Abstract:The technology of remote sensing and GIS has been mainly used in the national and regional survey of soil erosion,assessment and mapping of soil erosion,and building the information system on soil erosion and conservation etc.since the late 1970s in China. The application of spatial information technology in soil conservation of China in the early 21st century will be focused on:(1) spatio-temporal monitoring the national soil erosion and conservation;(2) developing the national assessment model of soil erosion;(3) surveying the　regional soil erosion and conservation periodically and rapidly;(4) building the national management information system of soil conservation.

Abstract:The Water Erosion Prodiction Project(WEPP) watershed scale model was developed　by the USDA for soil erosion assessment and conservation planning.Serveral sensitivity　analyses and evaluation studies have been conducted for the WEPP hillslope version, but few efforts have been made to evaluate the accuracy of WEPP watershed model predictions by comparing predicted results to measured data.The purpose of this study was to give a brief introduction of WEPP watershed model and to evaluate the WEPP watershed model applicability　and prediction accuracy for smal l watersheds under different climates,topographies,soils,and manag ements.Data from 15 watersheds of 6 locations in the United States were　compared to runoff and sediment yield estimates using WEPP95.The result shows that the WEPP predicted reasonable average annual and event runoff and sediment yield with default parameter estimation procedures for most of the sites and individual watersheds.Model efficiencies for storm by storm runoff and sediment yield were quite reasonable for general conditions.The distributions of measured and predicted events were similar.This study also pointed out the potential areas for model improvement,including better and more specific silage routines,inaddition of a weed component to the plant growth and management model,and better linkage of the sediment from contoured hillslopes to the watershed channel system.

Abstract:The quantitative evaluation of soil erosion in China began in 1950s.Some empirical models for soil erosion evaluation were developed in the early 1980s And physically-based models has been developed since the late 1980s.Meanwhile,the larger regional and even national evaluations of soil erosion and conservation were made.The quantitative assessment on soil loss and conservation in China can be divided into three scales,i.e.hillslope-small catchment-region or whole nation, and two types,i.e.empirical and physically-based models.Further researches should be focused on introducting overseas models,making models to be unification and generalization,intensifying the applications of remote sensing and GIS,and developing a complete erosion model system of China.

Abstract:The principle,adaptability and the limitation on assessment methods of comprehensive benefits for catchment management in China are analyzed with the case study,the quite same results are obtained with three methods,and the future development on assessing benefits of watershed management is also proposed.

Abstract:Based on an analyses of factors affecting soil erosion and the current results from various researches of soil erosion,the precipitation during flood season,content of soil aggregates, gully density,ratio of cropland to slope area, and degree of vegetation coverage were primarily selected as the indexes of GIS-based regional erosion evaluations to construct the quantitative assessment model for regional soil and water loss.

Abstract:Soil erosion classification system including three classes was advanced based on the agents, intensities and landscape conditions of erosion.The related influential factors were interpreted and evaluated with remote sensing images.And necessary validations were made with fieldwork.The basic information of soil erosion in Xijiang was clarified and the map of soil erosion types was made.

Abstract:The methods of relative positioning,software and instruments etc.on GPS were briefly introduced, and the advantages and disadvantages on GPS position in the loess hilly area were discussed in detail on the basis of the field experiences on GPS position and an analyses on survey data in Ansai county,Shaanxi province of China.The results show that the survey precision of GPS is as high as 0.1mm on the hillslope,and is poor in the gully because of the sudden negative landform there.

Abstract:Comprehensive analysis and study on the environmental factors that affect soil and water loss and conservation are important measures of research on soil erosion mechanics,quantitative evaluation of soil erosion and investigations of their temporal and spatial characters,and they are also the important contents of constructing the foundational information engineering of soil and water loss and conservation.As the part of quick survey of regional soil erosion,the design and construction of soil erosion environmental database is discussed,and some aspects are suggested for further studies.

Abstract:Soil conservation in the 21st century demands the support of info mation technology.China Management Information System of Soil and Water Conservation,a state practical　information system,is to be built.The system will provide information service and decision-making support for decision-making and scientific management of soil and water conservation for the state and local governments through collecting and fast processing of various soil water loss data.The system will be composed of 7 subsystems as:data management,file management,decision-making support, planning and design,dynamic monitoring and information processing,computeraided decision making and data communication.The system,has the functions such as information service,computeraided decision-making on soil and water conservation,planning and design of soil and water conservation,as well as information delivering.

Abstract:With the establishment and running of market economy of China, land resources as an irreplaceable factor is increasingly becoming commercialized.It has become an important issue of the land resource management to stregthen the controls of the government over land marketing so as to achieve the purposes of making efficient and sustainable use of lands.Land Information System will be a strong supporting tool for land management and decision making.Discussions and introductions are made on the design,development and initial applications of this local government-oriented LIS.

Abstract:Design and development of Land Information System(LIS) with object-oriented OLE programming,were done with the all purpose Chinese GIS system,City star,nd RDBMS,Visual Foxproas basic supporting system.Everyeffort was made to enhance programming,to provide to tally Chinese-based Land Information System(LIS) system and to make the system be easily popularized and used in the land management practice.

Abstract:The features of erosion,sediment yield and sediment reduction by the comprehensive controlling are studied in Zhifang gully catchment.It was showed that soil erosion in most area of the catchment is lower than the medium intensity,the sediment is mainly from the waste gully slope, and the sediment reduction of the controlled catchment is evident.

Abstract:Taking Liudaogou small watershed as an example,based on simulative experiment from laboratory and field observation,attempts to establish wind erosion loss prediction model which are furthur used to estimate the amount of wind erosion loss and wind erosion modulus.It is found through the model estimation that the wind erosion modulus in Liudaogou smallw atershed is 1887.27t/(km²·a) ,corresponding to 1.25mm/a,close to the severe erosion type.If the meam erosion modulus of this area is 25000t/a,the percentage of wind erosion out of total erosion is 7.55%,and the ratio of wind erosion to water erosion is 1∶12.25.Of the total erosion,99.98% is concentrated in spring and 99.30% is concentrated in April and May.The wind erosion season is followed by water erosion season,constituting severe erosion.