Abstract:There are three stages in the stabilization process of sand dunes, namely mobility, semi-fixed and fixed. Agriophyllum squarrosum, Artemisia halodendron and Cleistogenes squarrosa are the dominant species of communities on mobile sand dunes, semi-fixed sand dunes and fixed sand dunes, respectively. Main adaptive characteristics of Agriophyllum squarrosum include flat-shaped seeds and rapid growth of embryo roots after germination. The vigorous growth of Artemisia halodendron in semi-fixed sand dunes is promoted by positive growth reaction to sand burial promoting growth, rapid reaction to changed soil water conditions and perennial growth. Cleistogenes squarrosa is adapted to the arid conditions of stabilized sand dunes due to its (ability) to increasing root biomass.

Abstract:According to the remote sensing image information of 1998 and 2000 in Fujian Province, the changing state of vegetation species in typical districts of Fuzhou City was drawn, and it was proved that the changing of vegetation species accordes with Markov's course. The dynamic change of vegetation species of Fuzhou City in the following 50 years was predicted by Markov's model. The result indicated that the area proportion of dense woods, mixed needle leaf and broad leaf forest and bush of woods had certain increase, and the area proportion on the economic forest, grass family crops and naked land will have certain reduction. Therefore after the ecological construction for several years, the vegetation productivity of Fuzhou City from the whole aspect, will present the increasing trend and ecological environment towards good condition.

Abstract:Physical and chemical properties of soil under shrub-land and the artificial Chinese pine forest in the upper reaches of Minjiang River were studied. Results showed that the soil bulk density of artificial Chinese pine forest and the secondary shrub-land was 1.40 g/m³ and 1.01 g/m³, respectively. The soil water content under the artificial Chinese pine forest was higher than that under the secondary shrub-land. The saturated water capacity, capillary water capacity and no-capillary water capacity of soil under the artificial Chinese pine forest were 29.1%, 20.9% and 11.1%, respectively, which was 23.8%, 19.1% and 1.9% lower than that of the secondary shrub-land. The soil porosity under the secondary shrub-land was 53.0%, 21% higher than that under the artificial Chinese pine forest. The total soil nutrition content under the artificial Chinese pine forest was lower than that under the secondary shrub-land. The content of total K under the shrub-land was 181% of that under the artificial Chinese pine forest. The pH values under the two sites were 6.23 and 8.39, respectively. It is possible that the potential productivity of the soil under the artificial Chinese pine forest, which has been seriously disturbed by human activity, may be tending toward deterioration.

Abstract:An energy exchange model for soil erosion prediction has been developed around soil synthesis functions and soil erosion process factors. Model development was based on energy exchange principles and geographical information system(GIS) applications. This research is of theoretical and applied significance to soil erosion prediction, soil and water conservation, soil management, soil biodiversity management and the advancement of geographical principles.

Abstract:The variation of soil water in the process of vegetation restoration on abandoned lands in Zhifanggou, Xiannangou, Xigou and Guoyangwan watersheds of the loess hilly and gully region was studied. The results show that soil water content below 60 cm depth gradually decreases with increasing time since land was left to regenerate. Results of the soil water content evaluation for different topographies suggest: the soil water content on north-facing slopes is higher than that on south-facing slopes; the soil water content at the lower slopes of hills is higher than that at upper slopes of hills; and soil water content decreases with the increasing slope gradient. The soil water content under different types of vegetation differs: soil water content under grassland is relatively high and that under woodland is relatively low. Results for soil water content for different vegetation restoration measures suggest soil water content under natural restoration is higher than that under manual restoration. In addition, it was found that the greater the biomass, the lower the soil water content.

Abstract:Reservoir silting can be divided according to sediment dynamics into two basic types-reservoir (hydrodynamic) silting and river hydrodynamic silting, for which two types of sediment models can be constructed. The area of silting in reservoirs was estimated by measuring the area exposed during low water level periods. Statistical data was collected from 30 reservoirs through the combination of Landsat images. Silting degrees were divided into three grades: gradeⅠ, silting degree DEPDEV＜-0.3; gradeⅡ, silting degree DEPDEV=-0.3～1; grade Ⅲ, silting degree DEPDEV＞1. The results establish the characteristics of silting degrees in the larger drainage area.

Abstract:Based on a case study of the incision terrain at Ximayu, landslide erosion, forming characteristics, deformation and destruction characteristics are qualitatively analyzed. Results show that the Ximayu landslide-body is unstable. The authors constructed a geological model and a math-mechanical model, and then calculated the landslide body by means of finite elements. The result shows that stress has concentrated on the failure plane, which further supports the evidence that the Ximayu landslide is unstable and may move under heavy rainfall conditions, due to an earthquake or as a result of human activities such as slope cutting. It is suggested that engineering measurements be conducted in order to determine methods for stabilization and the prevention of further erosion.

Abstract:Land resources are the foundation of human existence. Soil erosion results in land degeneration and environmental degradation, and influences weather change. In this study, land resource condition is quantified by defining a soil erosion index in an ecotone between agriculture and animal husbandry. Applying (remote) sensing(RS)and GIS, coverages of the agricultural area and the area used for animal husbandry are put into GRID(100 m pixel resolution) and overlain. The output data are analyzed to determine type and (intensity) of soil erosion. The soil erosion background of land resource is put forward and the relationship between soil erosion and the land resource is explored. Finally, a regional analysis is undertaken.

Abstract:Cultivation of slope farmland influences surface runoff and sediment movement on slopes. This paper analyses the benefits to soil and water conservation of tillage measures, with reference to rainfall influences. The results show that: the benefit to water conservation of contour tillage is 70.56%~10.07%, with an average of 51.58%; the benefit to soil conservation of contour tillage is 76.60%~21.66%, with an average of 37.73%. In addition, the influence of tillage measures under different slope and rainfall intensity conditions is analyzed in order to demonstrate potential improvements on all slope farmland.

Abstract:Differing projects have differing effects on land resource. This paper presents analyses of four land aspect, namely land use, structure, soil type and soil erosion, in Chencang District of Baoji City. A scientific foundation is established for the effects of water supply project on these land aspects. Measures for alleviating these effects are also put forward.

Abstract:The eco-environment of the Yangtze River and Three Gorges reservoir area is severely impacted by serious soil erosion in Chongqing City. Using 1999 remote sensing information, soil erosion characteristics have been assessed and analyzed. Indices for soil erosion sensitivity evaluation have been developed, guided by five factors in the Universal Soil Loss Equation(USLE). The indices for soil erosion sensitivity are defined as none, mild, moderate and high. Also, the spatial characteristic of soil erosion sensitivity has been defined using a geographical information system(GIS). Methods for soil erosion control are discussed to promote sustainable development in the area of the Three Gorges reservoir.

Abstract:The reservoir area is subject to frequent human activities that are damaging the fragile balance of (ecosystem) dynamics. Remote sensing(RS), a geographical information system(GIS) and global positioning system(GPS) technology, as well as network techniques, have been utilized for the present research. A digital elevation model(DEM) was prepared; adjustment of orthographic reflection for images took place; interfusion of multi-source image data was undertaken; and multi-layer information was extracted. This work enabled comprehensive monitoring of soil and water conservation for the whole reservoir area from the middle 1980s to the late 1990s, and in 2000. Subsequently, the Three Gorges Project(TGP) commenced and has been ongoing for 7 years, and monitoring has included land use status, degree of vegetation cover, water loss and soil erosion(including wash erosion, mass erosion and mechanichal erosion), and their dynamic variations over the 15 year study period. On this basis, the concept of this paper has been developed with the aid of the ArcGIS software platform.

Abstract:Desertification is a serious environmental problem, particularly because desert ecosystem support sustainable development in desertified regions. Based on spatial information of vegetation in an environmental database and on associated remote sensing data and survey information, the authors analyze the spatial pattern of desert ecosystems in western China. Desert ecosystems are classified into five groups and fifteen sub-types. Their spatial distribution is related to elevation, latitude and longitude. Their spatial characteristics are then presented, along with some recommendations for combating desertification.

Abstract:The circle sliced method of analysis of earth slope stability analysis under gravity erosion is widely employed in engineering practice. However, it involves a complex calculation process, and the identification of a potential slip surface is associated with uncertainty. First, on the two dimensional section of slope, the ground surface is regressed as linear equations, while the slip surface is defined by a circle equation; then the accumulation can be substituted by integration with the equation of the Fellenus method. From this the analytical formula was derived. An alternate method for identifying the most likely slip surface is to convert the factor of safety to a function of a parameter of length t, aided by a geometric relation. If it is supposed that the first derivative of the function equals zero, it is possible to solve the equation to get the value of t. Accordingly, the minimum factor of safety and the corresponding radius of the slip circle can be defined. As differential positions for the top point and the thrust point of the slip surface were supposed, the minimum factor of safety and the corresponding slip circle can be defined.

Abstract:The IKONOS secondary planet image data depicted land use and land cover in Guanxingcha watershed in 2001. These data were analyzed and the results were contrasted to data of land use and land cover in 1982. The practice of integrated management in small watershed was evaluated objectively. Methods and experiences using the 3S technique are put forward for the investigation and survey of soil and water conservation work.

Abstract:This paper presents a GIS-based analysis of remotely sensed(RS) data for the Du'an Yao Autonomous County of Guangxi Zhuang Autonomous Region, including TM image background data and landform, land use, soil, geological and GPS　database data. An RS image integration index system for rocky desertification grades are established. A rocky desertification grade map and a digital soil map of Du'an County are presented. Finally, a connection between different degrees of rocky desertification and soil type, from the viewpoint of spatial correlation, is proposed.

Abstract:Regional ecological environment assessment provides an important foundation for drafting regional sustainable development plans and ecological environment protection measures. These are necessary because accelerating economic development in Shanxi Province is placing increasing pressure on the environment. This paper presents a feasible framework for regional ecological environment assessment based on the realities of the ecological environment of Shanxi Province. Grey comprehensive assessment is used to evaluate the quality of the regional ecological environment of Shanxi Province. Based on the framework and evaluation, some strategies for undertaking assessments are also advanced.

Abstract:Ejin Oasis located in the lower reaches of the Heihe River. The oasis has important ecological functions, including its role in protecting ecological function in the arid district of western China. In recent years, due to human activity and climate change, a series of changes have taken place in the ecological environment of the oasis. Analysis of changes in the water environment of the oasis, vegetation evolution and terrestrial ecological change has enabled proposal of ecological restoration and rehabilitation methods for Ejin Oasis. The proposals are aimed at reestablishing the natural cycles of the oasis ecosystem.

Abstract:Landform and soil conditions, farmland utilization and farmland requirement forecasts, and environmental quality in Shangluo Mountain areas are studied, and an analysis of the status of the farmland resource is undertaken. Suggestions are put forward for: improving relationships between economic development, urbanization, agricultural structural adjustment, ecological environment and farmland protection; and establishing and amplifying crucial farmland protection rules and regulations to protect Shangluo's farmland. It also proposed that more money be invested to improve the quality of the farmland in the area, in particular through economic adjustment measures and the application of comprehensive agricultural technology.

Abstract:Yanchi County is one of the most serious counties among the Ningxia Hui Autonomous Region, which desertification area is believed to occupy 39.4% of the total desertification area in Ningxia.This paper utilized Geographic Information System of the key windy-sandy region and based on the monitoring data of 1994 and 1999, to analyze the dynamic change of desertification and landuse, and study the relation between them. It also put forwards some advices for the Ningxia Hui Autonomous Region, to combat desertification in the future.

Abstract:Xi'an City's environment is a complicated system comprising three layers of environmental construction. Its development aims have not been consistent with new environmental aims. The factors restraining Xi'an in this regard are analyzed from natural and human environmental perspectives. Natural factors are found to restrict the city's development on a fundamental level, while current human factors restrict the potential for reaching ecological goals. To overcome these barriers, the authors propose an integrated suite of modifications to ideology, culture, policy and management. A model for overcoming the physical environmental restrictions is also presented in summary.

Abstract:The national compensation system provides crucial economic support for eco-environment construction and protection in western China. However, this compensation is only policy and is not safeguarded by any legal mechanism. Also, it is not integrated with a social compensation system, so it is hard to ensure that sustainable development results from the eco-environment construction and protection. The benefit of eco-environment construction and protection do not always materialize. Resolution of existing issues concerning the sources of compensation funds and the criteria and forms of compensation for the eco-environmental construction and protection in the western China are explored through consideration of the establishment and operation of the law and institutions of the national compensation system. Forms of social compensation systems for eco-environmental construction and protection are also discussed.

Abstract:During land use conversion from cropland to forest land, establishing the flexible resource between ecological system and economic system is important in order to form an integrated eco-economic system. Having considered the possibilities, the authors propose three characteristics of an integrated system, namely: defined purposes and effects of establishing an ecological system and an economic system, a steady eco-(economic) system structure and favorable feedback relationships and interrelated ecological, economic and social targets. The authors also discussed standards for constructing and integrated system and analyzed the suitability of these for Xiannan Valley Demonstrating Area.

Abstract:Based on soil erosion tests, this article analyses aspects of the problem of soil and water loss in the Yangtze River basin. These aspects include theories of soil and water loss, the basic course of soil erosion in sloping fields, the relationship between soil and water loss and river sedimentation, the basic theories of soil and water protection. Also, it is highlighted that soil and water loss in Yangtze River basin is serious, but is not strictly related to river sedimentation. The idea to "drain and protect soil" is put forward in place of the notion to "protect soil and water".

Abstract:Drought is a basic background condition necessary for the onset of desertification, while human (utilization) of land and land degradation are primary influences on the process of desertification in northwestern China. Therefore, measures to constrol land desertification should be focused on abating environmental impact of human activity, for instance population should be controlled and the carrying capacity of the land should be increased. Acknowledging existing challenges in preventing land desertification and undertaking ecological restoration, this paper presents a discussion of new thinking and management systems. The crucial problems that need to be addressed with respect to ecological environment construction are put forward.

Abstract:Soil erosion change, soil and water conservation measures and achievements, soil and water conservation organizations and environmental restoration technologies in Iceland are introduced. The driving forces of soil erosion in Iceland are vegetation destruction, livestock overgrazing, climatic intensity and volcanic eruptions. Controlling livestock grazing density and implementing environmental restoration are important measures for soil and water conservation in Iceland.