Abstract:A wind tunnel simulation of the characteristics of sand drift over a nylonnet barrier with a porosity of about 30%,a grass barrier,and Gobi and mobile sand surfaces has been conducted.The aim of this paper is to describe the relationship between different underlying surfaces and air current turbulence and how characteristics of the underlying surface affect the movement of wind-blown sand and the wind velocity profile in sand-laden layers.A attempt ismade to establish a theoretical base for optimizing the design of sand-control engineering in the field.This study has found that,for different underlying surfaces,there is a relationship between sand transport rate the same height above the surface at different velocities.Thus,air current turbulence can be considered as an index to determ ine the distribution of sand in the sand-laden layer and an important criterion determ ining impacts of movement.

Abstract:This investigation was conducted to estimate sand dune movement in Yulin and Jinbian areas of northern Shaanxi Province,China,Results indicate that total sand movement has been 24.433,21.147t for Yulin and Jinbian,respectively.The mean sand dune movement equates to a rate of 4.61 and 3.99m per year,but average monthly sand dune movement rates were 1.152 and 0.997m for the two locations respectively.The rates of movement occurred in Jul.follwed by Jun.,Aug.and Sep..Rates of movement depend on wind velocity,dune height,and dune length and slope ratio.The study reveals that cultivated lands extended obliquely to the direction of sand dune movement are extremely affected severely by the movement,while cultivated land segments extending parallel to the direction of movement are not affected.

Abstract:On the basis of comprehensive investigation and evaluation to the soil type,geologic and geomorphology and vegetation characteristic along the general canal of the middle line engineering of transferring water from the South to the North of China,site condition along the general canal are divided into four classes(2 site regions,4 site areas,7 site subareas,11 site types)by the main factor method.On the basis of site division,47 kinds of arbors and shrubs,and 27 kinds of protection forest space arrangement patterns are built, 38 kinds of shrubs and grasses, and 41 kinds of plants protection slope patterns are built,and all kinds of vegetation arrangement patterns are put on the different site types.

Abstract:This paper proposes that polluted water resources, increasing water shortage and inadequate science,technology and education are restrictive factors for sustainable development of the agricultural environment in Dongchnagfu County.The principles of eco-agriculture provide powerful means to abate damage to and sustain agricultural and environmental systems.These principles are to adjust measures to local conditions, to establish a cyclical and regenerative economy and to recognise the economic,social and ecological benefits of change. Elements of ecoagricultural construction include reforming farmland environments,water-farmland-forest relationships, farmland fertility and farmland structure. These changes are considered with development models for greenhouse/climate change actions,methane generation, planting and stock breeding, tourism, market vegetable farming and edible mushroom production.

Abstract:Soil in hilly regions in them iddle of Sichuan Province ismainly a type of purple soilwhich has been developed from the purple shale rock. The vegetation cover is scattered, and the steep slopes are intensively cultivated,leading to severe soil erosion.In addition,the land use pattern is very complex.The present paper introduced a conception of land block as basic unit for erosion monitoring and the potential multi-scale method for erosion assessment on different spatial scales.

Abstract:The relationship between solar activity and the width of Chinese fir grow th-rings has been analysed on the basis of wavelength.There are two periods,11 years and 6 years,for solar activity,and two periods,9～12 years,and 5～6years,for the width of Chinese fir growth-ringsin Fujian Province.The results of the study indicate a negative correlation between width of Chinese fir growth-rings and solar activity.

Abstract:Using multidimensional gray dynamic evaluation,comparisons of both static change and dynamic change on desertification control efficiency were studied in Hequ County,Shanxi Province.Meanwhile,change tendencies of land use system were estimated.And six types of change trends were divided,that is,high stable type,middle stable type,low stable type, rising type, descending type,unstable type.Results showed that the desertification control efficiency mainly shows a tendency to rise in the whole county.

Abstract:The long-term measured data of Sanmenxia Reservoir are analysed to enable consideration of the causes of water levels at Tongguan station. Measures to reduce flood heights are also analyzed. The main causes of rising water levels at Tongguan station are limited flow in the reservoir in flood season and high water levels in front of the dam in the dry season.To change the operational mode of Sanmenxia Reservoir is the most effective measure to reducing flood heights at Tongguan.

Abstract:High accuracy DEMs is an important data in study of soil erosion and terrain feature space analysis.Taking Nanxiaohegou watershed in Gansu Province,which is in the gully region of Loess Plateau as an example,and 1∶10000 relief map as an data source,the method of high accuracy DEMs and extract soil erosion index of watershed are discussed.The result shows that the terrain feature information is better and truly based on high accuracy DEMs, it is contented in the build of digital watershed at present.

Abstract:Based on preceding investigation, themonitored sample numbers on the slope of Shaanxi section on Xi'an-Nanjing railway are calculated under given reliability. Under 90% reliability and 92% estimation precision,the mean vegetation coverage and its error value is 15.81% and 1.2%, respectively.The mean soil erosion intensity and its error value are 1715.14 t/km² and 162.595 t/km² respectively under 90% reliability and 90. 52% estimation precision.

Abstract:According to the ecological factors which resulted from the ecological environment constrcution project of soil and water conservation in the loess plateau region,the monitoring stations scheme and monitoring content of every factor on the soilphysical and chem ical character,water quality,forest and grass coverage and local climatewere defined,and themonitoring method and correlation index were raised. Themonitoring results showed that the contents of soil nutrients raised and the forest and grass coverage increased,and the local climate was improved.

Abstract:The linear development and construction projects have longer distance and narrower width,and pass through multiple landform and climate strips and soil erosion regions. The characteristics of soil erosion, main monitoring objects,and methods of observation in field and questionnaire are discussed.Presently, the monitoring of development and construction projects is at the beginning.

Abstract:Sichuan Province is located in the upper reaches of the Yangtze R iver. Slope cultivated lands comprise 5.48×10⁶hm² of Sichuan Province,or 83.07% of the total area of the province. Slope cultivated lands are themain source of eroded soil and lost water.The paper introduces the type,quantity and status of slope cultivated lands, summarizes the definition of slope cultivated lands, and puts forward countermeasures to manage slope cultivated lands.Countermeasures involve farm ing skillmanagement, project management and biological management.

Abstract:The Dahaizi ground fissure,which is located in the sloping area between the Qianhe's four-step terrace and the loess tableland,is now in a phase of shifting and distortion.The physical and chemical quality of the loess is fundamental to the formation of the ground fissure.Soil water storage in the terraced fields storing have created ideal conditions for its movement.Continuous rain and rainstorms cause expansion of the ground fissure.Cutoff of foot slopes through human activity major cause of fissure expansion.Once the ground fissure forms,it contributes to the passage of surface water to the groundwater system.This disturbs the water-resistant structure of the former soil surface and enahances the potential for land sliding.Due to the risks created by fissure activity,this paper suggests that housing structures should be removed from this area,the terraced fields should be reconstructed,monitoring should be strengthened and villages should be properly planned so that damage that may be caused by fissure-related natural disaster can be relieved or eliminated.

Abstract:Based on analysis to the main causes of wind erosion in downstream area of Kezi river in Xinjiang Kaxgar river basin,the countermeasures of the comprehension ways are presented,which are the adjustment of land utilization structure,constructing sand-fixation forest to against the wind,dredging the downstream river course,irrigating forest belt by the utilization of flood water resources.

Abstract:Highway construction is very important to the economic development of Qinghai Province,but for various reasons highway construction has a serious impact on the natural environment.At the same time,the fragile environment of Qinghai Province makes highway construction very difficult.The environmental safe-guards of the highway construction system are vulnerable.We must improve the environmental safeguards by implementing effectivemeasures to reduce the environment impacts of construction.This will help achieve the goal of sustainble development of highways in Qinghai Province.

Abstract:Environmental impacts of landuse planning of Jilin Province are assessed in the course of ecological construction based on GIS.Indexes of landscape pattern and serve function value of ecosystem,and extracting the data by ArcView from the digital land cover mapping which scale is 1:100000 are used in the assessment.The types of ecological economy system in Jilin Province are divided in order to facilitate the valid use of land resources and the reasonable arrangement of agr-productivity.

Abstract:Eco-tourism attractions in Qinling National Ecological Function Zone are classified as 3 types that are forestry,mountainous and water resources respectively,and then types and integrated assessment are concluded.Based on 3-hierarchical method,tourism function zoning is analyzed including zone,district and subdistrict.Main problems on ecological environment are analyzed,and proposals of protection on biological resource,landscape resource and ecological environment in Qinling mountain are given.On the basis of the contradiction between soil erosion and ecological protection,measurements that include turning cultivated land back into forests and grasslands (TCFG),construction of ecological prediction mechanism,control of developing construction,management of zoning etc,the development of eco-tourism and environmental protection can be coordinated.

Abstract:Consideration of tree suitability is critical when selecting species for afforestation.However,tree suitability can not be clearly defined.At the same site, some tree species grow well in scattered plantings,but do not grow well in pure stands.In reality, some species may be characteristically suitable for the site but not be suitable for forestation.The authors advance here that tree suitability including for forestation should be emphasised. The tree suitability concept has been based on aims to establish woodlands of considerable area using specific forest species and structure in areas adapted to woodlands.A ccording as the principle of vegetation succession,bioecology,synecology and niche theory,it is necessary to select those species that can form stands as chief species.Such stands should be associated with companion plants to establish rational community structure.

Abstract:Evaluation of impact of soil and water conservation practices on river flow is very important in research of benefit analysis and planning of soil and water conservation.The scientific and reasonable method of evaluation is the core topic in such research.The current methods has been classified into two types and five kinds based on systemic review of various methods.Advantage and shortage of each method are distinguished. Some important suggestions are put forward together.