Shilin in Yunnan Province of China has the most typical and integrated sword-like karst landforms across the world continental area. It has served as the special term representative of such kind of geomorphology. Shilin area is not only the national conservation area of karst landscape, but also the national scenery spot. As a scenery spot, Shilin landscape enjoys the praise of marvelous spectacle on earth and becomes the focus of aesthetics. On the basis of Chinese traditional aesthetic theory of natural landscape and the research result concerning modern geology and geomorphology, this article takes the Shilin landscape as the aesthetic object, discusses and summaries its spatial structure and visual aesthetic characteristics,identifies the component elements making up the Shilin landscape and the factors which influence the aesthetic value. Natural landscape has always been the aesthetic object of the people, there are countless descriptions of the same landscape, but however, great differences exist in the descriptions of the same landscape. Although the issue of how to assess the aesthetic value of natural landscape has been the concern of the people for a long period of time,no consensus opinion has so far been reached. We believe that the disagreement on the identification of the evaluation elements is the key to the issue. The landscape evaluation method proposed in this article, which is to combine the landscape's scientific cause of formation, scientific value and beauty of modality together, to link the experts' evaluation with the systematic investigation and analysis, will definitely promote the in-depth study of the aesthetic value of natural landscape.
A new geographical curriculum standard will be introduced for middle school across China to replace the current general outline of geographical education and will instruct geographical education in middle school in the coming 20 years. The project, "Establishment of Geographical Curriculum Standard for Middle School", sponsored by the Ministry of Education,aims at constituting a scientific and reasonable curriculum standard for middle school. This paper discusses the importance and necessity of geographical education through analyzing the trend of geographical development,the social requirement to geographical education,the relations between psychological development of students and elementary education of geography.In addition,comparison between the elementary geographical education in China and that in other countries,such as the United States, France, Britain, Germany etc.is also made.It is different from China that the elementary geographical education in foreign countries seldom use the subject-system as the contentsystem but pay more attention to social events and students' life and consider students' in terests and development of individuality, cultivate geographical methods, abilities and thoughts and advocate explorative study. Finally,on the basis of illustrating the guidelines, goals and content-structure of the curriculum standard of geographical education in China,some important strategies are put forward.
As aging process speeds up, China is beginning to face the critical social problems of an aging population, which have already affected all aspects from the State's imperfect social security system to family traditions. After abolishing the traditional cradle-to-grave welfare system under the planned economy in the early 1980s, the retired people have gradudlly lost their links relations with their units where they once worked. Meanwhile, the size of families is growing smaller and smaller. The senior people fail to communicate with other people in society, and are more likely to feel lonely. The aged is about 20～30 % of the total population and some aged communities even emerge in urban districts of some large cities, such as Beijing, Shanghai, and so on. However, more attention has been paid to senior people's pension, medical care and living conditions. There are few studies on their need for leisure and leisure behaviors. This paper builds an empirical study on a survey, which records daily activities of 50 retired people for a whole year. With the help of time geography, the authors try to carry out a theoretical study on the need, quality and space-time pattern of senior people's leisure activities. The authors find out that (1) most senior people are living in a regular lifestyle; (2) the total daily leisure time is long, but the quality of their leisure activities is not high; (3) most of their leisure activities are carried out at their homes with their family members; (4) their leisure behaviors are different in sex, age, income, education, season and living place; and (5) the leisure facilities in communities and society are far from meeting their need nowadays. The outcome is believed to be useful to the spatial organization of leisure and urban planning in large cities.
For years, the Changjiang(Yangtze) Valley has played a key engine of China's industrialization successfully. With a continuing process of the national industrialization and urbanization in the early 21st century, the Changjiang Valley would devote itself more to the country's economy. Considering a nationwide intensified man-land relationship and a worldwide booming economic globalization, strategic readjustments for local industrial structure and location would benefit a lot to the Changjiang Valley to pursue its target. This paper argues, therefore, that the readjustments should concentrate on promoting farmers' income, improving efficiency of institutional management, innovating tax system, enhancing industrial relocation and urbanization, widening the margin of imported minerals, and curing environmental degradation as well.
Although the international societies, as well as countries throughout the world, have stressed food security and its conditions have been improved considerably since the 1970s, the future state will still be very severe because of population increase and agricultural productive condition deterioration. As to China, the productivity has been rising since the Reform and Openness. Chinese have gone out of the epoch of food shortage and the general level of food security has also improved substantially. But, there are still many factors restricting Chinese food security, such as population increase, productive resource shortage and so on. Therefore, to sustain China's food security is vital to realize Chinese social, economic and natural sustainability. Food productive and supply level, food structure diversity, habitant earning level or obtaining ability to maintain survival and other factors jointly affect food security level. In this paper, the meaning of food security is firstly discussed. Basing on fundamental factors influencing food security, the authors then select a set of evaluating indicators, formulate an integrated index evaluation model on food security. Using the evaluation model, food security integrated indexes covering 1950～1998 are calculated thirdly. A single-factor and multi-factor integrated evaluation on Chinese food security sustainability is carried out finally. The calculated results show that China was in a generally secure state of food in the 1950s, in an insecure state of food in the 1960s and the 1970s, and had entered a steady secure state of food in the 1980s through to the 1990s. Since the 1960s food security level in China has been rising year after year and since the 1980s a sustainable development trend has been maintained.
The concentration of the atmospheric CO2, one of the most important greenhouse gases, is increasing since the beginning of industrialization from its pre-industrial value of 280ppmv to its present value of 366ppmv. It has been proved that human activities, including fossil fuel burning, cement production, and land-use change, have severely disrupted the model of the carbon cycle, thereby alter the climate system and affect the processes and mechanisms in terrestrial ecosystems. Understanding the consequences of these changes in the coming decades is critical for the formulation of political, economic, energy, and security policies. So recently,studies in carbon cycle have increasingly become a focus of global change and geo-science in the world. The terrestrial ecosystem,one of the most important parts of the global carbon cycle, is most complex and most greatly affected by human activities. This paper, combined with the latest reports related to carbon cycle in IGBP and IPCC, introduces some major carbon pools, namely, lithosphere, atmosphere, ocean,and terrestrial ecosystem,in the global carbon cycle and their sizes and characteristics. Furthermore, four major approaches, including inventories method, eddy covariance measurements, inverse modeling and model of carbon cycle, which have been used to evaluate the biosphere-atmospheric exchange of CO2in the terrestrial ecosystems,are introduced. Using inventories method we can get an estimate of the actual accumulation of carbon in terrestrial ecosystem. The eddy covariance approach can detect small changes in net CO2exchange between terrestrial ecosystems and the atmosphere over various time scales. Inverse modeling approach can be used to infer carbon sources or sinks based on 3-D atmospheric tracer transport models and CO2 records from the atmospheric observations, fossil fuel combustion and land use change. Model of carbon cycle is a powerful tool to estimate and evaluate the temporal and spatial patterns of carbon sources or sinks in various scales. The existing problems of using these four methods are also analyzed. Moreover, the uncertainties in terrestrial carbon process are analyzed particularly.Additionally,some problems unsettled in carbon cycle and development tendency are specified concisely.
Based on the data up to 1999 from the hydro-climatological departments, this paper analyzes the climatic dividing implications of Qinling Mountains in regional response to the process of global warming, due to which the Grades of Dryness/wetness (GDW) in 100-year scale show that the northern region has entered an arid period, and the southern, a humid period. At decade scale, the D-value of annual average air temperature over Southern Shaanxi (Hanjiang Valley) and Central Shaanxi Plain (Guanzhong Plain) has narrowed, i.e. the former with slight change and the latter with rapid increase in temperature. Both regions are arid with decease in precipitation D-value, namely, the plain becomes warmer while the south drier. Qinling Mountains play a predominant role in the climatic dividing. The runoff coefficient (RC) of Weihe River decreases synchronously with that of Hanjiang River due to climate warming . The RC of Weihe dropped from 0.2 in the 1950s to less then 0.1 in the 1990s.Weihe valley (Guanzhong Plain) is practically an arid area as a result of the shortage of water .The successive 0.5 and 1.0℃ temperature anomaly over China marks, perhaps, the important transition period in which the environment becomes more vulnerable than before .The study shows the obvious trend of environmental aridity, which is of help to the understanding of regional response to the global climate change.
The altitudinal zonation of natural landscape have distinct characteristics on the northern slope of the grand Taibai Mountains. The landforms consist of the higher district of the mountain all over which glaciers remain scattered, the middle district characterized by stone forest, and the lower district covered with loess. The mountain climate may be divided into four zonations: subfrigid zonation→frigid-temperate zonation→temperate zonation →warm-temperate zonation. The altitudinal vegetation zonations are : zonation of alpine shrubby meadow →alpine conifer zonation →birch zonation →zonation of mixed Form. plnus armandi, Quercus and deciduous broad-leaved forests →low mountain and hill dry deciduous broad-leaved forests and oriental arborvitae zonation. Influenced by those factors, the representative altitudinal zonations of the soils have been formed on the northern slope of the Taibai Mountains. But when pedogenetic classification was applied, there were many different classification results of the soil altitudinal zonations on the northern slope of the Taibai Mountains. Because the pedogenentic classification was based on the biologic and climatic conditions, and the soil forming processes, the central conceptions were emphasized but the boundaries of the conceptions were neglected in the pedogenetic classification. For convenience of international communication, the Chinese Soil Taxonomy was published in 1995. Then the characterizations and the factors of soil formation were investigated on the northern slope. According to the Chinese Soil Taxonomy (revised proposal), the result of the soil Taxonomy is obtained:Umb-Cryic Cambisols (>3 500m) →Mol-Cryic Cambisols (3 300～3 500m) →Acid-Udic Cambisols(2 500～3 300m) →Hap-Udic Luvisols (1 400～2 500m) →Hap-Ustic Luvisols (<1 400m). The result of the Taxonomy coincides basically with that of the pedogenetic classification and the boundaries roundly identify with each other. The results of two soil classification systems show that the Chinese pedogenetic classification is based on the pedogenic theory, and the Chinese Soil Taxonomy is guided by soil genesis principle. There are close relations between two classification systems. In addition, measurable diagnostic horizon and diagnostic characteristics are used to classify soils in the Chinese Soil Taxonomy, which make soil classification more quantitative and more objective, and soil classification standardized.
Agroforestry is a newly developed technique, which includes various fields and is suitable for developing countries. Recently, the contour hedgerow-crop system has become one of the major forms of agroforestry on slopeland in developing countries. It was proved intercropping between the contour hedgerows is favorable for controlling erosion, increasing soil fertility and gaining higher benefit of the slopeland by relatively low input. The primary objective of applying hedgerows is to control erosion and non-point pollution on slopeland. The distance between contour hedgerows mainly decides the effect of erosion control and the cultivable area in the hedgerows-crop systems. Therefore, the design of the distance is very important to applying the contour hedgerow techniques. The existing studies have not paid much attention to the hedgerow's control process for erosion and nutrient in the temperate zone and semiarid region. The present study quantitatively analyzes the rules of various erosion zones on a slope by using plenty of field observed data in hilly loess area of northwest Hebei Province, as well as large-scale artificial rainfall simulation data from sloping field. Taking contour hedgerow-crop system as an example, this paper discusses the major mechanism of soil erosion and nutrient change processes, the design of level spacial structure of typical agroforestry systems in hilly area of northwest Hebei. The results showed that the critical slope length is 10-15m on the condition of rainstorm, which can control the generation of rills and make the erosion amount decrease obviously. The study provides a theoretical basis for the hedgerow plant, and the hedgerow can control the erosion and nutrient loss through changing the erosion process on slopes and control thes generation of rill erosion. The study has a scientific value for the application of the hedgerow-crops agroforestiy system in the temperate zone and semiarid region.
Crop productivity model research is an important means to study agricultural production, but the universally low adaptability of the model limited its popularization and application. Since Geographic Information System (GIS) owns powerful function of analyzing, processing,managing and visualizing spatial data, it has been widely used in agricultural production. The loess hilly-gully area is one of the most serious soil eroded areas in the world and serious soil erosion has made soil quality degrade and land productivity drop. Aiming at characters of serious soil erosion and low and unstable crop productivity, this paper firstly introduces crop production of Wangjiagou watershed in recent ten years. Then, supported by GIS and aided with crop productivity mode YIELD model, combining actual observation data of crops, it analyzes reasons accountable for changes in agricultural production from two aspects of meteorologicfactors (precipitation, temperature) and farming practices, mulching fertilizing and terracing. The result showed that changes of soil moisture and soil nutrient affected by precipitation and soil erosion are the main factors influencing changes in crop productivities.Effective tillage measures can greatly enhance level of soil water and soil nutrient and promote crop productivities.
Mn oxide minerals are very reactive components of soils. They could control the availability and toxicity of many life-relative elements. Meanwhile, Mn oxide minerals influence the fates of formation and transformation of organic materials, including humic substances, organic pollutants and humic acids, and affect the quantity and quality of crops. Ultimately, they make a notable impact on human health. As products of certain period of soil-forming processes, soil iron-manganese nodules are the main rich forms of Mn oxides. Studying on the mineral composition and geochemical characteristics of soil iron-manganese nodules can help us not only know the properties of soil iron-manganese nodules and Mn oxide minerals but also comprehend the soil-forming process and the ecological environmental conditions. The types and amounts of manganese minerals in several iron-manganese nodules in subtopical and warm-temperate zones were studied by means of X-ray diffraction and selective chemical dissolution. Their geochemical processes and characteristics were also investigated. The amounts and types of manganese mineral in different soils were distinct. Lithiophorite is a common mineral in all tested iron-manganese nodules with high degree of crystallinity. Compared with corresponding soils, Si, Al and Fe were still the main chemical elements in nodules. However, the increasing extent of iron content was higher than that of Al, and increasing extent of Mn content was higher than that of Mg and Ca. The enrichment order of some heavy metals was Pb>Co>Ni>Cu>Zn>Cr. During the processes of nodules formation, there exist nucleation and enrichment, mineral formation, specific adsorption and slight calcification.
Since the discovery of fossils of Dingcun Culture in 1954, many scholars have been studying the age of Dingcun Formation in different ways. But there is still no certain answer to it by now. Some researchers think it was formed in the late of middle-Pleistocene, and the others think it was in the early of late-Pleistocene. Their researches normally focused on the changes of the fossils of Mammal in Dingcun Formation and determined its age according to these changes. Because some animals had lived for a long time during middle-late Pleistocene, this made it difficult to do so. As a terrace of Fenhe River, the deposition of Dingcun Formation was strongly controlled by the development of Linfen Basin during middle-late Pleistocene. By studying the landforms in Linfen Basin, we find: 1) there occurred an extensive withdrawal of lake resulting from a regionally structural uplift; while S1 began to develop; 2) when L 1SS began to develop, the strong down dissection of Fenhe River led to the formation of the terrace(T3). The existence of an erosion surface in Dingcun section and the characteristics of Dingcun Formation indicated that there was a remarkable increase in hydrodynamics when Dingcun Formation began to accumulate. Taking all the above-discussed into account, we draw the following conclusions: 1)Dingcun Formation began to accumulate about 0.13MaBP when S1 began to form, while a structural uplift took place there. 2)The deposition of Dingcun Formation ended about 52kaBP. The wet and warm climate then caused a strong down dissection and the end of the deposition of Dingcun Formation when L1SS began to develop. 3)The accumulation of Dingcun Formation was in correspondence with the formation of S1 and the lower part of L1 in time.
The central-southern part of Inner Mongolia which lies in the edge of monsoon area of northern China is sensitive to the climatic change. It is important to research the relationship between the environmental change and the changes of pre-historical cultures in the region.The archaeological research in the central-southern part of Inner Mongolia indicates that the development of pre-historical cultures in the study area is divided into two phases.The first one is the period of primitive agricultural culture from ca1.7ka BP to ca1.3.5ka BP. The second is the period of farming-grazing transitional culture from cal.3.5ka BP to present. The change of the land use from farming to grazing happened in ca1.4-3.5ka BP.Environmental change is the major driving force for the development of archaeological cultures, such as land use patterns, the growth or decline of agriculture comparing to the pasturage culture in this area. The primitive agricultural cultures were developed and flourished during the warm and humid Holocene Megathermal Period. The sub-phases or interruption of the culture during the primitive agriculturalphase are responded to the phases of climatic change during the Holocene MegathermalPeriod. The transition of land use from farming to grazing duringcal.4ka BPto 3.5ka BP was a result of theabrupt cold-dry event that ended the Holocene MegathermalPeriod.
Spatial structural patterns are very important reformation inflecting regional characteristics. However, they are seldom explicitly expressed in geo-data bases. In order to express them in generalized maps derived from geo-data set, spatial structural units need to be identified beforehand. This involves in the classification, identification, description and generalization of spatial structural patterns. This paper includes three sections. The first two parts discuss the classification and identification of spatial structure patterns. Spatial distribution can be subdivided into three categories, i.e., point, linear, and areal phenomena, which can be further divided into uniform, agglomerate, or random point/areal patterns, and isolated, grouped, nested, dendriform, or netlike linear patterns. Spatial structural units can be identified by means of comparison between digital model and theoretic model, which are derived from geographical entity. Theoretic models of structural patterns are usually described by a group of parameters, such as polarity, linearity, and symmetry. The third section studies the method to generalize spatial structure of point, linear, and areal phenomena. Among point and areal distribution, clusters are the most important structural units. Clusters can be generalized by means of boundary adjustment and inner structure simplification. As for linear distribution, dendriform and netlike patterns are the most important units. The generalization of both of them involves in trunk lines selection and typification of characteristic patterns, which need to be dealt with different methods according to concrete situation.
Great complementarity exists between remote sensing image data and geographical knowledge. This paper tries to unify the image classification and geographical knowledge discovery through ground classes data, i.e.,to discover geographical knowledge with remote sensing data drive, to confirm, explain and evaluate image classification result with geographical knowledge, and to represent geographical knowledge with statistic value and distribution atlas. All these come to be an incorporated Remote Sensing and Geographic Classification System. The steps of this method are as follows: firstly, to divide the image into relative big number(>20) of classes using the unsupervised classification; then overlay these unknown classes with the DEM data and get some statistic values and distribution atlas for each class; finally use these values and atlases to name,explain and evaluate each class of the classification result. Meanwhile the correlation between the ground object type and the topographical data is acquired and expressed as well. The example shows that this method makes the classification more efficient and reliable, and it is useful to express and discover the geographical knowledge. The conclusion is that, we can use other data to interpret the result of unsurpervised classification, name and check each class, and at the same time, acquire the geographical knowledge from the pattern in the image data.
