Table of Content

20 July 2002, Volume 22 Issue 4 Previous Issue    Next Issue

Orientation and Tactics for 21st Century Sustainable Agriculture and Rural Development in China LIU Yan-sui, WU Chuan-jun, LU Qi 2002, 22 (4):  385-389.  doi: 10.13249/j.cnki.sgs.2002.04.385 Abstract ( )   PDF (641KB) ( )   Save China is an agricultural country with a long history, its peasants making up more than 70 percent of its total population, its rural areas taking up more than 86.1 percent of its whole resident areas and its agricultural output value nearly contributing 17.2 percent to its GNP. The basic conditions of China determine the pivotal roles of agriculture, rural area and peasants in national economy and the construction of modernization. After entering WTO, Chinese agriculture and the development of rural economy will not only face new opportunities but also are confronted with greater challenges. Based on the preliminary analysis of the traits and problems in Chinese agriculture and rural economic development, this article put forward that Chinese sustainable agriculture and rural economic development should select the developing direction and model of industrialization, ecologicalization, internationalization and localization in the 21st Century, and lay stress on optimizing the institutional environment, consummating the guaranteeing system and breaking through the structural limitation to further reform and innovation. References | Related Articles | Metrics

A Social and economic analysis of ecological deterioration in the Western China——A case study of West Sichuan CHEN Guo-jie 2002, 22 (4):  390-396.  doi: 10.13249/j.cnki.sgs.2002.04.390 Abstract ( )   PDF (767KB) ( )   Save The decision of taking ecological construction as one of important contents and goals in the Western development indicates a great prograss of construction thought in China history. Its signification is not only to give the ecological construction an outstanding strategical position in Western development, but also to emphasize the integration of ecological construction and economic construction. Ecological deterioration in Western China is causative of profound social and economic origin. The author in the paper wants to expound the homology of ecological deterioration and regional poverty, and their alleviation of integration by taking West Sichuan as an example. West Sichuan, which is a part of Qinghai-Xizang(Tibet) Plateau, provides an important ecological defence for the upper reaches of the Changjiang(Yangtze) River. At present, West Sichuan is suffering from ecological deterioration and ecological function weakening. Regional poverty and ecological degradation form a vicious circle. It is also facing a new contradiction and challenges between the demand of ecological construction and the hope of rapid economic development. The main causes of ecological degradation in West Sichuan include low economic development as a result of over-loaded carrying capacity of population; backward mode of production and backward life style in rural area, for instance, using plant and animal manure as fuel, deforestation, cultivated steep land and natural grazing, result in vegetation destruction, grass degradation and soil erosion.We should recognize the facts that obvious resource superiority in West Sichuan did not lead to alleviate its poverty, but to cause serious ecological and environmental degradation because of primitive exploitation for lack of advanced technology. There low density of population did not avoid the tragedy of overload carrying capacity either. We should re-assess and re-fixed the position of regional superiorities of resource and, low density of population and the choice of resource exploitation and pillar industries in West Sichuan must be thought of using advanced technology, getting high benelits and compatible with environment. For implementing ecological construction and the strategy of sustainable development, it is necessary to build an open dissipative structure of social, economic and natural complex system and to found an order structure and mechanism for social and economic development harmonizing with ecological construction. Meantime they should reform profoundly their agro-ecosystem and create or develop new agricultural structures, new modes of production, new planting patterns and manage patterns, re-build rural structure and inhabitant patterns. All efforts are to exclude social foundation of slash-and-burn cultivation, steep land cultivation and nomadic life. References | Related Articles | Metrics

Runoff and Sediment Changes Characteristics after Returning Cropland to Grass on the Loess Plateau PENG Wen-ying, ZHANG Ke-li, JIANG Zhong-shan, KONG Ya-ping 2002, 22 (4):  397-402.  doi: 10.13249/j.cnki.sgs.2002.04.397 Abstract ( )   PDF (689KB) ( )   Save The Loess Plateau is well known to the world for its intense soil erosion. Increasingly critical soil erosion is an important factor contributing to ecological environment degradation such as land degradation and high sediment concentration of river. Water and soil losses are considered resulting from the most important cause of mankind irrational land use, particularly vegetation degeneration and cultivating steep slope land, and the awareness of tillage erosion as a soil degradation process has become an increasingly important concern to conservation. A large body of literature indicates that returning the steep sloping field to forest and grass land, and adjusting measures to local conditions to restore vegetation is the important measure to control soil and water loss in the plateau in our country. The study of returning the cropland to forest and grass affecting on the regional soil and water resources has been the hot. Even though there were many researches on reduced runoff and sediment for forest and grass, but based on comparing forest and grass to naked land, and less clear is the efficiency of reduced runoff and sediment resulting from returning cropland to grass. So, runoff and sediment changes characteristics after returning farmland to forest and grass should be studied. According to the comparison of the runoff and sediment amount in grass and cropland in experiment plots, the efficiency of reduced runoff and sediment with rainfall, slope and time were studied. Runoff and sediment reduction after restoring forest and grass occur mainly in heavy rain, particularly reduced runoff efficiency, in light rain, is very weak or not. Based on data calculated and analyzed, the efficiency of reduced runoff and sediment are 0.44 and 0.84 as rainfall exceeding 50mm compared 0.31 and 0.7 when rainfall under 20mm. With slope gradient increasing the efficiency increase, increasing speed of reducing sediment efficiency is much more rapidly than reduction of runoff. In those larger storms years and rainy seasons the efficiency of runoff and sediment reduction is high. At any time, reducing sediment efficiency is more strong than reduction of runoff. Returning cropland to forest and grass has been identified as main measure for conserving soil and water. The study results show, returning cropland to forest and grass is necessary, and the sloping field with a slope of ＞25° should be retured to grassland and forest as soon as possible. And it is hoped that such analyses will help understand the effect on water and soil resources from returning cropland to forest and grass. References | Related Articles | Metrics

Comparison of Runoff and Sediment between Southern and Northern Rivers to Qinling Mountains under Global Change ZHA Xiao-chun, YAN Jun-ping 2002, 22 (4):  403-407.  doi: 10.13249/j.cnki.sgs.2002.04.403 Abstract ( )   PDF (519KB) ( )   Save The span of Qinling Mountains affected the geograply and climate between the southern and northern areas to it. And under the influence of the global change, the Qinling Mountains has more affected the runoff and sediment between the southern and northern rivers. Based on long-time observed data about the Hanjiang River and the Weihe River from 1935 to 1999, the change of runoff and sediment were analyzed. The result showed that the annual average runoff of the Hanjiang River and the Weihe River were 592.94 m3/s and 248.26 m3/s respectively from 1935 to 1999, the former was 2.4 times to the latter, but the annual average sediment of the Hanjiang River and the Weihe River were 0.88 kg/m3 and 52.03 kg/m3 respectively, the latter was 60 times approximately of the latter. The Weihe River has more sediment. Then the runoff and sediment of the Hanjiang River and the Weihe River were analyzed from 1981, the result showed that the annual average runoff of the Hanjiang River and the Weihe River were 585.05m3/s and 195.89m3/s respectively, which decreased 27.4% and 1.9% respectively. But the annual average sediment of the Weihe River was 54.85 kg/m3, which increased 4.90% compared to that from 1935 to 1980, and the annual average sediment of the Hanjiang River was 0.41 kg/m3, which decreased 53.41% Compared to that from 1935 to 1980. So from 1981, the annual average runoff of the Hanjiang River and the Weihe River decreased, but the annual average sediment in the Weihe River increased and the Hanjiang River decreased under global climate warming, the former was 133 times of the later. This showed that the climate environment of southern and northern areas to Qinling Mountains responded to the global climate warming. References | Related Articles | Metrics

Study on Trajectory of Development in Tianjin Binhai New Area JIA Yan-jie 2002, 22 (4):  408-412.  doi: 10.13249/j.cnki.sgs.2002.04.408 Abstract ( )   PDF (601KB) ( )   Save Tianjin Binhai New Area (TBNA) is a new economic zone in the seaside area of Tianjin. Developing TBNA is a great strategic decision of local macroeconomic development distribution. TBNA is consisting of five sub-areas. Tianjin Economic-Technological Development Area (TEDA) and Tianjin Port Free Trade Zone are core areas of TBNA with significant contributions in attracting foreign investment and promoting international trade. TBNA has grown up to be a "Head of Dragon" of local economy in Tianjin with massive state and foreign investments through seven years development, which offered as 34.4% GDP, 40% GOVI, 51.7% Total Export percentages to Tianjin in 2000. The great achievements of TBNA have caused Tianjin city undergoing dramatic restructuring towards remaking the city as a global city, moving up the urban hierarchy in China. In this paper, through the case study of TBNA, I reveal the trajectories of and factors underlying local development. Based on the relevant statistics during 1993-2000, I hold that local development is a quite complicated process in the period of transitional economy in China. The paper has shown that development process is influenced by a multitude of forces operating at global, national, and local levels. On one hand, the Chinese government still heavily regulates its domestic economy, and actively initiates development policies. Governments are playing a significant role in urban and regional development in China. The local government of Tianjin has been an active agent of local economic development by obtaining preferential policies from central government and implementing numerous local initiatives. The infusion of foreign investment is clearly related to the preferential policy provided to foreign investors. However, I maintain government policies alone do not adequately explain trajectories of local development. Local states are embedded in forces operating at local, national and global scales. There is a strong geographical foundation for the functioning of local state corporatism. Local development conditions or geographical foundations in particular provide the basis for the initiation and successful implementation of local government policies and the location choices of foreign investment. Local governments, in initiating local policies, must carefully study those opportunities and constraints. Competition and cooperation among cities in Bohai Rim have also strongly influenced on the development of TBNA. References | Related Articles | Metrics

Magnetic Susceptibility of Lacustrine Sediments and Its Environmental Significance: Evidence from Napahai Lake, Northwestern Yunnan, China YIN Yong, FANG Nian-qiao, WANG Qian, NIE Hao-gang, QING Zun-li 2002, 22 (4):  413-419.  doi: 10.13249/j.cnki.sgs.2002.04.413 Abstract ( )   PDF (957KB) ( )   Save Magnetic susceptibility measurements have been made on a long sediment core from Napahai, northwestern Yunnan, China. These results are set alongside those derived from total organic carbon and granulometric analysis to reconstruct the environmental and climatic processes recorded in the radiocarbon dated sediment column. It is shown that the variations of magnetic susceptibility in this sediment core are mainly the result of changes in size constitution, hydrological and sedimentological regimes and organic content, implying shifts in the sedimentary environment and climatic condition. Decided by the characterization of sediment source and proximal transport, the magnetic minerals, in this case, are mainly concentrated in coarser sand size fractions. The values of magnetic susceptibility in an organic-free shallow lake correlate positively with coarser sediment. The proportions of magnetic minerals are strongly linked to the increase of runoff around the catchment and high energy conditions in the environment. The magnetic minerals are mainly concentrated in silty sand in low energy conditions below wavebase and the values of magnetic susceptibility decrease due to the lack of coarser sediment, the major carrier of magnetic minerals. The magnetic susceptibility has no definitely link to a fixed grain-size fraction in lakeshore environment and extremely low values of magnetic susceptibility are encountered due to the dilution of organic matter. Six major environmental sages during the last 60,000 years from the core record have been identified on the basis of magnetic susceptibility. Two major environment shifts occurred in approximately 32 ka B. P. (14.99 m) and 15 ka B.P. (6.06 m) respectively, in response to climate change. Cold/moist and warm/dry assemblages dominated the area and a typical cold/moist climate occurred from 32 ka B. P. to 15 ka B. P. The incline of precipitation during this stage is due to an increased mass exchange between the cold/dry air of northern continent and the water vapor from the northern Indian ocean. References | Related Articles | Metrics

The Discovery and Research on the Ferriferous Clay Nodules of 5th Paleosol Layer in Xi'an and Baoji ZHAO Jing-bo 2002, 22 (4):  420-425.  doi: 10.13249/j.cnki.sgs.2002.04.420 Abstract ( )   PDF (661KB) ( )   Save According to the survey of 5th red-brown paleosol layer in the loess in Xi'an and Baoji areas, it can be discovered that red ferriferous clay nodules exist at the bottom of this paleosol and the top of underlying 6th loess. Most of the ferriferous clay nodules have the prismatic, tabular and ellipsoidal shapes mainly filling in the cracks and root holes. The minor-axis diameter of the nodules is about 2-4 mm, while the major-axis diameter can be accessibly about 10 mm.The material obtained by optical microscope indicates that these ferriferous clay nodules have the charatcter of red-brown optical clay films developed well. It can be known by electronic microscope that these ferriferous clay nodules is consist of ultramicro crystals. These ultramicro crystals apparently spread by orientation, which is the reason of possessing optical character just as the mineral crystal.X-ray diffraction reveals that in the ferriferous clay nodules, mixed structure mineral of illite-montmorillonite take 90% or so and quartz takes about 5%, plagioclaspe and sanguine and so on just a little. The mineral ingredient shows that weathering of early-middle period occurred for clay mineral forming. Laboratory analyses indicates that in these ferriferous clay nodutles, SiO2 takes 42.13%-43.44%, Al2O3 22.29%-23.46%, Fe2O3 9.95%-10.36%. In the paleosol SiO2 takes 65.91%, Fe2O36.42%, Al2O3 15.85%, which shows that SiO2 content is about 12% lower in the ferriferous clay nodules than in paleosol, and Fe2O3 and Al2O3 are about 4.5% and 8% more in the nodules than in the paleosol respectively.In Xi'an and Baoji areas, the cracks and root holes developed well in the layer where the ferriferous clay nodules of 5th paleosol exist, and there is no water-resistance layer. Fe2O3 is high in content and there is no mineral formed in reduction condition. These shows that the ferriferous clay nodules of 5th paleosol formed not under the water resistance layer but by the ferriferous film migrating and gathering by the strong leaching.In Xi'an and Baoji areas, the ferriferous clay nodules lying in the parent loess are under the clay grouding layer of the paleosol bottom 1 m, which indicates that the affected depth of weathering was bigger than that of soil-formation band and the soil formation at that time is stronger than that of the contemporary drab soil. The distributive depth of the ferriferous clay nodules in 5th paleosol in these areas is primarily same with contemporary sub-tropical Yellow-brown Earth in Liuhe of Jiangsu, which indicates that subtropical climate migrated to these two areas at that time and the mean annual precipitation was about 1 000 mm. References | Related Articles | Metrics

The Evolution of Vegetation and Climate on the Basis of Sporo-pollen Assemblages since Mid-Holocene in the Tongjiang Region, Heilongjiang Zhang Yu-lan, Yang Yong-xing 2002, 22 (4):  426-429.  doi: 10.13249/j.cnki.sgs.2002.04.426 Abstract ( )   PDF (224KB) ( )   Save Based on the sporo-pollen analysis and the 14C dating from the Tongjiang region of 96-QP core, the four sporo-pollen assemblages have been distinguished in ascendant order:Zone 1:Quercus mongolica—Betula—Artemisia—Carex—Gramineae—Polypodiaceae Zone.Zone 2:Artemisia—Cyperaceae—Gramineae—Betula—Quercus Zone.Zone 3:Betula—Quercus mongolica—Pinus—Artemisia—Cyperaceae—Gramineae Zone.Zone 4:Pinus—Betula—Quercus mongolica—Artemisia—Carex Zone.Sporo-pollen zones mentioned above can clearly represent 4 evolutional stages of vegetation and climate. In ascendant order these stages are:the temperate deciduous broad-leaved forest→conifer and deciduous broad-leaved mixed forest-grass→deciduous broad-leaved forest containing coniferous tree-grass→conifer as deciduous broad-leaved mixed forest dominated by Pinus. The climatic variations are:warm and moist-temperate and little dry-temperate and little moist-cool and moist. References | Related Articles | Metrics

Formation and Change of Ancient Lake on South Coast Plain of Laizhou Bay HAN Mei, ZHANG Wei-ying, LI Yan-hong, ZHANG Li-na 2002, 22 (4):  430-435.  doi: 10.13249/j.cnki.sgs.2002.04.430 Abstract ( )   PDF (1894KB) ( )   Save Based on the data of the historical geography, the analysis of stratigraphic section, the textual research of the place name and satellite photographic interpretation, the authors studied the formation and evolution of the ancient lakes on the south coast plain of Laizhou Bay where ever had three lakes: Judian Lake, Qingshuibo Lake and Biehua Lake. All the lakes formed 6000 years ago, evolved from the lagoons near estuary and experienced two periods, the golden age in the Middle Holocene and the shrinking age in the Late Holocene. The disappearance of the lakes resulted from the drying climate, the migration of river and the activity of human being. Among the three reasons, the migration of river is the main one. References | Related Articles | Metrics

Diagnostic Soil Characteristic of Wind Erosion in Donggou Small Watershed of Luanhe River Source Area ZHAO Ye, HAI Chun-xing, LIU Xiao, LIU Hai-peng 2002, 22 (4):  436-440.  doi: 10.13249/j.cnki.sgs.2002.04.436 Abstract ( )   PDF (713KB) ( )   Save Soil wind erosion is one of the most serious environmental and socio-economic problems in many semiarid ecosystems of the world. Donggou small watershed of the Luanhe River source area (41°31'36″-41°33'56″N, 116°06'06″-116°11'50″E, 1560-1960 m a.s.l.) is one of the prototype mixed pasture-agriculture-frost ecosystems in the North China, where the soil wind erosion is developing rapidly and receiving widespread attention. The properties of the soils, which are influenced by wind erosion, are very important information for the wind erosion prediction and conservation. Using the detailed ground-based investigations of the household livelihoods, land use, environmental characteristics and diagnostic soil characteristics of Donggou small watershed, this paper analyses the wind erosion properties of the Hap-Ustic Isohumisols (or dark chestnut soil) in the areas with different wind erosion intensities. The results show that: (1) During winter and spring, Donggou small watershed has very strong wind (cold wave) and little precipitation, the soil is in drying-friable state, and soil texture is sandy, these natural environmental factors have provided the material resource and kinetic energy for the wind erosion processes. For traditional farming intensity is becoming increasingly high, the livestock capacity on the grassland and demand for the fuel-wood is becoming more day-by-day. These anthropogenic factors have been the trigger driving-force for the wind erosion processes. (2) For drying-friable surface soil, which has lost the protective cover of vegetation, the fine sand (0.10-0.05 mm) and very fine sand (0.05-0.01 mm) are carried away first by suspension and saltation. But the coarse sand (2.00-0.25 mm) in the surface soil is relative nonerodible particles. (3) A quantitative index was used to estimate the wind erosion intensity in the study area, i.e. SWEI=CS/EF, where CS is the content of the coarse sand in the surface soil, EF is the content of the fine sand and very fine sand in the surface soil. In the distribution areas of the Hap-Ustic Isohumisols, the SWEI≤2.0; in the distribution areas of weakly eroded soils, the SWEI≥3.0; in the distribution areas of very strong eroded soils, the SWEI≥9.0; But in the wind deposition areas, the SWEI≤1.5. References | Related Articles | Metrics

An Topographic Analysis of Grasshopper Outbreak in the Region Around Qinghai Lake Aided by GIS ZHANG Hong-liang, NI Shao-xiang, ZHA Yong, WEI Yu-chun 2002, 22 (4):  441-444.  doi: 10.13249/j.cnki.sgs.2002.04.441 Abstract ( )   PDF (546KB) ( )   Save The topographic analysis of grasshopper outbreak is the base to develop the prediction model for grasshopper outbreak. With the support of Arc/Info and ArcView, grasshopper outbreak information from field sampling is overlapped with elevation, slope and aspect types derived from Digital Elevation Models(DEM) respectively, the databases for each topographic variable of grasshopper outbreak information are obtained and analyzed. Then two-sample t-tests for the continuous variables and chi-square tests for the categorical variables are separately used to test the significance level. The results show that the effects on elevation and slope to grasshopper outbreak are very significant (two significance levels are all 0.000), while aspect’s effect is not very remarkable (significance level is 0.039). References | Related Articles | Metrics

Comparison of Pb and Cd Adsorption to Surface Coatings Developed in the Aquatc Environment of Wetland LI Yu, DONG De-ming, HUA Xiu-yi, ZHANG Jing-jing, YANG Fan, QIU Li-min 2002, 22 (4):  445-448.  doi: 10.13249/j.cnki.sgs.2002.04.445 Abstract ( )   PDF (658KB) ( )   Save Pb and Cd adsorption to surface coatings, which was developed in different waters in Xianghai Natural Preservation Areas, was carried out. Langmuir isotherm was used to describe Pb and Cd adsorption to surface coatings with significant correlation (n =6, p =0.01). It was also found that the adsorption of Pb to surface coatings is greater than that of Cd, and the maximum adsorption of Pb and Cd to surface coatings is closely related to the contents of Mn and Fe oxides on surface coatings. References | Related Articles | Metrics

Study on Emission Standards of Total Nitrogen and Total Phosphorus at Taihu Valley in Jiangsu Province SHENG Xue-liang, SHU Jin-hua, PENG Bu-zhuo, WU Hua-qian, HUANG Wen-yu, YANG Jing 2002, 22 (4):  449-452.  doi: 10.13249/j.cnki.sgs.2002.04.449 Abstract ( )   PDF (653KB) ( )   Save At first this paper analyses water qualities of Taihu Lake and its rivers coming in and going out, and makes some statistics about nitrogen and phosphorus sources at the upper reaches and long the shores of Taihu valley in Jiangsu Province. Secondly, it calculates maximum permitted loads for total nitrogen and total phosphorus by a lake model which has been tested to be effective. Thirdly, according to the concentrations of total nitrogen and total phosphorus in some wastewater, present techniques of wastewater treatment, protection target for Taihu water body and economic condition etc. it puts forward some main technical parameters for determining nitrogen and phosphorus emission standards for domestic wastewater which is a principal contributor to nutritional salts, and draws up the emission standards of total nitrogen and total phosphorus applied to different pollution sources, which are classified into three scales corresponding to three protection districts at Taihu valley in Jiangsu Province. Then it discusses the relationship between the standard and other emission standards. Finally, the effect on water quality from the standard enforcement is also estimated. References | Related Articles | Metrics

A Study on Pollen Analysis of Qiguoshan Section and Ancestor Living Environment in Chifeng Area, Nei Mongol XU Qing-hai, YANG Zhen-jing, CUI Zhi-jiu, YANG Xiao-lan, LIANG Wen-dong 2002, 22 (4):  453-457.  doi: 10.13249/j.cnki.sgs.2002.04.453 Abstract ( )   PDF (757KB) ( )   Save The paper on palynology and archaeology reveals the living environment of ancestor and the mutual relationship between human activity and environment change by pollen analysis of Qiguoshan Section in Chifeng Area. The results show that 8 400-6 200 a B.P., the climate was warm and moist with grassland vegetation, ancestors did hunting, fishing, planting and herding; 6 200-4 000 a B.P., environment changed gradually bad, and the agriculture level dropped with destroying forest; 4 000-2 500 a B.P., climate was temperate and arid with grassland vegetation, ancestors planted dry crop; 2 500 a B.P.-today, vegetation was the typical grassland of Artemisia, with comparatively temperate arid climate, the agriculture and animal husbandry was comparatively developed, and influences of human activities on environment have been enhanced. References | Related Articles | Metrics

Copper Speciation and Bioavailability in Gills Microenvironment of Carp LONG Ai-min, TAO Shu 2002, 22 (4):  458-462.  doi: 10.13249/j.cnki.sgs.2002.04.458 Abstract ( )   PDF (529KB) ( )   Save The gill microenvironment of carp was characterized using a two-apartment apparatus, and pH, alkalinity, mucus (expressed as total organic carbon, TOC) were modeled based on measured results. Copper uptake by gills at various concentrations of copper complexed with EDTA and bound to kaolin particulate was studied, and copper speciation in and out of the gill microenvironment was compared with chemical equilibrium model MINTEQA2. It was found that the copper uptake by gills increased with copper complex and particulate copper due to their dissociation in gill special microenvironment. References | Related Articles | Metrics

Research on the Space-time Distribution of Agricultural Natural Disaster in Zhou, Qin, Western and Eastern Han Dynasties BU Feng-xian 2002, 22 (4):  463-467.  doi: 10.13249/j.cnki.sgs.2002.04.463 Abstract ( )   PDF (262KB) ( )   Save Various kinds of agricultural natural disaster occurred frequently in Zhou, Qin, Western and Eastern Han dynasties. Through dealing with natural disaster historical data, the result shows that the important agricultural natural disaster frequency was 8 times in Western Zhou epoch, 88 times in Eastern Zhou epoch and averaged 1 time every 6.2 years; 291 times in Qin and Han epoch and averaged 1 time every 1.5 years. Agricultural natural disaster showed obvious character in time distributing: ①agricultural natural disaster was not evenly distributed through a year, natural disaster taking place more times in summer and autumn than spring and winter. ②Natural disaster had many concentratedly freqent occurring periods in interannual distribution. There was 1 period in Western Zhou Dynasty, 9 periods in Eastern Zhou Dynasty, 20 periods in Qin and Western Han dynasties, 27 periods in Eastern Han Dynasty. Furthermore, the more late the time was, the more obvious the phenomena of agricultural natural disaster muster occurrence were. In the aspect of space distribution, the sum of various kinds of agricultural natural disaster was 131 times in Shandong disaster section, 113 times in Shanxi disaster section, 15 times in Jiangnan disaster section, 6 times in Northwest disaster section, 4 times in Sichuan disaster section. The heavy disaster areas were Shandong and Shanxi sections in Zhou, Qin, Western and Eastern Han dynasties. References | Related Articles | Metrics

The Research on the Structure of Urban Area of Lanzhou YANG Yong-chun, ZENG Zun-gu 2002, 22 (4):  468-475.  doi: 10.13249/j.cnki.sgs.2002.04.468 Abstract ( )   PDF (881KB) ( )   Save Lanzhou is a typical valley-basin city in the northwestern China. This paper analyses the status quo's feature and organized model of internal structure and outer morphology of Lanzhou, and nodal region and homogenous area of urban district of Lanzhou. The factors affecting the forming and development of urban area structure of Lanzhou are discussed in the paper. Urban area structure of Lanzhou manifests dispersing and zonal multi-center spatial structure. Both of the homogenous degree and agglomerating degree of Lanzhou's urban district's functional area are very low. The average homogenous degree of inner and outer industrial area in Lanzhou's urban district are all below 1.07,and the average agglomerating degree of it are all below 0.27. The agglomerating degree of Lanzhou is below 0.03, which proves the belt feature of Lanzhou. The nodal region structure of Lanzhou's urban district still theoretically complies with Hexagon Structure Modal although the rank system of it isn't perfect because of the effect of natural conditions, especially landform.Lanzhou's unique natural condition and industrial development have played a great role on the development of its internal structure and outer morphology. Urban area structure of Lanzhou manifests dispersing and zonal multi-center spatial structure. The circle structure of urban area structure of Lanzhou from inner to outer place can be outlined as belted core parts, inner suburban district producing vegetables, melon and fruit in valley belt of the Huanghe(Yellow) River and the Huangshui River, outer sector satellite towns, outer agricultural area in the valley and others that concretely shows CBD commercial and serving center, fringe belt of urban center, inner and outer industrial area, satellite towns and agricultural suburbs. Fringe belt of urban center has the integrated function consisting of commercial function, social function, cultural function, administrative function, medical function, insurance function, financial function, and light industrial function. Inner industrial area includes Donggang, Yantan, Yanchangbu, Qilihe and Anning. The outer industrial area has Xigu, Liancheng-Haishiwan and Hekou-Dongchuan. There are cultivated land, lawn and tree land between the inner industrial area and outer industrial area. The satellite towns of Lanzhou have Yongdeng County town, Gaolan County town and Yuzhong County town. Now Lanzhou is one of the cities to be heaviest polluted in China because of its industry system whose key industry is oil and chemistry industry and limited polluted degree that urban air and water system in valley-basin can bear. Moreover, because the quantity of suitably urban land is limited urban reserve land will be lacked after twenty or thirty years according to the speed of consuming urban empty land. At the certain stage they are key problems to be solved in urban development that urban area structure should be rationally planned and the direction of its development should be carefully determined and satellite towns should be prudently selected after the sort of cities reach the certain higher stage. It is so important that urban area structure should be strategically adjusted, and independent districts should be rapidly established and satellite towns should be perfected in the process of valley-basin City's construction. In future, belted urban agglomeration would maybe appear in the upper reaches of the Huanghe River. References | Related Articles | Metrics

Non-nativeborn Low-income Migrants Settlement and Below-up Urban Development TIAN Jian-ping, XU Xue-qiang, ZHAO Xiao-bin, CHEN Zheng-guang 2002, 22 (4):  476-482.  doi: 10.13249/j.cnki.sgs.2002.04.476 Abstract ( )   PDF (1038KB) ( )   Save In the course of social transfer from duality economy society to modern economy society in China, many rural surplus labor forces have entered into the cities and spontaneous settlement of the immigrants had appeared in the cities, which have a serious impact on the Chinese social and urban development. Through spot check and stress investigation of "urban non-nativeborn low-income migrants" in 50 villages in Guangzhou and Dongguang cities in Guangdong Province with visiting and questionnaire method, the thesis argued about below-up self-help housing and developing settlement model, which impact on urban development. And a below-up urbanization theory assumption happening in urban region was pointed out. References | Related Articles | Metrics

Changes of Water Price in China and Its Regional Characteristics ZHANG De-zhen, CHEN Xi-qing 2002, 22 (4):  483-488.  doi: 10.13249/j.cnki.sgs.2002.04.483 Abstract ( )   PDF (284KB) ( )   Save With the rapid deterioration of water resource, changes of water price and the relevant issues have received wide attention in China. This paper reviews the water price change and water policy in China since the founding of P. R. China. The regional difference in water price is examined in reference to the regional variation in society, economy, water resource and environment. Through studying the water price reform since the later 1990s, this paper analyses the present status and future prospect of water price in China. The basic theory for the increase of water price and the endurance of residents to water price are discussed. References | Related Articles | Metrics

The Impacts of RBD on Urban Development in Guangzhou City GU Shi-yun, BAO Ji-gang 2002, 22 (4):  489-494.  doi: 10.13249/j.cnki.sgs.2002.04.489 Abstract ( )   PDF (738KB) ( )   Save Urban recreational business district (RBD) has become a very important part of the urban tourism system, offering tourism for tourists, and leisure, entertainment and shopping experience to local and peripheral residents. Based on the research on RBD at home and abroad, this paper uses the RBD in Tianhe Plaza, Guangzhou City, as well as its neighbors Hongcheng Plaza, Tianhe Sports Center and Guangzhou Bookstore as the subjects of the study. The RBD of Guangzhou City gradually matured after Tianhe Plaza started business. As a result, it brought very good profit to the commerce of Guangzhou, especially to the business development in Tianhe. In 1996, the total amount of consumption in Tianhe district was ￥5.227 billion, with a 40% increase from the ￥3.73 billion in 1995. In 1997, the total consumption went up to ￥6.41, with a 22.63% increase from the previous year. The RBD improved further the business status of Tianhe district, bringing about a new network of retail shops. Back in 1990, the business center of the city was in the old part of the city. Since 1996 when Tianhe Plaza came into being, a new business center emerged in the eastern part of the city. As a result, there formed a new network of two business centers of retail shops, one new, one old, in the eastern and western part of the city. The success of Guangzhou's RBD came from the fact that people's need for consumption was satisfied in a very good shopping environment. Furthermore, this helped to bring about the business environment where people are the focus. The RBD stimulated the need for entertainment and introduced a new way for leisure. More and more residents went Tianhe district for leisure. Even those who were there shopping, got used to taking advantage of recreational facilities there. The development of RBD changed the way people spend money and time, giving them a more positive attitude to life. The development of RBD also attracted a lot of tourists, which had an impact on the flow and volume of the traffic. The most obvious change was in the increase of buses. The increase in buses in turn helped Tianhe district's development. The convenience in transportation made it easy for people to live in Tianhe. Consequently, the real estate in the district enjoyed very good sale. The new RBD in Tianhe attracted residents in the old part of the city to Tianhe district, expediting the development of the new district. In the mean time, the recreational facilities and leisurely environment makes the RBD very appealing. This diverted the traffic to the city center, and relieved the tension on the city's traffic. The formation and development of RBD has brought a new trend in the urban development: a new urban area with multiple functions can draw people to it, making it more competitive than an area with just one function. References | Related Articles | Metrics

An Example of Marginalized Region: Evolution of Yichun Urban System and Its Strategy XIU Chun-liang, YUAN Jia-dong 2002, 22 (4):  495-499.  doi: 10.13249/j.cnki.sgs.2002.04.495 Abstract ( )   PDF (242KB) ( )   Save This study is based on a series of field investigation works that were done specially in the early and late 1990s.Yichun is situated in the border area of northern part of Heilongjiang Province, and in the hinterland of Xiao Hinggan Mountains. Its social-economic and urban systems are formed with the large-scale exploiting of Xiao Hinggan Mountains forest reserves. In the regional development in the 1990s, its process in economy and living pattern has been falling behind the mainstream regions, and Yichun was increasingly becoming a marginalized region. A series of changes in the urban system had taken place: (1) Urbanization level was superficial high, and the population continued concentrating. (2) Resources and locations were the decisive factors of town's increasing, stagnating or falling. (3) Central city was still weak, urban size structure was proportionate, but the rank-size relativity fell. (4) As basic economic sector that supported urban growth, forest industry was declining, meanwhile, substitute ones grew slowly, only in isolated towns ecological tourism developed at the outset. (5) Expanded internal difference of urbanization between the south and north confirmed the existence of marginalization inside the municipal area.As a vast, sparsely populated area in good ecological state, Yichun has the opportunity to be lifted out of marginalization. Strategic points are creating conditions for reverses and qualitative changes, thus joining the external pioneer regions, giving impetus to development with interchange. Adopt unbalanced developing way. Separate the governments and enterprises, in order to establish an administrative system that suits to the needs of market economy and external opening. Join districts together and set up counties, cancel some districts and set up towns, in order to establish normal administrative area system. Promote central city to grow rapidly by way of integrating neighboring towns and concentrating the creams. Promote the port construction, develop business cooperation with Russia, in order to increase external contact ways, change the unfavorable influence of location. References | Related Articles | Metrics

Comparison of Methane Emission from Marsh and Paddy Field in Sanjiang Plain WANG De-xuan, LU Xian-guo, DING Wei-xin, CAI Zu-cong, Wang Yi-yong 2002, 22 (4):  500-504.  doi: 10.13249/j.cnki.sgs.2002.04.500 Abstract ( )   PDF (572KB) ( )   Save The Sanjiang Plain is the major distribution area of marsh in China. In the past twenty years, the area of paddy field has increased rapidly from 13.47?104 ha in 1983 to 46.74?104 ha in 1997. The conversion of marsh into paddy field changed intrinsic characters of the soil, which resulted in the change in methane emission. To investigate the difference in methane emission from marsh and paddy field, we simultaneously monitored methane emission from the Carex lasiocarpa marsh and paddy field converted from marsh in Sanjiang Plain from May through October 2001. The results showed that the flux of methane emission from Carex lasiocarpa marsh ranged from 1.32 to 46.38 mg/(m2·h) with an average of 17.29 mg/(m2·h) and from 0.05 to 24.37 mg/(m2·h), averaging 6.67 mg/(m2·h) from paddy field. The former was 2.5 times higher than the latter due to different water condition and soil physical-chemical properties. The obvious seasonal variation of methane flux existed and the highest value occurred in between July and August. References | Related Articles | Metrics

Composition of Physical Factors Before Huge Flood along the Changjiang River FENG Li-hua 2002, 22 (4):  504-507.  doi: 10.13249/j.cnki.sgs.2002.04.504 Abstract ( )   PDF (450KB) ( )   Save The huge flood along the Changjiang River is the catastrophic flood of the whole basin along the Changjiang River. The huge flood along the Changjiang River is a result of the comprehensive action of the various physical factors. Now it is demonstrated that the physical factors which play a main part in the huge flood along the Changjiang River are as follows: monsoon of Asia, subtropical high of the west Pacific Ocean, blocking high of the middle latitude, snow on the Qinghai-Xizang Plateau in winter season, El Nino event, sunspot activity and so on. The physical factors which play a next part in the huge flood along the Changjiang River are as follows: assemble of nine stars, trade wind, earth’s rotation rate, geothermal release, eclipse of the sun and so on. The concept of composition of the physical factors before the huge flood along the Changjiang River is put forward. Before every huge flood arises, there are generally the similar characteristics that are some inherent compositions between the main physical factors that have an effect on the huge flood. That is, in next year of El Nino event around the transformation year of magnetic cycle of sunspot activity, the position of subtropical high of the west Pacific Ocean in summer changes south because of the influence of sunspot activity and El Nino event. At the same time, excessive snow on the Qinghai-Xizang Plateau decreases thermal action of the plateau, and blocking high of the middle latitude changes south frontal zone south. Because monsoon of Asia become weaker by them, the position of main rain band of China in summer changes south. Hence the catastrophic flood of the whole basin arises along the Changjiang River. These compositions are strong signal of the huge flood along the Changjiang River, which is of important indication function for forecast research of the huge flood along the Changjiang River. References | Related Articles | Metrics

Study on the Effect of Land Use Change on the Eco-environment QIN Li-jie, ZHANG Yu, XU Hong-mei, LIU Xiang-nan 2002, 22 (4):  508-512.  doi: 10.13249/j.cnki.sgs.2002.04.508 Abstract ( )   PDF (625KB) ( )   Save With the increase of population and the development of economy, the land use change is more notable, and causes the change of eco-environmental background of land resources. Studying the effect of land use change on eco-environment can improve the conditions of agricultural production, and make the regional economy and ecoenvironment develop in a good way. Taking Qian Gorlos County as an example,the paper analyses the pattern of land use change, it shows that there was an obvious decrease in the area of grassland and forestland, while wasteland and paddy field increased in 1986 and 1996. Then the paper studies the effect of land use change on the eco-environment, the effect shows mainly at three aspects: ⑴ Land deterioration aggravated. Not only the area of land deterioration was enlarged, but also the degree of land deterioration was aggravated. ⑵ Water pollution was serious. With the farmland area enlarged and amount of irrigation water increased, the agricultural drainage resulted in water quality worsened. ⑶ Bio-diversity decreased. With the land use pattern changed, the landscape fraction increased while the dimension of patches decreased. References | Related Articles | Metrics