Abstract:It is concluded that potential distribution of broad leaved oak forests on the loess plateau of northern Shaanxi province ends at north border of Weibei loess plateau, namely along Longxian, Binxian and Yijun,Tong chuan and Huang long county, after a comparative analysis of up-to-now research results. Soil substrates is already dried and impoverished after a serious destruction and soil erosion. However,these are not their real situation. Soil substrates may gradually get recovered through vegetation reconst ruction. Pioneer tree species should be selected at first for vegetation recover. Juvenile plantations should be modified in time after a certain period of afforestation, so that to direct them to approach potential nature forests(vegetation). Meanwhile, a system of sustainable management should be set up too.

Abstract:The reviews eco-environment management system legislation process of our country is reviewed. The universality and diversity of western eco-enviro nment are analyzes,and the inter-function of global change,human activity and western region eco-environment change is discussed.The author suggests that western eco-environment construction should lay emphasis on comprehensive management.At the same time,we should formulate national and enterprise standard of ecological restoring,complete the eco-management agency in special region,raise the scientific content of eco-environment management,complete the agricultural water used management,set up evaluating institution of ecology safety and venture in the exploiting project,ecology examination institution and village social guarantee institution,ensure the achievement of the goal of western regional eco-environment management which was set up by the country.

Abstract:There is the worst region of the eco-envi ronment in northw estern Shanxi province.Therefore,to find the key problems and ways at the right time,erosion control should be performed by planting trees and grass to construct the right environment.In the view of the present problem, a more scientific a pproach should be put forward by using suitable strategies for environmental development,changing outdated traditional customs and promoting animal husbandry.

Abstract:By statistic analysis of surveyed data of precipitation,the flood and sediment of Sanchuan river basin,the mechanism of sediment transportation is probed,and a mathematical model of precipi tation-floodsediment transportation is set up through regression analysis.This model has been successfully used to calculate the sediment and the flood reducing benefits by soil and water conservation measures in Sanchuan river basin from 1970 to 1996,the sediment and flood variation in 1990s are analyzed emphatically.Another four kinds of hydro-ana lysis methods are also been used to verify the results.A serialization method for processing precipitation data and inclination of runoff coefficient variation as w ell as the variation of riverbed erosion and deposition are also analyzed.This method can be used for reference to other branches of the middle reaches of Yellow river with rich and coarse sediment.

Abstract:According to the rate of economic development and the characteristics of geographic location and to pographic structure of Hangzhou city, the spatial distribution characteristics of soil and water loss caused by urbanization construction are analyzed.The conclusions are as follows:(1) Taking city area as a center,the influence circle zones of urbanization construction expand toward west at fan-shaped.The width of influence circle zone is narrow;(2) The terrace topographic structure and two highways divide fan-shaped influence circle zones into checked net circle zones;(3) The transition is very sudden from the good results zone of protecting environment to the concentrated zone of construction;(4) The providing zone of building materials is the main occurring zone of soil and water loss;(5) The vegetable plots of various utility ways are main potential source of soil and water loss because these vegetable plots move toward slope land step by step.

Abstract:The study was conducted to exam the impacts of the vegetation types on soil nitrogen in Ziwuling secondary forest region loca ted in the middle part of the loess plateau.It was shown that the vegetation types could exert significant effects on soil total nitrogen according to the study results.The(0-5cm)total nitrogen contents of topsoilin the permanent grassla nd,bush land and forestland are 1.4～2.5 times of that in the farmland.The total nitrogen content of topsoil in the permanent grassland is almost similar to that in the forestland,which is higher than that in the bush land and restoring grassland.The total nitrogen contents of to psoil are much higher than that in the deep soil layers,and the soil total nitrogen contents decrease with the increase of soil depth in the profile in the grassland,bush land and forestland.Grass,bush and forest can raise the soil total nitrogen contents at the depth of 0-15cm,0-25cm and 0-50cm,respectively, indicating that soil nitrogen improvement depends on the vegetation types.The study results suggest that the soil total nitrogen can be significantly improved by conversing the farmland to grassland or forestland on the loess plateau.

Abstract:Four types flow velocity are measured using electroly tepulse method while rills are formed at slope,and when it rain for 10 minutes with intensity of 50mm/h. The results show that the method is feasible to measure the velocity of sheet flow,nomatter the rill is formed or not. The velocity of flow on soil surface can be measured and may be used to explain the mechanism of rill erosion.

Abstract:The loess plateau becomes famous for serious soil erosion,which has directly influenced agricultural production and security of people's lives and properties of this area,and also influenced the development of the whole national economy.Through analyzing the origin reason of the loess plateau,the economic effects,the ecological effects and social effect of the loess plateau are appraised on basis of the policy of national conversing farmland to forest and grass land.The focal point is in terms of input and output to comparatively analyze the economic effects of conversing farmland to forest and grass land in the loess plateau that take routine seeds as an example.Thus some policies and suggestions are put forward.

Abstract:The current concerning of the populations,cultivated land resource,and the grain system in Shaanxi province are analyzed.The tendencies of the populations,cultivatedland,and the grain etc in the coming 10 years are forecasted by means of Logistics'curve.The bearing capacity of population under the different average consumption level of grain is calculated.The cause and problem of existence the system disequilibria are analyzed,and the strategic countermeasures are finally put forward.

Abstract:Since the small watershed within city is an important part of urban ecosystem,the rational planning and comprehensive harness of these small watershed within city are important way to prevent water and soil loss and to facilitate sustainable development of the city.The Qing shui stream flows through the urban area of Chongqing city,and it has the problems such as heavy pollutions and environment deterioration, which becomes the barriers of city development.Based on the definition of the conception of the small watershed within city,the comprehensive harness and environmental benefits are analysis.The result shows that the small watershed within city should be repaired by the way of ecosystem renovation,and the benefits analysis should be taken in the aspects of eco-logy,economy and society.

Abstract:The current eco-environment issues of urbanization and contradiction of developing in southeast Fujian province are studied by using geography information system(GIS).After analyzing some kinds of existing contradictions which usually accompany the urbanization,some countermeasures which are beneficial to urbanization are put forward.

Abstract:The application of RS,GIS and GPS to soil erosion fast investigation is a beneficial at tempt for the application of Hi-tech to production reality,and is also afrontier for the application study of“3S”in soil and water conservation.Soil erosion investigation is a quite complicated task.Based on the experience summary on erosion remote sensing investigation at different times,aiming at the existed technical problems in the third remote sensing investigation on soil erosion,we carry out some analyses and put forward some corresponding suggestions so as to consult with colleagues and to provide a reference for decision making.

Abstract:Saltwater intrusion a risen in the lower reaches of the Weihe river has drastically devastated the regional economy,society a nd ecological environment.Based on deeply analyzing the mechanism of saltwater intrusion and the groundwater regime regularity.The scientific monitoring method of saltwater intrusion regime and the lay out of monitoring network are probed into.Three kinds of monitoring network are constructed:(1) the monitoring network of the water resources supplies and demands;(2) the monitoring network of groundwater table and qua-lity regime;(3) the monitoring network of geophysical methods.

Abstract:The building of the land resources dynamic monitoring information system and the constructing of the two application module of land resources evaluation and soil eroding evaluation are expouded based on the 3S technology.The technology foundation,system content,designing and building of application module are introduced,and the forther progress direction of the system are expatiated.

Abstract:Land degradation is not only agreat environmental problem at present,but a great economic and social problem.It is one of the important forms of global eco-environmental deterioration,which prevents the sustainable economic development of the upper reach of Minjiang river. The land degradation status,especially the soil erosion and water losses are described,the whole area of which is 10264.69km² in 1989 and 11913.14km² in 1999,and respectively makes up 41.56% and 48.24% of the total area of the upper reach of Minjiang river.The causes of land degradation are analyzed.Based on the situation of the study area,countermeasures for land degradation control are put forward,namely,adjusting the agricultural structure,increasing the reverting from slope lands into terrace,controlling the population explosion and streng thening the legal system construction as well as the supervision.

Abstract:Method of field survey for debris flow is classified into two types:regional survey and gully investigation.Two methods are systematically discussed.Regional survey is main to collect and analyze the background material of the formation and active area of debris flow,then to disting uish the debris flow gullies.The gully investigation is main on the landforms,geologic structure,weather and hydrology,etc.of some specific debris flow gully,there form to determine the different indices needed by the control engineering design of debris flow.

Abstract:On the basis of natural resources,socio-economic status and production obstructions in Shangzhou valley-plain area,the structure of planting and breeding should be actively adjusted.The construction of level terraced field should be gone from strength to strength.Highly effective eco-greenhouse should be developed.The production of walnut,persimmon,Chinese prickly ash and Chinese herbal medicine,mushroom should be intensified.By preventing hillsides from being grazed and fuel gathered to facilitate afforestation,planting trees and grasses in barren hills.This area will be changed into an eco-economic modern villages with green mountains,clear rivers and rich people.

Abstract:Based on the investigation on and soil water loss in Xingguo county,Jiangxi province,some factors of natural and social economical causes are analyzed,the man-made social economical factor is recognized as the main factor and some points are put forth that the harness and management of watershed should be abided by ecological economical level and set forth an energy record in theory for the harness of watershed in south China and proof of land desertification in northwest China.The ecoenergy system plotted in the harnessing of water-shed could strengthen the achievement in harnessing before done and alleviate the effect by human being,so the eco-energy system is an effective method for us to control the water and soil losses in the social ecological economical system.

Abstract:Some limit factors on Hongsipu New Oasis are frequency sand blown by wind disaster,singularity planting industry structure,extrot rusible contradiction with supply and demand of water resource,low soil ferti-lity,weak emigrant economic foundation and poor knowledge with science and technology.The problems with the sustainable development on the area are analyzed from the sustainable development of five related aspects,which are the survival sustained subsystem of sustainable development,developmental sustained subsystem,environmental sustained subsystem,social sustained subsystem and intellective sustained subsystem.It is suggested that to set up the water-saving type agricultural system,and realize water resource multiaplication;to build integrated shelter belt system and mix conservative tillage system of zero tillage and minimum tillage,and to cultivated soil quickly in order to set up high yield agricultural system.Countermeasures are brought forward,which are adjustability industry structure,control population number and improvement population quality.