According to the Law of Environment Assessment of China implemented in 2003, land use planning must conduct an assessment of its potential impacts on the environment, as to avoid the adverse environmental impacts of land use restructuring when the land use planning is implemented. For this purpose, this paper developed a procedure and proposed 11 indicators to estimate possible influences of the implementation of land use planning on the ecological security, environmental health, and land resources. These indicators cover five key aspects that may be affected by the implementation of land use planning, including ecological protection, land degradation control, arable land protection, built-up land expansion and its effects, and ecological risk of land reclamation. Further, as a case study, the procedure and indicators were applied to the China's Integrated Land Use Planning of 1997~2010, to examine the feasibility and reliability of the approach and indicators. The results of the case study show that implementation of the land use planning would greatly alleviate the environmental problems particularly of land degradation, enhance the ecosystems service functions, and improve the quality of arable land although the farmland area might decrease due to the built-up land encroachment. It concluded that the indicators can well reveal the potential effects of the implementation of land use planning on the environment, ecosystems and land resources, and thus the assessment is useful and valuable in supporting the land use planners or policymakers to sufficiently consider the environment issues in the formulation and implementation of land use planning.

This paper combines PS123 model with ordinary methods into a comprehensive model to calculate the main crops potential productivity from 1999 to 2001 in Hailun County, so as to propose a more objective and scientific method to calculate crop potential productivity. The photosynthesis potential productivity (PPP) is calculated by the equation established by HUANG Bingwei. The temperature potential productivity (TPP) and climate potential productivity (CPP) are determined by PS123 model. And land potential productivity (LPP) is calculated by multiplying an effective coefficient, which is decided by AHP approach. At the same time, based on the productivity of different levels, agricultural resources utilization assessment model is also established which is composed of productivity loss value, contented index and utility ratio. By this way it can be found the main restricting resource factors and the restricting degree to achieve the purpose of appraising agricultural resources utilization efficiency comprehensively. The result shows that in natural resources temperature restricts productivity most, then moisture condition and soil fertility condition. If TPP is regarded as the highest productivity that can be realized, then the TPPs of maize, soybean and wheat are 11998,7068 and 8813kg/hm², their resources use efficiencies are 51.0%,29.0% and 20.2％,there is still great potential on main crops in Hailun County. To improve the productivity, on the one hand, perfect farmland capital should be constructed, and fertilizer and water input should be performed to remedy the deficiency in the natural resources. On the other hand, the enthusiasm of peasants to agricultural production should be aroused, and their educational level should be improved for the easier adoption of new technology, fine seeds and the planting system and planting way should also be improved to higher resources utilization efficiency. At the same time, there still exists difference between crops in the need of agricultural resources. Following the characteristics of different crops to invest resources can distribute resources rationally to obtain higher product.

At present, the contradiction between water supply and demand has become acute in the developed and populous areas along the Yellow River, and the destruction of the ecological environment has become increasingly serious.As most essential and important element in ecosystems, water is seriously short in the upper and middle reaches of the Yellow River, and how to appraise the loss of ecological value caused by water shortage is always a complex issue.In this paper, it was attempted to assess the ecological value loss brought by water scarcity for the yellow River.Firstly, the ecological value was classified into two groups of use value and nonuse value, and the commonly used appraisal methods in China were also introduced in this paper. In case of calculation, according to the characteristics of the upper and middle reaches of the Yellow River, eco-water requirements were divided into three parts: sediment transport water requirement, basic ecological flow, and evaporation water requirement, the corresponding methods for each type of eco-water requirements were described in detail, and were calculated respectively. And then, the loss of ecological value caused by water deficit was calculated using the Market Value Method and Shadow Project Approach. The results showed that the total ecological value loss from water shortage was 5.88 billion yuan in the upper and middle reaches of the Yellow River in 2002, the biggest loss of ecological value was caused by sediment accumulation, which was 3.53 billion yuan. The losses caused by water pollution and fishery reduction were 1.55 billion and 0.8 billion yuan, respectively. Limited by the data, other losses of ecological value such as water and soil conservation, air purification, scientific study and education were not considered in this study. Finally, it was pointed out that inter-basin water transfer is an effective way to make up the ecological and environmental loss and can make a considerable ecological profit.

Land consolidation plays an important role in promoting rational land use and improving ecological environments. It produces the changes of land uses and their spatial structure to result in the changes of landscape pattern and ecological effects. Therefore, it is very important for planning and designing eco-environmental evaluation of land consolidation so as to study its landscape-ecological effects. Taking Huairou District in Beijing as an example, the changes of land use structure and landscape patterns for land consolidation are analyzed using GIS combined with method of landscape ecology in this paper. The following conclusions are drawn. The land consolidation converts most of other land uses into cultivated land, whose area is more than 70% of the project area. In this process, most of the unused land was transformed into the cultivated land, some forest land was changed into cultivated land. Whereas residential and industrial areas changed indistinctively. The number of land use patches and their density decreased by over 50%, the areas of average patch, the largest patch and the least patch increased 1.2, 0.4 and 79 times compared with those before land consolidation. However, the patch variance coefficient reduced by 24.18%. In the whole landscape, the land use patches became simple and regular, landscape edge density, shape index and splitting index decreased over 29%, whereas aggregation index slightly increased, when land consolidation has been finished. Land consolidation reduces landscape fragmentation. At the same time, it also causes decrease of landscape diversity. The Shannon's and Simpson's diversity index and evenness index reduce over 30%. Based on the characteristics of land consolidation and results of the previous researchers, the common 10 indexes of landscape effect analysis including patch level and landscape level are summarized.

Based on testing results of top-soils in the Three Gorges Reservoir District, distribution characteristics of element contents in soils were discussed by different types of parent rocks, such as mudstone and limestone. It can be concluded that, in the Three Gorges Reservoir District, the soils in the limestone areas are abundant in most of the elements, such as As,Br,B,Sb,C,F,I,Li,Mo,CaO and so on,which are more than twice the contents in soils rooting in mudstone areas. On the other hand, the soils in the mudstone districts are poor in most of the elements. Only several elements, such as Ba,P,Sr,Na₂O,SiO₂, are higher in contents than those in soils of limestone areas.The difference in elements distribution characteristics is closely related with the distribution of endemic fluorosis and Keshan disease in the Three Gorges Reservoir District. Endemic fluorosis mainly occurs in areas where soil content of fluorine is higher, which is the outcome of limestone-weathering and soil-forming process. And Keshan disease mainly happens in the lower-selenium soils areas, which is the result of mudstone-weathering and soil-forming process. Geological environmental conditions are responsible for the incidence of the endemic diseases in these areas. The research results can provide important reference to rational allocation of agriculture and rational planning of rural-urban areas in the Three Gorge Reservoir District.

Topographic index in TOPMODEL, ln (α/tanβ), is used to approximately characterize the spatial distributions of source area of surface runoff and groundwater tables in a catchment, the different algorithms utilized for computation of this parameter as well as the DEM in various spatial resolutions for such purpose can result in quite different estimations on spatial pattern and statistical distribution of the index. At present, the most widely utilized algorithm in the digital terrain analysis (DTA) method for calculating ln(α/tanβ) index is the multiple flow direction algorithm (FD8). On the basis of brief introduction to fundamental theory of FD8, a new algorithm to accurately calculate the effective contour length in the accumulated flow partitioning involved in ln(α/tanβ) computation by using internal tangent circle on conical surface method was proposed. Meanwhile the equations for calculating the cumulative upslope source area α were improved for rational computation of ln (α/tanβ) and a set of computing scheme for overcoming the noise of the abnormal grids to topographic index calculation was proposed. The new algorithm and original FD8 algorithm are both applied to two different catchments for comparison. Furthermore, we use four kinds of different resolutions (10-,20-,30- and 60-m) DEM to compute the spatial distribution of topographic index of Zhifanggou catchment. As a result, it is found that the new algorithm is more correct to express the relationship of upslope contribution area and soil water content in TOPMODEL and more accurate to reflect the hydrological similarity of real catchments. The new algorithm proposed in this paper will be useful to a certain extent to analyze watershed hydrological processes and quantify the land surface processes.

Construction land expansion is one of the notable features of urbanization.Analyzing the spatial-temporal features of construction land expansion can enhance the understanding of the nature of urbanization and provide with the grounds of decision-making for urban sustainable development. Based on the review of related research on construction land expansion at home and abroad, this paper takes Changsha urban area as an example, which is one of the most important cities in Central China.First, data on the variation of construction land in Changsha are obtained by employing the statistic and analytic function of GIS on the spatial data from remote sensing image data in different periods.Then the characteristics of construction land expansion are identified by using several methods in analyzing the spatial-temporal features of Changsha urban area from 1986 to 2004, which include expansion speed, expansion elasticity, fractal dimension, and rose map. The results obtained show that, during the last 20 years, the area of construction land has almost doubled, which is more obvious during the 2002-2004 period. Considering the relationship between the construction land area and population, the expansion speed of the construction land is far beyond that of the population, of which the erosion of arable land is most prominent. At present, the city sprawls by the way of low-density fill and the main direction of city expansion is NW270°-295° and SE165°-280°. Besides economic development and population growth, policy is also one of the important driving forces in construction land expansion. Especially in recent years, policy factor turns out to be the most determinant factor. In the future, the expansion mode of Changsha city will be that of mono-centric groups, and the direction of expansion will be more rational.

Taibai Lake, a shallow lake with a surface area of 26.1 km², is a presently algae-dominant lake and experiences obvious eutrophication. A multi-proxy analysis including diatoms, pollen, grain size, magnetic susceptibility and selected elements were applied to a 50 cm long sediment core extracted from Taibai Lake. Series of multivariables analysis such as canonical correspondence analysis (CCA), redundancy analysis (RDA) based on those proxies revealed that the minimum variables combination including Pinus percentage, sediment phosphorus, frequency-dependent susceptibility and total organic carbon percentage could explain significantly most of the variation of diatom community, which could reflect the changes of lake's nutrient status. The four proxies explained 51.5% of the diatom variance, only 6.4% less than those explained by all the sedimentary proxies, which is 57.9%. Based on the four indices mentioned above and the reconstructed historical total phosphorus concentration, four developmental phases were distinguished as follows. (1) 1800-1863AD: the earlier deforestation led to much intensive erosion, which resulted in much nutrient input. While the lake kept lower nutrient status as nutrient concentration was diluted by the sufficient precipitation. (2) 1863-1924AD: the lake was still in a mesotrophic status for the weakened human impacts. (3) 1924-1970AD: human activities became stronger and nutrient input increased. However with the flourish of aquatic plant, parts of nutrient were absorbed and consequently the nutrient concentration increased slowly. (4) Since 1970 the lake has gradually become much obvious eutrophic with the development of much stronger human activities including reclamation, fish-stocking and modern agriculture, as well as the discharge of waste water from local factories and dwellers. The four phases were also illustrated clearly by the RDA bi-axis plot, which indicated different driving mechanism for lake environmental change in different periods. The sediment records in Taibai Lake showed that human activities played an important role in the recent eutrophication process. It also concluded that lakes with higher nutrient background is much apt to become eutrophicated enforced by human activities, consequently rational management or exploitation will be necessary to protect Taibai Lake from further water quality deterioration.

Permutation entropy is a complex parameter for time series based on comparison of neighboring values, which can measure spatio-temporal complexity of weather factors, and more importantly, whose spatial pattern can get geographical explanation. Based on the climate physics elements for time series including daily temperature and daily precipitation from 1971 to 2000, this article takes southwest of Yunnan Province as a case to study the characteristic of varied atmospheric cirulations and complex landforms, measure the climate systematic complexity and probe into their geographic causes. It is concluded that it is simple and effectual to measure the systematic complexity of climate by permutation entropy. On the one hand, the spatial pattern of permutation entropy (based on daily temperature)can reflect the complexity of regional atmospheric circulation and the significance of Ailao Mountain barrier function. On the other hand, the spatial pattern of permutation entropy (based on daily precipitation)can not only indicate the direction of the water vapour sources, but also reflect regional difference of spatial precipitation variation intensity. In a word, there is a good geographical explanation of both atmospheric circulation and localized topography to climate elements.

Using a large data set gathered in household surveys conducted in Chongqing from December, 2003 to April, 2005, this paper examines some important aspects of agricultural land use under household responsibility system(HRS). The results indicate that the general trend is that the rate of land transfer is higher in the Yuxi economic corridor than in the metropolitan area, which, in turn, has a higher transfer rate than the Three-Gorges economic zone. Gradually, the mode of subcontracting has been accepted and adopted by the local farmers, and the modes of land renting and alienation in exchange of cash are beginning to appeal to some of the households. Land renting or leasing, is the chief form of land transfer in the metropolitan area, while most farm households in the Yuxi economic corridor and the Three-Gorges economic zone prefer the form of subcontracting, which does not terminate the original contract relations. The responses of land use patterns and land use environment to land transfer are noticeable in the sampling villages. Most of the transferred farmland in the metropolitan area is allotted to non-agricultural uses. In the Yuxi economic corridor and the Three-Gorges economic zone, only a small portion of the transferred land is used for non-agricultural uses and the intensiveness of land use is enhanced for most of it without major changes in land cover.The conditions of land tenure control the scope of land transfer without great inter-regional variation. The degree of development of the rural land market not only impacts the scope of land transfer in the region, but also constitutes the fundamental causes for the inter-regional variation in land transfer scope and in the evolution of transfer modes. Social security plays a decisive role in whether the farmers are willing to quit farming and in what way they will quit farming. Management of land transfer, which includes rights security management and land use management after the transfer, is essential for standardizing the behavior of the principal agents in land transfer, for reducing disputes in transfer and ensuring the smooth proceeding of land transfer according to law. Understanding the psychology of the farm households under the changing macroeconomic environment and their responses to the driving factors for land transfer is of tremendous significance to the establishment of a market law-abiding and human-oriented system for land transfer in China.

Xinjiang, the largest provincial region in China, is abundant in geological heritages. Influenced and restricted by the geological conditions and the geographical environment, the distribution of geology heritages in Xinjiang has an obvious spatial differentiation. Considering the deep fracture and the geostructure unit, which are the key factors influencing the spatial distribution of geological heritages, this thesis innovatively established the multi-level system of spatial pattern of geological heritages in Xinjiang. This system includes Altay, Zhunggar, Tianshan, Tarim and Kunlun-Altun, the 5 divisions of grade Ⅰ-- geological heritage belt; Southern Altay, Northern Altay, Western Junggar, Middle Junggar, Eastern Junggar, Northern Tianshan, Southern Tianshan, Western Tarim, Eastern Tarim, Western Kunlun, Middle Kunlun and Eastern Kunlun Altun the 13 units of grade Ⅱ-- the geological heritage area; and 35 units of grade Ⅲ-- the sub-geological heritage area. It designed 4 categories of quantitative indicators -- quantity, grade, type, protection condition, and 8 specific indicator factors -- quantity proportion and density of geological heritages, the proportion of nation and world-class geological heritages, geological heritage abundance, the average road distance from neighboring towns, the relationship with peripheral tourism resources, the proportion of protected geological heritages, the proportion of developed geological heritages. These indicators gave a comprehensive and quantitative characterizations on the spactial pattern of geological heritages in Xinjiang, and then, it was used to classify the units of Grade Ⅱ. These jobs laid the foundation of the research on the protection and exploitation of geological heritages in Xinjiang, which was based on geological heritage resources coupled with the human-land relationship. The results show that, in the cells of grade II, Northern Tianshan, Western Kunlun, Southern Tianshan, Northern Altay are identified to be excellent sites, while Turpan-Hami, Middle Zhunggar, eastern Tarim, Eastern Kunlun-Altun, Middle Kunlun, Western Tarim to be good; Southern Altay to be medium and Western Zhunggar, Eastern Zhunggar to be poor.

This article,chooses Datong city and seven counties under its jurisdiction in Shanxi province locating at the edge of the Loess Plateau and being eco-geographical sensitive region as research objects according to the long time climate survey data from 1971 to 2000, and based on the agriculture eco-climate amenity degree dynamic model established by GU Heng-yue and AI Nan-shan, and several vegetation experiments, tentatively points out eco-climate amenity degree attribution function; using which, calculates resource index,efficiency index and utilization coefficient by areas, and creatively concludes that temperature and precipitation amenity degree of Datong city and the other seven counties appear "Λ-shaped" tendency, and the peak value occurs in summer; while sunshine amenity degree of them appears "V-shaped" tendency, and the time of resource being abundant is longer, and the low value of resource amenity appears in July of every year. According to fuzzy clustering, the average efficiency index of every region by months, demarcates three types of agriculture eco-climate which are appraised respectively. The results show that the agriculture eco-climate resources of Guangling,Datong and Zuoyun counties are better, the value of C_e is between 1.5 and 2.5, especially the configuration of water and temperature resources is reasonable and the sunshine time is opulent; those of Tianzhen,Lingqiu and Yanggao counties are common, the value of C_e is between 1.0 and 1.5, water and temperature are synchronous, but the sunshine time is shorter than the former; and those of Datong city and Hunyuan county are the poorest, the value of C_e is less than 0.5, especially the sunshine time appears short throughout the year.

The assessment on regional desertification degree is very important to prevent and control desertification. However, there are some problems about the assessment method of regional desertification degree. For example, the ecological meaning of spatial distribution of different types desertified land was ignored. And the influence of spatial distribution of different types of desertified land on overall regional desertification degree was neglected. In addition, while the area of every type of desertified land in the regions assessed is equal the assessment model fails to work. Therefore, the factor of ecological meaning of land spatial distribution on different types of sand and the factor affected the regional desertification degree should be added to the regional desertification assessment methods. To solve these problems, we selected the landscape pattern index and aggregation index according to landscape ecology principle, and applied them to construct regional desertification degree assessment model through RS and GIS technology. Finally the regional desertification degree in the six counties of Hunshandake Sandy Land was assessed by applying the model. The result suggested that this method can distinguish the desertification degree in different periods. Therefore, according to the assessment result,Zhenglanqi should enhance the control of desertification,and Guyuan county and Taibus should prevent regional desertification.

The existence and extension of road networks affect adjacent landscape patterns and processes.The direct or indirect influences of ecological process caused by roads can extend from population to landscape level. Road development is a primary mechanism of fragmentation, removing original land cover, creating edge habitat, altering landscape structure and function, and increasing access for humans.Nowadays road ecology becomes a newly-emerging field in the ecologic research. Studies of the road effects on population and ecosystems were carried out in the past few years. But large scale research beyond ecosystem level has just been initiated.As series of potential ecological effects are brought out by landscape fragmentation due to road construction, it is significant to quantify the fragmentation features for management of road and its surrounding ecosystem.Meanwhile the regional ecological security attracts more and more attention as the road network expands.This paper focuses on the Lancang River valley and analyzes the relationship between ecosystem fragmentation and road construction and planning using GIS and FragStat software. By scenario analysis, the paper got the landscape change with seven road construction scenarios. The results show that the first level roads affect the largest area, next is the second level while the third level roads affect the least. The sequence of affected patch number is first level road > second level road > third level road > expressway. For the different ecosystems, the effect shows similar tendency and the area order is forest > grassland > arable land > shrub land > paddy field > construction land and patch number is arable land > forest.Scenario analysis showed that in the Lancang River valley road network development results in the increase of patch complexity and landscape fragmentation, also the trend suggests that the third level roads have larger effect on fragmentation.The average patch area decreases while the patch number and fractal dimension increase with the actualization of road construction and planning.But the expressway affects little in general. The results suggest that expressways may affect the larger ecosystem area, but they have far less effect on regional landscape fragmentation. Soil eroded area sequence is first level road > second level road > expressway>third level road and the erosion intensity mainly exhibits middle level.

As an index denoting vegetation cover, NDVI is influenced by many climatic factors such as precipitation and average air temperature. In this paper, NDVI is calculated on the basis of waveband characteristic of NOAA/AVHRR data (National Oceanic Atmospheric Administration/Advanced Very High Resolution Radiometer) for the Yarlung Zangbo River Basin. Then,the spatio-temporal change of NDVI is analyzed. The basin's NDVI is in consistency with season from 2001 to 2003. High value zone of NDVI is mainly distributed in the lower reaches and part of the middle reaches. Meanwhile, point data of principal climatic factors (precipitation and average air temperature) are interpolated to spatial grid data with Kriging method consistent with NDVI based on DEM of the Yarlung Zangbo River Basin. Then, the relation of NDVI and precipitation or average air temperature is analyzed with F checking and two-sample variance test in the basin. The result is P=0, which shows that correlation analysis has higher confidence. The linear and logarithmic correlation of NDVI and precipitation or average air temperature is analyzed at confidence level of 0.05. The conclusion is that NDVI and precipitation and average air temperature in the basin vary with seasons and are closely correlated. The linear correlation coefficient of NDVI and precipitation is 0.8, and that of NDVI and average air temperature is about 0.77. And the logarithmic correlation coefficient of NDVI and precipitation is 0.71, and that of NDVI and average air temperature is 0.7.

Coniferous forest in Helan Mountain is the relatively rare forest ecosystem in northwestern China. For the conservation of forest, the structure and floristic composition of coniferous forest have been studied. Based on principal components analysis of forest structure, mainly four kinds of forest could be obtained, that is diameter at breast height (DBH) of trees mostly less than 10 cm, DBH of trees mostly between 10 and 20 cm, DBH of trees distributed approximally equally and DBH of trees mostly greater than 30 cm. The result mainly reflected the times after prohibition of logging, and also indictated the effects imposed by altitude. Based on TWINSPAN analysis of species composition, six plant associations could be found, which were mainly influenced by altitude. The species density in spruce-moss forest was the minimum in the whole coniferous forest. Ascending from spruce-moss forest, the forest disappeared gradually and overlapped with alpine bushes and meadow, with species density increasing. Decreasing with altitude, the floristic composition changed and species density increased. Down to the lowest pine forest, the species was most abundant. The comparison of the classification of forest structure with that of species composition indicated that, though the criteria of analyses were different and the features of forest were viewed from different sides, there existed some inherent relations between foreset structure and floristic composition. The forest structure and species composition were all mainly influenced by altitude. When the forest structures were similar, several plant associations could be found, but one assicoation always belonged to single forest structural type.

Decomposition of fine roots plays an important role in carbon turnover and nutrients cycling in forest ecosystems. To date, several methods have been suggested to study the decomposing process of fine roots: (1) litterbag; (2) intact soil core; (3) minirhizotrons and so on. The method of litterbag is commonly used worldwide for researching on the process of decomposition of fine roots, and its primary disadvantage is strongly disturbing in situ conditions which may result in an underestimation of decomposition rate of fine roots. Intact soil core is another technique for researching on the fine roots decomposition. The major disadvantages of this method are laborious in sampling and different greatly among samples. Minirhizotrons is an advanced technique for studying the decomposition of fine roots, but may overestimate the decomposition rate. Therefore, the greatest challenge in study of fine-root decomposition is to design efficient experiments and develop new techniques. In this study, we applied the method of carborundum tube widely used in agriculture ecosystem into forest ecosystem to study the decomposing process of fine roots of C.carlesii, C.lanceolata(chinese fir) and their mixed samples, and compared it with the method of litterbag. The experimental site is located at Wanmulin Natural Reserve(27°03'N, 118°09'E)in Fujian province. This experiment was conducted from May 2002 to May 2004. Through two years’ experiment, the results show that: (1) fine roots of C.carlesii decomposed fastest in its community with the two decomposition methods, and its monthly decomposition rates are 0.0052(0~1 mm)and 0.0080(1~2 mm). In addition, fine roots of C.carlesii and its mixed samples decomposed in C.carlesii community show that the decomposition of 1~2 mm diameter is faster than 0~1 mm diameter; fine roots of chinese fir and its mixed samples decomposed in chinese fir plantation laws contrary. Soil condition and biochemical quality of fine roots are the main factors affecting fine roots decomposition. (2) The results of the two methods can be better fitted by Olso negative exponential equation and the fitted decomposition indicators shows small difference between the two methods. In subtropical forest ecosystems, carborundum tube method can be applied to study fine-root decomposition.

In this study, soil erosion is divided into natural soil erosion and anthropogenic soil erosion. The natural soil erosion is ubiquitous on the earth since the earth came into being. Erosive and accumulative topographic features, such as peneplain, river terrace, sedimentary basin, etc. , have disclosed the existence of natural soil erosion in the upper and middle Yangtze River since the early Quaternary. Using the thickness, dating and area of sediment deposited in the Dongting Lake, Poyang Lake and the ancient Yunmeng Lake, the specific sediment yield of the watersheds draining into these lakes is found to be 264.2t/km² · a, 312.5t/km² · a and 297.0t/km² · a, respectively. Moreover, the natural sediment yield from some experimental plots located in west Sichuan and the Three Gorge areas is estimated to be about 342.0t/km² · a and 75~270t/km² · a, respectively. Thus, the natural sediment yield ranges from 264.0t/km² · a to 342.0t/km² · a in the upper and middle Yangtze River, which is about 50%-60% of the modern sediment yield in the area. The results of this study will help us to understand the characteristics and tendency of the modern soil erosion in the upper and middle Yangtze River, and will be a sound background for realizing the goal of conserving eco-systems and building an environmental management in the area.

Soil erosion in black soil region in Northeast China leads to soil redistribution on a slope and great spatial variance in the thickness of soil humus layer. Changes of humus layer thickness will result in such physical properties variations as soil moisture and soil temperature. And soil moisture and soil temperature are important factors for freeze-thaw erosion, besides they can affect soil particles and chemical elements movement on the surface and soil profile. In order to explore the law of changes of soil moisture and soil temperature by time and depth of soil profile, two field monitoring points A and B were selected to monitor soil moisture and soil temperature simultaneously. At site A, soil humus layer is about 60 cm, and at site B, soil humus layer is about 130 cm. Soil temperature was recorded with a thermistor thermometer at eight o'clock a. m. everyday from 10 April to 14 June and twice a week from 23 January to 7 April. Soil moisture was monitored with an oven after sampling by drills. Soil moisture and temperature were measured at an interval of 10 cm from the surface to 150 cm deep on two profiles in the paper. Results show that the thickness of humus layer has significant influences on soil moisture and soil temperature. The thicker the humus layer is, the slower the rate of thaw. At site A, the rate of thaw was 2.4cm/day, however, it was 2.1cm/day at site B. Furthermore, the freeze time lags a week or so. At the same time, soil moisture of thicker humus layers is more than that of thinner humus layers in black soil region, as well as the moving extent of soil moisture is deeper. The humus layer has a great impact on the distribution of soil moisture on the profile. As a result, runoff rate during a rainstorm will occur differently from place to place because of the diversity in humus layer depth on a slope.

The source regions of the Yangtze River, Yellow River and Lancang River are located in the middle east of the Tibetan Plateau with a total area of about 198496 km². In recent years, the risk of vegetation degradation in the regions has been keeping increasing, which led to many negative effects. This study assessed the trend and temporal-spatial distribution of vegetation index change, which is related with vegetation degradation, in the source regions of the three rivers using multi-temporal NOAA AVHRR NDVI data (8 km spatial resolution) from 1981 to 2001 provided by NASA, DEM data (1 km resolution), roads, residents, rivers data (1 ∶ 250000) and collected field data. Data types converting and reclassifying and zonal statistic analysis are completed in Arcgis 9.0 software. Results show that: ①The decrease, improved and the invariant vegetation index occupied 18.92%, 13.99% and 67.09% of the whole study area respectively. ②The decrease rates of brush, needle-leaf forest, alpine meadow, alpine sparse vegetation and alpine steppes are 22.15%, 20.75%, 18.83%, 18.73% and 18.6% respectively; on the different frozen soil types, the decrease rates differ insignificantly.The vegetation index decrease rates on permafrost and seasonal-frozen ground are 19.78% and 19.41% respectively; the decrease rates are relative to the population density and livelihoods. ③The decrease rates are different in space, which in the source regions of the Yangtze River, Yellow River and Lantcang River are 13.56%, 32.51% and 18.1% respectively. ④The nearer to the roads and water sources is, the higher the decrease rates are; but to the distance buffers of the residents, the decrease rates rise with distance expending, and reach the top when arriving at the 24 km. ⑤The trend of decrease rates is according to the settlements density in different elevation zones with the correlation coefficient of 0.78. ⑥The vegetation decrease is highly related with the activities of human beings in the source regions of the Yangtze River, Yellow River and Lancang River.

By sampling along a representative section across the shelterbelt of Baotou-Lanzhou Railway at Shapotou area, grain-size characteristics of aeolian deposits in the shelterbelt and the influences of landform were studied. The total 20 sampling points covered various landform sites such as the windward and leeward slopes of sand dunes, dune crests, and inter-dune depressions.Three of which were located on the surface of a mobile dune at the upwind edge of the shelterbelt, and the other points were located in the straw checkerboard and artificial vegetation belt. The results show that clay and silt contents in surface soil increase greatly and mean grain-size decreases from moving sand area to the artificial vegetational belt due to the changes of the surface properties, and sorting becomes poor. It seems that silt contents decrease with relative height of surface in the shelterbelt; mean grain-size and sorting increase with surface height. Statistics further show that mean grain-size, sorting coefficient and silt content were well linearly related to the relative elevation. Dependence relation between clay content and landform was not observed. The possible cause is that clay material in the deposition was mainly sourced from general dust events. The influence of the landform on dust deposition is very limited. Clay sediments tend to cumulate in the shelterbelt under the protection of the straw checkerboard and artificial vegetation but hardly accumulate in moving sand area due to intensive aeolian activities. Vertically, silt content is high and sorting is poor in the surface 5 cm layer; below this depth silt content decreases and sorting becomes well. The grain-size profile varies among landforms. Estimated aeolian deposition rates around the crest of fixed dunes average 0.147 cm per year, versus more than 0.588 cm on the leeward side and in inter-dune depressions. As a whole, this study revealed the changing regulation of grain-size characteristics along the direction of NNW-SSE in the shelterbelt of Baotou-Lanzhou Railway at Shapotou area, demonstrated the relations between grain-size characteristics and landform, as well as the relations between deposition rates and landform. The results objectively reflected the effects of the landform on aeolian deposition in the shelterbelt.

Taking Pingchuan and Liuba oases in the middle reaches of the Heihe River as examples, the spatial diversification of soil moisture content in oasis and ecotone is analysed using methods of combination of field sampling with laboratory analysis. The results show that the level diversification of soil moisture content along the oasis-desert is distinct in nonirrigated areas, the soil moisture content is higher than that of ecotone and desert. The soil moisture content shows a declining trend from the oasis to ecotone and desert, that is, the soil moisture content decreases from 20% in oasis to 2.9% in the oasis-desert ecotone. Firstly, the differences of soil moisture content are mostly influenced by soil characteristics and soil texture, secondly, influenced by microclimate conditions such as level airflow near ground of oasis-desert belts where soil can transport vapor from oasis area to near desert, and thirdly, the oasis soil moisture content likely moves levelly to desert soil. The active layer soil moisture content at soil profile in the oasis shows an increasing trend from surface layer to understratum. In the range of 0~60cm, the trend of soil moisture content increases in evidence from surface layer to understratum, and the change extent is about 3.12%~21.77%. Whereas in the ecotone and desert soil profiles, the soil moisture contents in surface layer and understratum are lower than that in the middle layer of 20~30cm, this is likely related with the formation and movement of condensation water of desert soil. It is proved that there is dry sand bed in 0~20cm that has distinct restrained effect to evaporation in substrate.It is beneficial to soil moisture content maintenance in that layer. It has important ecological meaning for sandy vegetation. Because of over extracting of groundwater in the oasis and obvious impact of human activities in the ecotone, the ecological gap has been formed, constituting a threat to the ecosystem security. The changes of soil moisture content in the oasis-desert ecological ecotone reflect the extents of water utilization of human being.

The Wudinghe River Basin is a representative basin in the eolian-loess transitional zone of the Loess Plateau. Some projects actualized during the last three decades for soil and water loss has led the sediment and runoff processes of the river basin no longer being in a pure natural state but also affected by anthropogenic activities.In order to put forward effective measures to prevent soil and water loss, it is necessary to find the natural processes of sediment and runoff yield of the Wudinghe River Basin. In this work the varying processes and rules of sediment and runoff yield in the eolian and loess hilly-gully regions of the river basin were analyzed systematically according to the data measured in a certain period of time before 1970 because limited human activities had been thrown to the river system during this period. The results are as below. In the near natural state the varying ratio of discharge of the river in the eolian region is smaller than that in the loess hilly-gully region.The river sediment concentration in the eolian region is far smaller than that in the loess hilly-gully region, accordingly, sediment delivery ratio is very high in the rivers of the loess hill gully region but inappreciable in the rivers of the eolian region. The specific runoff yield of the rivers in both eolian and loess hilly-gully regions is very close, but great disparities of the specific sediment yield occur in different regional rivers: it is 118.58~725.38 t/km² · a for the eolian region and 1879.36~25112.15 t/km² · a for the loess hilly-gully region. Obviously, the tributaries located in the loess hilly-gully region are the main source of the sediment yield in the Wudinghe River Basin. So, these tributary basins are the main regions needed to prevent soil and water loss and the control of sediment yield in gullies of these tributaries is the key task.

Based on the field investigation of community plots, two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA) were applied to analyse the ecological relationships on subalpine meadow communities in Yunding Mountain, Shanxi province. It was showed that: (1)five meadow communities of 36 samples located in different altitudes were recognized by TWINSPAN and characteristics of the communities were described respectively, including distribution of dominant species and relationship with environmental factors. All results were confirmed by the two-dimensional ordination diagram of DCA.(2)The environmental variables, such as altitude, grazing intensity, moisture and heating conditions, were the major environmental factors affecting community's change. The results of DCA ordination showed that the five meadow communities had their different distributions along their environmental gradient. The first axis and the second axis of DCA reflect the gradient of elevation, grazing intensity and soil water conditions of the communities. (3) The distribution patterns of dominant species were highly similar to that of the communities. With the increase of the altitude, Kobresia bellardii, Carex lanceolata, Festuca ovina and Taraxacum mongolicum gradually took the dominant status on the communities, which showed that community distribution patterns were coordinate to the zonal vegetation distribution patterns due to the increase of elevation and the decrease of human interruption. (4)The difference in species diversity of the community had close correlation mainly to the specific evenness and grazing intensity, meanwhile, also had close correlation to the meadow habitat. Species diversity of the meadow distributing in the semi-sunny slope, semi-shady slope, shady slope and high altitude area, due to its better water supply and temperature environment, was much richer than that on the sunny slope and low altitude area. Also habitat conditions degraded because of intensive grazing. Meanwhile, species diversity plays an important role in the development and distribution of the meadow communities. (5) Grazing has an obvious interruption effect on the succession of subalpine meadow communities in Yunding Mountain, which has validated the previous researchers' opinions.

Flood disaster is still a threat in the lower Yellow River due to unusual precipitation caused by the deposit of channel, the hidden danger in the embankment and unfavorable riverbed in the lower Yellow River. Study on the embankment-break flood characteristics of the lower Yellow River can afford the scientific basis for flood disaster mitigation. According to the characteristics of the embankment-break flood in the Yellow River,flood routing characteristics of embankment-break is simulated at four different locations of the lower Yellow River by inputting terrain data, typical historical flood data and land use data of the study area to two-dimensional unsteady-state flow model. Simulated results show that: Firstly, routing flood encroach the rivers on the way and enter into the rivers after reaching the lower reaches;secondly, in the same river reach, flood submerged area of north band is bigger than the corresponding location of south bank towards the same historical flood;thirdly, it is different in flood submerged degree of different regions due to the different spatial locations of floodplain; and fourthly, the area of mainstream where flood depth is high and flood velocity is quick is relatively small, but the area of non-mainstream where flood depth is low and flood velocity is slow is relatively big. Flood disaster risk in the protected zone of the embankment will be analyzed by using the results of the simulated flood in this paper, on the basis of the simulated results, the spatial pattern of the flood disaster risk in the protected zone will be analyzed in the lower Yellow River in the future. The attempt on the simulated methods and technique of the flood routing can serve as a reference to the researches in other similar regions. In this study, some factors such as the sediment, infiltration and evaporation weren't considered, which is a limitation to research the hydraulic characteristic of the levee-breaking flood in the Yellow River. In the succeeding simulation, the sediment should be considered to research the long-term influence on the local environment of preventing flood due to the deposit of the sediment in the riverway. At the same time the surface features should the whole way be close to the reality.

This paper analyses the relationships etween the fractal dimension of soil particle size distribution, sand content, silt content, clay content and soil properties during the process of vegetation restoration in arid sand dune area. The result showed that fractal dimension of soil particle increased during the process of vegetation restoration with soil texture getting thinner and fertile.The longer the time of vegetation restored, the greater the fractal dimension of soil particle, the higher the <0.05mm content. The fractal dimensions tend to decrease with the texture coarser at the soil profile. Fractal dimension and soil texture have significant difference within different soil layers. There is a significant positive linear correlation between fractal dimension and the content of <0.05mm soil matter (p<0.0001), and a negative linear correlation between fractal dimension and >0.05mm content. So, <0.05mm content of soil particle size can be regarded as a critical diameter for determining fractal dimension which reflects the content of distribution of particle size fraction, the more the <0.05mm content, the higher the fractal dimension; adversely, the more the >0.05mm content, the lower the fractal dimension. With soil particle size getting thinner, the soil fertility changed remarkably associated with the process of sand dune stabilization. There are significant positive linear correlations between fractal dimension with all soil nutrient status (p<0.0001). Fractal dimension acts as a synthetical index. There a remarkable positive linear correlation with soil properties (p<0.0001).Therefore, the fractal dimension could be used to describe the texture and fertility states, evaluate degree of vegetation restoration in the arid sand dune area, and could be used as an integrated quantitative index to evaluate the degree of soil succession with the re-vegetation practice.

The Liupan Mountains are situated in the intersection of Ningxia Hui Autonomous Region, Shaanxi, and Gansu provinces, between 35°-36°10'N and 105°4'-106°30'E. The region is not only the transitional zone between semi-humid and sub-arid climate, but also has rich biodiversity on the Loess Plateau, even in Northwest China, with regional vegetation distributing from warm temperate deciduous board-leaved forest zone, forest-grassland zone to desert-grassland zone. Studies on the plants' floras of Liupan Mountains show that it comprises 836 species of vascular plant, belonging to 93 families and 359 genera. Its floras can be attributed to the following categories:Loess Plateau subregion, North China region, Sino-Japan forest subkingdom, and Holarctic kingdom. There are 13 distribution types and 12 subtypes of genera of seed plants, of which North temperate elements play an important role in the flora. The plant genera flora on Liupan Mountains connect closely with other floras but have little endemic genera. The floristic affinities of the study area with neighboring three mountains (Taibai, Xiaolong and Zhongtiao mountains) are close, and their coefficients of plant genera flora all exceed 60%, indicating that these mountains have similar bio-climatic conditions without any clear vicariance. While the coefficient with Helan Mountains is under 60%, because the Helan Mountains are located in arid desert and semi-desert region and it is supposed that there is intense vicariance in nature in the development of the Yellow River in Ningxia and Gansu.

Based on remote sensing images in three different years (1986, 1994 and 2002), patch-dynamics model is used to simulate the annual land use/cover change (LUCC) from 1986 to 2004 in Yuzixi catchment. Using the modeling results of LUCC, the linear regression model and multivariate nonlinear regression model are employed to analyze the relationship between runoff, rainfall and LUCC at different time scales. The results show that: (1) The correlation coefficients between rainfall and runoff at different time scales are significantly different. The coefficient at monthly scale is the largest, which is 0.807. The coefficient at daily scale is the smallest (0.311). The results also show that, at daily scale, the time lag of rainfall and runoff has to be taken into account. (2) The results of partial correlation analysis show that, at different time scales, LUCC has significant impacts on the relationship between rainfall and runoff. At yearly scale, the impact of rainfall on runoff is larger than that of temperature on runoff, while the results at monthly scale are the reverse. The relationships between runoff and LUCC in Yuzixi catchment at different time scales are also different. Only at monthly scale, the significance of partial correlation analysis is acceptable. (3) At different time scales, the modeling accuracies of multivariate nonlinear regression analysis are higher than that of linear regression analysis. The nonlinear characteristics of different factors at different time scales are different. For example, the nonlinear index of rainfall at monthly scale is the largest (8.3) and the nonlinear index at daily scale is the smallest (0.4) (runoff is the dependent variable). The nonlinear index of temperature is 2.2 at month scale and the nonlinear index is 1.6 at daily scale. The nonlinear index of resident area is 0.725 at monthly scale and the nonlinear index is 1.01 at daily scale.

Wavelet analysis, known as "Mathematical Microscope", has become a new mathematical approach in recent 20 years, being applied widely in many fields. Especially, with the significant advantage of characteristic of variable scale, it is suitable and effective enough to demonstrate the multi-scale traits of climate change, such as temporal series of temperature and precipitation. Accordingly, in this paper, Mexican Hat Wavelet is used to analyze the multi-scale characteristics of the climate change in Dari County, based on the temperature and precipitation of instrument data for 588 months during 1956~2004. Consequently, the periods and turning points of temperature and precipitation series in different time-scale are revealed, and the primary periods determined are 3 years or 4 years in a small scale and 16 years in a large scale. Meanwhile, the wavelet coefficients patterns exhibit a probable increasing trend in temperature and humidity in the following years. In the past 50 years, the temperature climbed to peak values for 3 times with the maximum at the beginning of the 21st century, and the precipitation is 2 times with the maximum in the early years of the 1980s. In general, the tendency of temperature and precipitation in Dari County is approximately consistent with that on the Tibetan Plateau and the source regions of the Yangtze and Yellow rivers except for some local lags in several periods. Changes in underdecadal scales are nested into complicated background in larger scales. The turning points varied along with the time-scale. According to the above analysis, we can conclude that there is a significant advantage of wavelet analysis in revealing the multi-scale characteristics, the primary period, and forecasting the trend of climate change in the following years.

Soil and water loss in hilly area of the Loess Plateau is affected by many environmental factors, such as climate, vegetation, soil, terrain and so on. Severe soil and water loss is also blamed to irrational land-use pattern and infeasible spatial allocation of tree, shrub and herb plants. How to adjust land use structure and how to distribute tree, shrub and herb plants over space is imperative in the Loess Plateau. In present study, four key ecological factors affecting the growth and distribution of plants were chosen, including elevation, slope degree, slope aspect and precipitation, and then a decision table was established for spatial optimum allocation of plant species. The study area was divided into five main groups and eighteen sub-groups based on multi-criterion decision analysis (MCDA) and GIS. In addition, by using cluster analysis and area statistical analysis in GIS, the main and sub-groups were distributed to specific spatial cells, and the area of each group was calculated. This article presents the following viewpoints and conclusions: (1)In order to avoid blindfold artificial plantations and grain-for-green projects, adaptability of species and plant communities to the four ecological factors was analyzed through MCDA and experts knowledge. (2)Under the condition of sticking the principle that the economic benefits, social benefits and ecological benefits are synchronistically improved, economic plants and medicinal plants were allocated to adaptable cells according to their ecological requirements. (3)The decision table showed that land with a slope of more than 15° to be shifted to forest and grassland. Meanwhile, spatial cells for natural restoration were restricted to the area with slope more than 35°, accounting for 9% of the total study area. (4)The results indicated that economic forest/agro-forestry ecosystems and the farmland/courtyard-economy ecosystems should be the two major spatial allocation models, covering 76.02% of the whole area. And the other three models covered about 25% of the whole area. Spatial allocation of plant species is not only beneficial to eco-environmental improvement, but also useful to regional planning in agriculture.