall and runoff, when the critical surface rainfall is predicted.

Abstract:[Objective] The objective is to investigate the losses of nitrogen and phosphorus in typical weathered granite parent material soil under erosive environment, and to discuss the contribution rates of nitrogen and phosphorus losses in slope runoff and interflow.[Methods] Slope gradients(8°, 25°) and rainfall intensities (30,60, 90, 120,150 mm/h) were selected as the variable factors for artificially simulated rainfall experiments, the study revealed the distributions of nitrogen and phosphorus losses in slope runoff and interflow based on mass concentration and runoff volume analyses.[Results] ① In the heavily eroded sloping fields, soil structure was instable; the soil was highly permeable, so the proportion of nitrogen and phosphorus loss in interflow was very large. The amount of TN loss in the interflow accounted for more than 90% of the total loss, and TP loss was slightly lower. ② The loss of TN with runoff was much greater than the loss of TP. TN in the slope runoff can reach 160 times higher than the total loss of TP. ③ The effect of rainfall intensities on the losses of nitrogen and phosphorus were greater than that of slope gradients; and the effect of runoff volume was greater than that of mass concentration. ④ There were two transitions in the effect of rainfall intensity on nitrogen and phosphorus loss, the first one was near 60 mm/h rainfall intensity, at which full-stored Horton runoff begin tranited to one dunne, and the second was 90 mm/min, from that on, the rain intensity became erosive.[Conclusion] Strong erosion affects both the loss of soil nutrients and the ratio of loss pathways. The losses of nitrogen and phosphorus in the interflow contribute a large proportion to the total ones, which inveitablly affects the quality of groundwater. Strengthening the prevention and control of soil erosion on sloping fields in rock formations soil is the basis for the control of non-point source pollution of surface water and groundwater, and it is essential to reduce soil nutrient loss.

Abstract:[Objective] The tree species mixation strategy in accurate quality improvement of Larix principis-rupprechtii plantation was studied in order provide reference for the forest management in the north of Shanxi Province.[Methods] Permanent sample plots of Larix principis-rupprechtii forests were set in Guancen Mountain with different mixed modes and different origins. The diameters were measured at breast height of each tree whose diameter was more than 5.0 cm in the sample plot in the summers of 2010 and 2015, respectively. The differences of the growth of mixed tree species under different origins and different mixed modes were compared by ANOVA and t test.[Results] ① For the tree species mixed with Larix principis-rupprechtii, the growth of DBH was as follows:ΔD_{Betula platyphylla} > ΔD_{Picea meyeri} > ΔD_{Salix pseudotangii}, the basal area increment of chest height was as follows:ΔS_{Betula platyphylla} > ΔS_{Picea meyeri} > ΔS_{Salix pseudotangii}, the cumulative growth rate is as follows:ΔV_{Betula platyphylla} ≈ ΔV_{Picea meyeri} > ΔV_{Salix pseudotangii}. ② Under different mixed modes, the differences of ΔS and ΔV of Larix principis-rupprechtii were insignificant. ③ Under the condition of natural young and middle aged forests, the growth of mixed tree species was ranked as follows:Picea meyeri > Betula platyphylla > Salix pseudotangii; Under the condition of young and middle aged plantation, the growth of Betula platyphylla was the largest. ④ The growth of Picea meyeri with natural Larix principis-rupprechtii was larger than the one with the planted Larix principis-rupprechtii; the growth of Betula platyphylla with planted Larix principis-rupprechtii was larger than that with the natural one.[Conclusion] In the young ages of Larix principis-rupprechtii plantation, Betula platyphylla can be planted in the glade, which can form a mosaic mixed structure of Larix principis-rupprechtii and Betula platyphylla. Through the mixed plantation of broadleaf tree species with Larix principis-rupprechtii, a more stable and near-natural ecological environment will be created. When the growth and the ecological function of Betula platyphylla declines, Betula platyphylla that cannot play effective ecological function should be cut and Picea meyeri is advised to planted under the canopy. Larix principis-rupprechtii and Picea meyeri can form stable, mixed, multilayer and different aged forests.

Abstract:[Objective] Quantitative reconstruction of the 100-year resolution precipitation sequence of the Qinghai-Tibet Plateau since Holocene provides basic data for the environmental evolution of the Qinghai-Tibet Plateau and its prediction of future climate scenarios.[Methods] Using the high-resolution spore-pollen data from the Ruergai Basin and Tarongcuo Lake on the Qinghai-Tibetan plateau, we reconstructed precipitation changes in the eastern and western plateau since the Holocene by weighted average partial least squares regression(WAPLS) and modern analogue(MAT).[Results] ① The precipitation variation on the plateau was obviously divided into three stages. The precipitation in the early Holocene(10.5~8.9 kaBP) tended to fluctuate, and the average precipitation was slightly higher than that of the modern. The middle Holocene(8.9~3.2 kaBP) was a period of abundant precipitation and the extreme time in the eastern and western regions reached 6.7 kaBP and 7.4 kaBP, respectively, and the precipitation was higher than the modern 42.4 mm and 200 mm respectively. In the later Holocene(after 3.2 kaBP), the precipitation in the east continued to decrease, which was about 70 mm lower than the previous period, while the precipitation in the west increased, similar to the modern level; ② Precipitation extreme events:the extreme drought events on the plateau were relatively consistent and occurred around 1.8, 3.4, 6.2 and 9.5 kaBP.[Conclusion] In the early and middle Holocene, the precipitation was generally higher than that in the modern times. At the end of the Holocene, the precipitation in the east and west had a downward trend, and the precipitation in the west increased around 1.2 kaBP. Reconstruction sequences are comparable to the other records with a high or low resolution, which means reconstruction sequences are representative and relatively accurate.

Abstract:[Objective] Exploring the influence of shearing method on the residual strength of remolded loess in order to provide a scientific basis for the evaluation and treatment of loess landslide engineering.[Methods] To explore the influence of different shear modes on peak strength, residual strength and deformation, ring shear test was carried out on Jingyang loess by ring shear apparatus.[Results] The peak strength and residual strength of remolded loess increased with the increase of effective normal stress, and the greater the effective normal stress, the easier the loess to achieve the residual strength. The deformation of remolded loess is shown as shear compression. The average value of residual strength index obtained by single-stage shear and multistage shear was close.[Conclusion] The shear method is recommended for single-stage shear.

Abstract:[Objective] The watershed division in complex topography area was conducted in order to provide basic data for regional ecological watershed construction and planning.[Methods] Hubei Province was selected as a case study area, where covers mountainous, hill land, plain, many rivers and lakes. Firstly, small watersheds were extracted automatically by using the ArcGIS base on DEM data. Then, small watersheds in the mountains were merged and revised manually with the assistance of gullies, remote sensing images and residential data. For plains, the conventional gullies were replaced by the high-precision river systems. At last, we analyzed the suitable threshold value, frequency, precision and river network density.[Results] There were 5 806 small watersheds in Hubei Province. The watersheds with areas changed from 30 to 50 km² account for 60% of the total number. Watersheds with area small than 20 km² had low-precision and dense in plain. In general, the classification accuracy of small watershed in mountainous area was higher than that in plain area, while the average river network density shows the opposite.[Conclusion] The results show the human-machine interaction correction could be used for the small watershed's division in order to get a better result. The accuracy of automatic division of small watersheds in plain area is lower than that in mountainous area, which needs to be corrected manually with high precision water systems.

Abstract:[Objective] The present study developed a system dynamics model to simulate the growth and water use processes of Eucalyptus in order to provide scientific support for the Eucalyptus plantation and management.[Methods] Two frameworks were coupled together by combining the calculation of leaf and root biomass with the simulation of plant water use. Two areas, the Tumbarumba site in Australia and the Jijia forestry farm in Guangdong Province, were selected to test the performance of the coupled model.[Results] In the Tumbarumba site:① The annual average evapotranspiration from the model simulation during 2001-2014 was 819 mm, while the average annual evapotranspiration from the measurements was 867 mm. ② The simulation accuracy of four parameters of chest height diameter, forest volume, tree height and plant density were 71%, 93%, 88% and 95%, respectively. In the Jijia forestry farm:① The evapotranspiration from the model simulation from October 1999 to September 2000 was 1 068 mm, while the evapotranspiration was 1 069 mm. ② The simulation accuracy of four parameters of chest height diameter, forest volume, tree height and plant density were:94%, 89%, 95% and 99%, respectively.[Conclusion] The model can simulate the growth and water use of Eucalyptus, and further improvements especially in the robustness of model are needed.

Abstract:[Objective] An optimal remediation technique for industrial contaminated sites was studied in order to provide a reliable approach for selection of remediation techniques in similar contaminated sites and engineering applications.[Methods] Taking an industrial contaminated site in Quanzhou City, Fujian Province as a case study, the matrix of the remediation technique selection was created according to its management plan and location. The combination of AHP(analytic hierarchy process) and TOPSIS(technique for order preference by similarity to ideal solution) was applied to build a remediation technique selection index system.[Results] This technique was verified with the actual screening outcome. The matrix that based on its location and management plan meets the actual needs easily. In addition, the application of both AHP and TOPSIS can not only overcome the issues of subjectivity of AHP in analyzing hard-to-quantify indices, but also avoid the shortcomings of TOPSIS that neglects index weights.[Conclusion] The application that combined the AHP with TOPSIS together could be effective in the selection of optimal remediation techniques for contaminated sites.

Abstract:[Objective] The heavy metal pollution status and pollution sources in soil of Tianjin City was studied in order to provide a theoretical basis for preventing soil heavy metal pollution.[Methods] A total of 146 samples were collected from the industrial areas, farmland, water sources, livestock farm and vegetable bases in Tianjin City. The pollution characteristics of heavy metals, mainly refering to the heavy metal content in soils of different land-use types, was evaluated by single factor pollution index and Nemero comprehensive pollution index method, and the sources of heavy metals were also discussed.[Results] The results showed that different heavy metals were all found accumulated in soils, but the overall pollution level in Tianjin City was lower. The over standard rates of Pb, Ag and Cd were 84.25%, 76.71% and 68.49%, respectively. And land-use types affected the accumulation degree and categories of heavy metals. The vegetable base had the highest accumulations of total heavy metal among 5 land-use types, mainly including Cd, Hg, As, Cr, Cu, Ni, V, Mn, Co and Ag. The industrial area had the highest Zn concentration, while the Pb concentration was higher in the farmland, and livestock and poultry farmland.[Conclusion] In an overall, the level of soil pollution in Tianjin City is relatively low. However, in terms of land-use types, the pollution levels of Pb and Zn in the industrial areas, farmland and livestock farms were higher, wherein it should be paid more attention to in the process of land use and management.

Abstract:[Objective] The forest ecological compensation standard in Hunhe river basin was measured in order to provide a scientific basis for making forest ecological compensation mechanism of the river basin.[Methods] This paper determined forest ecological compensation standard by using principal component analysis to form compensation coefficient, defining the development standard of society and economy, and calculating the forest ecological service value from top to bottom with ArcGIS 9.3, which took forest ecological compensation in Hunhe River basin as an example.[Results] The highest forest ecological compensation standard of Shenyang City is 412 million RMB every year, and the lowest is 7 million RMB each year in Dawa County.[Conclusion] Forest ecological service value was gradually reduced with the increase of the distance from the upstream. The more forest ecological service values from the upstream were, the bigger the compensation coefficient was, and the higher standard of compensation was.

Abstract:[Objective] The soil erosion prone area in the plain river network region of Zhongshan City was dividedfor the implementation of soil and water conservation law and the protection of precious soil and water resources in order to provide the scientific basis for the government to administrator according to law and implementation of the water and soil conservation management of production construction projects.[Methods] Through the analysis of natural characteristics of the region, such as weak soil erosion resistance, easy weathering of parent rocks, heavy rainfall with uneven distribution during the year, abundant water and heat conditions, and social and economic characteristics such as strong social and economic activities of human beings, GIS & RS technology is used.[Results] By dividing soil and water conservation zones, the range of plain river network areas, where soil and water was easy to lose, was defined. The sensitive factors of soil and water loss such as landform, rainfall, soil, vegetation are determined in Zhongshan plain river network area. Also, the index system of soil erosion prone area division is constructed by selecting quantitative and qualitative indexes, and the soil-erosion-prone area in the plain river network area of Zhongshan City is divided.[Conclusion] The soil erosion prone area in the plain river network area of Zhongshan City which includes Xiaolan town, Huangpu town and other 9 townships, whose land area is about 666.92 km², accounting for 37.39% of the total land zone of the city. The achievements in the division of soil erosion prone area can improve the planning system of soil and water conservation in Zhongshan City, and also can provide a scientific basis for the compilation of soil and water conservation planning at the prefectural level or for the formulation of rules and regulations.

Abstract:[Objective] The objectives of this study were to determine the critical rainfall of landslide and establish the threshold model of landslide in different geological hazard prone areas of Zunyi City in order to provide scientific basis for landslide prediction in this area.[Method] Hourly precipitation data from 2010 to 2016 were collected from automatic meteorological stations according to 59 landslides of Zunyi City in the Northern Guizhou Province. According to the duration and type of rainfall, the landslide were classified by using statistical analysis in different geological regions and the prediction model of threshold was established and assessed.[Results] Heavy rainfall of more than 10 mm/h and 20 mm/h generally occurred on the day of landsliding, but the duration of rainfall in the middle susceptible area was longer than in the high susceptible area. The uniform pattern of rainfall is the main pattern. For the the high susceptible area, the forecasting accuracy of the threshold model was the best using the parameters the maximum rainfall of 1 hour during the landsliding day and the cumulative rainfall of two days before the landsliding day. Therefore, the maximum rainfall of 1 hour during the landslidubg day was the triggering rainfall. For the middle susceptible area, the forecasting accuracy of the threshold model was the best using the parameters of the maximum rainfall of 3 hours during the landsliding day and the cumulative rainfall of the landsliding day. Therefore, the maximum rainfall of 3 hours was the triggering rainfall.[Conclusion] The critical rainfall of landslide varied among different geological regions. According to the new landslide information, the identified critical rainfall forecasting model is tested and evaluated. If the forecasting model is inaccurate for the new landslide, the landslide discriminant line must be adjusted so that the adjusted prediction model accurately predicts the landslide.

Abstract:[Objective] Characterization of the shape, type and spatial distribution of pore-fissure structure in paleosol was conducted accurately in order to provide an important basis for the study of hydraulic properties of paleosol in slopes.[Methods] X-ray CT was used to scan the undisturbed samples of S₅ paleosol at southern tableland of Jingyang County, Shaanxi Province. Three-dimensional digital paleosol model was established through filtering, thresholding and reconstruction by using 3D visualization software including VG studio Max and AVIZO. The two and three dimensional porosity were calculated, pores and fissures in paleosol were extracted and classified based on shape factors, and the characterization algorithms for various voids were proposed.[Results] ① The pores and fissures coexisted in paleosol, which was of significant verticality and spatial heterogeneity in space. The voids could be differentiated by the shape factors (SFs) into fissures (SF > 40.18), branching pores (7.01 < SF ≤ 40.18), long columnar pores (2.0 < SF ≤ 7.01), ellipsoidal pores (1 < SF ≤ 2), and spherical pores (SF ≤ 1) on spatial pattern; ② the macroporosity (the equal diameter larger than 100 μm) is 9.86%, accounting for 23.94% of the total porosity (41.18%), indicating that the voids with equal diameter smaller than 100 μm are dominant in paleosol; ③ the pore size distribution is between 0.1~5 mm, in which the pores within 0.1~0.7 mm are in the majority on count, and the pores within 0.7~1.0 mm are in the majority of volume contribution rate, and the maximum fissure opening is 5.1 mm.[Conclusion] Paleosol is a kind of double-medium soil with majority of micro, small, medium pores as well as special large pores or macropores accompanying micro fissures or fractures. In addition, X-ray CT and 3D visualization reconstruction technology provides an effective method for the identification and characterization of pore-fissure structures in paleosol.

Abstract:[Objective] The present study evaluated the ecological effects of land use change and discussed the characteristics of land use dynamic evolution in the Nansi Lake basin in order to provide a reference for rational development and utilization of land resources and protection of ecosystem.[Methods] Based on the land use data of Nansi Lake basin during 2000-2015, we calculated and analyzed the ecosystem service value and its dynamic characteristics using the ecosystem service value accounting model and the CLUE-S model.[Results] From 2000 to 2015, the area of cultivated land, grassland and unused land in the Nansi Lake basin decreased, while the area of woodland, the waters/wetland, and urban-rural construction land increased. The overall ecosystem service value increased by 910 million yuan, but the ecological function of grain production, gas regulation and soil conservation decreased by 0.85%, 0.85% and 1.29%, respectively. Ecological problem still exists in this area, such as uneven distribution of ecosystem service value and the larger area of the ecological impairment areas than the ecological value-added zones. In 2030, the value of ecosystem services in the basin will increase slightly, while the ecological functions such as grain production, gas regulation and conservation of soil will continue to decrease. The area of extremely low ecological value will expand from city-centered to surrounding area, and the ecological value-added zone will reduce.[Conclusion] Although the value of ecosystem services is increasing, the distribution of ecological values is unbalanced, and the function of ecological services is unstable. Therefore, it is necessary to take effective measures to control the conversion of land use types and balance the ecological environment in this basin.

Abstract:[Objective] The evolution characteristics of soil microorganism in the process of vegetation restoration in Loess Plateau were studied in order to which provided scientific reference for the ecological restoration and reconstruction of the loess plateau.[Methods] The present study focused on the vegetation restoration in the Loess Plateau and made a systematic analysis of soil microorganism evolution based on the literature data from the database of "Web of Science" and the "China National Knowledge Infrastructure" using CiteSpace bibliometrics tools.[Results] The number of literatures related to soil microorganism during the vegetation restoration of Loess Plateau during 2002-2018 presented an increasing trend. The related works mainly focuses on the soil microbial biomass, microbial community structure, enzyme activities, and especially on the microbial biomass. Vegetation succession caused an increase in microbial biomass and enzyme activities and led to a succession from oligotrophic microbial community to eutrophic community. In general, soil microbial community structure and function was improved during the vegetation succession. Vegetation types had different effects on soil biological quality. The mixed forest had the best quality, followed by the Robinia pseudoacacia and Caragana korshinskii pure forest, abandoned grassland, and Pinus tabuliformis pure forest.[Conclusion] Research on the soil microorganisms in the vegetation restoration of Loess Plateau in the future should focus on the key identification of soil microbial taxa in microbes involved in the carbon, nitrogen and phosphorus cycling, and the impact of global changes on the microbial community.

Abstract:[Objective] This paper aimed to review existed collapsing gully control techniques in order to provide some theoretic references for making more reasonable collapsing gully restoration strategy.[Methods] By reviewing related literatures, and based on the spatial structure characteristics of collapsing gully, this paper reviewed the presently practiced collapsing gully control techniques, systematically summarized the control techniques for different parts of collapsing gully from the aspects of catchment slope, collapsing gully wall, collapsing gully pile, flow channel and alluvial, as well.[Results] The characteristics, applicability as well as the problems of these techniques were discussed. In addition, treatment models of collapsing gully were also summarized. The prospects of some directions for future collapsing gully control technique research were aslo pointed out.[Conclusion] The combination of engineering and biological technologies is the most widely used treatment measure. Future researches on collapsing gully control technique should focus on establishing assessment indicators system, exploring soil and water conservation mechanism, combining restoration tehcnology and agricultural production, developing innovative restoration technology, and prevention treatments, etc.

Abstract:[Objective] This paper studied the spatiotemporal evolution and driving factors of agricultural eco-efficiency in China in order to provide theoretical support for promoting the sustainable development of eco-efficiency.[Methods] Spatiotemporal evolution and driving factors of agricultural eco-efficiency in China in 2007-2016 were analyzed by using super-efficiency DEA-Malmquist index, spatial autocorrelation model and grey relation model.[Results] During the observation period, the value of total factor agricultural eco-efficiency increased steadily, and technical progress was the main reason for the improvement of agricultural eco-efficiency. The spatial distribution of agricultural eco-efficiency has a national autocorrelation, and some regions such as Shandong Province and He'nan Province show "low-low" agglomeration characteristics. The change of agricultural eco-efficiency is mainly influenced by 10 factors, such as scientific and technological support, land approval, agricultural machinery density and agricultural scale level, etc., and there are differences in the effects of various factors in the different periods.[Conclusion] During the observation period, agricultural mechanical density replaced urbanization level as the main driving factor. The driving factors of the change of agricultural eco-efficiency are gradually changing from the macro environment and policy orientation to the development of agriculture itself.

Abstract:[Objective] The drought and waterlogging characteristics in the water source & receiving areas of the middle route of the south-to-north water transfer project were studied, and the risk of "both drought " caused by climate change was analyzed and predicted in order to provide a basis for scientific decision-making.[Methods] Based on daily precipitation data of 265 meteorological stations during 1961-2015 and drought & waterlogging data of past 500 years in the middle route of the south-to-north water transfer project region, the drought and waterlogging characteristics in one water source area(the upper reaches of Hanjiang River) and three water receiving areas(Tangbai, Huaihe, and Haihe river basins) were analyzed, and the efficiency of water transfer in three water receiving areas were calculated. This study also investigated the future drought and waterlogging characteristics under the RCP 4.5 scenario based on the simulation results of 21 CMIP 5 global climate models.[Results] ① In the past 500 years, the probability of occurrence of drought decreased first and then increased in the water source area, In the 20th century, the probability of occurrence of drought in the water source area reached highest in the history(31.7%). ② The Huaihe River basin showed the highest efficiency of water transfer(87.3%) while the Tangbai River basin showed the lowest(78.4%). ③ Since the beginning of the 20th century, the unfavorable probability at each river basin and the water source region reached a maximum. The probability of simultaneously occurrence of multi-year droughts in the water source area and Tangbai & Hai river basins is greater than Huai River basins. ④ The water transfer efficiency during the autumn flood season(SON) is the highest, and that in all the 3 basins during the non-flood season is over 80%. ⑤ The efficiency of water transfer in each water receiving area in the future is above 87%.[Conclusion] The synchronous encounter probability of drought in water source & receiving areas in 20th century reaches a maximum in the past 500 years. The simulations show that it will benefit the water transfer of the project in the future. However, in late 21th century, the risk of waterlogging in both the water source and water receiving areas simultaneously will increase.

Abstract:[Objective] Screening of provincial land resources assets auditing divisions and identifying the land-control resource priorities in each city were conducted in order to improve the efficiency of auditing land assets in China, and to mprove the application of geographic information technology for homeland audit.[Methods] Based on the perspective of land landscape pattern, ENVI and ArcGIS were used to convert the four phases of remote sensing image data from 2000, 2005, 2010 and 2015 in Zhejiang Province to the grid resolution of 30 m ArcGrid data format. Also, Fragstats 3.3 was used to calculate the degree of fragmentation and concentration of the land, which is used as the key selection criteria for the audit of land resources in Zhejiang Province.[Results] ① We have constructed an important regional geographic audit model for land resources assets based on the land fragmentation index and the concentration index. It focuses on a global review of the quantity and quality changes of land use types in each jurisdiction, and can reveal the use and protection scenarios of land-based resource assets across the audit area and variation trend. It confirms that the application of landscape ecological assessment to land resources assets leading cadres leaving audit are effective. It also helps to remedy the shortcomings of the past audits of leading cadres, which only simply measures the number of assets and ignore the measure of ecological value; ② Dominant land types were empirically screened out in Zhejiang Province:woodland, grassland, and water areas in Hangzhou City; cultivated land and water areas in Huzhou City; cultivated land and construction land in Jiaxing City; cultivated land, grassland, construction land in Jinhua City; forest land in Lishui City; water areas in Ningbo City; forest land and grassland in Cangzhou City; cultivated land and construction land in Shaoxing City; grassland in Taizhou City; grassland in Wenzhou City; construction land in Zhoushan City. The audits of the quantity and quality of land types mentioned in various cities of Zhejiang Province should be the focus of the audit of the departure of leading cadres of land resources assets.[Conclusion] When auditing land resources assets, we should pay attention to the combination of land resource inventory and modern geographic information technology to enhance the visual interpretation of the recognition efficiency and audit results of regional subjects.

Abstract:[Objective] The response of the ecosystem service system to vegetation change in the Qinghai-Tibet Plateau conservation area from 2000 to 2010, and to further clarify the relationship between ecosystem services and remote sensing vegetation index were studied in order to provide a scientific reference for regional ecosystem service assessment and ecological protection.[Methods] This study focuses on various types of protected areas on the Tibetan Plateau and uses MODIS (moderate-resolution imaging spectroradiometer) EVI (enhanced vegetation index) products for vegetation change mapping. The ecosystem services such as carbon fixation, soil conservation, water conservation and habitat protection are used to determine the consistency of ecosystem services and EVI changes in the Qinghai-Tibetan Plateau conservation area from 2000 to 2010.[Results] The EVI of the Qinghai-Tibetan Plateau was dominated by non-significant changes from 2000 to 2010, and the non-significant increased samples were greater than the non-significantly decreased samples in both the grid and the protected areas, indicating that the vegetation on the Qinghai-Tibet Plateau is characterized by overall improvement and local degradation.[Conclusion] The ecological system services in the Qinghai-Tibet Plateau conservation area were mainly non-significant changes from 2000 to 2010, but the non-significant reduction samples of ecosystem services was significantly more than the non-significant increased samples, which was inconsistent with the change trend of EVI.

Abstract:[Objective] The objective of this study is to present practical research on the long-term equilibrium relationship between utilization of water resources and economic growth and provide decision reference for the sustainable and coordinated development of water resources and social economy in karst ecologically fragile areas with rapid economic development.[Methods] Selected Bijie City of Guizhou Province as a case study, and employed the VAR(vector autoregressive) model for analysis. The equilibrium relationship between utilization of water resources and economic growth of the industrial system in Bijie City from 2001 to 2016 was analyzed by ADF smoothness test, co-integration test and granger causality test, generalized impulse response and variance decomposition analysis.[Results] ① There existed long-term equilibrium relationship between economic growth and total water consumption, agricultural output and agricultural water consumption, industrial output value and industrial water consumption; ② The impulse response of agricultural output value to agricultural water consumption and industrial water consumption to industrial output value was positive, and the others were negative; ③ The contribution of industrial water consumption to the average variance decomposition of industrial output value was 54.584%, the contribution of agricultural water consumption to agricultural output value was 1.629 7%, and the variance contribution of other variables was relatively large, indicating that development still requires a lot of water resources development and utilization.[Conclusion] The effect of agricultural water consumptione on promoting agricultural output value was little, and industrial water consumption on the increase of industrial output value was strong. However, the shortage of industrial water consumption impedes industrial development. Along with economic growth, the investment in production and water saving technologies should be further strengthened.

Abstract:[Objective] The benefit of flood resources utilization in Baicheng City of Jilin Province was analyzed to provide scientific basis for rational allocation of flood resources in this area.[Methods] By means of grey relational analysis method, the evaluation of the utilization efficiency of flood resources in Baicheng City from 2008 to 2017 and the changes of economic benefits, ecological environment improvement and social development on which it depends are correlated. The index parameters and index system are determined from three aspects:direct economic benefits, ecological environment benefits and indirect economic and social benefits.[Results] At present, the impact of flood resources on ecological and environmental benefits is the most obvious, accounting for 43% of the total benefits.[Conclusion] Grey relational analysis provides a new way of thinking and evaluation for the effective utilization and management of flood resources. The flood resources in Baicheng City are more likely to be used in its natural form by the environment and ecology, and the benefits are more predominant for the ecological resources themselves. The local flood resources have a great development potential.

Abstract:[Objective] In order to provide theoretical reference and technical methods for the implementation of the next round of overall land use planning and the carrying out of the land resources management, we aimed to accurately identify and detect the potential conflicts between land use control zones and urban expansion.[Methods] Based on the CA-Markov model, the land use status of Changzhou City, Jiangsu Province in 2020 was simulated. Then, the spatial analysis technology of GIS was applied to identify and detect the potential conflict areas between the spatial regulation zone of construction lands and the development trends of Changzhou City from 2015 to 2020.[Results] ① The total scale of construction land and the amount of newly increased construction land will reach 101.16% and 159.97% respectively, which will exceed the goal of the overall land use planning by 2020; ② Little potential conflicts between construction land and the prohibiting construction zone was detected during 2015-2020; there is more areas of potential conflict between construction land and the limiting construction zone compared with the prohibiting construction zone, and about 59.15% of the potential conflict areas are mainly distributed in Wujin District.[Conclusion] The goveronment of Changzhou City should strengthen the control and management of the potential conflict areas in the limiting construction zone during the next round of land use planning.

Abstract:[Objective] In order to provide a theoretical basis for urban planning and disaster prevention and mitigation engineering, the zoning evaluation on urban landslide proneness was conducted.[Methods] The evaluation was conducted at urban area of Yichang City, Hubei Province. Evaluation indicators, i.e. elevation, slope gradient, lithology, normalized difference vegetation index(NDVI), distance to watercourse and roading density, were identified by GIS platform; the relations between landslide proneness and evaluation indicators were analyzed based on likelihood ratio method, and the evaluation indicators could be quantified using the generalized likelihood ratio. As the independent variable in Logistic regression model, the regression model of landslide proneness evaluation was established based on sample datum.[Results] The significance of evaluation indicators was tested notable. The overall accuracy and the area under the ROC curve of evaluation model reached to 79.2% and 0.871 respectively. The extremely low proneness zone and the low proneness zone covered 61.59% of the total area, where landslide contributed 11.29% of the total landslides. Landslides in the high proneness zone and the extremely high proneness zone accounted for 68.55%, although it covered only 17.88% of the total area. The evaluation outcomes were conincided with the distribution of historical landslides by and large.[Conclusion] The landslide proneness of urban area of Yichang City is classified. The result of landslide proneness evaluation based on GIS and Logistic regression model is accurate and reliable.

Abstract:[Objective] Characteristics of water pollution in the Tokto section of the Yellow River and selection of water quality evaluation index is of great importance for assessing the the water quality in the Tokto section.[Methods] Based on the data of 9 sampling sections in the Tokto section from April to August in 2017, we comprehensively evaluated the water quality by establishing the evaluation index system using principal components analysis.[Results] ① The water quality in the Tokto section could be classified into class Ⅳ, and the main pollution factors are total nitrogen, total phosphors, chemical oxygen demand, belonging to organic type and eutrophication pollution.② The water quality from upstream to downstream was becoming better The water quality of the Heihe River at the entrance of tributary became worse due to the excessive pollutant discharge into Heihe River during flood season. The water quality was the worst in August and April, and was better from May to July.[Conclusion] The water quality evaluation method based on the principal component analysis and the synthetic water quality index can not only accurately reflect the water quality, but also compare the water quality of different sections. The water quality in Tokto section of the Yellow River is poor(the whole class Ⅳ), which belongs to organic pollution and eutrophication.

Abstract:[Objective] The status of land ecological security development in the light-to-severe rocky desertification mountainous area of Guangxi Zhuang Autonomous Region was studied in order to provide scientific reference for land ecological security and its sustainable development in study area.[Methods] Based on PSR model, and from three aspects including pressure, state and response, this paper constructed a land ecological security early-warning index system for the light-to-severe rocky desertification mountainous area of Guangxi Zhuang Autonomous Region. The entropy weight method and the integrated model of ecological security were used to calculat the comprehensive index of land ecological in 2005 and 2015 in study area.[Results] The main affecting factors of land ecological security in the rocky desertification mountainous area of Guangxi Zhuang Autonomous Region were the population density, the integrated energy consumption per unit of GDP, the land cultivation rate, the per unit area yied of grain, the urbanization level, the natural population growth rate. Pressure index, state index and response index jointly determined the comprehensive index of land ecological security evaluation in the rocky desertification mountainous area. With respect to time differentiation, from 2005 to 2015, the land ecological security in the rocky desertification mountainous area had changed from critical level to mainly relatively safe level over the past 10 years, the situation of land ecological security was mainly due to the improvement of the response state system, which made the comprehensive land ecological security index increased. With respect to spatial differentiation, the land ecological security was the lowest in 2005, and the level of land ecological security was at a relatively unsafe level in Nanning, Guigang, Laibin areas in 2015.[Conclusions] Although the land ecological security in the rocky desertification mountainous area of Guangxi Zhuang Autonomous Region raised slightly, limited by the level of carrying capacity of pressure and state subsystem, the land ecological security of the study area is still at an intermediate level, the construction of land ecological security needs to be further strengthened.

Abstract:[Objective] The change of habitat quality of Jingwei wetland nature reserve in Xi'an City was investigated to provide scientific reference for the future development and environmental protection of the reserve.[Methods] Based on the InVEST biodiversity model and land use/cover data, this study analyzed the habitat quality of the reserve.[Results] ① In 2006-2016,the farmland was severely decreased and mainly converted to the grassland, forestland, and wetland. ② The habitat quality of the reserve showed an increasing trend, and a decreasing trend in some areas, Meanwhile, the whole habitat tended to be medium. ③ Among the three districts, the habitat quality of the Baqiao is the highest, followed by the Weiyang and then the Gaoling. Compared with 2006, their habitat quality in the 2016 increased by 21.05%, 50.01%, and 37.84%, respectively;[Conclusion] The main driving factor of habitat degradation is the artificial habitat including traffic land, residential land, industrial land, and farmland. Natural habitat including wetland and forest is beneficial to the maintenance of biodiversity, but the forest area is slightly insufficient in the reserve.

Abstract:[Objective] Taking Hubei Province as an example, the tradeoffs and synergy between cultivated land functions and the strength of each function were studied in order to provide technical supports and decision-making suggestions for the multi-purpose utilization and management of cultivated land.[Methods] The principal component analysis(PCA) was used to identify the relationship between functions.[Results] ① The basic living security function of cultivated land in Hubei Province is the strongest, the ecological security maintenance function is second, and the employment security function is the weakest. ② There is a synergy between the basic living security function, ecological security maintenance function and employment security function, between the social stability maintenance function and the food security function, between the employment security function, the family economic contribution function and the national economic contribution function, respectively. ③ The social stability maintenance and food security had a tradeoff with the family economic contribution and the contribution to the national economy.[Conclusion] The PCA method can not only express the strength of each function, but also intuitively express the relationships and their degree of interaction between functions. Therefore, it can provide certain technical support and decision support for the multi-purpose utilization and management of cultivated land.

Abstract:[Objective] The objective of this paper was to analyze the causes and processes of aeolian desertification in Gonghe basin of Qinghai Province, and to provide scientific basis for controlling the ecological environment.[Methods] Google Earth and ArcGIS were used to analyze the distribution characteristics of aeolian desertification in different regions. The movement velocity of sand dunes and the velocity reactivation of fossil dunes were monitored by comparing the interpreted remote-sensing images in six periods. The temperature, precipitation, wind speed, and livestock number were analyzed by the SPSS. In addition, the formation process of aeolian desertification was studied according to the field investigation, grain-size test, and analysis of stratigraphy.[Results] The mobile dunes and sand sheets are widely distributed in Gonghe basin of Qinghai Province. There have a large number of aeolian Yardang landforms, and the sandy lands are interlaced with patch and strip. Stratigraphic analysis showed that the surface of fixed dunes is covered by sandy silt with different thickness, and the layer under there is relatively loose sand. The main forms of aeolian desertification are the reactivation of fixed sand dunes, the exposure of fine sands from rivers and lakes, and the reactivation of fixed sand belts and fossil dunes.[Conclusion] Cemented silts layer is a protective shell of the loose sand, and trampling of grazing animals is main reason for the damage of this protective layer. Under trampling of grazing animals damage, sand flow, and gravity erosion, the collapse and destruction of the silts layer lead more loose sand exposed. The circulation of this process made the reactivation of fixed sand dunes and formed the blowouts, which is the main process of aeolian desertification formation and development in the Gonghe Basin of Qinghai Province.

Abstract:[Objective] The changes of habitat quality and its affecting factors in the nature reserve were studied for the formulation of effective local ecological protection policies.[Methods] Taking the Pogang nature reserve in Xingyi City of Guizhou Province as an example, based on the images of Landsat-5 TM, Landsat-7 ETM⁺, Landsat-8 OLI, and combining ArcGIS with ENVI software, we used habitat quality estimation model and habitat quality contribution rate of land use transformation to analyze the land use change and its impact on habitat quality from 1990 to 2017 and to quantitatively assess the effect of the policy of grain for green on the improvement of habitat quality.[Results] The land transformation of reserve mainly occurred from grassland and cultivated land to forest land, and from other land types to grassland and forest land from 1990 to 2017. During the past 28 years, the overall habitat quality of the reserve showed a trend of first increase and subsequent decrease. The increase was by 15.71% in comparison with the value in 1990. The average habitat quality of the reserve in 1990 was ranked as:buffer area > core area > pilot area; whereas the average habitat quality of the reserve after 2001 was the core area > buffer area > pilot area. As the policy of grain for green was carried out, the average habitat quality index of Pogang Nature Reserve increased significantly from 0.88 to 0.92.[Conclusion] The establishment of Pogang Nature Reserve, the implementation of the reforestation project and the increase of human activities are the main reasons for the change of the habitat quality.

Abstract:[Objective] The heavy metal pollution and potential ecological risk of soil in Kanas scenic area were evaluated to provide reference for scientific management and protection of scenic area resources.[Methods] The Kanas area was used as the study area to determine As, Pb, Hg, Cd, Zn, Cr, and Cu contents of soil samples, through the pollution load index. A comprehensive evaluation of the heavy metal pollution in the Kanas area was conducted. The potential ecological risk index was used to evaluate the potential ecological risk of heavy metals in the soil. The correlation analysis and principal component analysis were used to analyze the heavy metal sources and pollution levels.[Results] ① The average contents of As, Pb, Hg, Cd, Zn, Cr and Cu in the surface soil of the study area were 6.48, 16.60, 0.10, 0.08, 84.71, 2.47 and 32.23 mg.kg-1, respectively, of which As, Pb, Hg and Cd were high. The soil background values in Xinjiang area, Zn, Cr and Cu are lower than the soil background values in Xinjiang area. ② The human activities were different from the 7 kinds of heavy metals, their contents were different. ③ Hg was a heavy pollution in a extremely strong disturbance plot of human activities, a strong disturbance plot of human activities, and a slight disturbance plot of human activity(PLI values are 5.70, 4.36, and 4.64 respectively). And Zn, Cr and and Cuwere slightly polluted. All metal RIs were less than 150. There was only a slight ecological hazard in the study area, but Hg pollution in the study area needed more attention. ④ Correlation analysis showed that most of the 7 heavy metals had a relationship. The sources of Cd and Hg are the same and the source of As, Zn and Cu may be the same.[Conclusions] The Kanas scenic area interferes with the accumulation of heavy metals in the soil by tourism activities, and the heavy metal pollution in the soil is more serious.

Abstract:[Objective] The net primary productivity(NPP) change and its correlation with climate over the Luoshan nature reserve were investigated in order to provide scientific basis for the ecological environment protection in Ningxia Hui Autonomous Region and its surrounding areas.[Methods] Based on the data including MOD17A3H NPP from 2004 to 2015, SRTM DEM, and annual average temperature and precipitation, and the methods including correlation analysis, trend analysis, and linear regression analysis, this study analyzed the spatiotemporal change characteristics of the NPP and the effects of climate, population, ecology, and immigration policy on the NPP.[Results] ① There had a high correlation between the NPP and annual precipitation with correlation coefficients equaling to 0.609 and 0.648(p<0.05) in the core and non-core areas, respectively; ② The NPP represented a fluctuating increasing trend with 0.076 Pg/a over the entire study area, which is higher than the NPP trend with 0.008 Pg/a over the China; ③ The forest area increased during 2010-2015 in the Daluoshan and the area of forest with NPP ranging from 350 to 500 g/(m²·a) was 4 times of that during 2004-2009; Baseline vegetation in the Xiaoluoshan was converted from desert to desert grassland; ④ The dominated ecological pattern determined by the NPP was the desert with area percent of 64.9%, followed by the desert grassland with 29.6% and the forestland with 0.38%.[Conclusion] The NPP of arid area is highly dependent on the precipitation. Although the ecological structure of the Luoshan region has been improved, the forest ecosystem there is still extremely fragile.

Abstract:[目的] 总结利用黄土高原淤地坝沉积泥沙研究小流域土壤侵蚀的主要成果，并对其目前存在的问题和以后发展方向进行探讨，以期为深度解译淤地坝沉积泥沙中赋存的小流域土壤侵蚀信息提供基础支撑。[方法] 通过查阅国内外文献，结合野外调查和研究经验，总结利用淤地坝沉积泥沙研究小流域土壤侵蚀的相关工作。[结果] 黄土高原大量的淤地坝、坝地泥沙明显的沉积旋回和现有的可靠断代技术是利用淤地坝沉积泥沙研究小流域土壤侵蚀的基础；利用淤地坝沉积泥沙可估算小流域土壤侵蚀强度的变化，识别小流域侵蚀泥沙来源；淤地坝内的泥沙沉积量、理化性质及生物标志物的变化能够反演小流域环境演变过程。[结论] 黄土高原广泛分布的淤地坝沉积泥沙赋存有大量小流域土壤侵蚀和侵蚀环境演变的信息，在黄土高原小流域土壤侵蚀机理及小流域环境演变研究中具有重要作用。