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    15 November 1997, Volume 52 Issue 6 Previous Issue    Next Issue
    BASIC FEATURES AND TRENDS OF THE ECONOMIC BASE OF BEIJING
    Yang Kaizhong
    1997, 52 (6):  481-490.  doi: 10.11821/xb199706001
    Abstract ( )   PDF (418KB) ( )   Save
    In China, systematic studies on economic base of a single city is very weak. Based on the 1990 census and relevant statistics during 1991-1994, this paper is designed to study Beijing economic base systematically by comparing with those of Shanghai and Tianjin. The major conclusions include: (1) Beijing is not only the national political and cultural center but also the national economic center. The latter is reflected in the national centers of commercial service, external economy typed and knowledge intensive manufacturing industry with lower input of water and less environmental pollution, and it suits the need of the political and cultural center. (2) Although the industry with higher input of water and/or serious environmental pollution just are economic bases based on regional market, but this situation is not rational relative to Beijing’s natural endowment of water and environmental resources. (3) Beijing’s economic base of industry is smaller, more regional market based, and the economic base of service is more diverse, larger and more super regional market based than the Shanghai’ and Tianjin’s. (4) With the development of socialist market economy and implement of sustatinable development, the external economy typed and knowledge intensive manufacturing industry with lower input of water and less environmental pollution, and information intensive service industries will tend to concentrate further, and the industry with higher input of water and/or severe environmental pollution will tend to decentralize.
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    A COMPARATIVE STUDY ON THE CHARACTERISTICS OF PRECIPITATION SURFACE SOIL EROSION IN BARE LAND AND EUCALYPTUS FOREST LAND OF NORTH TROPIC REGION
    Zhou Guoyi
    1997, 52 (6):  491-499.  doi: 10.11821/xb199706002
    Abstract ( )   PDF (467KB) ( )   Save
    The relation between water drop kinetic energy and surface soil erosion has been studied here. Two types of land surface have been taken into consideration, they are bare land without any vegetation on it and eucalyptus forest land without any undercover. The results showed that there was a close relation between water drop kinetic energy and soil erosion intensity of unit rainfall, and the water drop kinetic energy was the direct factor which caused the soil erosion of land surface. For bare land, its erosion intensity was determined by atmospheric raindrop kinetic energy. However, for eucalyptus forest land, it was relative to throughfall water drop kinetic energy and had no relation with that of atmospheric rainfall. Throughfall kinetic energy can not be affected by atmospheric precipitation intensity, but it is determined by the structure of forest canopy (including tree species, canopy density, leaf area index, height of canopy etc). And thus, when atmospheric precipitation intensity in open place is smaller, the parameter λ (in %) will be larger, which means that the forest canopy will enlarge the soil erosion of forest land. Correspondingly, when atmospheric precipitation intensity in open place is larger, the parameter λ (in %) will be smaller, which means that the forest canopy will reduce the lashing of waterdrops to forest land, and thus, have the positive effects on soil conservation. The value of λ changes with atmospheric precipitation intensity, rainfall, height of canopy and canopy density. The characteristics of soil erosion for these two studied areas were different. Soil erosion from the eucalyptus forest land was mainly caused by the rainfall with middle and small precipitation intensity, but that from bare land was mainly caused by the rainfall with heavy precipitation intensity. As a whole, the canopy of eucalyptus forest increased the impact of water drop to land surface, especially in the situation of middle and small intensity of atmospheric precipitation. This study explained that we should consider the influence of forest canopy structure on forest land erosion when making plantation.
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    MINERAL LIFE CYCLE CURVE AND ITS IMPLICATION IN REGIONAL DEVELOPMENT
    Zhang Lei
    1997, 52 (6):  500-506.  doi: 10.11821/xb199706003
    Abstract ( )   PDF (221KB) ( )   Save
    Regional development in the modern world is dependent to a great extent on the development of mineral resources. For minerals, regularities in the historical patterns of demand for those commodities permit the description of a lifecycle of mineral consumption. Many evidences support the fact that the curve shape of such a lifecycle is determined by the changing patterns of three causes-regional economic structure, technological advantages and mineral substitution. Basically, such a lifecycle has two concepts. One can be defined as the time series of long run mineral demand following an invert-U shape when plotted against increasing per capita GDP or income. The other can be described as the spatial organization disaggregated by developing countries, moderately developed countries and developed countries in responding to their own consumption behaviors based on a classification of old, young and new minerals. As a key factor in regional development, the mineral lifecycle has grat influences on changing patterns of industrial location, spatial organizations of urban growth, constructions of regional infrastructure and standards of environmental protection. For developing countries, particularly the large ones, the implications of mineral lifecycle and be deduced as follows: 1. An expending domestic and international mineral market will be the fundamental force in speeding up regional development when a shift in overall economic structure away from agriculture occurs; 2. In order to meet an increasing domestic need, national development stategy should center on expanding the exploitation of old minerals rather than young and new ones; 3. It is also important to implement a policy of family planning for releasing the great pressure from the growth of high mineral consumption activities, such as build basic infrastructure and heavy industries; 4. Mineral import will play an important role in regional development when economic structure is turning to less mineral-intensive activities, such as manufacture and services, and conflicts beween resources use is becoming more seriously; 5. The larger population a developing country has ,the greater potential mineral market it will have, and the longer span of mineral lifecycle it will be.
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    URBAN SUSTAINABLE DEVELOPMENT AND SPATIAL DECISION SUPPORT
    Zhang Xinsheng, He Jianbang
    1997, 52 (6):  507-517.  doi: 10.11821/xb199706004
    Abstract ( )   PDF (473KB) ( )   Save
    Urban is a synthetical body in which there are highly dense social and economic activities. Urban sustainable development has special connotations: ① Spatial Connotation——urban spatial structure plays an important role in regulating the key variables of sustainable environment of urban. ② Temporal Connotation——this emphasizes that the evolution mechanism of urban spatial structure is one of the important contents of sustainable development research. ③ Restriction Connotation——urban system will be restricted by its surroundings, that is, within the limits of services which urban ecological store supplies for urban ecological system,the optimal spatio temporal pattern of urban social, economic and ecological elements can make full use of the resources of urban ecological stock. ④ Region Connotation——urban and its hinterlands are interrelated and interacted on each other,urban sustainable development emphasizes that urban and its hinterland must co exist and develop harmoniously. Urban is a very complex system, it is impossible to distinguish the relation of spatial or non spatial interaction and inter feedback among all urban subsystems, let alone building mathmatical models to describe and optimize them. Thus, we must try to dissect the main structures of spatial interaction and interfeedback, and simulate the dynamic mechanism of evolution of urban spatial structures, so as to provide a strong support for working out the optimal alternative of regulating and controlling urban spatial structures. The paper emphasizes that urban sustainable development is a spatio temporal process of feedback regulation, and the spatio temporal evolution of urban system must be considered, and the spatio temporal dynamic models for urban sustainable should be approached. Urban spatial growth is a special example of the evolution of urban spatial structures. Regulation and control of urban spatial growth must be based on urban spatial dynamic modlling. We consider that the process of urban spatial growth is composed of three sub processes: ① Employee spatial growth driven by urban basic industries. ② Residence housing stock spatial growth dynamics. ③ Service expenditure flows service facility stock spatial growth dynamic. The subprocesses of three multi time scales are interrelated and interacted on each other, and run together to drive urban areas to grow in space and urban spatial structure to evolve. In the paper,on the basis of analysis of configuration of urban spatial dynamics,urban spatial dynamic models are built. These models include intrinsic and exogenous varibles, intrinsic varibles are a bridge among all subsystems, and exogenous varibles are the interface between urban system and its surroundings. Through these interfaces, people can regulate and control urban spatial growth. Under the support of GIS, spatial analysis and spatial visualization, the dynamic modelling system of urban spatial growth and pattern changes is developped. The system may be used to simulate the dynamic process of urban spatial growth caused by different alternatives, and provides strong support for policy evaluation and alternative choices. The system was also numerically tested in Beihai city in Guangxi Automomous
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    REGIONALLY SUSTAINABLE DEVELOPMENT AND THE DEVELOPMENT OF INDUSTRIES
    Chen Chuankang
    1997, 52 (6):  518-527.  doi: 10.11821/xb199706005
    Abstract ( )   PDF (230KB) ( )   Save
    Sustainable development has become a state basic policy in China, and governments at various levels are struggling to realize it. Localities must take actions in several steps to reach the goal of sustainable development. The most important step is, based upon enivronmental conservation, to enhance the level of economical development by means of all possible meausres, and to satisfy qualitatively and quantitatively the increasing demands both of population growth and living standard improvement. In order to really achieve regionally sustainable development, the relationship between ecological environment conservation and economical development and demands satisfaction must be dealt with well and coordinated with each other, the development should be planned in short term, middle term and long term respectively and in a compatible or trundling way; and all policies and measures should be operationalizing. Regional development can be seen as a complex of the development of various industries. Thus the development and sustainability of industries is the guarantee for regional development. This topics may be discussed at three levels: 1. How to ensure the development of industries and their enterprises? Only if the enterprises’ production keeps profitable, industries can develop or even be enlarged. When the marginal benefit of the products decreases the scale of enterprises will not be enlarged. In the situation of market process adjustment, enterprises can achieve economic efficiency only if they reach certain scale. Enterprises with products lack of competition capacity will not get profit and may wither and even go bankrupt. 2. The development and sustainability of an industry should be conformed to the law of the industry. So industries can sustain their development only if continuously innovate and develop new products so as to advance to a new stage of development and occupy new markets. 3. Industries development should be long sighted without eagerness for quick success and instant benefit. Therefore, the environmental protection should be emphasized. Production could not damage the regionally ecological balance between nature and society, through any kind of pollution (including eyesight pollution and ethic pollution, in extensive comprehension). Exploitation profit of industry should not be at the cost of social diseconomy. Short sighted behaviors run in the opposite direction of sustainable development, and will be punished by the feedback mechanisms of environment and socity. The roles of government are improtant in coordinating the enterprises’ operation and industries’ management with regional development. By means of policies, the government can direct the development of industries and enterprises, at the three levels mentioned above, to be beneficial to overall regional development. It should be emphasized that the key of sustainable development in underdeveloped and developing regions is the current starting measures. These can be identified stey by step through regional diagnosis, causal analysis and CI (certified identity) design. Regarding the concept of sustainable development, more attention is unilaterally paid to ecological environment at present, and the importance of the function of economic growth is relatively ignored. In fact, sustainable development will not come true without the support of economy. Ecological and social effects can be seen as the goals of sustainable development, while the economical benefit is the key of operationalizing sustainable development. The development of industries is closely related to regional economy, so should be studied deeply in the research on regionally sustainable development. Development strategies of industries are also discussed and suggested in this paper, taking tourism, agriculture and industry (narrow sense) as examples.
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    A CALCULATION MODEL ABOUT TRANSPIRATION-WATER REQUIREMENT IN WHEAT FIELD
    Xie Xianqun, Wu Kai
    1997, 52 (6):  528-535.  doi: 10.11821/xb199706006
    Abstract ( )   PDF (248KB) ( )   Save
    According to the study using Penman Monteith method, this paper gives an improved model for the calculation of transpiration water requirement in the well irrigated wheat field, it is CWR= [Δ(Rn-Rsn )+ρC p/rac]/[Δ+γ(1+rST/rac)]and the author makes some correction for the parameters in the model, such as racand rSTrac =ra[1+φH/[ln(z-d)/z0]]where φH is function of stability of boundary layer depending on Richardson number Ri , rST =rS/LAI , where the LAI is Leaf area indix and rS is the minimum stamatal resistance of leaf on the top of Canopy. The testing result in the field at Yucheng Experimental Station shows that the mean value of the minimum stamatal resistance of canopy is about 40 s/m-60 s/m in the whole wheat growing season, the mean value of aerodynamic resistance of boundary layer is about 50 s/m in the full wet soil moisture condition, but it changes with the weather. The values of CWR of well irrigated field is close to the ET in the field and the values of T on the non full wet field are only 76% of ET . It means the given model in well irrigated condition is good to be used.
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    SEASONAL VARIATION OF ENERGY BUDGET AND EVAPOTRANSPIRATION PARTITIONING IN WHEAT FIELD
    Mo Xingguo, Liu Suxia, Yu Huning, Liu Changming
    1997, 52 (6):  536-542.  doi: 10.11821/xb199706007
    Abstract ( )   PDF (350KB) ( )   Save
    Based on the experiments conducting in Luancheng Agro ecological Experimental Station, Chinese Academy of Sciences, from March to June, 1995, the characteristics of radiation budget, energy balance, as well as evapotranspiration partitioning into canopy transpiration and soil evaporation in wheat field are analyzed. The results show that the ratio of the absorbed to the incoming short radiation in canopy soil system is varying with wheat growth stages. The value is 0 8 in the jointing, decreasing with the increase of leaf area index ( LAI ), and reaches the minimum of 0 75 in the booting. It then increases again and finally reaches the maximum of 0 86 with the appearance of ears and wilting leaves. The ratio of net radiation to incoming radiation enhancing with the growth stage can be distinguished by three periods. The value is 0 45 in the jointing, becomes 0 5 in the booting and finally increases to 0 57 in the milking. The experiments identify that with the increasing of LAI , the ratio of soil heat flux to net radiation decreases from 0 13 in the jointing to 0 06 in the milking. However the ratios of latent heat flux and sensible heat flux to net radiation all increase, sometimes the former is larger than 1 and the latter turns to negative. LE is shown the main component of energy balance in the system. From jointing to maturing, i.e., from April 1st to May 28th, total evapotranspiration ( Et ) in field is 250 mm with 50 mm from underneath soil evaporation and 200 mm from canopy transpiration. The relative evaporation (Et/Ep) tends to increase with the season, the average of which is 0 70. The value of evapotranspiration, 4 3 mm/d, based on aerodynamic energy balance method, is agreeable with that based on water balance method. The similar results of Et/Ep and daily evapotranspiration are also found in Yucheng Experimental Station, CAS, locating in North China Plain.
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    FIELD RESEARCHES ON WATER POTENTIAL, TRANSPIRATION AND RESISTANCE TO WATER FLOW FOR WHEAT AND MAIZE
    Zhang Xiying
    1997, 52 (6):  543-550.  doi: 10.11821/xb199706008
    Abstract ( )   PDF (506KB) ( )   Save
    Measurements of leaf water potential, evapotranspirtaion and soil evaporation rate, stomatal resistance and soil water contents were made for winter wheat and maize under sufficient water supply conditions in 1995 and 1996. The plant resistance to liquid water flow and its relationship with transpiration rate were calculated and evaluated. The results showed that the resistance was decreasing non linearly with the rising of transpiration rate. The resistance to liquid water flow in winter wheat is higher than that in maize, and also the stomatal resistance of winter wheat is lower, so the plant water condition of maize is more favorable for crop growth than that of wheat, which may be one of the reasons that water use efficiency of maize is higher than that of wheat. For the components of the resistance to liquid water flow, the resistance of root in it plays an important role. Then how to reduce the resistance in root water uptake is a key factors in increasing soil water utilization by plants. Ways for reducing this resistance include: increasing root length density and depth in soil by measures such as modification of soil conditions, water supply patterns and fertilizers; reducing the “junction resistance” to water flow in root systems by breeding new varieties and etc..
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    WATER USE EFFICIENCY IN WINTER WHEAT FIELD AND ENVIRONMENTAL INFLUENCE ON IT
    Li Jun, Yu Huning, Liu Suxia
    1997, 52 (6):  551-560.  doi: 10.11821/xb199706009
    Abstract ( )   PDF (491KB) ( )   Save
    Evapotranspiration and CO2 fluxes were measured using Bowen ratio energy balance method in winter wheat field in North China Plain from April to June 1996 and instantaneous water use efficiency ( WUE ) was obtained. L-shaped or U-shaped diurnal variation of WUE was found when soil moisture was low. Instantaneous WUE varied from 0.0194 to 0.6414. It was high and decreased quickly in the morning. It was low and stable during the daytime. The range of daily difference of WUE was from 0.1138 to 0.6321. When soil moisture was high, no obvious diurnal variation of WUE was found. Instantaneous WUE varied from -0.0157 to 0.1381. The range of daily difference of WUE was from 0.0616 to 0.1537. The seasonal variation of WUE was obviously and influenced by soil moisture. From elongation stage to milking stage in winter wheat field, Average of daytime’s WUE varied from 0.0110 to 0.0532. Daily difference of WUE varied from 0.0616 to 0.6321. Both highest values were found in May, 13. Average and daily difference of WUE fluctuated and decreased in milking stage. Negative correlation between average of WUE and available soil moisture in the depth of 0 cm-60 cm was significant at 0.05 level. No remarkable correlation was found between average of WUE and available soil moisture in the depth of 0 cm-20 cm and 0 cm-100 cm. Negative correlation between Instantaneous WUE and saturation deficit was significant at 0.01 level. It was power regression between them when soil moisture was low. It’s linear regression between them when soil moisture was high. Positive correlation between Instantaneous WUE and CO2 mixing ratio above winter wheat canopy was significant at 0.01 level when soil moisture was low.
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    RESEARCH ON DIFFERENTIAL PROFIT CALCULATING METHOD-A CASE STUDY IN JIXIAN, TIANJIN
    Qiao Lixin, Xu Limiao, Dai Xuelai, Zhang Jiantao
    1997, 52 (6):  561-564.  doi: 10.11821/xb199706010
    Abstract ( )   PDF (129KB) ( )   Save
    The theory of producing function in grey system is combined with differential profit calculating method to evaluate the standard industrial land price.It proves the theory and method of grey system′s applied prospects in the work of land evaluation. This paper also presents an operative way to evaluate land price with differential profit calculating method if the land market is undeveloped.
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