Study on the decomposition of 12 kinds of forest defoliation and the role of soil animals in Pinus koraiensisbroad-leaved mixed forest and spruce-fir of Xiao Hinggan Mountains.The method of eliminating the role of soil animals of different groups from different mesh decomposition bags was adopted.The results show that the decomposition efficiency of the defoliation is large mesh > small mesh >check, that is to say the role of large-type and middle-small-type soil animals and microorganism > the role of middle-small-type soil animals and microorganism > the role of microorganism only.The average decomposition efficiency of three years is 28.9%(large mesh), 28.2%(small mesh) and 26.2%(check mesh).By the end of the third year, the degree of decomposition of three kinds of mesh bags is 86.7%(large mesh), 84.6%(small mesh) and 78.7% (check mesh). The decomposition of latifoliate defoliation is entirely higher than conifer defoliation in three kinds of mesh bags.In latifoliate defoliation, the decomposition degree of Phellodondron amuriensis,Fraxinus mandshurica,Ulmus laciniata,Juglans mandshurica andAcer mono is the highest.But in conifer defoliation, the decomposition degree of Pinus koraiensis is the highest.From the decomposition of 12 kinds of defoliations in 3 years, the decomposition of defoliation is effected not only by large-size soil animals but also by middle-small-size soil animals, but the degree of function is different.In the prophase of decomposition, the role of soil animals was gradually increasing and the biggest value appeared in October of the second year.Subsequently, the sole of soil animals was decreasing, and the role of large-type soil animals > the role of middle-small-type soil animals.The role of soil animals is different when the kind of defoliation and the time of decomposition are different.

On the basis of taking into account the main feedback relations of carbon cycle terestrial surface system,the authors employ highly integrated and simplified methods to establish a carbon cycle zero-dimension model of land surface system (CCZDM),and study carbon fluxes among four carbon reservoirs (land biota, litter carbon, soil carbon and atmospheric carbon), by taking impact of human activities and ocean influence as external factors. The CCZDM supposes that Human Being's impacts are not enough to break the natural balance of carbon cycle before the year 1860, but since then the balance has been broken owing to the industrial revolution. A large quantity of CO 2 was emitting into the atmosphere by burning fossil fuels, intensifying agriculture and destroying segments of the vegetation cover of the earth. With the increase of atmospheric CO 2 , the global temperature increased accordingly, which, in turn , affects carbon cycle of terrestrial system. The changes of four carbon reservoirs and temperature are simulated through CCZDM from the year of 1860 to 1997 and the results show that the simulated data are compatible with observational as well as other research findings. This demonstrates that the model is reasonable and the parameter values are correct. The study of CCZDM can provide theoretical guides to that of two-dimension carbon cycle of land surface system.

In the last decades, especially since the 1980s, variations in runoff and sediment yield have occurred to the trunk stream and the tributaries of the Yellow River. As a consequence of drastic decline of runoff volume and sediment load, downstream channel shrinkage and dried up as well as disasters induced by a minor flooding event happened. In order to understand these new problems and new situations, a great deal of research work and investigations on impacts of climate and human activities on variations of runoff and sediment yield as well as variation characteristics and causes of changes were carried out in China. At present, runoff and sediment change investigations are mainly focused on studies of hydrologic method and water conservation method in the middle reaches of the Yellow River. Since the middle reaches of the river have distinct natural zonal distribution characteristics, both runoff and sediment processes in the drainage system are synthetically affected by environmental factors. Based on observational data of the controlled primary tributary from Hekou to Longmen at midstream section, this paper analyses the variations and causes of runoff and sediment load by using method of geographic environmental factors. The results indicate that runoff volume and sediment load in the Hekouzhen Longmen section of the drainage basin are closely related to the impact of geographic environmental factors. Runoff and sediment variations are a product of synthetic action of natural environmental factors and human activities. In the 1970s, runoff and sediment reduction is mainly affected by decrease of precipitation as control and management practices then are inadequate. In the 1980s, impact of human activities plays a leading role in reducing runoff and sediment load in the basin as control measures of reservoir and dam projects are effective in reducing water and silt load on the Loess Plateau. Since the 1970s, precipitation has played a less role in reducing runoff and sediment but human activities played an increasing role as a result of improvement in soil and water conservation measures. The average water and silt reduction impacted by climate fluctuation and human activities in the 1970s and 1980s is respectively 53.4%, 28.6% and 46.6% and 71.4%.

This paper reveals spatial characteristics of the recent inter provincial(municipal,regional) flow of social economic elements in China. Firstly, thepaper reviewsthe studies on the trans regional flow of social economic elements in China Then, based on the survey data,it conducts a comprehensive analysis of the spatial characteristics of the productive element flow such as the inter provincial migration, passenger railway flow, airborne passenger flow,railroad freight flow and information flow, by adopting GIS spatial analysis and visualization techniques. The spatial distribution of the inter provincial flow is influencedevidently by the provincial economic status and the pattern of inter provincial economic relations The eastern China shows its great importance on the distribution of the inter provincial flow The three economic heartlands of China, Jing Jin Tang (Beijing, Tianjin, Hebei), Hu Su Zhe (Shanghai, Jiangsu, Zhejiang) and Guangdong also act as the main centers of inter provincial flow The gravity centers of all the inter provincial flows are relatively close to the population and economic centers of China, but deviate far more from the geometric center of the territory This means the spatial distribution of inter provincial flow is basically consistent with the socialand economic situationof China Further, the paper concludes the spatialdistribution of the flow of social economic elements as four fundamental patterns, which are tested in each type of the flow and two holistic styles are deduced

Many factors affect the runoff modulus and the variation coefficients of low flow, such as climate,rock, soil, plant, landforms, and so on. In karst drainage basins, the factors of geology, topography and landforms are complicated and they affect the low flow modulus together since they influence each other and condition each other. In this paper the authors study the characteristics of low flow modulus making use of specific properties of different landforms.Firstly, landforms in karst regions are divided and digitized by means of GIS and SPSS software.All drainage basins were classified according to different types of landforms through cluster analysis in order to research the dimensions of low flow modulus in regions with different landforms types.In general,the following points are identified as: 1)the low flow modulus is smaller in regions with Fengcong landforms than Fenglin landform;2)the low flow modulus is smaller in karst regions than in non-karst regions; and 3) it is bigger in regions with mixed types of landforms than in others. Secondly, the impact of different types of drainage landform on low flow modulus are analyzed through different spatial distribution of landform types.The result is that even in karst regions with the same types of landforms,the low flow modulus would vary because of differences in spatial distribution. In a word,landform types constitute an important factor affecting low flow runoff modulus and this conclusion is essential in evaluating the value of water resource in karst regions.

Distributed erosion model is one of the effective methods to evaluate soil loss. The land patch is a key componentin establishing adistributed erosion model. Now many researchers prefer rectangle as cellsin the model. However, they had not made an agreement about the cell size. Furthermore, when the rectanglecells are employed, it is somehow difficult to keep a balance between the precision and the load of the model, because both of them are decided from the size of the cell. The larger the cellis, the more laboriousthe work is, but it is not always the case that the model will be more precise. Actually, thecellsize should be determined according tothe uniformity of the land in the region where the model is to be applied and the accuracy of the model needed. However, there is a chance that the user of the model, and even the designer of the model, have no actual image of the region, and then have no idea about what size the cell should be. Similarly, when a cell is chosen, the accuracy is not clearly presented. Zhifanggou catchment is a typical area of the hilly loess region in the Loess Plateau. Supported by GIS and SPSS, the authors got the patches of the catchment which haveuniform characters respectively, and analyzedthe statistic result of the patches' areas. It was indicated that the areas rangedfrom less than 1 m 2to almost 200,000 m 2. On the other hand, nearly 67% of the patches congregate into two groups: either below 500 m 2or between 1,000 m 2to 5,000 m 2. Accordingto the results, one can get anapproximate image of the hilly loess region and then be more reasonable to establish or usea distributed erosion model forthat region.

The fractal theory, a new study tool, has been widely applied in soil sciences in recent years. The fractal features of soil granule as well as progress made in soil science research on grain distribution, soil moisture, soil bulk capacity variance and so on are discussed. Based on the fractal theory and relative model, the fractal features of soil granule structure of forest land and different reclaimed farmland were studied in this paper. The results show that the fractal dimension of soil granule structure of forest land and different reclaimed farmland are between 2.32～2.91. The less the contents of the granule >0.25 mm and the water-stable granule, the more the fractal dimension of soil granule and the higher the soil fertility are. There exists close relationship between fractal dimension of soil granule and the contents of soil granule or water-stable granule composition in all kinds of land. The soil physical properties of forest land and different reclaimed farmland vary with the variations of the fractal dimension. The less the fractal dimension, the more the contents of >0.25 mm soil granule and the less the soil bulk density, the better the soil self-restraint capacity. The more the fractal dimension, the less the contents of >0.25 mm soil granule and the greater the soil bulk capacity, the less the soil self-restraint capacity. The results show to certain extent that man-made unreasonable land use is the main cause of soil degradation and eco-environmental deterioration.Vegetation recovery and vehabilitation as well as increase ground coverage are principal countermeasures to reduce the Yellow River sedimentation and accelerate comprehensive control of the Loess Plateau.

The vulnerability of eco-environment and its sensitivity to global environmental change characterize the transitional area of farming and pasturing in Northeast China. The moisture regime is a principal factor, by which the spatial differentiation and variation of the physiographical environment are influenced directly. The temperate and precipitation changes in the last 45 years (1951～1995) were analyzed using wavelet analysis method, mainly on the multi-scale properties and law of the changes. The result of the wavelet analysis indicates that changes of the precipitation at each sampling site were dynamic and the distribution of the relative higher and the lower period was in alternation. During the 45 years, the variation trend of the precipitation was impalpable. The temperature changed periodically but rose gradually in the 45 years. An important reflection to regional environmental change is desertification. The relation between the temporal and spatial distributions of precipitation and the plant growth also was analyzed. The result shows that the fluctuation coefficient of plant output is greater than that of precipitation. This phenomenon has a significant effect on the structure and the function of the regional system and the expansion of desertification. By using the vegetation index (NDVI), the result of comparison of land cover for two periods of time indicates that under the impact of the natural conditions and the human activities, regional change of land cover is obvious. The seasonal change of NDVI values of different vegetations shows that the correlation between monthly average NDVI and precipitation is 0.871～0.953, and the correlation between monthly average NDVI and the temperature is 0.832～0.895. For the study area, the trend of land desertification and salinization did not change at all from the 1950s to the 1990s. The vulnerable soil parent materials, strong wind force as well as concentrated precipitation and its great annual variations have effective impact on the desertification in the area. So the temperature and precipitation change is the major driving force for the land degradationand the environmental change.

The Yellow River is the Mother River of the Chinese nation literally, but it is also a disastrous river with excessive sediment that cannot be easily harnessed. The eco environment is highly vulnerable to the hazardous erosion by water and wind in the middle reaches while channel aggradation, flood menace and frequent change of course occur in the lower reaches. Although great achievements have been made in the Yellow River harnessing and resources utilization, hazards of erosion in the middle reaches and the potential failure of the channel in the lower reaches still exist and the conditions still need to be improved. It is generally accepted that solving the Yellow River problems fundamentally needs systematic considerations. The concept of the fluvial system proposed by Schumm in the 1970s provided a theoretic basis for this issue. The Yellow River system needs to be divided further into subsystems for utilizing the concept of the fluvial system to solve the problems. The Yellow River system is decoupled based on morphological and hydrological data in this paper following Schumm's theory. It meets well with the idealized fluvial system model, thus, an example of the Schumm's idealized fluvial system mode is offered. On the whole, the upper reaches up stream Hekouzhen is the water producing zone (subsystem); the middle reaches between Hekouzhen and Taohuayu section is sediment producing zone; the section from Taohuayu to Lijin is transfer zone;and downstream Lijin is deposition zone. The Yellow River system is a hierarchic structural system. Within the upper reaches of the Yellow River up stream Hekouzhen, upstream Longyangxia is the water producing subzone, the section between Longyangxia and Qingtongxia is the sediment producing subzone, and that between Qingtongxia and Hekouzhen is the transfer subzone. In the middle and lower reaches downstream Hekouzhen, the section from Hekouzhen to Longmen is the sediment producing subzone, that between Longmen and Taohuayu is the water producing subzone, and between Taohuayu and Lijin is the transfer subzone. This decoupling of the Yellow River system is not exclusive, actually, the subsystems are in the dynamic status from the long term point of view. Each subsystem has its characteristics of geomorphologic process. The subsystems from the upstream to the downstream form a cascading system by materials (water and sediment, etc.) movement and energy dissipation. The Yellow River system is also a process response system because the subsystems are closely related with the input and output of the material and energy. These subsystems need to be coupled as a whole. The coupling of the sediment producing zone (the Loess Plateau) and the transfer zone (the channel of the lower reaches) is primarily important to the Yellow River harnessing.

Being the core and frontier issue in the global environmental change and sustainable development disciplines, studies on land use/cover change (LUCC) has gained increasingly attention. China, restricted by its large population and less land, is one of the developing countries facing serious ecological and environmental problems in the world. Many problems of sustainable development confronting China have inherent and inevitable associations with LUCC. Therefore, systematic LUCC researches, aiming at the implementation of sustainable development strategies in China, have great significance in both academic and practical respects. Their relations between the problems of sustainable development and LUCC, and the research objects, contents, investigative methods and key issues of LUCC based on sustainable development in China are briefly discussed in this paper. The interrelationship between LUCC and sustainable development in China is very complex. Generally speaking,the linkage can be shown as the balance between land water resources demand and supply. Thus, the orientation and content of LUCC and sustainable development researches should be developed along with the critical issues for sustainable development driving force of human being scenarios of LUCC optimized decision making for sustainable development. Meanwhile, different situations under different temporal and spatial dimensions should be incorporated into the researches. The key issues to be studied are how to reveal the land supply and demand relationships under the multiple driving forces, as well as its changing extents and influences. Upon them, the framework of scientific decision making and comprehensive management for LUCC in China, which is confined by the sustainable development relationship between food and resources supply, ecological protection and economic growth, is proposed.

Based on social investigation material this paper analyses oasischange and its impact on Minqin Basin at the lower reaches of the Shiyang River in Hexi Corridor of western China.Furthermore,it discusses human mechanism caused oasischange in the context of human behaviorof water use and quantity balance of water use.Minqin oasischange is closely related to the expanding mechanism of traditional agriculture which can not be easily broken in a limited period of time.Howerver,if the human mechanism leading to environmental deterioration continues to exist, all human actions attempting to turn back the trend of the oasischange in the same area will have little effect. The worse trend of Minqin Oasisin the lower reaches of the Shiyang River is the process of the rapid decline of underground waterlevel, desertification, salinizification-alkalization and degeneration of vegetative cover that have greatly affected the agricultural production since the 1950s. The human factor causedthe oasischange is chiefly due to theunlimited demand of agricultural water use incited by the enlargement of farmland resulting from rapid population increase of the Shiyang drainage basin. The decrease of upstream runoff and the increase of water requirements have explained the decline of underground water level and the worsening of the underground water quality that caused the rapid salinizification and the rapid decline of the crop production,constituting one of the main reasons for farmland enlargement. All of these factors mentioned above are attributed to the degenerated vegetative cover and the disasterof the ecosystem.

Southwest China is a mountainous region. Elevation and landform (e.g.slope) are two key factors to limit the land usemode, furthermore, to influence food variety and yield. Food Yield-Estimation (FYE) by Remote Sensing is an advanced and mature technology. Because of the complicated landform and fragmentary surface of Southwest China and the limitation of Remote Sensing source, the study of FYE lags behind other regions. It is of great significance to the establishment of the FYE model in mountainousareas of SouthwestChinaboth in theoretical value and practical aspect. Anning river basin is a SN-trended intermontane basin,and the second largest food production base in Sichuan province. The authors makeuse of the combination of Remote Sensing, GIS and GPS to place point and line field samples, get the sowed area of winter wheatand establish the winter wheat yield-estimation model. The establishmentof the yield of the winter wheat is decided by factors of two aspects. One is the sowed area;the other is the per unit area yield model of the winter wheat. The acquisition of sowed area of the winter wheat is depended on the agrarian area interpreted by remote sensing and the percentage of the winter wheat. The establishment of the unit yield model is depended on the choice of the formula and the parameters used to make up the formula. There are severalkinds of factors to influence the growth condition and decide the unit yield of the winter wheat, such as climate (include temperature, precipitation, moisture, sun shine etc.), biological factor, planting method, soil potentiality, landform and so on. In these factors, the elevation and the gradient are two factors that can reflect the natural features of the winter wheat in Southwest China. The winter wheat's planting position and yield are influenced by elevation andslope. In fact, the remote sensing factor is not really a factor to decide the yield, but only the compositive reflection of other factors on the sensor. Zone division is anotherkey factor to decide the choice of the parameters of the formula and influencethe precision of the model, because different zones have different major factors to influence the yield. The selection of the formula is dependedon the mathematicmethod, the knowledge of the region's natural and economic conditions and the accumulation of experience. The precision of the model is decided by the representative of the formula and the parameters.

surface sediment samples were collected from Yuehu during November- December 1998 and August-September 1999, respectively.These samples were analyzed using a Cilas940 L Laser Analyzer and by sieving (for particles with a diameter of <2 mm and >2 mm, respectively) to obtain grain size parameters. Three grain size parameters, i. e., mean grain size(μ), sorting coefficient(δ) and skewness(sk) are then calculated by a moment method.Five main sediment types are present in Yuehu according to the sediment classification scheme proposed by Shu Gao(1993, slight modification based on Folk(1980) classification scheme). The result shows the sediment appears annular distribution and is mainly composed of fine materials: From bank to center the sediment becomes finer gradually, i.e., from gravel sand, muddy sand, sandy mud to mud in turn. Sand is only distributed on ebb delta and north-east corner of the lake. There is a close relationship between mean grain size for sediment and sediment types in Yuehu where the mud area is mostly enclosed by 6  contour. The mean grain size for sandy mud is between 6 and 4 and muddy sand is between 4 and 2. In the sand and gravel sand distributed area the mean grain size is less than 2. Sorting coefficient and skewness value for sediment in Yuehu is 2.0～2.5 and 1～2 respectively. But the sediment located over flood delta is not well sorted with the sorting coefficient value between 3.0 and 3.5. At the same time the sediment near the mouth is negatively skewed with a value of 0.5 and the skewness is near 0 in a small area to the east of the center. The two dimensional model for grain size trend analysis proposed by Gao and Collins(1992 ) is adopted to identify sediment transport pathways in the study area. The net sediment transport pathways derived by using this model show that sediment is transported from bank towards the center, except the net sediment transport pathways are not obvious over ebb delta and main channel.At the same time the result shows that the north and west part of the top of the lake, flood delta and center are deposition centers. Such patterns are highly consistent with the sediment distribution pattern. Therefore this model is applicable for such a small area as Yuehu.

This article summarizes research progress in some basic problems on paleogeographic revolution of the Tibetan Plateau in the last 50 years, especially recent decade. Based on reviews of current viewpoints and analysis of Miocene and Pliocene paleogeographies, it was suggested that altitude of the Tibetan Plateau was less than 1000m before 3.6Ma BP and intense uplift of the plateau began at that time. The ages of last three glaciations in the plateau are 725～581,289～136 and 82～10ka BP respectively, which are comparable with oxygen isotopic stages in deep sea. Large ice sheet did not exist in the Tibetan Plateau in the Maximum Glaciation of Pleistocene. Environmental changes were frequent with high amplitude and desiccation occurred in the Tibetan Plateau since the last interglacial period. Important phases and events of paleogeographic evolution in Cenozoic are: tropical and subtropical lowland controlled by planetary wind system between 38 and 22Ma BP, appearance of paleo-monsoon and development of main planation surface between 22 and 3.6Ma BP, intense uplift resulting in the formation of the modern monsoon and development of water system between 3.6 and 1.7Ma BP, entrance of cryosphere and maximum glaciation between 1.1 and 0.6Ma BP, and intense uplift and desiccation of climate in the inner plateau. Finally, some important problems need to be researched in future are suggested. It is indicated that key to breakthroughs in paleogeographical research lies in analysis of depositional basins and stratified landforms in and around the plateau, precise dating and explanation of high-resolution environmental information.

Based on social and economic statistical data, general surveys, detailed surveys and analysis as well as field surveys and investigations of land in rural areas of the Bohai Rim since the 1980s, firstly, this paper analyses the trend of cultivated land occupation inevitably related to population growth, urbanization, development of industry, development of transportation facilities and water conservancy, construction of environment, and natural disasters in the surroundings of the Bohai Sea. Secondly, it examines the position of cultivated land quantity degradation and quality improvement related to less support of farmland resources, low quality of opened up land, greater exploitation difficulty, and necessity of making intensive use of farmland in the study area. Thirdly,it puts forward measures for farmland protection such as strict management of land use, strict control of farmland occupation for construction purposes, achieving overall balance of farmland quantitatively, protection of basic farmland and cultivated land in key region, transformation of middle low yield farmland, controlling of groundwater exploitation, protection of farmland eco environment, and adjustment of agricultural structure in the surroundings of the Bohai Sea. Fourthly, it discusses land increment potentials and ways of exploitation related to policy of land use management, farmland and village consolidation for sustainable land use, land reclamation and land exploitation in Bohai Rim.

In view of sustainable land use, the frequencies, characteristics and reasons of drought are studied in red earth hilly area of southern China. The intensity of drought restricting to land use and its temporal and spatial variations, relation between the pattern of land use and the degree of drought as well as measures taken to control drought are dealt with in this paper. Yujiang County of Jiangxi Province was chosen for a case study, the regional drought was assessed by using quantitative methods such as Zi index, coefficient of variation and departure value of precipitation. High frequency and types of drought in the hilly area are distinguished during the period 1951 to 2000. Compared to the case of northern China, the degree of drought was more tiny and alleviated. Drought restricts the three dimensional distribution of landuse and consumably occupies cultivated land resource. Restricting strength index (K) was used to quantify the effect of drought on the restricting degree of agricultural land. Taking a very drought year, the results indicated the K value of the effect of drought on paddy rice is 0.08～0.11, belonging to low restricting strength;that on the dryland is 0.46, high restricting strength; and on farmland for comprehensive evaluation is 0.21, moderate restricting strength. The reasons of drought in red earth hilly area are becauseof the seasonal change of atmosphere circumfluence in eastern China, lower availability in soil moisture,inappropriate human activities and lack of socio-economic ability in combating drought. The regional drought has a high tendency as the human-controlling factors change their condition. Such measures to alleviatethe drought should be taken as follows: (1)including seepage control of dykes several hundred kilometers long in the area, intensification of canalized irrigation networks and development of mini electromechanical irrigation project in hummocks; to perfect irrigation canal system and expand irrigated area by diverting other water resources;(2) to construct small scale water storage ponds in remote and high hummocks; (3) to popularize water-saving agricultural techniques such as intercropping forest and grain plant straw mulching technique, drought-resistant crop(e.g. peanuts)selecting, terracing and scale pitting; (4) to control strictly dryland development in the area and return part of cultivated land to forest on north-south hummocks; and (5) to increase appropriately the ratio of land used for construction and optimize the structure of landuse.

Zhangshiyan of Hebei Province is a national tourist scenic spot. It has many strange, perilous, graceful and beautiful geomorphic types. They were formed since 37 MaB.P., and experienced three major geomorphic cycles during the Early Tertiary, the Late Tertiary and the Quaternary eras and left many geomorphic types of different evolutional stages of infancy, youth, maturity and old age. The major evolution patterns were strong tectonic uplift, collapse, side and headward erosion, and raze. The rocks of sandstone and limestone also played an important role in landform evolution. The predominant geomorphic evolution situation in future will still be infancy stage to youth stage for a long period of time. But as tourism developed, the strange and beautiful scenic spots of maturity stage development level are more liable to be destroyed by tourists. So, how to prevent these geomorphic types from being destroyed is a pressing issue.

It is difficult to monitor growing crops in a large scale. There isn't, up to now, a satisfied method to know what the way a crop is growing and how can get accurate yield estimations of the growing crops, which scientists have been intending to probe into. Remote sensing was used to monitor growing crops in North China and Northeast China. However, in arid land of Xinjiang in Northwest China, this method has not been used because of special geographical environment. In this paper, the researched subject is the winter wheat planted on the northern slope of Tianshan Mountains. A new method to monitor growing crops was experimented supported by modern spatial technology which integrated remote sensing, geographic information system, global positioning system, and other measures such as intensive ground surveys and the analysis for the situation in its history, in order to obtain more exact results. Geographic information system and global positioning system were properly integrated by GVG sampling system for the purpose of monitoring crop growth with the support of GVG system. Field investigations for the growth of winter wheat has been carried out and the database for yield evaluation has been built, which will be not only used to analyse the growth of crops, but also used to estimate the crop yieldmore exactly by contrasting the result from remote sensing imageries with information from intensive ground surveys. Three methods were used in estimating crop yield: remote sensing aided by GIS, field investigation and analysis for historic yield. It was showed that crop growth monitoring and yield estimation using this integratied method is practical, which should be extensively applied in arid land in Northwest China.

The West Liaohe River Basin is located to the east of Inner Mongolia of China and lies approximately between 117°00′～123°30′E and 42°00′～45°00′N. This region is a transitional zone of forest, forest steppe and steppe. According to researches on many archaeological sites of middle Holocene found in this region, wild pig ( Sus scrofa ) occupied a dominant position in the wild herbivores, and the bones of David's deer( Elaphurus davidianus ) was found in individual site.Wild pigs normally dwell in coniferous forest and mixed coniferous and broad leaved forests.This means forests played an important role in vegetation in middle Holocene in this region. And in the beginning of the Christian Era, wild horse ( Equus przewalskii ) was the main local product. This means that the steppe might have expanded. But in the Medieval era (during the beginning of the 10th to the beginning of the 12th century A.D.), the nomadic Qidan nationality established powerful Liao Dynasty, and there were a lot of documents about the West Liaohe River Basin. During this period, the David's deer( Elaphurus davidianus ) was recorded by many travelers, but however,no record of wild horse could be found in all historical documents during this period. This means that the forests had been expanded. And in the beginning of the Qing Dynasty (the 17th century AD), the wild horse was recorded as one of the local products. This means that the steppe could be expanded, and the forest reduced. And before the mid Qing Dynasty (the 18th century AD), tiger, beer and leopard were extensively distributed.However, after the mid Qing Dynasty, especially after the end of the 19th century, tiger and leopard became less and less and could not be found in any historical documents. The changes of animal geography before the 18th century were the result of natural changes, because the population was very sparse during this period of time. However,the changes of animal geography after the 18th century were induced by human activities, because the agricultural population migrated massively from the Yellow River Basin to the West Liaohe River Basin plus rapid population growth after the mid Qing Dynasty.This resulted in forest reduction and steppe expansion.

This paper systematically discusses the impacting factors on human height development from fetus to adult and the future trend. The results show that development of body's height is progressing according to certain time series, and it is the function of time. The stature of fetus increases with the month age, which has no obvious difference in various regions and from various mother's bodies.However, the heights of newborn babies have no clear difference in different regions and sex, and there are statistical differences between city and countryside. The clear difference of body's stature between city and suburb appears from infancy to preschool period,and this kind of difference will last to adult period. These indicate that spatial environmental factors and socio-economic factors are mainly factors affecting body's stature after newborn period. The impact of spatial environment on body's stature is an extensively diverse factor which has many meanings and can be controlled, which includes the effects of natural environment and social surrounding. With the development of socio-economy, there is increasing effect of social environment on body's height and weight, which brings a series of social medical and public health problems. It has theoretical and practical importance on development of human physique (including body's stature and weight) to study the relation between spatial environmental factors and body's stature.

Research on grain size of seashore loess in Liaodong Peninsula indicates that kind of loess was the product of frigid climate in Quaternary ice age Due to geographical locations adjacent to coastal zone, the loess has distinctive formation process compared with loess in other areas Divulged alluvium and sands of Bohai seabed in the last glacial period constitute another important material source of this loess which are transported by sand saltation mode Grain size of this seashore loess bears a great deal of formation about changes of Bohai sea level Sedimentary process of this seashore loess is controlled by two factors, which are wind power and Bohai sea level's fluctuation in the last glacial period Wind deposits derived from adjacent source of materials make grain size distribution of this loess from normal to abnormal Goodness of fit of grain size distribution and 2 3Φ size percentage content reflect history of transgression and regression of Bohai Sea and strong and weak Mongolian high pressure of the last glaciation. These changes are identical with paleo environment reflected by sporo pollen assemblage, and also corresponding to sea leeventsl changes in the neighbouring areas and stage of δ 18 Ο/ 16 Ο Goodness of fit of seashore loess grain size distribution is a major substitutional index of paleo environmental changes Heinich events are recorded in Rosin's grain size distribution There are 5 high values of goodness of fit of Rosin's grain size distribution in profile of this seashore loess These events of high values occurred in transgression period of Bohai Sea during early and later phase of the last glacial period, and are records of extreme cool events which occurred during the last glacial period It is difficult to compare these events with Heinich events due to limitations of precision of chronological orders

Based on the statistical data at provincial and county levels from 1949 to 1998, the dynamic change of grain production and regional differences are discussed In the last 50 years, the total grain production took on an increasing trend on the whole In the period of 1949～1998, the total grain production increase was 24480 thousand tons with an annualaverage increase of 489 6 thousand tons and the per capita grain production increase was 320 8 kilograms Because of the differences in natural conditions and agricultural history, the spatial difference in grain production increase is very notable The regions with higher annualaverage increase rate of grain production are mainly distributed in the piedmont plains where irrigation conditionsand agricultural base are better such as Shijiazhuang, Handan, Xingtai, Baoding. However, the regions with lowre annualaverage increase rate of grain production are mainly located in the mountainous and hilly areas such as Zhangjiakou, Chengde and the easternplain with poor naturalconditions According to the grey systemtheory, factors affecting grain production are analyzed and correlative degree between factors and grain production is quantitatively measured The results show that per unit area grain yield, effective irrigated area and grain sown area are the most important factors that affect grain production Moreover, the countermeasures to realize the sustainable development of grain production are discussed such as relying on scientific progress to increase per unit area grain yield, protecting arable land and stabilizinggrain sown area, popularizing technology of intercropping and improving multi crop index, strengthening capital constructionof farmland and enhancing the synthetic ability of agricultural production This paper provides a scientific basis for sustainable agricultural development in Hebei Province

In recent years, sandstorm weather and its impact on environment and human health has attracted more and more attention. Researches on related domain have shown that desertification of arid and semi-arid regions has provided rich source for the formation of sandstorm weather. For this reason, to protect the large eco-environmental vulnerable area in North China from being desertified or degraded and to slow down the desertification process of the said area have become highly important and meaningful in practice. In order to do this, basic information about soil, vegetation and other features are indispensable for the study of land desertification. Field spectral data as one of these basic data sets can provide some valuable information about land desertification. Along with other data, they are useful in monitoring and classifying land desertification in certain areas. It also can be helpful to the study of the dust source of sandstorm weather. This article focuses on the frequently occurred sandstorm weather since the 1990s and the serious land desertification in North China and Beijing region, taking dry farming area,intertock area of farming and pasturing and pure pastoral area around Beijing as study areas. Fengning in Hebei province, Duolun and Xianghuangqi in Inner Mongolia have been selected as representatives of the above mentioned three areas. Field spectrum data of different land-cover and different desertified land had been measured using the ASD FieldSpec FR instrument in those study areas. Analyses and comparisons of processed field spectrum data of degradations to different degrees and degradations to same degrees in different seasons or with various vegetation cover rates have been done respectively. Farmland with different crops have also been measured and analyzed. According to the analyses of the sampled spectrum data, the spectrum characters and their responding mechanisms had been discussed. The conclusion is that soil water content, types of grass, height of grass, grass coverage and growth period of vegetation are related to the average spectrum characteristics of the desertified land. Spectrum curves vary with changes in environmental factors. Studies of soil and vegetation spectrum characteristics should be taken as further reference for the study of desertified land. Spectrum curves also changed with annual and seasonal vegetation growth. Thus the accumulation of long-term field spectrum data is more important and necessary.

The coast of Jiangsu is famous for its dynamic singularity of both serious eroded coast reach and rapid progradingone. The erosional coast of Jiangsu is 301.7km long or 31.6% of the province total shoreline. Of them muddy coast is 271.6km and sandy coast, 30.1km, which is the only segment of sandy coast in Jiangsu. This singularity is relevant to the following three features. The first one is the effect by great changes of the two big river mouths. The lower reaches of the Huanghe River began to enter the Yellow Sea by north of Jiangsu in 1128 after capturing the Huaihe River and was back to the Bohai Sea by Shandong Province in 1855. This evolution of the Huanghe River, which famous for carrying plenty of sediments, caused great hydrodynamic change, especially the sedimentation conditions of the Jiangsu coast. The second one is the long muddy coast.During the 700 years that the Huanghe River entered the Yellow Sea by Jiangsu, the coast was transformed from sandy coast to muddy, and 92% of the shoreline of Jiangsu is muddy coast now. The third one is the diversity of the openness of the several coast reaches. With the substantial change of the large-scale submarine sand ridge fields on the inner continental shelf, the screening state of the coast reaches changes accordingly. There are four segments of the erosional coast reaches in Jiangsu. The first one is the abandoned Huanghe River Delta coast. The delta shoreline and the subaquatic delta have been heavily eroded because of the losing of sediments supply. Meantime, the coast reach of the abandoned river mouth retreated rapidly and has not been controled until the 1970s when the seawall and the bank protection were built. But this promotes the vertical erosion on the intertidal flat.The average rate of vertical erosion from 1980 to 1992 is 13.5 cm/a. The isobath of 15 m is only 4.65 km away from the bank, and the isobath of 10 m moved 0.37 km every year toward the bank from 1937 to 1994. The second isLusi coast, the southern part of the coast of Jiangsu. The erosion of this segment is mainly because of large-scale tidal channel movement toward the bank and development of winding. The shoreline retreated more than 1 km from 1916 to 1969. The super tidal flat in front of the seawall was wholly eroded, and the rate of vertical erosion on the intertidal flat is 3.6 cm/a. The third segment is the Jianggang coast. Some tidal creeks on the tidal flat moving toward the bank caused heavy erosion, and some erosional mud cliffs are as high as 5 m. The cliffs can retreat 20-30 m within one spring tide cycle. The fourth is the sandy coast in the northern part of Jiangsu coast. Some dams were built on some rivers flowing into the sea and break off the sediment source supplying the coast. Meanwhile, digging of coastal sands helped the erosion.

The West Liaohe River Basin is a typical ecotone and eco-vulnerable zone in northern China. Shaped by the long-term human's overuse, regional eco-environment in West Liaohe River Basin was seriously destroyed, which has threatened the harmonious and sustainable development of future human and nature relationships. Archeological studies show multifold cultures had evolved in this typical area since Holocene and civilization has been lasted through to present. By using GIS software, the authors first build DEM model of the study area and cultural landscape layers of different phases during the early historic period.They then overlay them to create DEM model of cultural landscapes of the early historic period, which distinctly revealed the relationships between distribution of cultural landscapes and natural landscape. All the analyses are based on four different spatial scales, which are typical archaeological site, Jiaolaihe River Valley, Aohan Banner and Chifeng area. Based on these studies, this paper identifies the basic evolving modes of the vertical change and horizontal change of the cultural landscapes during the earlier historic period of Holocene in West Liaohe River Basin. At the smaller scales of the three typical archaeological sites and Jiaolaihe River Basin, cultural landscapes mainly showed vertical change, including vertical expansion and downwards migration. Vertical changes of cultural landscapes had close relationships with cultural development, changes of production modes and life styles, and evolution of geomorphic landscapes. Evolution of the geomorphic landscapes, especially the river terraces, was an important driving factor. Configuration of small or middle scales of landform units and water sources, development of river systems, and combination of landform units directly influenced the formation of cultural landscapes at these scales. At the larger scales of Aohan Banner and Chifeng area, cultural landscapes mainly showed horizontal change. From Xiaohexi Culture to Hongshan Culture, cultures of this region were in expansion period, mainly featuring the spatial expansion of cultural scales. During Xiaoheyan Culture period, culture was in a period of contraction. After Xiaoheyan Culture period, culture of this region entered into a new expansion period again. Heterogeneity of regional natural landscape shows great influence on the formation of cultural landscape patterns during the earlier historic period.

During the last two decades, a lot of innovations have appeared in the field of urban and regional research. New paradigms and approaches such as dynamics of complex systems, self-organization, evolution theory, have been recognized for better understanding the evolutional process of regional spatial structure. It can be seen as a cumulative and aggregated order which results from numerous locally made decisions. Therefore the basic force driving the evolution of regional system is inherently microscopic. Regional system is an evolving complex system which grows from simple to intricacy. Inspired by the concept of biology, regional system also evolves into a complex, multiplex and vitality state by certain natural selection and adaptation. The understanding that the region is a complex adaptive system (CAS) means that microscopic simulation emphasizing the way in which locally made decisions and interaction between all kinds of local agents such as households and enterprises give rise to global patterns is highly appropriate. The methodology of CAS model is a part of theory of CAS. The CAS such as urban and regional system is conceived as societies of autonomous agents who are able to act both on themselves and on their environments. The general behavior of the regional spatial evolution is produced by the combination of actions of the households and enterprises. The determinants of an agent's behavior have a local character and there is no global constraint on the system's evolution. These agents can adapt to other agents and environment continuously by learning from their own experience. The classifier system is a good learning algorithm for representation of the agent's adaptation. Therefore, it is a good alternative way of simulating the evolutional process of the regional spatial structure by modeling behaviors of these local active agents and their interactions. It is easy to build and understand the CAS model. The CAS model can overcome the limit of perfect rationality by introducing learning algorithm and integrate any qualitative or quantitative description of an agent, whose behavior may be very complicated. The flexible modeling method allows for a much more detailed representation of spatial interactions and of some local properties and also makes it possible to introduce new agents or new rules in the model without changing the other parts. This paper basically reviews the simulating ideas and methodology aiming at two types of traditionally modeling strategy on the study of regional spatial evolution, in addition, primarily introduces the theory of complex adaptive system, one of the most important achievements of studies of complexity, and besides, discusses the general characteristics of the region as a complex adaptive system, expounds the technical problem of regional simulation based on the CAS and the original idea of the CAS model.

World Heritage belongs to all the peoples of the world, irrespective of the territory on which they are living. The World Heritage List draws attention to the wealth and diversity of the Earth's cultural and natural heritage. Historic Cities in World Heritage List agglomerate the elite of the noblest stage in human civilization history, whose outstanding history, artistic and scientific values make them the living fossils of urban historic study. To the end of January 2000, the total number of ancient cities in World Heritage List is 94. They are 1/7 of the total world heritage sites. These ancient cities are distributed in 56 countries of the four continents. Of which 42 cities of 24 countries are in Europe, 22 cities of 11 countries are in Africa and Arabian region, 16 cities of 11 countries are in Asia and Pacific region,and 14 cities of 10 countries are in America. The paper firstly analyses the study significance of these ancient cities, then exploringly sets up a suit of research system including research methods and main contents. The research methods are demonstration method, holistic and systematic method, dynamic and evaluative method, as well as comparative method. These methods are the main ways in studying the ancient cities in World Heritage List. At the same time, the main research contents of these cities include the value study of many sides, the protection study and the development study. Finally the paper takes the world cultural heritage-the Chinese ancient city of Lijiang as an example to reveal its special research value and significance covered mainly in the three aspects.

The Internet is a major symbol of the contemporary world that is predominated by two interwoven tendencies, i e., globalization and informationalization. It is now widely accepted that the world is moving fast towards an information age and the Internet is a major channel to such a historical change. Indeed, no technological progresses in the last several decades can match the advent of the Internet in term of its profound and extensive influences. The increasingly wide use of the Internet is causing fundamental changes in people's daily life and hence probably in the entire socio economic system of the world as well. In particular, the Internet makes the propaganda of information and knowledge much easier and faster than ever. In such a sense, its development as an industry is not only a part of the knowledge based economy but also an accelerator of the development of the latter. The explosion of electronic business/commerce (e com) on the Internet is a result of the fast and vast information and knowledge flows. The implications of such developments for industrial spatial changes are very important and interesting research topics for economic and industrial geographers. It is reported that the Internet economy has been a major contribution to the US's recent economic growth. In Asia, the recent recovery from the 1997 98 financial crisis has also been attributed partially to the rapid growth of business to business (B2B) e com. In China, the development of the Internet in the last several years has been incredibly fast. The number of domains registered under ".CN" increased from 4,066 in late 1997 to 127 thousand by the end of 2001, and that of the Internet users rose from 620 thousand to 33.7 million. The rapid development of the Internet has also led to fast growth of e com in the country. This paper will investigate the development of the Internet in China with special attention to its geographical features and then analyze the spatial implications of such development. It hopes to offer a general background to and be a stepping stone for future more detailed studies on the issue.

Based on the reviewing the development of Three-Gorges Program, the problem of the Farewell Tour of Three Gorges promotional program has been identified. By applying the event tourism,system dynamics and tourism marketing theories, a systematic and dynamics approach is adopted to analyze the internal structures of the Three Gorges Tourism Development and to explain and to predict the dynamic impacts of the Farewell Tour of Three Gorges. It is expected that the study provides not only an analytical framework to the similar problems but also the cautions to adopt the high risky promotional strategies. A simple model of Three Gorges Tourism Development based on the Bass model of product life cycle was constructed to replicate the basic behavior.The model is composed of four sectors thatare linked by feedback structures: tourist sector, attractionsector, public infrastructure sector and service facility sector. Tourist sector is the most important. It has been identified that tourists of Three Gorges are determined by the potential tourists, increasing rate of potential tourists, potential tourists who have lost interests before making decisions to travel and the tourists who make revisitation decisions. These four variables are governed by the feedback structures which are characterized by the delays and non-linear functions and therefore misconception is prevailing in the tourism management. It has been found out that although Farewell Tour of Three Gorges can induce more potential tourists to make travel decisions within a short time, the revisitation tourists, and the new potential tourists decline. As a result, the potential tourists reduce sharply right after the Farewell Tour of Three Gorges and can only increase very slowly in the long run if remediationactions are taken. Similar patterns are observed to the newly added tourists who visit Three Gorges. Apart from the reduction of tourists, other consequences, such as quick expansion of service capacity, vigorous and non-regulated competition, the damaged investment environment for long term public infrastructure and new attraction projects and delayed government actions accelerate the vicious cycle of the decline of Three Gorges Tourism after the implementation of the Promotional Program. The study concluded that Farewell Tour of Three Gorges is a very risky promotional program. The program in fact only benefits a few in the short term and brings long term negative effect to the tourism industry of Three Gorges Tourism.

The research area, the southeastern part of Alxa, lies in the west of Inner Mongolia Plateau in China. It bounds Mt. Yabrai and Mt.Bayan Ul to the west and Helan Mountains and Yellow River to the east,connects Hexi Corridor to the south and Langshan Mountains to the north. The area includes Tengger Desert and Ulan Buh Desert. The well-known Jartai Salt Lake lies in Ulan Buh Desert. Topographically it is the connection part of Alxa Plateau, Loess Plateau and Qinghai-Tibet Plateau. It is also the transitional zone between the semiarid dry-grassland areas and arid-hyperarid areas.Its climate is arid and semiarid. This is the sensitive region of global change and is one of the sand storms most frequently hit areas in China. In the late Pleistocene, Tengger Desert and Jartai Lake were large broad fresh water lakes separately. In Tengger Desert, there were more than 400 lakes of different sizes. The Alxa Plateau had ever been such a geographical environment with many rivers and lakes. Due to the effect of the uplifting of the Qinghai-Tibet Plateau, the moisture laden ocean air current was blocked from entering in. This turns central-Asia into inland arid climate region, and its environment became deteriorated.The cause of the aridity is due to two aspects:First, the climate became dry, and the water of the lakes was strongly vaporized. So, the areas of the lakes turned smaller and smaller, and finally into dry basin and lacustrine sediments exposed to the ground to turn into desert under the wind erosion. Secondly, due to the funnelling effect, drifting sand from Yamaleike Desert in the west of Jartai and from Badain Jaran Desert in the west of Tengger Desert invades along the narrow passageway.That is a very important factor leading to desertification of the lake basin.In the arid and semiarid regions, the structure of the eco-system is very simple,which is liable to induce ecological calamities.Today the main problem in these areas is the invasion of the drifting sand and sandstorms.Therefore, based on studies of remote sensing images,relevant measures for improving the research area's ecological environment are identified as to block and fix the sand in the west, and to establish ecological protective belt in the east, to renovate and control sand encroachment in divided blocks. With these measures to harness ground surface environment, the invasion and expansion of the drifting sand, the occurrence and the intensity of the sandstorms from the area's surface can be controlled effectively. The prevention and control of the sandstorms of the area is of very important to the mitigation of the sandstorm calamity in Beijing.