Table of Content

    25 June 2005, Volume 20 Issue 3 Previous Issue    Next Issue
    Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    Spatial Optimization of Land Use Based on Soil Water Distribution in the Hill,gully Areas of the Loess Plateau - A Case Study of the Xingzihe Watershed
    XIAO Qing-wen, NI Jin-ren, LI Tian-hong
    2005, 20 (3):  317-325.  doi: 10.11849/zrzyxb.2005.03.001
    Abstract ( )   PDF (405KB) ( )   Save
    Based on the cumulate soil water replenishment model,soil erosion mode l,and multiple objective nonlinear optimum models,an allocation model for spatia l optimization of land resource was established.The method includes four steps.T he first step,with the objective of making spatial distribution of water resourc e suitable for crop growth in the study area,is to establish the water distribut ion models based on grid data model,SCS discharge model and the principle of wat er content equilibrium.The second step is to establish a soil water prediction model to analyze watershed soil and water loss situation.In this step,Digital El evation Model(DEM),land use map,soil type distribution map,climate,meteorologica l and hydraulic data are required.The third step is to integrate the water conte nt distribution model,soil and water loss model,and a multiple objective model f or land use optimization in order to get the quantitive structure of land use.Th e last step is to allocate the optimized land use structure spatially based upon the current land use patterns and the principles of ecology.To test the model,a typical watershed,Xingzihe watershed,on the Loess Plateau in northern Shaanxi p rovince was selected as the study area.As a result,land resources at the watersh ed were allocated based on the local integrated regulation programming.The ecolo gical and economic benefits of the optimum land use structures were discussed.It is indicated that the eco,environment of the study area would be apparently imp roved after watershed regulation.Moreover,the local farmers' income would be gre atly increased,and the major source of agricultural income would be shifted to w oods and fruits.At the same time,the case study also revealed that both of the e conomic benefit and the ecological benefit will increase until the management de gree reaches 30%.When the degree exceeds 30%, the economic benefit will continue to increase but the ecological benefit will remain almost unchanged.The propose d method can produce better result for local land use structural regulation.
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    A Preliminary Study on Land Exploitation and Utilization Models of Water,Level,Fluctuating Zone (WLFZ) in the Three Gorges Reservoir Area of Chongqing
    SU Wei-ci, YANG Hua, ZHAO Chun-yong, LI Qing
    2005, 20 (3):  326-332.  doi: 10.11849/zrzyxb.2005.03.002
    Abstract ( )   PDF (1239KB) ( )   Save
    The Three Gorges reservoir is one of the largest water conservancy and control pro,jects in the world.After the accomplishment of the project,a 30,met er high water,level,fluctuating zone will appear along the both banks,and become a kind of seasonal humid ecosystem where the area covers 291.1km2.This paper,ac cording to the program of water storage in the Three Gorges reservoir,explores t he distributed features and useful values;and states the five principles that sh ould be followed in the process of land exploitation and utilization,namely,sust ainable land use,preference of ecosystem safety,exploitation of WLFZ according t o the types and grades,market requirement,and dealing with easy ones first and difficult ones afterwards.Meanwhile according to the types,grades,soil textures ,shapes of landforms and climate conditions in WLFZ,six models for land use were suggested as:(1)agricultural development model in open terraces of WLFZ;(2)farm ing and pasturing model on moderate and gentle sloping(slope<15°)land of WLFZ;( 3)aquatic product breeding model in river bend of WLFZ;(4)tourism development mo del in areas with unique landscapes of WLFZ;(5)closing hillsides to facilitate a fforestation model through natural and artificial ways in gorges or rock expose d regions of WLFZ;and(6)town (city)landscape construction and geologic disaster prevention model of WLFZ.Some eco,environmental and pollution problems maybe app ear in the development of WLFZ were also analyzed,and corresponding proposals we re put forward.This will provide scientific basis for the planning and developme nt of land resources of the Water,Level,Fluctuating Zone.
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    Analysis of the Situation and Mechanism of Land Use Conversion in the Southeast Coastal Area
    LIU Yan-sui, PENG Liu-ying, WANG Da-wei
    2005, 20 (3):  333-339.  doi: 10.11849/zrzyxb.2005.03.003
    Abstract ( )   PDF (213KB) ( )   Save
    The southeast coastal area of China has played a more and more importa nt role in promoting China's economy and increasing its international competitiv eness since the reforming and opening up.Land resources have made remarkable con tribution to the development of region's economy.In southeast coastal area of Ch ina,the utilization ratio of land reaches 89.8%,much higher than the national av erage level of 74.1%. Simultaneously, due to the intense exploi,tation,especiall y the unreasonable land use,the pattern of land cover in this region has markedl y changed.Based on the analysis of the features and problems of land use change in the southeast coastal area in the 1990s,by introducing the following judge in dexes such as LDD,LAD and LCD,the degree,spatial,temporal heterogeneity and driv ing mechanism of regional land use conversion are identified.According to the re search, the arable land of this area decreased 122.2×104hm2 contrasting to an i ncrease of 85.9×104hm2 of construction land in the recent 10 years.The developm ent level and structural alternation of the regional economy and society have pr ofound effect on the situation of land use type conversion.The consummation of m arket economic system and institutional innovation of individual economy speed u p the conversion of land use type in the southeast coastal area.The increase of population and the technical advance,ment are the primary driving forces of land use type conversion,and by the way of accelerating the construction of all kind s of industrial gardens (including developing area) and central town and village s,the two forces prolong their effects on the whole process of land use conversi on. Therefore,it is very necessary to regulate the hot economic investments and construction of the development districts by the state government.And the conver sion from arable land to built,up area ought to be restricted in order to create a fine condition of sustainable land use for enhancing social and economic deve lopment rapidly in the southeast coastal area of China.
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    Relationship between Land Productivity and Land Use Structure
    LI Xiao-juan, NI Jin-ren, LI Zhen-shan, HAN Peng, LI Tian-hong
    2005, 20 (3):  340-346.  doi: 10.11849/zrzyxb.2005.03.004
    Abstract ( )   PDF (314KB) ( )   Save
    Severe soil erosion and low land productivity have become serious ecol ogical problems in the Loess Plateau region.This paper focuses on the relationsh ip between land use structure and land productivity through a case study at Wang jiagou watershed in western Shanxi. It is indicated that there are remarkable linear relevant relations betwee n the potential productivity and the land use structure index (SI).The potential productivity would increase with the increase of SI.Another index PrI is introd uced and well defined as the rate between the disparity of the potential product ivity and actual productivity.The PrI and SI have good linear positive correlati ons.The larger the PrI and SI,the more pains to increase actual yield.The mechan ism on how the landuse structure affecting the land productivity is revealed. Soil erosion would be decreased with the increase of SI.As a result,the l oss of soil fertility can be improved.Therefore,land use structure can be adjust ed properly so as to improve the land productivity.Therefore, wise planning for regional land use structure and conservation of soil and water would be helpful to gain more crops.Consequently,both economic and ecological benefits could be o btained in the same process.
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    Study on the Agricultural Water Resources Balance in Northwest China
    YANG Yan-zhao, FENG Zhi-ming, LIU Bao-qin
    2005, 20 (3):  347-353.  doi: 10.11849/zrzyxb.2005.03.005
    Abstract ( )   PDF (293KB) ( )   Save
    As land and water resources are out of proportion and the spatial,temp oral distribu,tion of water resources for agriculture is quite uneven in Northwe st China,it is important to study the agricultural water resources balance in th is region.This paper systemically analyzed the agricultural water resources bala nce from two hierarchical aspects and identified the calculation methods for bot h steps.Taking 314 counties as examples,it studied the agricultural water balanc e in Northwest China.Results showed that precipitation can not meet water demand of the crops,hence water deficit is the prime characteristic in water balance i n Northwest China.Deficits of all 12 crops were 898.28mm in Tulufan county,and t he precipitation satisfied ration ranged from 2.74% to 3.71& for different crops .Total water deficits of 12 crops in Xinjiang reached to 628.02 mm,and the preci pitation satisfied ration was only 13.65%.So water deficit was serious in Xinjia ng.The precipitation satisfied ration was 82.37% in Shaanxi province,and the sit uation was the best.Satisfaction ration for different crops were not the same,as for vegetables and rice,since the water demand was much higher than the other c rops,the satisfaction ration was the worst,but the case for potato and hemp was the best.The results showed that even irrigation water was taken into account,it still can not meet the crop water demand in Xinjiang.In the year 2000,the net i rrigation water demand was 141.95×108m3,the water supply can't meet its demand, and the total water deficits were 18.24×108m3.The irrigation water can basicall y meet the water demand in other provinces,water surplus was 9.42×108m3 in Shaa nxi,7.87×108m3 in Gansu,7.38×108m3 in Qinghai,and 23.33×108m3 in Ningxia.Ther e is still certain potential to enlarge irrigated areas in these provinces.
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    Study on Integrated Benefit of Rainwater Resources Utilization in Small Watershed on the Loess Plateau
    ZHAO Xi-ning, FENG Hao, WU Pu-te, WANG Wan-zhong
    2005, 20 (3):  354-360.  doi: 10.11849/zrzyxb.2005.03.006
    Abstract ( )   PDF (305KB) ( )   Save
    Rainwater resources utilization is an effective measure for solving wa ter resources shortage and eco,environmental rehabilitation in Loess Plateau of China.Research of rainwater resources integrated benefit evaluation is a core pr oblem concerning development of dryland agriculture,soil and water environmental protection as well as coordinated economic and eco,environmental development.No wadays the evaluation models and indicators system of rainwater resources mostly use economic benefit maximum as optimized objection function,regardless of soci al benefit and eco,environmental benefit.Especially research of rainwater resour ces integrated benefit in Loess Plateau is inadequate.Based on the current situa tion of rainwater resources utilization and the characteristic of converting rai nwater into rainwater resources,applying analytic hierarchical process theory,th is paper establishes the mathematical model and indicators system for integrated benefit evaluation of rainwater resources utilization by taking small watershed as a research unit and rainwater resources as a research object.The evaluation indicators system is proposed based on characteristics and principles of scienti fic,practical and concise.The indicators system includes three aspects such as e conomic benefit,social benefit and eco,environmental benefit and systematically reflects rainwater resources utilization features in small watershed.Because of the complex relation of indicators factors,synthetically benefit evaluation incl udes quantitative and qualitative aspects.The evaluating model and the indicator s system are applied to evaluate synthetically the status of rainwater resources utilization in Nihegou watershed in Shaanxi Province.The evaluation model playe d an important role in the evaluation and management of rainwater resources sust ainable utilization and eco,environment construction on the Loess Plateau.
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    Transboundary Flow Change of the Lancang River and its Response to the Variation of Precipitation Field over Yunnan
    YOU Wei-hong, HE Da-ming, SUO Miao-qing
    2005, 20 (3):  361-369.  doi: 10.11849/zrzyxb.2005.03.007
    Abstract ( )   PDF (3255KB) ( )   Save
    Recently,with the fast development of the important regional cooperati on actions in e,conomy such as the economic cooperation of Lancang,Mekong River Subregion,the changes,regularity and influence of the water resource system in t his drainage basin have become the focus of the attention and hotspot of researc h internationally.In order to investigate the basic facts which the climate chan ges influence on the hydrological and water ecological environment variations of the Lancang,Mekong River Basin,this paper studies the multi,timescale characte ,ristics of the transboundary flow variations for the Lancang River and its resp onse to the changes of precipitation field over Yunnan based on the observationa l data of the Lancang River flow and precipitation field in Yunnan and using the wavelet transform and correlation analysis method. The results show that the an nual variations for the Lancang River flow in the upper,lower reaches obviously appear multi,timescale features,their difference are mainly on the smaller times ,cales,but they are very analogous on the larger timescales.There are very signi ficant correlations between the annual variations of the Lancang River flow in t he upper,lower reaches and the precipitation field over Yunnan.The multi,timesca le characteristics of the annual precipitation over Yunnan are analogous to the ones of the Lancang River flow in the upper,lower reaches.In brief,the main reas ons for the transboundary flow variations for the Lancang River are the changes of the precipitation field over Yunnan,specially on the larger timescales,the fl ow changes of the Lancang River in the upper,lower reaches have highly response features to the variations of the precipitation field over Yunnan.
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    Conception and Countermeasures about Sustainable Utilization of Water Resource in the Oasis of Heihe River Basin
    LI Qi-sen, ZHAO Wen-zhi, FANG Qi, SU Pei-xi
    2005, 20 (3):  370-377.  doi: 10.11849/zrzyxb.2005.03.008
    Abstract ( )   PDF (151KB) ( )   Save
    Aiming at some problems about the water resource shortage,with its dyn amic change and distribution under different time and space scales,and its impac t on the social,economic,ecological development and evolvement in the oasis of t he Heihe River Basin,this paper makes a systemic analysis and an in,depth study for gaining innovative development on the conception, countermeasures,and ways o f sustainable utilization of water resources.Reasearch results indicate that the key reasons affecting social,economic,ecological development and sustainable ut ilization of water resources are idea renewal,reasonable population regulation a nd control,appropriate high efficient utilization of water and so on.At the same time,we should also rationally face the long,term,complicated,and arduous cours e in the maintenance of the ecosystem stabilization and environment improvement. Taking the river basin as a whole,the embodiment of the main characteristics in sustainable exploitation and utilization of the water resources,is to possess pr oper proportions and supply of the water resources for keeping social,economic a nd ecological sustainable development in each district.For instance,the availabl e water resource is more abundant within the scope of a certain time and space,a nd its sustainable utilization level should be higher;however,even though some p roblems beyond anticipation may still occur.Besides,due to characteristics of th e higher openness,dynamic condition,fragibility,etc.,of the river basin and the oasis system that determine the unbalanced time,space distribution and the unsta bility of the water resources in different sections of the river basin,greater d ifferences in social,economic,ecological development should be resulted in each district.Therefore,sustainable exploitation and utilization of water resources s hould follow the principle of moderate development between nature and mankind so ciety. First of all,a series of feasible population development programs and the reasonable socio,economic development ways should be worked out.And then full e xert the human's subjective ability in the course of searching for the effectiv e countermeasures and techniques/ways should be brought into full play.Specific measures are to renew and change the traditional development principle and conce pt relating to society,economic and population;reasonably adjust and control wat er resources and practise reasonable water allocation of the district;promote th e application and development of the water saving techniques;and establish and perfect water resources scientific management system with the commercialized mar ket operation system in Heihe River Basin.
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    Comparative Analysis of the Superiority of China's Phosphate Rock and Development Strategies with that of the United States and Morocco
    ZHANG Wei-feng, MA Wen-qi, ZHANG Fu-suo, MA Ji
    2005, 20 (3):  378-386.  doi: 10.11849/zrzyxb.2005.03.009
    Abstract ( )   PDF (385KB) ( )   Save
    Focusing on protecting the resource and enhancing its utilization, thi s article compared the reserves,grade,heavy metal content,centralization degree of reserves and transport distance of the phosphate rocks in China,USA and Moroc co.It is found out that Moroccan phosphate rock resources have extremely strong advantages,and the American resources are also superior to China.Comparsons of t he mineral production scale,recovery rate,production,cost and sustainable utiliz ing years revealed that USA and Morocco were superior in these aspects to China. It was estimated that the phosphate rock production in China had exceeded 40 mil lion tons (47.2 million tones in 2003) according to the phosphorus fertilizer pr oduction,which was the highest in the world.If the recovery rate was considered, more than 100 million tons might be exploited in 2003.That means 58.4 million to ns of phosphate rock were wasted.The phosphate rock all over the world can meet the demand of 100 years,but in China if no measures were taken to improve the te chnology of mining and to cut down the wastage,the phosphate rock which contains more than 30% of P2O5 would be used up in 2014.However,if the recovery rate was improved,it can last to 2022.With the exhaustion of the phosphate rock 20~30 y ears later in USA and China,Morocco will become the biggest phosphate supply cou ntry in the world.Despite the advantage of the heavy metal,i.e.,the low cadmium content,China's phosphate rocks are facing a gloomy future for its low,efficienc y utilization strategy. To the above question,this article has proposed several suggestions for the rational utilization of the phosphate rock resource in China .
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    Comparative Study of the Soil Erosion and Control in the Three Major Black Soil Regions in the World
    FAN Hao-ming, CAI Qiang-guo, CHEN Guang, CUI Ming
    2005, 20 (3):  387-393.  doi: 10.11849/zrzyxb.2005.03.010
    Abstract ( )   PDF (642KB) ( )   Save
    In this paper the conceptions of the black soil and the black soil reg ion have been clarified.We have zoned the black soil area into the typical black soil region and the black soil region in China.The three black soil regions in the world have been compared in terms of the soil,forming condition,the process of exploitation and utilization,and the soil erosion and the soil and water cons ervation.Although there are some similarities in natural conditions in the three black soil regions,the black soil in China is prone to be eroded for its undula ting relief.The large,scale land reclamation and the unreasonable farming practi ces are the prime reasons to cause soil erosion and the soil degradation in the three black soil regions.Most of soil erosion taking place in the black soil reg ion of China is water erosion,but the wind erosion dominates in the other black soil regions in the world.Comparing with the other black soil regions in the wor ld,the black soil region in China is still lagging behind in some aspects in soi l and water conservation,such as cropping system, land use policy,funds invested ,propaganda and education and scientific experiment in soil erosion control.The disadvantages in the control of soil erosion and water loss in China's black soi l region are identified through comparing with soil and water conservation measu res conducted in the other black soil regions in the world.Problems that have to be settled urgently in soil erosion control in the black soil region of China a re proposed.
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    Research on the Impact of Natural Resources on Urbanization Level of China
    CHEN Bo-chong, HAO Shou-yi
    2005, 20 (3):  394-399.  doi: 10.11849/zrzyxb.2005.03.011
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    China has entered the stage of rapid urbanization since 1996.The paper makes a con,clusion that natural resource is a strong restriction of rapid urba nization of China by adopting general equilibrium method in terms of supply and demand.Urbanization includes two aspects, one is urbanization quality and the ot her is urbanization level.This paper divides natural resources into two categori es,one is for production purpose and the other for living.In theory,we can subst itute urbanization level approximately with resources for production,so is the c ase of urbanization quality with resources for living.Under restriction of natur al resources,the optimum result of resources distribution indicates that there i s a substitutional relationship between the urbanization level and urbanization quality.On the basis of the above discussion,we make a comparative static analys is on the equilibrium result.Both change of natural resources endow,ment and fu nction utility will lead to variations in equilibrium result.The study shows tha t the economic globalization is favorable for the increase of the supply of natu ral resources,and the preference of urbanization road directly influences the ur banization level.Facing the double pressure of labor force transferring and prom oting urbanization quality in the rapid urbanization process of China,both the u rbanization quality and quantity should be regarded as equally important,and the mode of economic growth should be changed.
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    A Study on the Intensity and Spatial Pattern of Urban Residential Growth in Shanghai from 1947 to 2002
    ZHAO Jing, CHEN Hua-gen, XU Hui-ping
    2005, 20 (3):  400-406.  doi: 10.11849/zrzyxb.2005.03.012
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    Based on the multi,temporal land use map and SPOT data,modes,intensit y and spa,tial pattern of residential growth of built,up area in Shanghai from 1 947 to 2002 were studied according to the calculated land use intensity index wi th GIS gridding analysis.The results indicate that:(1)Spatial growth of the resi dential area was not increasing continuously with time,the growth intensity,spe ed and the area of all the growth types presented a descending trend from 1947 t o 1979 with the minimal value occurring during 1964~1979,and a gradual ascendin g trend was observed from 1979 to 2002 with the maximal intensity and speed occu rring during 1996~2002,the difference between the maximal and minimal intensiti es was about 100 times.(2)Growth modes of the residential area were distinct in each stage, and showed a "gradual circle growth mode" according to the growth in tensity from the centre to the verge of the built,up area in the initial stages( gradual growth dominated the central built,up area during 1947~1964), an interl aced intensity pattern of "leap growth mode" in the medium stages(from 1964 to 1 988)and an"integrated growth mode"of the foregoing two types from 1988 to 2002(m ixed growth mode consisting of gradual circle and leap growth),thus the urban la nd use functions became more complicated.(3)The growth processes of the resident ial area showed strong difference in each stage,and were influenced by the macro scopic policies and economic development in different periods,which provided abu ndant data and materials for the studies of the urban growth mechanisms.
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    From Static Assessment to Dynamic Processing: Resources Flow and Its Contents and Methods
    CHENG Sheng-kui, MIN Qing-wen, YAN Li-zhen
    2005, 20 (3):  407-414.  doi: 10.11849/zrzyxb.2005.03.013
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    Resources shortage and environmental issues resulting from unsuitable resources exp,loitation and utilization have promoted the development of resourc es science.Many researches have been made in the field of resources science but most of them focus on the qualitative analysis or semi,quantitative analysis.Acc ording to the progress stage of resources science, tradi,tional stage is a stati c research focusing on two main contents:the research of investigation and evalu ation of natural resources and of synthetical research of population,resources a nd environ,ment.In this article,on the basis of reviewing the progress and featu res of resources science in different stage and from the angle of the influence of ecology on resources science,the authors attempt to illustrate the concept,co nnotation and methods of resources flow.Obviously,the weaknesses of traditional research lie in that the same resource belongs to different departments and the separation in benefit distribution has led to the confusion of resources managem ent and a low rate of resources utilization. Modern stage has imbibed the though t and method of ecology.Absorbed the principles and methodology of ecology,espec ially the ecological system and flow analysis,resource flow takes the resources as the compound of a net structure composing of different disciplines,different regions and different departments and a link structure from exploitation to cons umption.The analysis of resource flow is helpful to describe the dynamic process and mechanism of exploitation and utilization of natural resources.Lastly,two t ypical cases of timbers and maize were analyzed.
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    Review on Studies of Economy,wide Material Flow Analysis
    XIA Chuan-yong
    2005, 20 (3):  415-421.  doi: 10.11849/zrzyxb.2005.03.014
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    Material Flow Analysis(MFA) is a basic method for studying sustainable development. In general,MFA could be applied at three levels:economy,wide level ,sector level and product level.Among the above three levels,economy,wide Materi al Flow Analysis (economy,wide MFA) developed most rapidly in recent years.This article comprehensively introduced the history,typical viewpoints and applicatio ns of economy,wide MFA,pointed out the typical advantages and limits of this met hod,and identified some issues that should be paid more attention to in recent r esearch of economy,wide MFA.Some conclusions were drawn as follows:(1)The advant ages of economy,wide MFA are that compact sustainable development indicators can be obtained for comparison,(2)The limits of economy,wide MFA include that major material flow may dilute the definition of description of total material flows, that links between material flows and environmental impact are not close,and tha t its applied range is limited,(3)In future,social research value of the result of economy,wide MFA,combination of economy,wide MFA and land use analysis,and PI OT ( Physical Input,Output Table) should be paid more attention to.
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    Review on Land Use and Land Cover Change Models
    2005, 20 (3):  422-431.  doi: 10.11849/zrzyxb.2005.03.015
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    Land Use and Land Cover Change (LUCC) study has been carried out for a long time in the world.Recently,because of contribution and response of LUCC to global change,it is necessary to predict LUCC.Therefore,more and more scientist s devote themselves to studying LUCC models,and have made positive progress in t his aspect.This paper presents some correlative issues about LUCC models,i.e.,sc ale dependency of LUCC modeling,data issues of LUCC modeling,and location and qu antity of land,use change prediction.It reviews the available five kinds of main LUCC models:1)Agent,based Models of Land,use/Land,cover Change(ABM/LUCC);2)Empi rical statistical models;3)Optimisation Model;4)Hybrid/Integrated models;and 5)D ynamic simulation models.It then summarizes the problems of the existing models, and discusses the future developing direction of LUCC models.Although much progr ess has been made in theory and practice of LUCC models,and many new modeling me thodology and technique have been developed with multiple purposes,there still e xist certain problems in these models.The understanding of LUCC models multi,sca le attribute is inadequate and there is a lack of interaction of the temporal an d spatial studies of the models,so the validity of the models is affected.Finall y,we should further strength the integration of modeling methodology and constit ute more effective LUCC models.
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    Utilization of Weed Resource in the Remediation of Soils Contaminate d by Heavy Metals
    WEI Shu-he, ZHOU Qi-xing, LIU Rui
    2005, 20 (3):  432-440.  doi: 10.11849/zrzyxb.2005.03.016
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    Phytoremediation of soils contaminated by heavy metals refers to the u tilization of some special plants to clean polluted environment through extracti on,volatilization,translocation and stabilization.The two main methods are phyto extraction and phytostabilization,i.e.,to remove heavy metals using hyperaccumul ators from contaminated soils or stabilize them by excluder plants in situ.At pr esent,phytoremdiation technologies are not successfully used in large,scale reme diative practice.The results partly lie in many disadvantages of the documented hyperaccumulators, such as small aboveground biomass,slow growth and long maturi ty phase.As for excluder plants, there are few materials published.With the prop erties of strong endurance to adverse environment,fast growing and high reproduc tion,especially the characteristics of the fast increase in biomass under feasib le environmental factors,weed can make good the defect or cover the shortage of the available remediation plants,so it is a kind of ideal remediative resource.B ased on our researches into phytoremediation,applications and screening methods of remediative weed plants were introduced,moreover,the dispose of remediative p lant biomass was also discussed.It was suggested that the comprehensive utilizat ion of weed plant resource would make a great progress in the remediation of soi ls contaminated by heavy metals.
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    National Scientific and Technological Plan and Resource Science Development in China
    FENG Zhi-ming
    2005, 20 (3):  441-446.  doi: 10.11849/zrzyxb.2005.03.017
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    China has framed seven national scientific and technological plans ove r the past de,cades,research on resource science has grown from an integrated su rvey of natural resources at initiate stage to comprehensive interdisciplinary a t current time.In particular,"1956~1967 National Scientific and Technological L ong,term Plan"and"1978~1985 National Scientific and Technological Development C ompendium" impressed mostly on the formulation and development of resource scien ce.This paper gives some advice on national scientific and technological mid, to long,term development plan concerning resource science at the early stage of th e new century,based on an overall review of national scientific and technologica l development plans and the development of resource science in China.
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    An Approach to Basic Questions of Resources Science
    GUAN Hua, LI Yan
    2005, 20 (3):  447-452.  doi: 10.11849/zrzyxb.2005.03.018
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    At present,some questions concerning basic theory of resources science have not been solved.Such kind of situation can restrict the establishment and development of resources science.Therefore,it is necessary to make an approach t o these questions.Both natural and social resources are dealt with via studies o f resources science,but they are not the study objects.The study object of resou rces science will be regional resources system.Resources science is a frontier s cience formed between geosciences,social science,and technical science,is a grad e,1 branch of learning of "geographic science" which was proposed to set up by Q ian Xuesen,and its study object will belong to the resources category of epigeos phere which is the foundation of regional development.Resources science has thre e features:comprehensiveness,this is the disting,uishing feature and is the foun dation of it's being;and regionalism,this is the channel of its comprehensive st udy and is the formation of it's being;and intercross,this is the source of its research questions and is the necessary condition of it's being.The subject syst em of resources science can be set up from two angles:content's subject system o f resources science can be set up according to the levels of its study contents, and the type's subject system of resources science can be set up according to th e characteristics of study object and the angles of study methods. The intercros s of the two subject systems can form a great deal of subjects of resources scie nce,and all of them form the subject system.
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    Critique on Non-market Valuation of Natural and Environmental Resources
    ZHANG Yao-qi, LI Yi-qing, PAN Yi
    2005, 20 (3):  453-460.  doi: 10.11849/zrzyxb.2005.03.019
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    This paper attempts to distinguish the differences between the followi ng pairs of con,cepts:physical scarcity versus economic scarcity,intrinsic value versus exchange value, marginal value versus total value,cost versus value,cons umer willingness to pay(WTP)versus shadow value.The purpose of non,market valuat ion is for efficient allocation of scare resources. There are many kinds of valu es.Only the exchange value can be used to guide resource allocation.It is pointe d out that the economic scarcity of a resource is reflected in price when market exists,or shadow value when the market does not exist.Measuring total value oft en does not make sense when we deal with resource allocation since our decision is usually marginal change.It is particularly argued that WTP is not a good indi cator to measure resource scarcity and guide resource allocation.It is emphasize d that that non,market valuation should be conducted in the framework of demand and supply and in the marginal perspective.Appraisal value is suggested as a pot ential alternative for non,market valuation.
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    The Use of Land Use Change Models to Support the Conversion of Unsustainable Dry Land into Forest Land or Grassland - A Case Study in Tongliao Region
    ZHANG Yong-min, ZHAO Shi-dong, ZHOU Cheng-hu, Peter H. Verburg
    2005, 20 (3):  461-470.  doi: 10.11849/zrzyxb.2005.03.020
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    During the past decades, the rapid expansion of desertification has be come one of the most serious environmental problems in northern China.Northern C hina is a region sensitive to environmental change due to its transitional locat ion and the high potential for sandy deserti,fication.To mitigate the deteriorat ing eco,environmental conditions,the conversion of unsuitable dry land to forest land or grassland has been proposed as one of the major ecological programs by the Chinese government.To help the implementation of this program a new method t hat helps to identify suitable dry land for converting into forest land and gras sland is presented in this paper taking Tongliao region as a case.The regional l and use change model,CLUE,S,is used based on system theory to allow the integrat ed analysis of land use change in relation to socio,economic and biophysical dri ving factors.Land use change was simulated for Tongliao region from 2000 to 2010 .Then,suitable locations converting dry land into forest land and grassland were identified by overlapping the simulated land use change map of 2010 with a map showing the distribution of dry land in 2000,which was extracted from the land u se map of 2000.According to the result of the two overlapped maps,suitable locat ions for land conversion are mainly found in the central,the southern,and the ce ntral,northern parts of the study area.The central part of the study area,with r elatively high population density,is situated in the inland of Horqin Desert whe re desertification has always been very serious during the past decades.In order to mitigate the degradation of living environment,much unproductive dry land wi ll be reforested or converted to grassland in this sub,region.The southern and t he central,northern parts of the study area are more hilly and mountainous where soil erosion is very serious due to excessive reclamation.So,much dry land will also be chosen as the priority area for land conversion into forest land and gr assland in these two sub,regions.This paper illustrated that CLUE,S model is a u seful tool for implementing land management decisions,and that the results of th is study can provide valuable information for the conversion of unsustainable dr y land into forest land or grassland in the study area.
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    Remote Sensing Research of Sandy Desertification along the Great Wall in Northern Shaanxi
    GAO Hui-jun, JIANG Qi-gang, HUO Xiao-bin
    2005, 20 (3):  471-475.  doi: 10.11849/zrzyxb.2005.03.021
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    Using MSS satellite image data in 1975 and ETM image data in 2000 as r emote sensing information source,we studied the status quo and dynamic change of sandy desertification along the Great Wall in northern Shaanxi through building scientific classification system for sandy desertified land in combination with GIS analysis method.The result indicates that after 25 years prevention and con trol,the trend of sandy desertification has been distinctly reversed.Nevertheles s,the sandy desertification intensity was still very high,especially the scale o f severe sandy desertification was large.At the same time,the exploitation of co al,petroleum and natural gas has a long,term and potential negative impact on th e sandy desertification.So we must set up the rational resource exploitation and environmental protection system.
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