Abstract:In the course of establishing resource saving society,environment friendly society,eco-civilization,and implementing international conventions,soil and water conservation monitoring shoulders more and more important historic missions.Some rules for soil and water conservation monitoring station distribution should be persisted in,such as fully covering typical soil erosion regions,making existed relevant monitoring stations the better,being convenient for bringing into automatic monitoring,making long-term running,and being in scientific and practical use.According to the rules,47 monitoring stations are established in different typical soil erosion regions all over the China;62 main stream monitoring cross-section stations and 55 key branch stream monitoring cross-section stations are selected in seven great river basins and the continental rivers and greater outflow rivers;and one monitoring station is established in each of the 42 state key soil erosion prevention and management regions.Long-term fixed orientation monitoring is achieved by the net of soil and water conservation monitoring stations of China,including soil erosion monitoring stations,hydrologic monitoring stations,and the monitoring stations for key prevention and management regions.

Abstract:Debris flow is a natural disaster in mountainous areas,so estimation of its criticality is substantial in regional disaster prevention and reduction.Based on system theory and the analysis of the basic situation of debris flow disaster in Miyun County,this study uses analytic hierarchy process to quantify 10 factors which affect debris flow risk degree and construct a model for debris flow risk degree assessment.In the model,the percentage of inner factors is 41.4% and the percentage of external factors,58.6%.The model is applied to assess the risk degree of local debris gullies.Result obtained has a high relativity to the real situation.The study indicates that this kind of assessment is feasible and veracious for the assessment of the debris flow risk degree.The future tasks should be the reliability research on study methods and thus provide the accurate evaluation result for users.

Abstract:Debris flow is a natural disaster in mountainous areas,so estimation of its criticality is substantial in regional disaster prevention and reduction.Based on system theory and the analysis of the basic situation of debris flow disaster in Miyun County,this study uses analytic hierarchy process to quantify 10 factors which affect debris flow risk degree and construct a model for debris flow risk degree assessment.In the model,the percentage of inner factors is 41.4% and the percentage of external factors,58.6%.The model is applied to assess the risk degree of local debris gullies.Result obtained has a high relativity to the real situation.The study indicates that this kind of assessment is feasible and veracious for the assessment of the debris flow risk degree.The future tasks should be the reliability research on study methods and thus provide the accurate evaluation result for users.

Abstract:By means of GPS measurement data in research areas and combined with GIS spatial analysis and statistical regression method,this paper validated the foreign critical relations for occurring ephemeral and gully erosion in the hilly-gully region of Loess Plateau and established the critical relations for determining ephemeral gully erosion and gully erosion areas,respectively.The research results indicated that in the Loess Plateau area,with an increase of slope gradient,the threshold values(a) for occurring ephemeral gully and gully erosion increased;and meanwhile,the high rainfall intensity caused the exponential value(b) of the critical upslope area decreased,which reduced the effect of the critical upslope area.Under the same condition,occurring ephemeral gully erosion needed less critical upslope area than that of occurring gully erosion;and with the same critical upslope area,the occurrence of gully erosion needed higher slope gradient than that of occurring ephemeral gully erosion.By using the foreign critical relations of ephemeral gully and gully erosion to draw occurring areas of ephemeral gully and gully area in loess hilly-gully region,the predicted ephemeral and gully erosion area was over-estimated.By using our establishing critical relations of ephemeral gully and gully to delineate occurring areas of ephemeral gully and gully area in the loess hilly-gully region,the predicted ephemeral and gully erosion area very matched to the actual distribution of ephemeral and gully erosion in the field.That is,ephemeral gully erosion mainly happened on hillslopes with 15°~35°,accounted for 60% of the hillslope area;and the gully erosion mainly occurred on gully slopes with more than 35°,occupied 93% of the whole gully slope area.

Abstract:Land purchase,soil and water loss,division function zones,and main body functions in Shanxi electric transmission line project were analyzed and appraised based on the soil and water conservation plan of electric transmission line project.Analyses indicated that the land purchased for the project was composed of permanent land and temporary land.Permanent land was used for tower footing area and temporary land included construction area,construction roads,and abandoned slag plots.The ratio of permanent land to temporary land was found to be 1∶9.The amount of soil erosion from construction roads was the largest,accounting for 40%~70% of the total amount of soil erosion.Therefore,construction roads were the important prevention and monitoring parts.The area for electric transmission line was divided into the plain area and the mountain and gully area by topographical features.Then they were subdivided into tower footing zone,construction yard zone,construction road zone,and abandonment slag plot zone.According to analysis,the measures in feasibility study report and the system of soil and water conservation were perfect in tower footing zone.However,the system of soil and water conservation was not designed in the temporary zone,and it should be emphasized during comprehensive prevention in the temporary zone.

Abstract:Based on the current research achievements of GPS data application,a recent advance in combining GPS technology with digital camera was applied for showing fieldwork efficiently.Firstly,a photograph was taken for the GPS screen with the GPS time on it when it established a contact with satellite.The time was compared with the digital camera's time to get the difference of the time between the GPS and the digital camera.Then,photographs were taken for the scenery on the track of field work and the position was located with GPS where the photographs were taken at the same time.With the GPS receiver,spatial information of the position,including longitude,latitude,and altitude,was recorded.Finally,the time of the photographs was edited with RoboGEO software and the time of the photographs and the GPS data were kept the same based on the difference of the two kinds of time.With the common fields of the matched time,the spatial information obtained by GPS can be endowed to the photographs.Using RoboGEO software,one can export the data in various formats,such as the JPG file with the time,and the spatial information of latitude,longitude,and altitude displaying on the photographs and written into the Exif(a standard option for most digital cameras) header.Modern digital photograph management systems such as Picasa can use date,time,and location to organize and display photographs.One can also export files of tracks with located photographs to Google Earth using the KML format.With Google Earth software,one can display the track of the field work.Multiple photographs can be opened in Google Earth software and the field work and the scenery obtained by the survey can reappear.It is also possible to edit the KML file so that the photographs and data can be stored at a central web server and made available to users world wide.

Abstract:In the construction and production processes of Shiyaodian coal mine,vegetation on the soil surface may be destroyed to a certain extent,soil structure may be significantly changed,some existing soil and water conservation facilities may be damaged,and a large number of discarded soil and dregs may be produced at the same time.In view of the existing problems of serious soil and water loss and deteriorating ecological environment in the construction and production stages,the area of disturbed primary landform,the area of land damage and vegetation destruction,the total amount of disposed soil and dregs,the damaged area and amount of soil and water conservation facilities,and the possibly increased amount of soil erosion by water and wind are predicted based on the investigation information and the analyses of related data and documents.The results of the predication can provide a scientific foundation and technical supports for rational implantation of the measures for soil and water conservation and ecological rehabilitation of Shiyaodian coal mine.

Abstract:Transportation is the industry foundation of economical development in China and is also the main force to promote economical development and social progress.In recent years,expressway has a great increase of thousands kilometers every year in China.Now the development of expressway has become one of important factors to broaden internal needs and promote the development of national economy and its importance has been recognized by governments.With the rapid development of expressway,environmental effects have also increased protrudes out from eco-environment,land utilization,hydrogeology,soil and water resources,sound environment,and production and living of residents.Through the analyses of the factors influencing social economy,nature,and eco-environment,relevant protection measures are proposed to reach the purpose of sustainable development.

Abstract:An experiment was conducted to reveal vegetation characteristics and soil properties under four different habitats in the transitional zone in south fringe of Mu Us sandy land and to explore sandy desertification status in the region.Results showed that total vegetation coverage,herbaceous coverage,and species richness were all decreased,and perennial species gradually gave place to psammophyte annuals,shrubs,and semi-shrubs from gentle slope hilly ridge,through saline bottomland and fixed and semi-fixed dune,and to shifting and semi-shifting dune.Landform units,in terms of soil water content,were in the ascendant order of shifting and semi-shifting dune,fixed and semi-fixed dune,gentle slope hilly ridge,and saline bottomland.Soil clay and silt particles,organic matter,total N and other nutrient contents decreased,while soil sand particles increased from gentle slope hilly ridge to shifting and semi-shifting dune as a whole.Changes of pH and soluble salinity concentrations had no obvious laws observed.Overall,vegetation was unstable,floristic composition was dominated by adversity-resistant species,and annual species had a higher ratio in this region.The dominant soil particle was sand and soil water and other nutrient contents were low.The eco-environment was fragile and erodible.

Abstract:Forecast of river runoff has been one of the objectives that hydrologists persevere to pursue for decades.However,because of different sources of water vapor throughout the country and the features of different rivers,using a common set of forecasting options can not give an accurate and timely prediction for flood prevention and drought controlling capabilities.Spectrum analysis is used to analyze and forecast low water runoff.Models are developed through forecasting runoff analysis of Nanming River basin in the karst area.Simulated results indicate that the forecasting of basin runoff involves in three notable low water cycles(two years,four years,and around seven years).Result from forecast can provide a basis for the economic development of Nanming Rive basin.

Abstract:On the basis of introduction to the basic theory of TOPMODEL and in view of topographic index algorithm,runoff generation mechanism,and flow confluence method utilized in the current TOPMODEL,we present an improved TOPMODEL for overcoming several problems met in watershed hydrologic modeling as current TOPMODEL is used.For investigating and examining the applicability of the model in different watershed scales and different climatic conditions,the improved TOPMODEL is applied and examined for two different typical watersheds,namely the small-scale Ziwu River watershed in humid area and the medium-scale Malian River watershed in semi-arid area,with the research focus mainly on quantitative analyses of the hydrological processes.The study indicates that the improved TOPMODEL can accurately express the spatial distribution characteristics of the important topographic parameters of real watershed and objectively describe the inner mechanism of watershed hydrological processes.The improved TOPMODEL gives rise to better testing results in small-scale humid watershed.Though a relatively lower accuracy of simulation is obtained in medium-sized semi-arid watershed,the improved TOPMODEL can still simulate and interpret the most mechanisms of hydrological processes of the watershed.

Abstract:Through field investigation on wind speed,aerodynamic roughness,rate of sand transportation,and structure of wind-sand flow on different underlying surfaces,we found that vegetation cover can effectively prevent soil erosion by wind.In comparison of the fixed sandy land of 40% vegetation coverage with the drifting sand dune without coverage,the average wind speed at the height of 0.2 m was reduced by 43%,the successive time of threshold wind velocity for soil erosion was reduced by 85%,the threshold wind velocity for soil erosion was increased by 70%,and aerodynamic roughness was increased as much as 180 times.Compared with the drifting sand dune,when the speed of wind-sand flow is similar,the rate of sand transportation on the semi-fixed sandy land was reduced by 62.33%,while fixed sandy land,by 93.07%.The results indicate that a single plant can also reduce wind speed.Two single Artemisia ordosica can reduce wind speed at the height of 0.5 m by 59.4% and 19.8%,respectively.

Abstract:Field survey and laboratory experiment were conducted to study the characteristics of soil seed bank for the grassland in a typical prairie on the Loess Plateau,such as species composition,density,spatial and temporal pattern distribution,and diversity.Results showed that there were 37 species in the seed bank,which belongs to 11 families.For the species of seed bank,Gramineae,Compositea,Labiatae,Leguminosae,and Panunculaceae were dominant.From green up stage to withering stage,the percentage of Leguminosae,Gramineae,and Violaceae decreased and however,the percentage of Compositea and Labiatae increased greatly.Density of soil seed bank increased significantly.For the vertical distribution,the number of seeds took on a decreasing trend with soil depth increasing.In terms of the level distribution of soil seed bank,landforms were in the descendant order of fenced grassland and grazed grassland;lunar slope and solar slope;and top slope,middle slope,and bottom slope.Results from the study indicated that the Margalef and the Shannon—Wiener diversity indexes of soil seed bank were higher in the enclosed grassland,and Pielou evenness index was higher in the grazed grassland.They all decreased from green up stage to withering stage.

Abstract:Soil moisture is mainly replenished by rain water in the subsided area of Shenfu-dongsheng coal field.It is a crucial factor in maintaining vegetation development.By taking Daliuta coal mine for an example,soil moisture in different slope positions and layers is studied using neutron probe.Results show that in vertical direction,soil moisture increases firstly and then decreases.By using standard deviation and variation coefficient,vertical distribution of soil moisture may be divided into the rapid change layer,active layer,and stable layer.Soil moisture in the subsided area is lower than that in the non-mining area.Soil moisture is low in June and July during observation and high in May and August.Comparing with the non-mining area,soil moisture loss at the top and bottom of slope is higher in the subsided area,while it is significantly lower at the middle of slope.Mining subsidence causes soil moisture decrease significantly.

Abstract:The distribution patterns of Tamarix chinensis population under the environmental gradient of different water table depth were analyzed using two fractal analysis methods—box dimension and information dimension.The box dimension changed little with different water table depths and kept a high dimension,which means that Tamarix chinensis population may keep a high spatial possessive degree for different water table depth.However,the information dimension in general decreased with the decline of water table depth.When water table depth was below-1.55 m,the information dimension was large,indicating that in this section of water table depth gradient,the micro-structure of Tamarix chinensis population was much complex and the pattern intensity was high.When water table depth was above-1.55 m,the information dimension was generally very small,indicating that the micro-structure of Tamarix chinensis population was very simple and the pattern intensity was low.The water table depth of-1.55 m may be a threshold of the distribution patterns of Tamarix chinensis in wetlands of the Yellow River Delta.

Abstract:Based on GIS and landscape pattern theory,dynamic landscape pattern of land use and soil and water loss in the Ertan Reservoir area of Yanbian County were analyzed using translated data from remote sensing images in 1988,1999,and 2003.Results showed that the area percentage of farmland decreased obviously,while the percentage of woodland,bush-land,and grassland increased.The patch number of farmland increased and its mean patch area and patch density decreased.The patch number of woodland decreased,its mean patch area increased,and its patch density decreased.The patch number of grassland and its mean patch area increased and its patch density decreased.The AWMSI of farmland,woodland,bush-land,and sparse forestland decreased slightly and its patch shape became simple.The AWMSI of grassland increased and its patch shape became complicated.In view of the land-level,the general characteristics of landscape pattern change were that the patch number and patch density increased,while the mean patch area and LPI decreased,indicating an increase in fragmentation degree.The CONTAG decreased,while IJI increased,implying an enhanced connectedness of landscape.Landscape diversity and relative land use rationality index increased,indicating that an improved land use structure.Soil and water loss status in the Ertan reservoir area of Yanbian county was improved greatly from 1988 to 2003.

Abstract:SWAT was applied to Xitiaoxi catchment for surface runoff simulation.The model was calibrated and verified using observed data of stream flow at Fanjiacun gauging station in 1988—2001.An efficiency of greater than 0.88 was achieved in quantifying the model's fitness with the observation.A deviation of less than 4% was found in comparison of the predicted volume of stream flow with the observed one.Rainfall-runoff relationship and water balance were analyzed on the basis of the modeling results.The outcomes indicate that rainfall-runoff relationship in Xitiaoxi catchment has no significant alteration in the simulation period.The annual rainfall precipitation varies significantly.The monthly runoff and peak storm flow in wet seasons have a tendency of slow increase,which is affected mainly by rainfall.The water balance analysis indicates that the percentages of stream flow,evapotranspiration,and groundwater recharge over the amount of rainfall are 54.1%,45.8% and 17.3%,respectively.

Abstract:Based on field experiment and comparative analysis,physical and chemical properties of soil crust at the base of the Salix gordejevii sand barrier with row spacing of 5 m and 8 m and at 2 m away from the base(for contrast) are investigated.Results show that soil is alkaline at the base of the two row Salix gordejevii sand barrier,while soil at 2 m away from the base is acidic.The soils in the 5 m and 8 m row spacing sand barriers do not have significant difference in pH value.The content of organic matter,total N,and total P at the base of the sand barrier are greater than the contrast.Compared with the base and the location 2 m away from the base,available nutrients in both 5 m row spacing and 8 m row spacing are higher and available N are lower than the contrast.Both available N and available P in 8 m row spacing sand barrier are greater than those in 5 m row spacing sand barrier.The formation of soil crust in the Salix gordejevii sand barrier is a physical process which takes sand grains as skeleton and fill soil pore space with the fine kernel(d0.02 mm).

Abstract:Soil water declining process in 0—100 cm soil layer in a sloping field after rainfall was analyzed.Results indicated that soil water redistributions for different cultivations appeared similarly and the content of soil water within 10 cm of soil surface quickly decreased after infiltration.The content of soil water in 20—60 cm soil layer increased at the beginning and then decreased.The content of soil water below 60 cm changed appreciably.Soil water redistribution was affected differently by varied cultivations.Water retaining effects of film mulching were best in ridge tillage and worst in bared field.

Abstract:This article contrasted the enclosed and unenclosed grasslands for soil water,soil nutrients,water stable aggregates,and community structure.Results showed that in grasslands,soil water active layer was 0—20 cm,and meanwhile,compensatory depths were 140 cm and 20 cm in enclosed and unenclosed grasslands,respectively.Below the depths,soil water content kept the level of 9.5% and 8.5% in enclosed and unenclosed grasslands,respectively.With soil depth increased,soil water stable aggregate content(1 and 0.25 mm) was reduced gradually and in enclosed grassland,it was greater than that in unenclosed grassland.Except the available P,the contents of soil organic matter,total N,available K,available N,NO3-—N and NH+4—N in enclosed grassland were much greater than those in unenclosed grassland.The number of species,Simpson index,Shannon—Wiener index,and Pielou index in the two grasslands were similar.The average plant height and coverage in unenclosed grassland were less than those in enclosed grassland and the differences were significant.

Abstract:Taklimakan Desert region is known as its extremely rigorous natural conditions.Soil moisture loss is very serious because of its extremely strong evaporation.Under such conditions,the shelterbelt along the Trim Desert Highway is difficult to manage and protect,so water-saving and water-keeping of shelterbelt is imperative.In this study,one new type hydrophobic polymer named Guilspare~ is used to text the inhibition on soil evaporation.Results show that Guilspare~ can limit soil evaporation and maintain soil moisture,which is of great significance in shelterbelt for it can improve soil and plant hydrological environment.Firstly,Guilspare~can reduce soil evaporation obviously.The largest inhibition amount is 21.06 mm and the initial inhibition efficiency is about 70%.Secondly,in field evaporation experiment,water content within 5 cm of soil surface is affected largely by Guilspare~ and below 5 cm,it is affected relatively less.Thirdly,after irrigation,plant water potential is reduced gradually with Guilspare~ concentration increase and hydrological environment of plant is improved better.

Abstract:Based on the topographic map of 1∶50 000,fractal dimensions and their spatial variation characteristics of 10 sub-watersheds in Dali River watershed were calculated and analyzed through the construction of digital elevation model(DEM) and by the fundamental principle of variational method and the functions of ArcGIS 9.2 Windows analysis.Results showed that the geomorphologic fractal characteristics of Dali River watershed revealed the spatial variation of topography fragmentation extend and complexity degree,with fractal dimentions increasing significantly from upper stream to down stream and the geomorphologic fractal dimension of right bank being more than that of left bank.The study is of great scientific significance to propel the application of geomorphologic fractal dimensions in the fields of geomorphology and soil and water loss.

Abstract:The construction of plant community is very important to an ecological river.The main ecological functions of river are analyzed as an important geographical element and an ecological corridor for a regional ecosystem.By assuming vegetation measures to be a positive artificial disturbance,biodiversity can be effectively improved by edge effects and corridor effects.It is proposed that in river construction,ecological functions should be taken into account.Biodiversity conservation demands on environment should be met and a steady and healthy river ecosystem should be resumed and maintained.In addition,the concepts,contents,and functions of an ecological river are discussed.The near-natural river management is considered to be an effective way to ecological river construction and vegetation measures are the main content of near-natural river management.

Abstract:Spatial distribution and correlation of soil phosphorus,inorganic phosphorus forms,and enzyme activities in loessial soil and dark loessial soil under different land uses were studied on the Loess Plateau of Gansu Province.Results showed that as the depth of soil layer increased,inorganic phosphorus decreased,as well as organic phosphorus in dark loessial soil in orchard and vegetable garden.However,total phosphorus in farmland and alfalfa land increased with increased soil depth.There was a very significantly positive correlation between soil phosphorus and organic phosphorus in 0—20 and 20—40 cm soil layers for each land use type,as well as between soil phosphorus and total phosphorus.In terms of the average inorganic phosphorus content,Ca₁₀—P,Ca₈—P,Al—P,Fe—P,Ca₂—P,and O—P were ranked in descending order.As the depth of soil layer increased,Ca₈—P,Al—P,and Ca₂—P in loessial soil decreased,but they increased in dark loessial soil in orchard,farmland,and vegetable garden.In terms of the correlation between soil inorganic phosphorus forms and enzyme activities,orchard,vegetable garden,farmland,wasteland,sea buckthorn forest,and alfalfa and tobacco lands were ranked in descending order.In terms of the correlation between soil inorganic phosphorus and soil enzyme activities,Al—P,Ca₁₀—P,Ca₂—P,Ca₈—P,Fe—P,and O—P were ranked in descending order.

Abstract:The characteristics of groundwater movement and its quality after shaft well irrigation and drainage in Hami basin,Xinjiang Wei Automous Region are analyzed by using MODFLOW and MT3DMS.Calculated results show that the shaft wells make groundwater level to decline,but salinity may exist in unsaturated zone without horizontal drainage.Salinity is enriched after a long time and thus may harm the safety of soil and groundwater when the exterior conditions change.Therefore,the monitoring system should be established to guarantee stability of regional hydrogeology and to avoid environmental disasters.Actually,how to find the balance area that can control soil salinity,groundwater salinity,and falling groundwater level is the key to keep sustainable development.

Abstract:The evaluation of land readjustment potentiality is not only a basic work during land readjustment,but also a basis for the demarcation of the key areas of land readjustment in provincial area or county area.Its accurate degree directly impacts on revising comprehensive land use planning.The evaluation of land readjustment is a complex task which is influenced by many factors.It is greatly important to develop scientific and rational indicator systems and methods for land readjustment potentiality.Taking Chongqing City as a study area,an evaluation index system which includes natural,social,and economic factors is constructed by using Delphi.The potential grade of realizable land readjustment potentiality for Chongqing City is classified by using number axis method.Finally,three key regions of land readjustment in Chongqing City are determined: Yu-northeast,Yu-southeast and Yu-west.

Abstract:Based on a comprehensive review of previous researches on ecological disturbance degree,this study aimed at watershed-scale landscape pattern on the Loess Plateau in West Shanxi Province.Watershed landscape naturalness(WLN),a new index,was introduced to describe landscape pattern characteristics,and its spatial expression on map and the methods of quantitative analysis were developed as well.Landscape of Caijiachuan watershed is composed of woodland and the patch mosaics of shrub-land,wasteland,and cropland.In the watershed,the middle part shows the highest degree of patch fragmentation,most significant heterogeneity,obvious edge-effects,and relatively even distribution of all types of patches.In the lower part,although patch fragmentation decreases,the area of natural landscape types is reduced and meanwhile the area of artificial landscape types increases.The slight edge-effects in the upper part of the watershed indicate favorable habitat and high biodiversity.From the upper to the lower part of the watershed,the ecological disturbance degree caused mainly by human activities increases and the WLN decreases gradually,while semi-natural landscape and man-made landscape show an increased trend.

Abstract:In estimating parameters of non-linear models for landslide prediction,the traditional method is to develop into Taylor series at the parameter approximate value and only obtain one item,and then handle by linear model.Because of ignoring the items of two steps and above two steps in linearization,model errorwiu occur inevitably.By introducing Gauss—Newton method and taking Saleshan landslide for an example,Gauss—Newton method is used to optimize parameters of the two non-linear models on the basis of establishing grey GM(1,1) model and Verhulst model of the landslide.Results indicate that the prediction precision of the two models after optimizing parameters is obviously higher than that of the models before optimizing parameters.So,it is an effective and feasible method for improving landslide prediction precision to use Gauss—Newton method to optimize parameters of non-linear models.

Abstract:The weighted coefficient optimization method has been applied to a small watershed management in Danjiangkou reservoir area.It gives different weighted coefficients to each objective function and changes multi-objective issue into single objective.The sound answer can be gotten through solving the single objective issue.The method not only simplifies the issue and saves time and labor,but also improves the accuracy of calculations.It is scientific and effective for a given period of time.After planning with it,in view of ecological vegetation,soil erosion can be effectively controlled,natural disasters can be mitigated,and water quality in water source areas can be purified.In view of society and economy,the purpose for farmers' income increment and people affluence may be achieved.

Abstract:Debris flow in Hongshui valley located in the upper area of Seregu hydropower station in Heishui County,Sichuan Province is studied.Based on the survey of the debris flow site,the formation conditions of debris flow and its dynamics features are analyzed and its hazard assessment is made.Results show that the material factor,rainfall factor,and physical feature satisfy the formation conditions of debris flow in the valley.The formation conditions are sufficient and the scale is medium.Its hazard degree is high and its development trend has been accelerated.

Abstract:Based on the complex nonlinear characteristics of rainfall-runoff on slope,a three-layer feed-forward back-propagation network model for runoff in different landuses(grass and shrubby slope,cutting slope and plowing slope) is established.Structure of the model has five input variables,including vegetation coverage,rainfall intensity,gradient,antecedent soil moisture content,and soil bulk density and one output variable of runoff amount from single rainfall event.The network model is validated by using the data observed from field simulated rainfall experiment.The BP network model is compared with conventional method as well.Results show that the BP network model may improve the precision of forecast.

Abstract:Soil water content at different soil depths is simulated using distributed hydrological model and crop model.Leaf area index(LAI),increment of dry matter,and grain yield are simulated respectively using the crop model,together with linked distributed hydrological model and the crop model only.Finally,the spatial distribution of grain yield in the whole watershed is simulated using the crop model linking distributed hydrological model.Results show that the accuracy of soil water content simulated by distributed hydrological model is higher than that calculated by crop model.The accuracy of winter wheat growth and grain yield simulated by the crop model linking distributed hydrological model is higher than that simulated by crop model only.The simulation of spatial distribution of grain yield is consistent with that of observed yield and statistical yield on the whole,and the distribution in high yield region and low yield region is consistent with the actual distribution,basically.The study is a fundamental trial of the application of crop model coupled with distributed hydrological model and attempts to promote the development of the research on crop model and yield forecast through incorporating distributed hydrological model into crop model.

Abstract:Express highways have been built in the loess area of Shaanxi Province.Research on plant protection for loess cutting slope of highway is one of the important problems that are being studied recently.Based on it,the main styles of plant protection for loess cutting slope of highway built and being built are analyzed and plant protection effects for the loess high-cutting slope are discussed.At the same time,the major problems existed in plant protection are analyzed so that the conclusions can be referenced for the loess cutting slope during the highway construction in other loess areas.

Abstract:Ecological footprint theory and model have been applied to calculate the ecological footprint and ecological capacity,according to the investigation on the three natural villages of Zhifanggou watershed in the loess hilly and gully region.Before the implementation of cropland conversion to forest land project,the ecological footprint was 0.991 0 hm²/cap,the ecological capacity was 0.892 6 hm²/cap,and the deficit was 0.098 4 hm²/cap(1999).After the first stage project(2007),the ecological footprint was 1.018 8 hm²/cap,and the ecological capacity and the ecological surplus had reached 1.270 3 and 0.251 5 hm²/cap,respectively.The results indicate that the cropland conversion into forest land project has given rise to sound effects.Meanwhile,the ecological footprint order for the three natural villages did not change,which was unanimous with its regional characters.Ecological agriculture with commodity economy should be developed and the relation between industry and resources should be consolidated in the watershed to realize the sustainable development in the region,according to the development process of the 3 natural villages.

Abstract:Based on the mechanism of agricultural landuse conversion at household level,the relationship between the conversion and its related factors was analyzed by using the Tobit model and 329 valid questionnaires in Tongshan City,Rudong and Changshu counties.The three investigated regions respectively represent the south,middle,and north area of Jiangsu Province.Results from the analysis showed that agricultural land conversion was greatly influenced by the participation of land market and labor market,location,endowment of households,and so on.When land market was adopted,agricultural landuse conversion tended to occur.As far as labor transfer concerned,different types of labor transfer had different influences on landuse conversion,and landuse conversion increased with the income from increased nonagricultural activities.Furthermore,these impacts showed a zonal difference.

Abstract:As the important part of water resource planning and management,water environment evaluation and forecast are of vital realistic significance to promote sustainable utilization of water resources.Using the data derived from the surface water environment monitoring of industrial park in Cangxi County,surface water environment evaluation of Diemagou River is made by applying the method of single standard pollution index.Then,the method combining complete mixing model with one-dimensional water quality model is applied to carry on surface water environment prediction in the downstream of sewage outfall of Diemaqiao River.The result of evaluation and prediction is analyzed preliminarily.At last,corresponding countermeasures for prevention and control of water pollution are presented to provide an essential scientific basis for making macro-policies of water environment and a regional economic development plan.

Abstract:With the intensification of the global shortage of water resources and drought,utilization of rain water has become a worldwide issue.In order to make a better study of the collection and utilization of rainfall so as to achieve the spatial and temporal redistribution of precipitation,the experiment adopted the method of fixed point observation and observed the outcomes by different surface processing techniques.It was found that the relation of the amount of collected rainfall to rainfall intensity was a power relationship,namely,the more the rainfall,the more the amount of collected rainfall was;and the greater the intensity of rainfall,the more the amount of collected rainfall was.The cement hardened area had a higher rate of collected rainfall with nearly zero content of silt,while the rate of collected rainfall on grassland was very low with a higher level of sediment.In fitting the curve of the relationship between the amount of collected rainfall and rainfall intensity like,it was found that with the increase in the ratio of the cement hardened area to the area of grassland,collection coefficient,increased,but rainfall index,and rainfall intensity index,decreased.In comparison of the effectiveness of the terrace crops that have or do not have irrigation measures,it is concluded that we should guide farmers to readjust industrial structure and plant economic crops for a higher economic efficiency.

Abstract:Non-point source pollution is becoming more and more serious in China with population growth and socioeconomic development.Thus,sloping lands are paid a great attention in order to gain much more products.While forest coverage decreases there,when heavy raining happens,soil erosion gets worsening.In this case,much more nutrients enter rivers and lakes which result in eutrophication.For controlling non-point source pollution from the sources,sloping land management in the headwater regions is necessary.It has been approved that contour hedgerow system is the most favorable art for soil and water conservation,which is considered as a vital measure to control agricultural non-point source pollution in practice.By implementing hedgerow intercropping,it can fix nitrogen through plants so as to reduce chemical fertilizers input,prevent soil erosion,uptake soil nutrients,and hold up pollutants.Through hedgerows,N and P are reduced by 89% and 80% respectively,which provides habitats for wildlife.Moreover,the planting techniques of hedgerows in sloping lands are also discussed such as design of the system,methods of site preparation,and type of planting,as well as tending and maintaining measures.

Abstract:Characteristic agriculture is a basic industry to empower the state and enrich the people.It produces products with striking features,including characteristic planting,breeding,and processing which is characterized by distinctive regional advantages.Moreover,characteristic agriculture has distinct regional features and may be extended nationally and internationally.In recent years,characteristic agriculture in Northern Shaanxi Province has developed quickly and conspicuously.Based on the analyses of the connotation and characteristics of characteristic agriculture,this paper discusses the general situation of characteristic agriculture in Northern Shaanxi Province and points out key feature items to be developed,such as seed cultivation,maize,fruit,vegetables,livestock product proceeding,sheep keeping,and various food crops.Lastly,this paper also comes up with the corresponding countermeasures for the further development of characteristic agriculture.

Abstract:Wetlands in Fenhe River watershed are composed of various kinds of wetland,including wetland in inland estuary,river wetland,lake wetland,reservoir wetland,swamp wetland,and meadow wetlands.The total area of the wetlands is 930.51 km².The eco-environmental characteristics of the wetlands are of broad distribution,various types,and abundant biodiversity.They are severely degraded because of human activities and other natural causes.Polluted water from mining coal,chemical engineering,and metallurgical enterprises results in the faster deterioration of wetland eco-environment.Unsuitable exploration of flooding plain and lakes causes the gradually decreased wetland area and seriously damaged vegetation of wetland.Over-reclamation of the wetlands destroys the habitat for waterfowl and over-prey and illegal hunting lead to greatly decreased biodiversity.Over-exploration of underground water and coal mining accelerate the deterioration of wetland eco-environmental functions.

Abstract:Shangzhou is located in the southeast of Shaanxi Province and characterized by widespread gullies and low mountains.It is a place where geologic hazards easily take place.Due to natural and human-induced events or processes,it is suffering from serious soil and water loss.Debris flow and ground collapse happen frequently.By investigating and analyzing the causes of geologic hazards such as landforms,soil,vegetation,water resources,and human activities,the paper gives some advices on hazard control.They are establishing a scientific prevention plan by integrated planning;strengthening vegetation protection and building an ecological Shangzhou by enhancing environment sense;enhancing management and sustainable use of lands;enhancing comprehensive rehabilitation of mining area.

Abstract:Research on the restoration and reconstruction of disturbed ecosystem has increased since the 1970s.Degradation of ecological system has been recently considered as one of scientific hot spots and public focuses.The long history of human settlement in most parts of Europe means that landscapes have become highly modified.Based on the review of the references on ecological restoration,the emphases of the study on European ecological restoration and reconstruction,including the current status of ecological restoration and constraints,are discussed in view of the ecosystem types of Europe.Ecological and socio-economic constraints,especially scientific uncertainty,are also analyzed.Some important cases of ecological restoration and rehabilitation are summarized and analyzed,including many ecosystem types such as forest,river,lake,wetland,and wasteland.Driving forces for ecological restoration in Europe are discussed,including establishment of the European Union,implementation of international agreements and national priorities,development of ecological networks,public opinion,and financial aids,etc.Lastly,the problems and development trends are discussed on European ecological restoration and rehabilitation.