Abstract:[Objective] Hippophae rhamnoides is a typical species that controlling alpine desertification. Study on the responses of this artificial plant to wind-sand hazard is of great importance in exploring the vegetation adaptive mechanism and directing the sand-control work.[Methods] The annual vegetation quadrat survey and the sand surface erosion monitoring.[Results] The H. rhamnoides community features have been found changed temporally and spatially with the sand surface erosion intensity. Firstly, patterns of light wind erosion and medium sand accumulation contributed to the plant growth and community development of H. rhamnoides. Comparatively, the average vegetation height and canopy in fixed or semi-fixed sand dunes were 3~6 times larger than that in mobile sand dunes. Secondly, significant parabolic relationships were found between the community features and the erosion/deposition depth with the optimal sand deposition depth of 30-40 cm for eight-years-old H. rhamnoides forest. Thirdly, the H. rhamnoides community features changed with the sand transport rate, surface roughness and annual erosion depth as significant fitting curve of exponential decline, multiple functions increase and quadratic increase, respectively.[Conclusion] H. rhamnoides showed a strong resistance to wind erosion and sand-burial. A number of influential factors, including afforesting sites, forest structure optimizations and enrichment of other vegetation species, should be taken into accounts in protecting community succession and ecology restoration.

Abstract:[Objective] Taking the upper reaches of Huaihe River basin as a case study, this paper investigates the law of runoff and its response to climate-driven factors in order to provide the scientific basis for flood control, reasonable planning of water resources and economic sustainable development.[Methods] By using hydrological statistics, cross wavelet transform analysis and elastic coefficient method, we analyzed the variation trend and the periodicity of the runoff in Huaihe River. The relation between the meteorological factors and the runoff in multi-time scales was analyzed as well in the study area.[Results] ① The runoff and precipitation exhibited a decreasing trend at a rate of -3.8 m³/(s·10 a) and -26.3 mm/10 a, respectively. The variation of potential evapotranspiration was not obvious. Precipitation was the most dominant factor controlling changes of annual runoff, and the correlation coefficient was 0.9 between precipitation and runoff. However, both precipitation and potential evapotranspiration influenced runoff processes within a year. ② Wavelet analysis showed that periodic variation of annual runoff in the upper reaches of Huaihe River was 6~12 a. The variation of precipitation and potential evapotranspiration presented a same periodicity of 2 a. There were significant correlations among annual-runoff, annual-precipitation and annual-potential evapotranspiration in 1990s. ③ The responses of runoff to climate-driven factors were not stable, changing with time. Elastic coefficient of annual precipitation and evapotranspiration were 2.30 and -0.47, respectively. Annual runoff had a significant correlation with precipitation while little correlation with the potential evaporation, indicated that precipitation change was the main factor that influence variation of water resources in future.[Conclusion] With the comprehensive impacts of climate change, underlying surface of watershed and human activities, the annual distribution of runoff uniformity will be changed greatly.

Abstract:[Objective] To explore the adaptive mechanisms of soil microorganism and soil enzyme activity under grazing exclosure conditions in order to provide scientific basis for the recovery of degraded pasture.[Methods] Soil samples were collected from different soil layers (0-5 cm, 5-10 cm and 10-20 cm) in Seriphidium transiliense desert under different exclosure years (0 a, 3 a and 11 a) by zigzag sampling method. Then, the soil organic matter, catalase and urease activities, and the amount of soil microorganisms were measured by the conventional methods.[Results] The organic matter content in 0-10 cm soil layer increased with the increasing exclosure years, and the soil organic matter content of 11-year enclosure was 14.2% higher than that of the control. In the composition of microorganism, the largest amount was bacteria, followed by actinomycetes, and fungi was the least. The amount of bacteria and actinomycetes in 0-5 cm soil layer decreased and the amount of fungi increased with the increase of exclosure years, and compared with the control, the amount of bacteria and fungi of 11-year exclosure were decreased by 47.3% and 25.5%, respectively, while the amount of actinomycetes increased by 15.5%(p<0.05). There was no significant difference in the amount of bacteria in the 5-20 cm soil layer among different exclosure years, but the amount of fungi and actinomycetes increased with the increase of exclosure years. There was no significant difference on catalase activity in 0-20 cm soil layer among different exclosure years in S. transiliense desert. The urease activity in 0-10 cm soil layer increased with the increase of enclosure years, and that was decreased in 10-20 cm soil layer.[Conclusion] The long time enclosure is beneficial to the accumulation of soil organic matter, and can improve the amount of actinomycetes and urease activity in the topsoil.

Abstract:[Objective] A field experiment was carried out to investigate the responds of maize yield and soil physical characters to different tillage managements in order to provide the scientific basis for agriculture production in the western part of Heilongjiang Province.[Methods] Five tillage strategies including rotary tillage, plowing, deep plowing, deep subsoiling and local conventional tillage were used.[Results] By plowing and deep subsoiling, soil water content and field water capacity increased in topsoil but decreased in plow bottom soil. Soil three phase structure distance (STPSD) and generalized soil structure index (GSSI) were preferable in plowing, deep plowing and deep subsoiling treatments, but poor in plow bottom soil. Both GSSI and STPSD were not affected by rotary tillage. Compared to local conventional tillage, plowing and deep subsoiling increased maize yield by 17.6% and 6.0%, respectively. Maize yield with plowing was 10.9% higher than that in deep subsoiling. The maize yield in deep plowing was 5.58 t/hm², which was 8.1% lower than that in local conventional tillage.[Conclusion] Without soil breaking at plow bottom, plowing was the best tillage management in the aeolian sandy soil of Northeast China.

Abstract:[Objective] To investigate the relationship between the vegetation coverage change and topographic factors (elevation, slope and slope aspects) in order to provide basics for environmental monitoring and restoration, soil and water conservation, and disaster assessment and prevention in Wenchuan earthquake area.[Methods] By using dimidiate pixel model to estimate vegetation fraction in the earthquake area, the relationships between vegetation fraction and topographic factors was analyzed.[Results] Vegetation fraction had negative correlations with slope and elevation(<3 000 m). Similar negative correlations were also found between the topographic factors and the proportion of low vegetation coverage. The effect of earthquake on the vegetation was dramatic in the area with elevation <500 m, and area with elevation ranged from 500 to 1 000 m and slope <5°, where the recovery period was longer. Until May 2015, vegetation recovery has not reached to the level before the earthquake. Besides, there were no significant differences between variation of vegetation coverage and proportion change of high, middle and low vegetation coverage area among different slope aspects. The proportion of high, middle and low vegetation coverage area in the east, south, north and southeast had been restored to the levels before the earthquake.[Conclusion] Vegetation fraction is closely related to topographic factors, and dynamic monitoring of vegetation status can be obtained from topographic changes.

Abstract:[Objective] The effects of planting spring wheat and forage grass on salinization of cultivated land were analyzed in order to provide scientific basis for the prevention and control of soil secondary salinization in irrigated region of Northwest China.[Methods] Triticum aestivum, mixed grass (Elymus dahuricus/Medicago sativa) and soil under them were taken as the study objects. The coverage, height, above-ground biomass of vegetation and soil moisture and electrical conductivity were measured to investigate the impacts of spring wheat and forage grass on land salinization.[Results] During the whole growth stage, the coverage, height and biomass of T. aestivum and grass increased significantly. After wheat harvest, wheat field was bare as naked land, while grass still covered the land surface. Compared with the bare land, surface sunlight intensity, temperature and salt content of surface soil (0-5 cm) under vegetation coverage were much lower, while ground humidity and soil moisture content were much higher. Correlation analysis indicated that the strongest correlation occurred between biomass and soil moisture and between coverage and soil salt, and there was a negative relation between soil moisture and salt. Regression analysis demonstrated that soil moisture content increased by 6% as biomass increased by 1 kg/m², and soil electrical conductivity decreased by 2.2 μS/cm as vegetation cover increased by 1%.[Conclusion] Planting spring wheat in irrigated regions of Northwest China will cause soil secondary salinization, while planting forage grass may weaken hazard of soil secondary salinization.

Abstract:[Objective] To investigate the hydrological benefits of litters and soil in different forests in order to choose an appropriate stand type for water retention.[Methods] Different forests including Larix kaempferi pure forest (Ⅰ), the mixed forest of Larix kaempferi and Betula platyphylla and Populus davidiana (Ⅱ), Betula platyphylla and Populus davidiana (Ⅲ) were selected as the research objects in Disanxiang forest farm of Chengde City. Water holding capacity of litters and soil was investigated by using indoor immersion method, ring knife method and indoor drying method.[Results] The total reserves of litters were ranked as:Ⅰ (26.58 t/hm²) > Ⅱ (25.01 t/hm²) > Ⅲ (21.55 t/hm²). The maximum water holding capacity of litters was ranked as:Ⅲ (56.88 t/hm²) > Ⅱ (56.24 t/hm²) > Ⅰ (51.91 t/hm²). The relationship between water-holding capacity of litters and the change of immersion time showed a logarithmic function. The relationship between water absorption rate of litters and the change of immersion time showed a power function. The effective interception volume was ranked as:Ⅱ (46.22 t/hm²) > Ⅲ (43.90 t/hm²) > Ⅰ (43.36 t/hm²). Soil bulk density was ranked as:Ⅰ (1.13 g/cm³) > Ⅱ (1.12 g/cm³) > Ⅲ (0.99 g/cm³). Soil porosity was ranked as:Ⅲ (51.89%) >Ⅱ (49.13%) > Ⅰ (41.38%). The maximum water holding capacity of soil was ranked as:Ⅲ (1 037.80 t/hm²) > Ⅱ (982.50 t/hm²) > Ⅰ (827.53 t/hm²).[Conclusion] Based on the analysis of the litters and soil water retention characteristics of three different forest stands, it was found that the water holding capacity of B. platyphylla and P. davidiana forest was the best, while L. kaempferi pure forest was the worst.

Abstract:[Objective] To investigate the adaptation and tolerance mechanism of Zizyphus jujube seedlings to salt stress in order to provide academic reference for selection of cultivars on saline-alkali land.[Methods] Annual Zizyphus jujube seedlings was taken as research object, pot water control experiments were conducted, to study the influences of different NaCl concentration (CK, 1.5, 3, 4.5, 6, 7.5 g/L) treatment on Z. jujube seedling growth, chlorophyll content, gas exchange parameters and antioxidant enzyme activity.[Results] ① When NaCl concentration was between 0~3 g/L, there was no obvious impacts on the survival rate and growth status of Z. jujube. When the concentration of NaCl was greater than 3 g/L, the survival rate of Z. jujube dropped significantly. Especially, when NaCl concentration was 6~7.5 g/L, the growth of Z. jujube was inhibited seriously. As a result, salt tolerance of Z. jujube was 3 g/L. ② With the increase of salt concentration and stress time, superoxide dismutase(SOD) activity, peroxidase(POD) activity, catalase(CAT) activity of Z. jujube seedling leaf showed a rising trend initially and then decreased. In contrast, the content of malondialdehyde(MDA) and proline(Pro) increased. ③ Photosynthetic pigments content showed a decline trend, similarly, net photosynthetic rate (P_n), stomatal conductance (G_s) and transpiration rate (T_r) showed a decline trend as well. While intercellular CO₂ concentration (C_i) showed a rising trend initially and then decreased. The decline of P_n was caused by stomatal factors at the beginning, and then caused by non-stoma limitation factors.[Conclusion] Low NaCl concentration (<3 g/L) stress has little influence on the survival rate and growth status of Zizyphus jujube. But with the increase of NaCl concentration, the chlorophyll content, antioxidant enzyme system of Z. jujube seedlings will be suppressed, plant growth and development will be severely affected.

Abstract:[Objective] To analyze the change of stratum displacement and stress induced by fault dislocation and groundwater level change in the hanging wall and the foot wall of ground fissure in order to provide references for the further research in the formation mechanism of ground fissures.[Methods] Taking Gaoliying ground fissure in Beijing City as research background prototype, the relationship between the formation of ground fissure and fault tectonic activity, and the change of groundwater level were analyzed, based on the activity characteristics of the ground fissure. The change law of modeled stratum displacement and soil internal stress induced by these two inducing factors was studied using numerical simulation.[Results] Due to the fault dislocation, the settlement deformation on the hanging wall was greater than the foot wall, the curve of vertical displacement of surface showed an opposite "S" shape, and the range of the stress reduction zone of the hanging wall was larger than the range of the stress enhancement zone on the foot wall. Stratum settlement amount increased with the decline of groundwater level, and the stress curve was approximately "centrosymmetric".[Conclusion] The differences in settlement displacement and stress changes between the two sides of the fault were significant. The differential settlement was positively correlated to the descent of groundwater level, and the influence range of ground fissure induced by descent of groundwater level was 45 m on the hanging wall while 35 m on the foot wall. The research results can provide scientific theoretical basis for disaster prevention and mitigation in the ground fissure areas.

Abstract:[Objective] To explore the endangered reasons of Picea mongolica at the seed ecology level in order to provide theoretical references for making the conserve measures of P. mongolica natural forest.[Methods] Seed viability was tested with different habitat storage periods. The responses of seed germination to temperatures and lights were investigated. The tolerance of P. mongolica seed to salinity during seed germination and seedling growth and the responses of seedling emergence to sand burying were studies.[Results] ① The viability of matured P. mongolica seeds was 79%, of which, about 12% seeds suffered from freeze injury and the remaining 67% suffered from the pest nibble and disease harm. The buried seed viability was reduced at a speed of 9.5% every year. ② Germination of P. mongolica seeds was very easy and the germination percentage was more than 40% when the temperature was more than 10℃. The seed germination rate at a dark-light alternation condition was higher than other light conditions, and the optimal sand burial depth for P. mongolica seedling emergence was 0.5 cm as it satisfied the light and temperature requirements of seed germination. The germination characteristics increased the morality as a lot of seeds germinated in desert habitat environments. ③ Seed germination and seedling growth were significant decreased with the increase of NaCl concentration. When NaCl concentration was around 0~100 mmol/L, the germination rate (R_IG) was decreased from 69% to 49%, recovery germination rate (R_GR) was increased from 0 to 6%, and the initial seedling length (L_IS) was reduced from 7.12 to 1.16 cm. The recovery seedling length (L_RS) was increased from 0 to 0.03 cm when the concentration of NaCl was more than 100 mmol/L, the seed germination and seedling growth were completely inhibited(IGR<49%,ISL<1.16 cm) and the ability to recover was poor (R_GR<10%, L_RG<1 cm). Unfortunately, soil salinity contents over 100 mmol/L were widely distributed in the natural habitat of P. mongolica. ④ Seedling emergence was significantly decreased with the increase of sand burial depths. The emergence rate reached 69% with the 0.5 cm sand burial depths and reduced to 8.5% with the 2.0 cm sand burial depths. The habitat of P. mongolica with sand burial depths over 2.0 cm was widely distributed, thus the seedling emergence was less than 8.5%. The P. mongolica seedling was continuously suffered from the pest nibble, disease harm, salinity and moisture stress, freeze injury and interspecific competition.[Conclusion] The main endangered causes of P. mongolica were the serious diseases and pests, low seed viability in habitat soil seed banks, the low survival rate of seedlings and badly environments in habitats.

Abstract:[Objective] To explore the effects of poplar farmland shelter belts on the structure of soil under forest in order to provide guidance for rational allocation of tree planting density in black soil region.[Methods] This study investigated soil aggregate and analyzed the aggregates contents, percentage of aggregate disruption, mean weight diameter, geometric mean diameter and fractal dimension stability based on different space(1.5 m×1 m, 2 m×1.5 m, 3 m×1.5 m) in Baiquan County, Heilongjiang Province. Abandoned farmland was taken as control treatment.[Results] ① The percentage of aggregate disruption(PAD) of surface soil was the lowest and the percentage of aggregate disruption decreased with the decrease of forest belt density. The percentage of aggregate disruption in forest belt was less than control. ② With the increase of soil depths, mean weight diameter(MWD) and geometric mean diameter(GMD) decreased. There was a significant difference between forest belt and control(p<0.01). ③ At 0-20 cm depth, the dry-aggregates fractal dimension(D) and water-stable aggregates fractal dimension(D) decreased with the decrease of forest density, while an opposite trend was showed at 20-60 cm depth.[Conclusion] The structure of soil under the forest belt is better than the abandoned farmland. The forest belt increases soil clay content and enhances the stability of the deep soil. As the increase of forest belt density, the soil under forest will be improved effectively, but the aggregate disruption in surface soil will be increased.

Abstract:[Objective] To evaluate the effect of returning field materials on soil nutrient after remediation in vacant villages for agricultural land in order to provided scientific references for improving the quality of new cultivated land.[Methods] This study was conducted in the rural abandoned homestead using different field returning materials. The trend of nutrient content was monitored by 7 different kinds of treatments including TS (ameliorant, FeSO₄), TF (organic fertilizer, manure), TC (fly ash), TSF (ameliorant + organic fertilizer), TFC (fly ash + organic fertilizer), TSC (ameliorant + fly ash) and T₀ (no fertilization measures) in 0-105 cm soil profile.[Results] The average available phosphorus content was the highest in the treatment of TSF, and the available phosphorus in TSF treatment with 30 and 0-105 cm soil cover was 254.49% and 146.37% higher than that in the treatment of T₀, respectively. The average available potassium content was the largest in the TSF treatment, and the available potassium in TSF treatment with 30 and 0-105 cm soil cover was 19.13% and 14.01%higher than that in T₀ treatment, respectively. The average total nitrogen content in the soil profile was the highest in the treatment of TSC, and the total nitrogen in TSC treatment with 30 and 0-105 cm soil cover was 29.63% and 27.06% higher than that in the T₀ treatment, respectively. The average organic matter content in the soil profile was the highest in the treatment of TF, and the organic matter in the treatment of TF with 30 and 0-105 cm soil cover was 247.47% and 42.63% higher than that in the treatment of T₀, respectively.[Conclusion] Soil nutrient increases rapidly with the addition of ameliorant (FeSO₄) and organic manure (chicken manure) after the planting of three-season crop with maize-wheat-maize, and immature soil is improved into cultivated land of remedied vacant village.

Abstract:[Objective] To understand the characteristics of speciation and bioavailability of heavy metals (Cu, Cd, Pb, and Zn)in greenbelt surface (0-20 cm) soil within the 5th ring road of Beijing City in order to provide reliable information for soil heavy metal pollution control in Beijing City.[Methods] A total of 151 surface soil samples were collected from greenbelt land built 2~400 years ago. A modified BCR extraction technique was used to analyze the chemical forms of heavy metals from the collected samples. Risk assessment code (RAC) and the ratio of secondary phase and primary phase (RSP) were used to evaluate the bioavailability of the heavy metals.[Results] The average content of total Cu, Cd, Pb, and Zn in soil samples were 31.42, 0.29, 29.89 and 76.78 mg/kg, respectively. The content of total Cu and Zn were higher in the northeast and central region, Pb was higher in central region, and there were a few high-Cd areas existed in the northwest, northeast, and south region. The speciation distribution of Cu, Cd, Pb, and Zn were ranked as:residual > oxidizable > weak acid soluble > reducible, and the concentrations of stable heavy metals were much higher than available heavy metals. The bioavailability was ranked as:Cd > Zn > Cu > Pb. Risk assessment code (RAC) showed that Cd and Zn was at low environmental risk level, and Cu and Pb was no environmental risk. The ratio of secondary phase and primary phase (RSP) showed that the RSP values of Cu, Cd, Pb, and Zn was 0.06, 0.49, 0.18 and 0.13, respectively, most of the soil samples were not polluted by heavy metals.[Conclusion] The environmental risk and pollution of heavy metals (Cu, Cd, Pb, and Zn) of greenbelt soil within the 5th ring road of Beijing City are at a low level, but enough attentions need to be paid on heavy mental occurrence form.

Abstract:[Objective] To provide a basis for studying the vulnerability of subgrade under the action of debris flow, model test is used to research the scouring and silting mechanism of the debris flow on the subgrade.[Methods] The debris flow gully in China-Pakistan K1561 highway was selected as the research prototype. A similar test model of the debris flow gully was built. Test data was obtained from the simulation of the prototype valley. The scouring and silting mechanism of highway subgrade was studied by control variate method, based on the model tests performed on 6 factors of 25 groups.[Results] The results of prototype gully model test were in good agreement with the field investigation results. Five factors, namely circulation area slope, the distance between the subgrade and the mountain pass, the maximum amount, the severity and the frequency of debris flow, showed obvious impacts on the subgrade vulnerability, while the influence of the angle between the main channel and the subgrade was not significant.[Conclusion] Five factors have important influences on subgrade vulnerability, and can be used as important evaluation indexes for debris flow vulnerability assessment.

Abstract:[Objective] The study analyzed the variation of soil organic carbon (SOC) and nitrogen (N) content under different micro-topography in alpine grassland area in order to provide a theoretical basis for the reasonable use of grassland in alpine grassland.[Methods] This study selected 7 different kinds of micro-topography in alpine grassland of Tianzhu to measure SOC and N in the land surface(0-30 cm).[Results] With the increase of soil depths, the content of total N and NH₄-N decreased at the flat area of valley bottom. The content of soil total N showed a "V" trend and NH₄-N decreased in different position of north-facing slopes. In different position of south-facing slopes, the content of soil total N decreased, but soil content of NH₄-N showed an increase trend initially and decreased later. With the increase of soil depths, the content of SOC decreased in all micro-topography, while the content of soil hydrolyzable nitrogen decreased in terrace, middle and south-facing slope, middle and north-facing slope micro-topography. The content of hydrolyzable N decreased initially and then increased in bottom and south-facing slope and bottom and north-facing slope micro-topography, while increased initially and then decreased in top and south-facing slope and top and north-facing slope.[Conclusion] The variation of total N, hydrolyzable N and SOC content at different topographic positions was ranked as:bottom slope > top slope > middle slope. The content of NH₄-N decreased initially and then increased. In conclusion, the variation in micro-topography impacts the content of SOC and N dramatically.

Abstract:[Objective] To investigate soil infiltration and its impact factors in different landscape types in order to provide references for the conservation and sustainable development of the cultural heritage in the Hani rice terraces of Honghe Autonomous Prefecture.[Methods] Seven sample plots located in different landscape types including grassland, forest land, dry farmland and tea garden land were selected. Soil moisture infiltration meter Hood IL-2700 was used to measure soil infiltration. The impacts of litter water holding capacity and soil physical features on soil moisture were analyzed.[Results] Due to the impacts of human utilization, soil infiltration capacity of the sub-ecosystem of forest and grassland was ranked as:natural forest > secondary forest > planted forest, and waste grassland > fern grassland. At the four types of landscape scale, soil infiltration capacity ranked as:tea garden land (which was plowed) > grassland > forest land > farmland (which was during the un-planting season). It indicated that human activity had a significant impact on soil infiltration. Correlation analysis between soil infiltration and its influencing factors showed that, except for the tea garden land, the soil infiltration in the other landscape types significant related to the indices of litter and soil physical property.[Conclusion] The soil infiltration capacity of the four landscape types are significantly different, and the features of litter and soil physical properties are the key factors that influence soil infilration.

Abstract:[Objetive] In order to provide the theoretical basis for Astragalus mongholicus introduction, domestication and planting in saline land, the seed germination and seedling growth of A. mongholicus were investigated in different concentrations of NaCl, Na₂SO₄ and NaHCO₃ treatment to understand the effect salt stress on A. mongholicus.[Methods] Seed germination test were conducted in germination box, and the germination rate, germination potential, relative salt injury rate, root length, seedling height and ratio of root and stem of A. mongholicus were measured in different concentrations of NaCl, Na₂SO₄ and NaHCO₃ treatments.[Results] ① A. mongholicus seed germinated normally under the salt stress with the concentration of NaCl<0.2%, Na₂SO₄<0.6% and NaHCO₃<0.3%, and the germination rate and germination potential were all greater than that of control treatment, vice versa. ② The relative salt damage rate of A. mongholicus seed was negative at low concentration (NaCl 0.6%, Na₂SO₄ 0.8%, NaHCO₃ 0.3%) as it promoted the seed germination, while it inhibited the germination of A. mongholicus when the concentration was higher. ③ The stem length, root length and ratio of root and stem of A. mongholicus seedling increased with the increase of salt concentration. When the concentration of NaCl and Na₂SO₄ were 0.4%, 0.6% and 0.6%, 0.3%, respectively, the stem length and root length of A. mongholicus seedling were the maximum. While the stem length and root length of A. mongholicus seedling started to decrease as the concentration of NaCl and Na₂ SO₄ increased. The maximum ratio of root and stem was 1.658, 1.709 and 1.291, respectively, when the concentrations of NaCl, Na₂SO₄ and NaHCO₃ was 0.6%, 0.8% and 0.3% respectively, while it decreased when the concentrations increased.[Conclusion] The seed and seedling of A. mongholicus could germinate and grow normally under salt stress with the concentrations of NaCl<0.6%, Na₂SO₄ <0.8% and NaHCO₃ <0.3%.

Abstract:[Objective] To study the adjacent tap root and root nodes of typical soil and water conservation plants Caragana korshinskii, Hippophae rhamnoides and Medicago sativa in the different diameters of bending resistance and bending strength in Midwestern Inner Mongolia, in order to provide a scientific basis for the study of the inner mechanism of the plant root network.[Methods] Using bending test of cantilever beam, the tap root and root nodes of three kinds of plants was investigated.[Results] In the test root diameter range of 1~5 mm, the bending resistance of three plant root nodes and adjacent tap roots were positively correlated with the diameters, and the of three plant root nodes and adjacent superior tap root was ranked as:C. korshinskii > M. sativa > H. rhamnoides. In the test root diameter range of 2~5 mm, the root node bending force of three plants was smaller than their adjacent superior tap root, and ranked as:C. korshinskii (21.87, 24.33 MPa) > M. sativa (10.69, 17.02 MPa) > H. rhamnoides (4.81, 4.95 MPa).[Conclusion] The capacity of the C. korshinskii root system to resist bending deformation is the best among three plants. The least bending strength differences have been found between H. rhamnoides root nodes and adjacent tap roots, indicating that the bending resistance of H. rhamnoides root system is the best at all levels, which is beneficial to the consolidation of root systems.

Abstract:[Objective] To study the form of calcium carbonate and its effect on the loess microstructure in order to provide basis for the study of influence mechanism of calcium carbonate on the loess liquid and plasticity limits.[Methods] First, using distilled water to wash soluble salt in loess, and obtained loess samples with different contents of calcium carbonate processed by 1 mol/L acetic acid solution. Liquid and plastic limits joint meter was used to measure loess liquid plastic limit indicator. The scanning electron microscope (SEM) was used to analyze the X-ray energy dispersive microanlysis(EDX).[Results] ① Under the action of acetic acid, the liquid plastic limit decreased significantly with the decrease of calcium carbonate. ② Calcium carbonate blocks and superfine calcium carbonate were exposed as the skeleton and set granules to Si, Al and Si-Fe, and its main function was to connect the cementation between the particles and the pore skeleton of the loess.[Conclusion] In the early stage of acetic acid treatment, the calcium carbonate was mainly dissolved in the clay granule, and the loss of granule led to the loss of loess sand soil and eventually affected the liquid and plastic limit index.

Abstract:[Objective] To improve the existing evaluation methods on initial conditions and understand the mechanism of rainfall infiltration on slope stability, in order to provide effective suggestions for landslide early warning.[Methods] Taking Liaoji landslides in southern of Tianshui City, Gansu Province as a case study, soil was defined as a natural or wet state based on whether there was a antecedent rain. The Boltzman model was applied to turn pore water pressure into water content. And the fluid-solid coupling models were established to make a numerical analysis.[Results] In a natural state, soil absorbed the rain rapidly, and infiltration were confined in the superficial layer of 1—2 m. The stability coefficient decreased significantly in the early stage, but slowed down with the stagnation of infiltration, and formed shallow landslides ultimately, similar to plastic sliding. In wet condition, soil held water slowly, but the infiltration reached deeper position(3—4 m) and increased its pore water pressure. As the increase of infiltration depth, the process of soil softening became stronger and stronger and the sliding surface was often occurred in the deep position. When the soil was dry, the 7-day rainfall warming was an effective method for disaster warming. While in the rainy weather, soil kept in wet, and the pore water pressure blow 4 m and the slope displacement should be monitored.[Conclusion] The initial conditions of soil have significant impact on the process of unsaturated seepage and stability changes. Consequently, it is an integrant factor in stability analysis of rain-induced landslides.

Abstract:[Objectives] With the object-oriented classification techniques for low-altitude unmanned aerial vehicle(UAV) remote sensing image data, this study monitored soil and water conservation for development and construction projects, to provide technical supports for soil and water conservation monitoring.[Methods] Unmanned multi-rotor aircraft was used to obtain the low altitude remote sensing images in soil and water conservation monitoring target areas. Digital surface models were constructed by oblique photography. The optimal segmentation scale parameters were selected by the estimating the scale parameter(ESP) segmentation scale evaluation tool, and supervised classification by the nearest neighbor classification of multivariate feature space metrics was used. The classification accuracy was verified through the location information validation method and error matrix.[Results] The total accuracy and the Kappa coefficients of target area in monitoring the soil and water conservation were 86.10% and 0.841, respectively. This result could meet the precision requirements.[Conclusion] The object-oriented classification techniques used for low-altitude UAV remote sensing image data achieved fast, accurate identification and classification in the monitoring of soil and water conservation for development and construction projects.

Abstract:[Objective] Using unmanned aerial vehicle(UAV) remote sensing monitoring technology to monitor the response of leaked CO₂, in order to provide a theoretical basis for monitoring accident risk of carbon capture and storage(CCS).[Methods] By environmental background value monitoring, experimental monitoring, theoretical simulation and data comparison analysis, the response of UAV remote sensing monitoring platform to the risk assessment of CCS leakage was studied.[Results] The standard deviation of CO₂ concentration change in the environment caused by CO₂ emission that over the highest value of the environmental background of a section, was taken as the response concentration difference. Under the experimental conditions, the UAV was located at a horizontal distance of 10 m and a vertical distance of 9 m from the source of leakage. The response concentration was 502 mg/kg, when the environmental background value was 448 mg/kg. Calculation from Gaussian model showed that the theoretical value of the CO₂ diffusion under the experimental conditions at the experimental location was 40 mg/kg.[Conclusion] The UAV remote sensing monitoring platform can respond to the leaked CO₂ and can be applied to the actual CCS leakage accident risk assessment. As the large amount of leakage under the industrial scale, the UAV remote sensing monitoring platform can provide effective monitoring for large space field.

Abstract:[Objective] To review soil and water conservation technologies in the purple soil area of Southwestern China in order to provide basis for the practices of regional soil and water conservation.[Methods] The practical application of various soil and water conservation technologies in the purple soil area was analyzed through literature review from different aspects.[Results] According to the literature review, the ideas for controlling soil erosion were elaborated, and the main soil and water conservation measures were summarized. The suitable conditions and the technical approaches for different soil and water conservation measures were briefly introduced. Meanwhile, suggestions were proposed to address the issues existed in the current working practices.[Conclusion] The priority of soil erosion control in the purple soil area is small watershed management, which is mainly composed of soil erosion control in sloping farmland and slope runoff regulation engineering. Althoug a variety of engineering, biological and agricultural technical measures were formed in practice, there is still a lack of the relevant technical criterias and reliability assessment for soil and water conservation measures in this area. It is necessary to develop the technical criteria, evaluate the soil erosion control efficiency, and optimize technology configuration in future.

Abstract:[Objective] To explore the classification, distribution and influencing factors of gullies in Hengduan Mountainous area, in order to provide a basis for the study of influences of gully erosion on soil erosion and land degradation processes in this area.[Methods] The high-resolution images available on Google Earth combined with GIS software were applied to investigate the gully density in Hengduan mountainous area according to the visibility principle. Totally, 2 242 quadrats with the same size of 1 km×1 km were set randomly in the region.[Results] The gullies were observed in 571 quadrats, which accounted for 25.5% of the total quadrats, and the average density was 2.20 km/km². Gully erosion was intensive at the low mountain regions(elevation<1 500 m), and the gully density increased with the increasing slope gradient. The relationship between gully density and annual precipitation was quite weak. Grassland was the main land use type for gully development, and gully erosion in the dry red soil region was more intensive than other soil species. According to the domestic and international gully classification systems, the gullies observed in this study were mainly classified as permanent gully (including gullies with debris flow events).[Conclusion] The permanent gullies were widely distributed and intensively developed in Hengduan Mountainous area, which were clearly influenced by elevation, slope, land use and soil species.

Abstract:[Objective] To solve the issues in area superposition and flow superposition method in order to improve the discharge design in storm sewer.[Methods] Flow superposition method was modified by correcting the calculation method of storm intensity in downstream sewer. A maximum flow method based on exhaustion method was proposed.[Results] A case study indicated that the design discharge with improved flow superposition method was less than that of area superposition method, except for the initial sewer. The average design discharge based on maximum flow method was increased by 7.0%, and the maximum increase rate was 13.0%.[Conclusion] Maximum flow method is more reasonable and safer, and is of great importance for relieving urban flooding.

Abstract:[Objective] To establish optimization decision model of coal dust inhibitors in order to provide a useful theoretical reference for scientific evaluation and decision of coal dust inhibitor.[Methods] Based on the technique of order preference by similarity to ideal solution (TOPSIS), seven evaluation indexes were selected, and then weights were confirmed by using the pull-up method to avoid the subjectivity of decision maker.[Results] This model was applied to evaluate 10 research results of coal dust inhibitors in the last ten years. The results showed that the degradation dust suppressant was the best solution, followed by the coal dust inhibitor, while oxidized starch grafted acrylic acid acrylamide dust suppressant was the worst.[Conclusion] The model can effectively evaluate the comprehensive performance of dust suppression scheme by quantitative data, and which is of great importance for scientific decision making.

Abstract:[Objective] Determing the optimal amount of N-fertilizer inputs for rice production is significant to improve the agricultural management in the coastal saline reclamation area, Eastern China.[Methods] Combining denitrification decomposition model(DNDC) and dichotomy method, this study simulated rice yield dynamics during the whole life cycle under six fertilization situations (10%, 20%, 30%, -10%, -20% and -30% of additional N-fertilizer inputs). And the optimal interval of N-fertilizer inputs and corresponding ecological impacts were explored.[Results] ① The rice yield in the study area was 6 431.67, 5 939.22, 5 439.66, 7 686.51, 7 739.94 and 7 739.94 kg/hm² 10%, 20%, 30%, -10%, -20% and -30% N-fertilizer inputs, respectively. ② The optimal interval of fertilization was from 10% to 20% of additional fertilizer inputs, namely, 519.0~566.18 kg/hm² of N-fertilizer inputs. And the optimal N-fertilizer inputs was 528.214 kg/hm², according to dichotomy analysis. ③ Based on the optimal amount of N-fertilizer inputs, the nitrogen oxide emission was 9.24 kg/hm² during full rice growth period, which showed a good environmental benefit.[Conclusion] The optimal amount of N-fertilizer inputs during rice production in the study area is 528.214 kg/hm². This optimal N-fertilizer inputs, can improve the rice yields of saline soil to the top level and produce a better environmental benefit.

Abstract:[Objective] The impact of the Three Gorgesreservoir water level and rainfall on Bazimen landslide is analyzed to evaluate its stability.[Methods] Landslide monitoring data were used for qualitative analysis of Bazimen landslide deformation. Based on the quantitative analysis of water level and rainfall in the reservoir area, 20 different kinds of working conditions were then determined, and the stability of Bazimen landslide was calculated through Geo-Studio.[Results] The accumulated displacement monitoring curves from 10 GPS monitoring points in the Bazimen landslide were all ladder-shaped and increased with time, and they showed a synchronous morphologic change. Under the 20 different kinds of working conditions, the stability coefficient of the Bazimen landslide was more than 1. When the rain fall condition changed, the minimum stability coefficient varied mildly under the constant reservoir water level. When the reservoir water level changed, the minimum stability coefficient varied greatly under the constant rainfall. The minimum stability coefficient was successively reduced under five different conditions including stable reservoir water level at 175 m and 145 m, reservoir water level fluctuation in 2014, average reservoir level, and reservoir water level fluctuation in 2013.[Conclusion] The Bazimen landslide is in a stable state, its stability is affected by rainfall and reservoir water level, and reservoir water level is the main factor. The stability of Bazimen landslide will be worse with the larger water level change in the reservoir area.

Abstract:[Objective] This study investigated the spatial and temporal variations of soil erosion and its causes in a stretch of north main line of drawing water from the Yellow River to Shanxi Province in order to provide basis for ecological management and soil erosion control.[Methods] Using LUCC, digital elevation model(DEM) and Landsat TM4-5 imagery, coupled with monthly precipitation data from 2005, 2010 and 2015, the temporal and spatial characteristics of soil erosion intensity were derived.[Results] Soil erosion in the year of 2005 and 2015 was slight, but moderate in the year of 2010. From 2005 to 2010, soil erosion increased by 80.91%, followed by a decrease of 47.87% from 2010 to 2015. Taking the north main line as the boundary, the differences of soil erosion on both sides of the boundary was significant. The most severe soil erosion occurred near to Shuozhou City. R factor was positively correlated with soil erosion. The largest erosion area occurred when the soil type was chestnut soil, slope was 8°~15°, and land use type was cultivated land. Most serious erosion occurred in forestland and grassland with slope more than 25°.[Conclusion] The construction of the water diversion project has exacerbated soil erosion along the reach. Main controlling factors such as rainfall, soil type, slope, and land use type are closely related to the soil erosion distribution in the study area. Therefore, priority areas of water and soil conservation should be determined, and regulations should be made to prevent soil erosion and to protect local environment.

Abstract:[Objective] To construct a reasonable and feasible evaluating indicator system in order to improve decision-making for open-pit quarry reclamation modes under different conditions.[Methods] Analytic hierarchy process(AHP) was used to calculate the weights of evaluation factors under three different land reclamation modes.[Results] ① With the consideration of topographical, natural and socio-economic conditions, eight evaluation factors including slope gradient, slope roughness, vegetation coverage, average effective soil thickness, average annual precipitation, socio-economic level, distance to city center and degree of quarry aggregation were selected to establish the evaluating indicator system and criteria. ② Beishan open-pit quarry reclaimed as the Fengshanzhen National Mine Park in Jiaozuo City was analyzed as a typical example. The results verified suitability of the evaluating indicator system.[Conclusion] The evaluating indicator system and criteria can provide references for land reclamation mode of open-pit quarry of related areas.

Abstract:[Objective] To explore the best technical route for salt salinity estimation based on spectral indices in order to provide theoretical basis and technical reference for the quantitative calculation and rapid remote sensing monitoring of soil salinity in the study area.[Methods] Taking Kenli County of Shandong Province as the study area, samples were collected in the field, the content of soil salt and its main ions(Cl^-,Na⁺,Ca²⁺)were measured, and the hyperspectra were obtained. Two different methods were used to select the sensitive spectral indices. The first one was to select the sensitive bands of salt and its major ions and then to build five spectral indices. The second one was to combine any two bands and to construct the five spectral indices, and the sensitive spectral indices were then filtered. The random forest(RF) method was used to build quantitative hyperspectral models of soil salinity and ions contents.[Results] The RF model of brightness spectral indices(1 750, 1 620 nm)exhibited the best precision, thus it was the best estimation model of soil salinity in the study area, and the brightness spectral index was the best spectral index. The characteristic spectral range based on the second method covered the selected sensitive bands based on the first method, thus was more conducive to the spectral characteristics analysis. Meanwhile, the salt prediction model built based on the second method was better than that on the first one. Therefore, the best technical route was to construct the spectral indices by combination of any two bands firstly, then to select the sensitive spectral index of soil salinity and its main ions by correlation analysis, finally to build the RF model.[Conclusion] The technical route is suitable for the extraction of soil salinization information in the Yellow River delta.

Abstract:[Objective] To analyze the evolution and driving forces of land desertification in order to provide technical references for land desertification controlling and the rational exploitation and utilization of land resources in the Fengning County, Hebei Province.[Methods] Through remotely sensed imagery interpretation based on remote sensing and GIS, we analyzed the temporal and spatial evolution of regional land desertification and its driving factors in the Fengning County in 2009 and 2014.[Results] The desertification land showed an obviously regional distribution, which was mainly distributed in the fixed sandy land of the midwest areas. Over the past 5 years, the total area of desertification land generally decreased despite the moderate desertification area increased, in which the area of mild desertification decreased by 560.9 hm², the area of severe desertification decreased by 1 872.6 hm², and the total area of desertification land decreased by 809.2 hm². The plateau was easier to form desertification than the lower hilly zone, the degree of desertification was more severe in the arid zone than that of semiarid zone.[Conclusion] Based on local landscapes and environmental conditions, developing and using land resources rationally, increasing forest areas, will effectively reduce the land desertification.

Abstract:[Objective] To evaluate water production function quantitatively and study its spatial expression of watershed ecosystem in order to provide scientific support for optimal allocation and sustainable management of water resources and improvement of ecological efficiency.[Methods] Taking the upstream catchment of Daling River as the study area, we firstly evaluated the water conservation service in 2015, and analyzed the spatial distribution characteristics using the water yield module of integrated valuation of ecosystem services and tradeoffs (InVEST) model. Then, the obtained water conservation evaluation results were normalized and divided into different classes.[Results] ① Total water conservation capacity of the upstream catchment in Daling River reached to 1.82×10⁹ m³ in 2015, and it showed obvious spatial heterogeneity. ② The normalized results showed that high grade area of water conservation was located in the central and northern part of the Kalaqin Left Wing Mongol Autonomous County, while low grade area of water conservation was located in the northern part of Aohan and Ningcheng County of Inner Mongolia and Pingquan County of Heibei City. Moderate grade area of water conservation was widely distributed, which accounted for 34.7% of the study area. ③ The Kalaqin Left Wing Mongol Autonomous County and the southwest part of Chaoyang City was important water conservation area, which should be strictly managed and protected.[Conclusion] Factors such as land use type, climate and soil texture have important influences on the heterogeneity of water conservation, the spatial distribution of water conservation is uneven and the difference is significant.

Abstract:[目的]研究扫描电镜下黄土微观结构的特征，为分析马兰黄土的孔隙特征提供一种新方法。[方法]利用IPP影像分析软件对扫描电子显微镜获得的泾阳南塬马兰黄土不同放大尺度下的微观影像进行分析，并对马兰黄土中的孔隙进行统计分类。[结果]在不同放大尺度下，微孔隙的孔隙率维持在2%，小孔隙的孔隙率与放大倍数呈线性负相关，相关系数为-0.98，其余孔隙无特定变化规律；在相同放大尺度下，微、小孔隙在马兰黄土中分布均匀，中、大孔隙较为分散。[结论]扫描电子显微镜影像可以方便、迅速地为我们提供黄土孔隙特征分析。

Abstract:[Objective] To study the growth of Suaeda salsa transferred from a terrestrial habitat to a floating-bed saline habitat and its effect on the in-situ water remediation of aquaculture ponds, in order to provide methods for aquaculture water body remediation by floating bed.[Methods] The growth, physiological and biochemical indexes of S. salsa under saltwater floating bed and land habitats during the restoration period were measured. Water quality of the aquaculture ponds was monitored as well.[Results] The S. salsa was well-adapted the floating bed habitat during the experiment period. Biomass was increased significantly, and the root activity and leaf nitrogen content of S. salsa in the floating bed habitat were higher than that in the land habitat. The total nitrogen, total phosphorus, ammonia and chemical oxygen demand was 3.34, 0.20, 0.47, and 0.35 mg/L, respectively, which was lower than the control treatment.[Conclusion] S. salsa can adapt to the aquatic environment after transferred from terrestrial habitat to floating-bed saline habitat, and it can remove nitrogen, phosphorus and other elements in the water through the root absorption. S. salsa has a good potential for in-situ remediation in aquaculture pond water.

Abstract:[Objective] The relationship between surface freezing/thawing index and runoff over the upper reaches of Heihe River in Western China was discussed in order to provide scientific basis for the runoff prediction and the rational development and utilization of water resources in this basin.[Methods] The impacts of precipitation, air temperature and surface freezing/thawing index on runoff during the period from 1979 to 2006 were investigated over the upper reaches of Heihe River basin in Western China. Changes in freezing/thawing index and river runoff in freezing/thawing period and the relationships between surface freezing/thawing index and runoff were further explored.[Results] There was a significant decrease trend in freezing while a significant increase trend in thawing index, and the most significant change occurred in 1990-2005. The variation of runoff was not obvious in thawing period, while it decreased dramatically in freezing period, especially in winter. The reduction of winter runoff was influenced by the variation in soil seasonal freezing and thawing. The freezing index was reduced significantly, indicating that air temperature increased in seasonal soil freezing process, and more snow sublimated in winter, so that the supply of runoff was reduced. The thawing index increased significantly, leading to a 13~14 cm increase in the depth of seasonal thawing soil, which resulted in an increase of the soil storage space to store part of the groundwater and a decrease in winter runoff.[Conclusion] Changes in the soil seasonal freezing and thawing play significant roles in the runoff of the upper reaches of Heihe River in Western China.

Abstract:[Objective] In order to provide scientific basis for selection and collocation of afforestation tree species in the Ili River valley, soil nutrients content and enzymes activity characteristics of five typical afforestation models were studied.[Methods] Soil chemical properties and enzymes activities at 0-20 cm and 20-40 cm depths were investigated, and the correlations between them were analyzed.[Results] Soil enzyme activities was greater and nutrient content was higher in 0-20 cm layer. Soil nutrient contents were significantly different among five afforestation models. The content of soil available nitrogen(N) and phosphorus(P) in elm shelterbelt was the highest, and total potassium(K) and available K was also at a higher level. The content of soil total N, total P and organic matter in forest grass inter-cropping system was the highest among five models, and soil available N was also at a higher level. A correlation had been found between soil enzyme and soil nutrient. Soil urease showed positive relationships with total P, available N, available P and organic matter. Soil peroxidase showed positive relationships with total K and available K, while negative relationships with total N, total P, available N and organic matter.[Conclusion] A close relationship has been found between soil enzyme and nutrient. Soil enzymes activity can be widely used to evaluate the forest soil fertility.

Abstract:[Objective] To investigate the non-additive effect of different maize straw components on soil organic carbon (SOC) mineralization in loessial soil in order to provide technical support for soil CO₂ emissions.[Methods] By laboratory incubation experiment, five treatments were set including soil with no maize straw addition (CK); soil with stalk litter addition (CKS); soil with leaf litter addition (CKL); soil with leaf sheath addition (CKLS) soil with mixed maize straw addition (CKM).[Results] The amounts of observed soil accumulative carbon mineralization were significant higher than the predicted value in the end of experiment, and the promotion was mainly happened in the fast decomposition stage (1~28 d). The predicted remaining mass and carbon-nitrogen ratio were higher than the observed values, while the predicted content of soil total nitrogen was lower than the observed value in the end of experiment. The content of microbial biomass carbon (MBC) was the highest under CKS treatment, and there was no significant difference among other treatments. The content of microbial biomass nitrogen (MBN) showed a decreasing tendency, the MBC/MBN increased under litter addition treatments and the differences among CKS, CKL and CKM treatments and CK treatment was significant. The content of dissolved organic carbon (DOC) was higher under CKLS and CKM treatments than under other three treatments, and the difference between CKS and CKL treatments was not significant.[Conclusion] To mix litter in proportion had a synergistic effect on litter decomposition, and the decomposition of mixed litter promoted litter nitrogen accumulation.

Abstract:[Objective] This paper studies the evolution of land use efficiency of 282 prefecture-level cities in China from 2000 to 2015 in order to provide a reference for the optimization of resource allocation and the continuous improvement of land use efficiency.[Methods] The VRS-DEA model and GIS spatial analysis method were used to study the evolution characteristics and its influential factors of land use efficiency in 282 prefecture-level cities.[Results] ① The land use efficiency of Chinese cities was at a low level. Among them, the eastern city had the highest efficiency, the western city took the second place, and the central city had the lowest efficiency. The larger of the city, the higher of the efficiency and the faster of the growth rate was. ② The land use efficiency was caused by pure technical and scale efficiency, pure technical efficiency contributed more than the scale efficiency. Eastern cities and high-grade cities had more advantages of pure technical efficiency. ③ Influencing factors of land use efficiency were changed from the built area and the excessive investment of the number of employees in the tertiary industry into the investment in fixed assets and the excessive investment of the number of employees in the secondary industry. At the same time, the impact of the insufficient output value-added of the secondary industry was significantly greater than that of the tertiary industry.[Conclusion] Different solutions need to be used to improve the land use efficiency in different regions and cities at different scales, for example, strictly control the scale of megacities and mega cities, control the scale of large cities in a targeted manner, and increase the investment of pure technical efficiency in medium-sized cities and small cities.

Abstract:[Objective] To understand the water consumption law in the ecological restoration of Tarim River, in order to provide references for the rational planning and allocation of ecological water.[Methods] Data including MODIS NDVI and evapotranspiration(ET) was collected in subsection of Alar-Daxixaizi in Tarim River from 2000 to 2014. Mann-Kendall method and Theil-Sen median trend analysis was used to investigate the spatiotemporal variations and the relationships between vegetation cover and ET.[Results] ① In the Alar-Daxixaizi section of the Tarim River, the average value of NDVI and ET years was 0.33 and 118.41 mm, respectively. The spatial variation of the NDVI and ET was highly consistent, both were characterized as:upper reach (Alar-14th regiment) > down reach (Charla-Daxixaizi) > middle reach (14th regiment-Charla). The spatial distribution of ET was controlled by vegetation cover. ② For the inter-annual variability, the difference between the spatial variations of NDVI and ET was obvious, and the change trends of them were generally reversed. NDVI increased significantly (Z_C>1.96), while ET decreased (-1.96 < Z_C < 0). NDVI in 48.83% of the whole area decreased, which mainly located at the middle reach. The proportion of ET with decreasing trend accounted for 70.57% of the whole area, which was widely distributed in the middle and down reach. ③ Compared to NDVI, runoff and water vapor pressure, the annual variation of ET was more closely related to temperature and precipitation.[Conclusion] Although the spatial distribution of the ET in Tarim River was controlled by the vegetation cover, the spatiotemporal variations between them was distinct.

Abstract:[Objective] To analyze the land spatial evolution characteristics and formation mechanism in order to provide the feasible basis for the governance of the abandoned lands.[Methods] Ping'an and Zhuyuan Township of Fengjie County were selected as the study area. Google Earth HD remote sensing images in the year of 2002, 2012 and 2016 were collected. GIS and RS softwares were used and interactive interpretation was adopted to obtain land use data. The land use dynamic degree, spatial autocorrelation and landscape pattern research theories and methods were used to conduct the related analysis.[Results] ① The area and growth rate of abandoned land was increased sustainably from 2002 to 2016 in the study area. ② The fragmentation and heterogeneity of abandoned lands was decreasing, and patch connectivity was better as patches were getting larger and more concentrate. ③ The abandoned lands in study areas showed strong spatial agglomeration characteristics, yet the local agglomeration situation was different, and the homogenization was high and spread year by year.[Conclusions] The spatial-temporal evolution of the abandoned lands in study areas is basically consistent. The spatial distribution is closely related to natural factors such as slope and elevation, and it is also related to the distance between residential areas. In conclusion, the spatial distribution of abandoned lands is affected by the loss and shortage of rural labor force.

Abstract:[Objective] In order to provide appropriate theoretical foundation for conservation of water and soil in southern red eroded soil region, the relationships between topography, land use and soil bulk density were analyzed in Zhuxi watershed.[Methods] The study was conducted in the area of Zhuxi watershed in Changting County, Fujian Province. Based on classical statistics and the geostatistics methods, the article analyzed the spatial variability of soil bulk density. The spherical model was selected as the best option for semivariogram. Ordinary Kriging interpolation was applied to predict the spatial distribution of bulk density. Zonal statistics function of ArcGIS was used to analysis the relationship between mean value of bulk density and elevation and slop, and raster overlay analysis was applied to calculate the area of bulk density in different land use types.[Results] ① The soil bulk density in watershed increased from northeast to southwest, and the lower bulk density area was located in west, and northwest and the higher bulk density area was located in southwest and central region. ② The bulk density decreased with the increase of elevation and slope, in contrast, slope position and slop aspect had little impact on spatial heterogeneity of bulk density in Zhuxi watershed. ③ Residential land and traffic land had a higher mean value of bulk density than the area covered by forests and grass.[Conclusion] Topography and land use were important factors which influence soil bulk density, while elevation and slope were regarded as the main terrain factors for spatial heterogeneity of bulk density in study area. There was a significant difference among different land use types, and the area with a good vegetation cover had a lower value of bulk density than other types. Therefore, to improve the soil structure in study area, vegetation conservation should be strengthened.

Abstract:[Objective] To explore the response characteristics of precipitation change in the Shaanxi, Gansu, Ningxia and Inner Mongolia bordering area under global warming in order to provide scientific theoretical basis for the sustainable development of natural ecosystem and social economy in this area.[Methods] Precipitation data was collected from 40 national meteorological stations during the period from 1961 to 2015. The spatial-temporal variation of precipitation in the past 54 years was analyzed, using linear trend estimation, Mann-Kendall mutation test and ordinary Kriging interpolation mathematical analysis methods.[Results] ① With the global warming, the precipitation decreased in the study areas during the past 54 years. ② Spatially, the annual precipitation reduced roughly from the southeast to northwest, and the tendency rate showed a decreasing trend initially and then increased from the southeast to northwest. ③ The changes in precipitation anomaly showed that the precipitation increased in spring, summer and winter, but reduced in autumn, and the rate of precipitation change ranked as:winter > spring > autumn > summer. The spatial differences of precipitation in four different seasons were obvious, which reduced gradually from the southeast to northwest.[Conclusion] A warm-drying trend is expected in the Northern Shaanxi, Gansu, Ningxia and Inner Mongolia contiguous area, and it is obvious in four different seaons. Further studies are needed to confirm whether the climate will transferred from the warm-dry to warm-wet since the precipitation in the region has shown an obvious increasing trend since 2000.

Abstract:[Objective] To implement the concept of people-oriented in order to explore new ideas for the development of production-living-ecological spatial planning in villages and towns under the background of ecological-civilization.[Methods] Based on the scientific definition of geomantic theory, the paper combined the ecological layout requirement of geomantic theory with the actual demand of new rural construction to evaluate the spatial planning of production, life and ecological in village. Fangniuping village in Yubei District of Chongqing City was taken as a case study.[Results] The production space planning in the study area was suitable to local conditions and had prominent features. The living space planning was ecological, livable and intensive. The ecological space planning was effective, beautiful and harmonious. The ecological civilization construction requirements and scientific geomantic theory was mutually confirmed.[Conclusion] ① The concept of geomantic theory can improve the process of village planning. ② The natural geomantic condition in the planning area can be used to verify the rationality of the village space planning. ③ More attention should be paid on the psychological demands and cultural identity of rural residents in geomantic theory.

Abstract:[Objective] To evaluate the level and spatial distribution differences of urban land use performance in order to provide scientific basis for the optimization and improvement of land use performance in Fujian Province.[Methods] The urban land use performance evaluation index system was constructed from three dimensions of social, economic and ecological performance. The weights were determined by AHP method and principal component analysis method. Using coordination degree functions, the performance level of land use in Fujian Province was calculated and analyzed.[Results] The performance level of urban land use in 9 cities in Fujian Province showed a pattern of "low in the west and north, but high in the east and south". The differences in land use performance among the cities were significant. Social, economic, and ecological performance subsystems have different spatial distribution characteristics. The social and economic performance subsystems showed strong spatial agglomeration characteristics, while the ecosystem performance subsystem showed a scattered spatial distribution trend. The comprehensive performance of urban land use in 9 cities in Fujian Province could be divided into four types of performance. The high performance area was Xiamen City; the medium performance area included Quanzhou City and Fuzhou City; the lower performance area was Zhangzhou City; and the low performance area included Putian, Sanming, Nanping, Longyan and Ningde cities.[Conclusion] The performance level of land use varies greatly among different cities in Fujian Province. The development of subsystems subordinated to each district-city land use performance evaluation system is unbalanced, and the overall level of coordination is close related to the economic development level. The degree of internal coordination is reflected in the increase of the overall level of peripheral areas driven by high-performance areas.

Abstract:[Objective] To evaluate the value of urban forest ecosystem service function in order to provide scientific basis and theoretical support for the continuous improvement of urban ecological environment and economic development.[Methods] Forest ecosystem of Beidaihe District of Qihuangdao City was chosen as the research object. Water balance, alternative engineering, opportunity cost, production cost, carbon tax, market value and subscription intention methods were adopted to evaluate the service function of forests ecosystem including soil and water conservation, carbon fixation and oxygen release, air purification, forest protection and recreation and leisure.[Results] The service function value of forest ecosystem in Beidaihe reached to 1.487 billion Yuan/a. Among them, function value of recreation and leisure ranked first, reached to 1.087 billion Yuan/a, accounted for 73.12% of the total value. The service function value of various forest ecosystem ranked as:leisure recreation > purification of atmosphere > water conservation > carbon fixation and oxygen release > soil conservation > forest protection.[Conclusion] Forest ecosystem plays an important role in urban ecosystems. In particular, the development of tourism can promote the development of economic development in Beidaihe District. To use and manage the forest resources rationally, the sustainable development of forest resources in Beidaihe District will be realized ultimately.

Abstract:[Objective] To examine the spatiotemporal characteristics of land use/cover change and underlying forces in the Dongjiang River basin in order to provide useful information for optimizing the way of land use and supporting the construction of the big-bay area in Guangdong, Hongkong, and Macao.[Methods] Based on a series of land use/cover data derived from remote sensing images, we analyzed land use/cover change in the basin during 2001-2013 using several metrics such as land use net change, annual change rate, and the integrated degree of land use dynamics. The gray-relevance analysis was used to explore the driving forces of land use/cover change in the basin.[Results] ① Evergreen broadleaf forest, grassland and cropland used to be four major types of land use/cover in the basin, while evergreen broadleaf forest became the dominant type during 2001-2013. ② Although shrubs, mixed forest, evergreen broadleaf forest, and grassland experienced significant change, their areas were relatively stable due to the inter-conversions among those land types. ③ The extent of built-up land was the highest in the lower-reach areas, higher in the mid-reach areas, and the lowest in the upper-reach areas of the basin. ④ Population growth, urbanization, technology renovation, and rapid economic development were the main driving forces that trigger land use/cover change in the basin.[Conclusion] Land use/cover change in the Dongjiang River basin over the past decade was beneficial to the protecting of ecological environment and water resources, and was also contributive to the construction of the big-bay area of Guangdong, Hongkong and Macao.

Abstract:[Objective] Taking areas of cropland and coal resources as a case study to research land use function in order to provide support for the development of regional function.[Methods] From production-living-ecology aspects, 15 indexes with different function were selected to construct a suitable evaluation index system in study area. Based on the established index system, the land use function was evaluated quantitatively using entire-array-polygon indictor method from 2009 to 2015.[Results] ① The entire-array-polygon indictor method used in this study was intuitionistic, accurate, widely involved and low subjective. It could be applied to evaluate regional land use function. ② The single index showed that the indexes of each subsystem tended to change slightly, but the dominant obstacle factor remained stable in 2009-2015. ③ Within the 7 years, the production function was the regional leading function in the study area. Due to the regional impact of coal mining, cut-off point of intensive land use comprehensive index occurred in 2012, and showed an increasing trend initially and then decreased.[Conclusion] Coal mining activities have a significant impact on land use in the areas of cropland and coal resources, and the level of regional land function change and land intensive use is close related to the development and change of regional coal industry.

Abstract:[Objective] To evaluate water resources carrying capacity and analyze the causes of overloading problems of Hangzhou City, Zhejiang Province in order to study countermeasures and improvement approaches.[Methods] Based on national trial water resources carrying capacity evaluation method, we proposed a new evaluation method considering water volume, water quality and upstream conditions. The water resources carrying capacity of 8 units (central downtown and 7 counties, cities or districts) was studied by the new method, and overloading causes were analyzed by a set of proposed indexes.[Results] The water resources carrying capacity of Hangzhou City experienced continuous improving in the past 3 years (2013-2015), the number of overloading and critical overloading units (counties) declined from 7 to 2. There were four reasons for the overloading and critical overloading problems:① total water consumption difference among 8 units enlarged due to rapid urbanization, ② water demands increased by modern urban lifestyle, ③ insufficient self-purification capacity in river network plain, ④ relatively low efficiency of water utilization in some upstream units (counties).[Conclusion] Water resources management policies and measures should be improved in aspects of protection, rectification, restriction and supervision in the overloaded areas.

Abstract:[Objective] To explore the key issues that restrict the development of China National Sustainable Communities (CNSCs) in mountain area of central south of Shandong Province in order to provide decision-making references for the development of CNSCs in mountain area.[Methods] Based on the 3-dimensional interpretation of sustainable development science and the conceptual definition of sustainable development degree of CNSCs, this paper chose 29 index from economy, society, environment, science and technology aspects, to evaluate the development of subsystem, development degree of CNSCs, coordination degree, sustainability and sustainable development degree of four CNSCs (three types) in mountain area of central south of Shandong Province in 2009-2015.[Results] CNSCs was characterized by weak sustainable development as the increase of development degree fluctuated. The coordination and sustainable development degree was low, and the coordination degree had the most significant effect on sustainable development degree of CNSCs. Science and technology subsystem did not give fully play to a leading and support role, and there were no obvious association between sustainable development characteristics and the type of CNSCs during the study period. Unfortunately, the key issues that restrict local sustainable development had not yet been fundamentally solved.[Conclusion] We should strengthen the construction of regional innovation system, explore new ways to guide the coordinated and sustainable development of CNSCs, establish sustainable development model according local conditions, to promote coordinated and sustainable development of CNSCs in mountain area of central south of Shandong Province in future.

Abstract:[Objective] To analyze the land use/cover change and its driving forces in Fujian Province in order to promote the sustainable development of resources and environment in coastal areas, and provide references for land use policy formulation.[Methods] Based on ArcGIS 10.2 software, the land use/cover change (LUCC) data during 2005-2015 in the study area were analyzed, and the driving mechanism was discussed by the gray relational degree method.[Results] ① The land use types in the coastal zone of Fujian Province in 2005-2015 were mainly arable land, woodland, waters and urban, rural, industrial and mining land and residential land, with less proportion of meadow and unutilized land. During the study period, the area of woodland, waters and unutilized land decreased, while the area of cultivated land and urban and rural areas, industrial and mining areas and inhabitants increased. The area of meadow remained basically unchanged. The land use types were mainly turned into urban and rural areas, industrial and mining areas and residential areas during the period from 2005 to 2015. ② The land use change of coastal zone in Fujian Province was mainly affected by the social and economic development, among which, social affluence, technology and population driving force were the main factors.[Conclusion] Rationally defining the boundary of urban and town development, delineating the basic farmland protection area around the big cities and delineating ecological space such as woodland, meadow and waters, are the effective measures for the management of land use.

Abstract:[Objective] This paper analyzed the changing characteristics of precipitation in the Tieshan reservoir basin, a drinking water source of Hu'nan Province, in order to provide basis for the utilization and schedule of water resources in the basin.[Methods] Methods including linear regression, moving average, Mann-Kendall test, accumulative anomalies analysis sliding t-test and wavelet analysis, were used to analyze the changing characteristics of annual precipitation, precipitation in the flood season and precipitation in the non-flood season during the period from 1968 to 2014.[Results] ① The annual precipitation, precipitation in the flood and non-flood seasons increased slightly over the past 47 years. ② The annual precipitation showed abrupt change in 1987 and 2003, while the precipitation in the flood season showed abrupt change in 1992 and 2003. There was no abrupt precipitation change in the non-flood season. ③ Annual precipitation and precipitation in the flood season had a dominant period of about 29 years, and the precipitation in non-flood season had a dominant period of about 28 years. Basically, the periods for all the precipitations were the same.[Conclusion] The changing characteristics of the annual precipitation, precipitation in the flood and non-flood season were basically consistent with each other in Tieshan reservoir.

Abstract:[Objective] To study the vertical zonality characteritics of debris flow along Zhamo highway in Tibet in order to provide basis for pre-warming and control of debris flow disasters.[Methods] Based on the field surveys conducted during the period from 2009 to 2015, the influences of zonal factors on the distribution, genetic types and fluidic properties of debris flow along the Zhamo highway were discussed, and then the vertical zonality of debris flow were summarized by genetic analysis and case study.[Results] From south to north, Zhamo highway was divided into two sections by Mt. Gangrigabu, which passes through 5 vertical belts in the south and 8 vertical belts in the north. With the descending of altitude, the density and frequency of debris flows showed a low-high-low tendency. The genetic types gradually changed from debris flow induced by glacial lake outburst flood, glacial debris flow, meltwater-rainfall debris flow, into the rainfall debris flow. Correspondingly, the fluidic properties gradually changed from the mud flow to diluent debris flow, sub-viscous debris flow, and finally into viscous debris flow.[Conclusion] With the vertical belt along the highway descending from theⅠbelt to the Ⅷ belt, distributions of debris flow, genetic types and fluidic properties changed regularly, particularly, the vertical zonality characteristics tend to be more conspicuous in the south section of the highway.

Abstract:[Objective] To investigate and analyze wild plant species with seasonal coloration around Lanzhou City in order to select the ornamental species from wild seasonal coloring species suitable for landscape in the semi-arid regions of Gansu Province.[Methods] Firstly, the integrative evaluation model of wild plant resources with seasonal coloration was set up based on 5 evaluation criteria(overall feature C₁, foliage value C₂, ornamental flower C₃, fruit value C₄ and adaptation C₅) and 17 evaluation indicators. Then, the 14 kinds of wild plant species with seasonal coloration were evaluated by the method of analytic hierarchy process. Finally, they were divided into different levels based on the evaluation result.[Results] ① Among the 5 evaluation criteria, C₅ had the biggest constraining force to destination layer. ② Among the 17 evaluation factors, crown aesthetic(P₁), leaf colour(P₅), cold resistance(P₁₅) and heat resistance(P₁₆) provided most of contribution to ornamental value. ③ The comprehensive assessment levels were divided into three levels.[Conclusion] The first level included 3 species, which were Acer tetramerum, Quercus wutaishanica and Sambucus adnata. The second level included 5 species that were Berberis kansuensis, Berberis brachypoda, Berberis diaphana, Cotoneaster multiflorus and Cotoneaster acutifolius. The third level included 6 species, such as Berberis potaninii, Lespedeza formosa, Quercus aliena, Swida bretschneideri, Daphne giraldii and Coriaria nepalensis.

Abstract:[Objective] Vitiveria zizanioides is an ideal herb to maintain soil and water, study on the growth of V. zizanioides in sandy land of the Poyang Lake and its impact on sandy environment can provide a reference for the sand-control in Southern China.[Methods] Field investigation and laboratory experiments were conducted to study the influences of distance to the lake and different treatments on the growth of V. zizanioides, and the impacts of V. zizanioides on soil temperature and humidity.[Results] ① The effect of distance to the lake on the height of V. zizanioides was not significant, while its effect on the tiller number of V. zizanioides was significant. Mowing and tillering treatments showed a positive effect on the height of V. zizanioides. The mowing treatment could promote the tillering of V. zizanioides while the tillering treatment was not conducive to the tillering of V. zizanioides. At the end of growth period, the indexes of V. zizanioides were different. ② V. zizanioides could reduce soil temperature, but increase the soil water content. ③ Both the distance to the lake and the growth height of V.zizanioides had a significantly positive correlation (p<0.05) with the tiller number of V.zizanioides. In addition, soil temperature and water content were significantly negatively correlated(p<0.01).[Conclusion] V. zizanioides has a high survival rate in the heavily sandy land. The distance to the lake and different treatment methods can affect the growth of V. zizanioides, and V. zizanioides planting can improve the soil in sandy land.

Abstract:[Objective] To study oversea utilization of urban rainwater resources with low impact development (LID), such as in United States, United Kingdom, Germany, Japan, Singapore and Australia, in order to provide support for the development of management and technology on the construction of sponge city in China.[Methods] According to the literature review, this paper firstly analyzed the oversea experiences on LID in terms of government policies and regulations, application technologies, management system and public awareness. Then, suggestions for promoting the construction and development of sponge city in China were proposed based on the practical domestic situation.[Results] To solve the problems of urban waterlogging, water shortage and poor ecological environment during the construction of sponge city in China, we proposed a series of solutions, including making and improving relevant policies and regulations, strengthening the research development and application of advanced technologies, creating new financing resources, optimizing the management system and improving public awareness.[Conclusion] The results indicate that successful cases and experiences from oversea can greatly promote the construction process of sponge city in China.