2002 Vol. 12, No. 1
Display Method:
2002, 12(1): 1-8.
Abstract:
Based on the provincial units evaluation, this paper makes an assessment for sustainable developing capability of the integrated agricultural regionalization in China. At first, an index system of agricultural sustainable development in China is built up, which includes 5 supporting subsystems of agricultural resources, agricultural development, environment and ecosystem, rural society, sciences education and management. We selected 95 factors on provincial level as basic indexes. Second, a relative assets/debt assessing method is used to gain relative net assets values (relative superiority) of every provincial unit, which are as supporting data for assessment. We also overlaid the Administrative Divisions Map of China and the Map of Integrated Agricultural Regionalization of China by Geography Information System (GIS) to gain the area units of assessment. Third, according to the relative coherence principle of regionalization, we transform administration units to natural units through homogenizing all provincial relative net assets values in every agricultural assessing unit. After making order and grade, we complete the sustainable developing capability assessment to integrated agricultural regionalization in China. The assessing outcome shows that the total sustainable agricultural developing capability of China is not high. Only about 1/3 in number or in area has reached the level of agricultural sustainable development. The relative net assets values exists a reducing trend from East China to West China. It needs a long period and great efforts to realize sustainable agricultural development over all China. Finally, there is a discussion to the study method.
Based on the provincial units evaluation, this paper makes an assessment for sustainable developing capability of the integrated agricultural regionalization in China. At first, an index system of agricultural sustainable development in China is built up, which includes 5 supporting subsystems of agricultural resources, agricultural development, environment and ecosystem, rural society, sciences education and management. We selected 95 factors on provincial level as basic indexes. Second, a relative assets/debt assessing method is used to gain relative net assets values (relative superiority) of every provincial unit, which are as supporting data for assessment. We also overlaid the Administrative Divisions Map of China and the Map of Integrated Agricultural Regionalization of China by Geography Information System (GIS) to gain the area units of assessment. Third, according to the relative coherence principle of regionalization, we transform administration units to natural units through homogenizing all provincial relative net assets values in every agricultural assessing unit. After making order and grade, we complete the sustainable developing capability assessment to integrated agricultural regionalization in China. The assessing outcome shows that the total sustainable agricultural developing capability of China is not high. Only about 1/3 in number or in area has reached the level of agricultural sustainable development. The relative net assets values exists a reducing trend from East China to West China. It needs a long period and great efforts to realize sustainable agricultural development over all China. Finally, there is a discussion to the study method.
2002, 12(1): 9-13.
Abstract:
As a kind of natural disasters, sand dust storms frequently occur in deserts and their surrounding areas. The occurrence of this disaster in China's northwest and north China has exerted an extremely adverse effect upon the environment in China. The management of sand dust storms is of a systematic project closely related with the environment such as agriculture, ecosystem, forestry, water conservancy, meteorology and other aspects. Therefore, studies of the formation, the basic features, causes, temporal spatial distribution, developing trend and related disasters of sand dust storms in China are conducted based on satellite data. The experience of sand dust storms control and countermeasures in the United States and some other countries are referred. Meanwhile, preliminary countermeasures relating to sand dust storms in China are proposed.
As a kind of natural disasters, sand dust storms frequently occur in deserts and their surrounding areas. The occurrence of this disaster in China's northwest and north China has exerted an extremely adverse effect upon the environment in China. The management of sand dust storms is of a systematic project closely related with the environment such as agriculture, ecosystem, forestry, water conservancy, meteorology and other aspects. Therefore, studies of the formation, the basic features, causes, temporal spatial distribution, developing trend and related disasters of sand dust storms in China are conducted based on satellite data. The experience of sand dust storms control and countermeasures in the United States and some other countries are referred. Meanwhile, preliminary countermeasures relating to sand dust storms in China are proposed.
2002, 12(1): 14-22.
Abstract:
Based on the field investigations, this paper analyzes systematically the achievements and problems of constructing the demonstrating areas of the ecological rebuilding and economic sustainable development in Hexi, Gansu Province, and then the thoughts on constructing the demonstrating areas are brought forward. It is considered that all kinds of ecological demonstrating areas should be merged in order to construct large scale characterized demonstrating areas which go beyond the district. In other words, in Hexi Region, Zhangye District should be constructed as the largest ecoagriculture demonstrating area of high technology; Wuwei District should be constructed as the largest ecological demonstrating area of agricultural comprehensive exploitation; JiuJia District, which is the shortened form of Jiuquan and Jiayuguan, should be constructed as the largest ecotourism demonstrating area; and Jinchang City should be constructed as the largest ecoindustry demonstrating area. At the same time, the constructing pattern should be selected according to the actual circumstances; science and technology should be applied to construct the demonstrating areas and accelerate the industrialization in the big market. Additionally, it is important to smooth the constructing system and implement the flexible and efficacious running mechanism, and it is suggested that the committee should be organized to administer the ecological demonstrating areas in Hexi Region.
Based on the field investigations, this paper analyzes systematically the achievements and problems of constructing the demonstrating areas of the ecological rebuilding and economic sustainable development in Hexi, Gansu Province, and then the thoughts on constructing the demonstrating areas are brought forward. It is considered that all kinds of ecological demonstrating areas should be merged in order to construct large scale characterized demonstrating areas which go beyond the district. In other words, in Hexi Region, Zhangye District should be constructed as the largest ecoagriculture demonstrating area of high technology; Wuwei District should be constructed as the largest ecological demonstrating area of agricultural comprehensive exploitation; JiuJia District, which is the shortened form of Jiuquan and Jiayuguan, should be constructed as the largest ecotourism demonstrating area; and Jinchang City should be constructed as the largest ecoindustry demonstrating area. At the same time, the constructing pattern should be selected according to the actual circumstances; science and technology should be applied to construct the demonstrating areas and accelerate the industrialization in the big market. Additionally, it is important to smooth the constructing system and implement the flexible and efficacious running mechanism, and it is suggested that the committee should be organized to administer the ecological demonstrating areas in Hexi Region.
2002, 12(1): 23-29.
Abstract:
The Hexi Corridor is an important base of agriculture development in Northwest China. According to recent statistics, there are 65.94×108m3 of water resources available in the Hexi Corridor. At present, net consumption in development and utilization is 43.33×108m3. Water supply and demand reach a balance on the recent level of production, but loss of evaporation and evapotranspiration is as much as 25.69×108m3. So net use efficiency of water resources is 59%. Based on analyzing balance between water and land considering ecological environment at present, there exists the serious water shortage in the Shiyang River system where irrigation lands have overloaded. There is a comparative balance between supply and demand of water resource in the Heihe River system; and the Sule River system has some surplus water to extend irrigation land. Use of agriculture water accounts for 83.3% and ecological forest and grass for 6.9%. The Hexi Corridor still has a great potential for water saving in agriculture production. Water saving efficiency of irrigation is about 10% by using such traditional technologies as furrow and border dike irrigation and small check irrigation, and water saving with plastic film cover and techniques of advanced sprinkler and drip/micro irrigation etc. can save more than 60% of irrigated water. Incremental irrigation area for water saving potential in the Hexi Corridor has been estimated as 56%-197% to original irrigation area. So the second water sources can be developed from water saving agriculture in the Hexi Corridor under Development of the Western Part of China in large scale. This potential can be realized step by step through developing the water saving measures, improving the ecological condition of oasis agriculture, and optimizing allocation of water resources in three river systems.
The Hexi Corridor is an important base of agriculture development in Northwest China. According to recent statistics, there are 65.94×108m3 of water resources available in the Hexi Corridor. At present, net consumption in development and utilization is 43.33×108m3. Water supply and demand reach a balance on the recent level of production, but loss of evaporation and evapotranspiration is as much as 25.69×108m3. So net use efficiency of water resources is 59%. Based on analyzing balance between water and land considering ecological environment at present, there exists the serious water shortage in the Shiyang River system where irrigation lands have overloaded. There is a comparative balance between supply and demand of water resource in the Heihe River system; and the Sule River system has some surplus water to extend irrigation land. Use of agriculture water accounts for 83.3% and ecological forest and grass for 6.9%. The Hexi Corridor still has a great potential for water saving in agriculture production. Water saving efficiency of irrigation is about 10% by using such traditional technologies as furrow and border dike irrigation and small check irrigation, and water saving with plastic film cover and techniques of advanced sprinkler and drip/micro irrigation etc. can save more than 60% of irrigated water. Incremental irrigation area for water saving potential in the Hexi Corridor has been estimated as 56%-197% to original irrigation area. So the second water sources can be developed from water saving agriculture in the Hexi Corridor under Development of the Western Part of China in large scale. This potential can be realized step by step through developing the water saving measures, improving the ecological condition of oasis agriculture, and optimizing allocation of water resources in three river systems.
2002, 12(1): 30-34.
Abstract:
Southeast China coastal areas belong to subtropical monsoon climatic zone, thus easily affected by floods resulted from typhoons and rainstorms. Since the areas of river basins are small, rivers flood regulation capacities are low, and therefore flood hazard is grave. In this paper, taking the Yongjiang basin in southeast China as an example, the approaches and methods of geographic information system(GIS) applied to flood disaster control and reduction research on small basin are explored. On GIS help the rainfall runoff calculation model and the river channel flood routing model are developed. And the evaluating flood submerged area and the damage assessment models are built supported by digit elevation models. Lastly the decision support system on GIS supported for flood control in research basin has been set up. This greatly improves flood proofing decision making capacities in river basin, and provides valuable information and a mode for flood prevention and reduction in the medium and small basin. Meanwhile, the research indicates that technologies of GIS provide a powerful tool for flood disaster control.
Southeast China coastal areas belong to subtropical monsoon climatic zone, thus easily affected by floods resulted from typhoons and rainstorms. Since the areas of river basins are small, rivers flood regulation capacities are low, and therefore flood hazard is grave. In this paper, taking the Yongjiang basin in southeast China as an example, the approaches and methods of geographic information system(GIS) applied to flood disaster control and reduction research on small basin are explored. On GIS help the rainfall runoff calculation model and the river channel flood routing model are developed. And the evaluating flood submerged area and the damage assessment models are built supported by digit elevation models. Lastly the decision support system on GIS supported for flood control in research basin has been set up. This greatly improves flood proofing decision making capacities in river basin, and provides valuable information and a mode for flood prevention and reduction in the medium and small basin. Meanwhile, the research indicates that technologies of GIS provide a powerful tool for flood disaster control.
2002, 12(1): 35-43.
Abstract:
A regional multiple objective water resource and economic optimization model was developed using a quantitative method of systematic analysis. Input to the model includes indexes of economic structure and development, water resource utilization, wastewater and pollutant discharge, and investment in wastewater treatment. The model, which consists of production structure and industrial structure optimization modules, was applied to the Guanzhong region in the middle reaches of the Huanghe (Yellow) River basin in China. By evaluating several alternative production and industrialization schemes, the modal indicate that water pollution will get worsen though wastewater treatment improves if the economy continues to develop at the planned speed without structural adjustment. However, the results also show that not only economic goals but also water resource protection and pollution control targets can be achieved under an alternative, recommended production and industrial structure. This example illustrates that economic development and environmental protection can be improved coordinately by the regional multiple objective water resource and economic optimization model. It provides an operable approach to the simultaneous sustained development of water resources and economic growth.
A regional multiple objective water resource and economic optimization model was developed using a quantitative method of systematic analysis. Input to the model includes indexes of economic structure and development, water resource utilization, wastewater and pollutant discharge, and investment in wastewater treatment. The model, which consists of production structure and industrial structure optimization modules, was applied to the Guanzhong region in the middle reaches of the Huanghe (Yellow) River basin in China. By evaluating several alternative production and industrialization schemes, the modal indicate that water pollution will get worsen though wastewater treatment improves if the economy continues to develop at the planned speed without structural adjustment. However, the results also show that not only economic goals but also water resource protection and pollution control targets can be achieved under an alternative, recommended production and industrial structure. This example illustrates that economic development and environmental protection can be improved coordinately by the regional multiple objective water resource and economic optimization model. It provides an operable approach to the simultaneous sustained development of water resources and economic growth.
2002, 12(1): 44-49.
Abstract:
Rainfall resource is very important to the development of society and economy,especially to eastern Jianghuai watershed which is now facing serious challenge of water shortage. Based on the observational records covering the period from 1957 to 1999,the characteristics of precipitation changing over eastern JiangHuai watershed and its connection to sediment discharge in Chihe River valley were studied using tendency analysis and correlation analysis .Results show that the rainfall in this area had a declining tendency in Spring at a rate of-21.2mm/10a, annual and Summer precipitation was increasing at the rate of 10.6mm/10a and 14.8mm/10a. The gray correlation analysis shows that sediment discharge correlates most closely with runoffs and the frequency of the rainstorm with a daily precipitation of 50-100mm, on the second place,with the rainfall and the frequency of the rainstorm of a daily precipitation no less than 100mm;and thirdly with the number of rainy days. In addition, the paper suggests the major countermeasures and methods for controlling of soil and water losses in this area.
Rainfall resource is very important to the development of society and economy,especially to eastern Jianghuai watershed which is now facing serious challenge of water shortage. Based on the observational records covering the period from 1957 to 1999,the characteristics of precipitation changing over eastern JiangHuai watershed and its connection to sediment discharge in Chihe River valley were studied using tendency analysis and correlation analysis .Results show that the rainfall in this area had a declining tendency in Spring at a rate of-21.2mm/10a, annual and Summer precipitation was increasing at the rate of 10.6mm/10a and 14.8mm/10a. The gray correlation analysis shows that sediment discharge correlates most closely with runoffs and the frequency of the rainstorm with a daily precipitation of 50-100mm, on the second place,with the rainfall and the frequency of the rainstorm of a daily precipitation no less than 100mm;and thirdly with the number of rainy days. In addition, the paper suggests the major countermeasures and methods for controlling of soil and water losses in this area.
2002, 12(1): 50-54.
Abstract:
In the modern times, the population growth, development of industrial and agricultural production and the petroleum exploitation, brought about the unceasing expansion of artificial oasis and abrupt increase of water demand. The artificial hydraulic irrigation engineering took the place of the natural river system, the reservoirs took the place of natural lakes, which in turn enhanced the space time redistribution of surface water based on the natural evolution, and so did groundwater. The groundwater recharge reduced 26.2% in 46 years from 1950 to 1995 in the southern piedmont flood plain of Tarim Basin due to mean yearly population increase rate of 27.7‰ and associated with the water use rate increasing from 24.6% to 58.4%. At the same time the artificial water system seepage give primary play to groundwater recharge, which is up to 57.6% whilst that of the natural system reduce to 33.7%. As a result, groundwater level drop 3-5m widespread except some irrigation area and surroundings of plain reservoir. Spring water discharge also reduce about 37.6% and discharge zone continuously move away to the north with the value of 0.5-1.2km in the past 40 years.
In the modern times, the population growth, development of industrial and agricultural production and the petroleum exploitation, brought about the unceasing expansion of artificial oasis and abrupt increase of water demand. The artificial hydraulic irrigation engineering took the place of the natural river system, the reservoirs took the place of natural lakes, which in turn enhanced the space time redistribution of surface water based on the natural evolution, and so did groundwater. The groundwater recharge reduced 26.2% in 46 years from 1950 to 1995 in the southern piedmont flood plain of Tarim Basin due to mean yearly population increase rate of 27.7‰ and associated with the water use rate increasing from 24.6% to 58.4%. At the same time the artificial water system seepage give primary play to groundwater recharge, which is up to 57.6% whilst that of the natural system reduce to 33.7%. As a result, groundwater level drop 3-5m widespread except some irrigation area and surroundings of plain reservoir. Spring water discharge also reduce about 37.6% and discharge zone continuously move away to the north with the value of 0.5-1.2km in the past 40 years.
2002, 12(1): 55-60.
Abstract:
The article analyses the temporal spatial changes of profiles by EOF (Empirical Orthogonal Function) analysis and DTM analysis of GIS. These profiles, which are not affected by engineering, are chosen from the coast with successive field monitoring data from 1990 to 1999. Temporal and spatial EOF indicates the obvious stability of coast profile parameters in Fengxian tidal flat. In spatial scale, high tidal flats and deep water terraces are in a balance state while upper clino with steep slopes are sensitive and the stability is easy to be destroyed. In temporal scale, the erosion and deposition in this area are kept in balance in a whole. There are almost no change below-8--9.5m. At the same time, it is the lower limit of tidal affection and the erosion and deposition process from it to high tidal flat keep in balance for many years. So the closure depth is appointed to from-8m to-9.5 m (Wusong datum mark).
The article analyses the temporal spatial changes of profiles by EOF (Empirical Orthogonal Function) analysis and DTM analysis of GIS. These profiles, which are not affected by engineering, are chosen from the coast with successive field monitoring data from 1990 to 1999. Temporal and spatial EOF indicates the obvious stability of coast profile parameters in Fengxian tidal flat. In spatial scale, high tidal flats and deep water terraces are in a balance state while upper clino with steep slopes are sensitive and the stability is easy to be destroyed. In temporal scale, the erosion and deposition in this area are kept in balance in a whole. There are almost no change below-8--9.5m. At the same time, it is the lower limit of tidal affection and the erosion and deposition process from it to high tidal flat keep in balance for many years. So the closure depth is appointed to from-8m to-9.5 m (Wusong datum mark).
2002, 12(1): 61-67.
Abstract:
Sustainable use of natural resources is different from sustainable development. As the most important natural resource, sustainable use of land resource is the essential guarantee of sustainable development. The nature of sustainable use of land resource is to retain the quantity and productivity of land resource from generation to generation.The evaluation of sustainable use of land resource is an important method to ensure land use to get onto the sustainable track. Furthermore, building index system is the key of the evaluation. In view of tendency of the evaluation indexes chosen so widely, the evaluation indexes should include only three kinds in the researches on the evaluation of sustainable use of land resource. The first is the stock and structure index of land resource, viz. Areas quantity structure of land resources. In China, it is especially paid attention to the per person index of land quantity and rate between cultivated land and farmland. The second is the productive index of land, which includes the productivity, potentiality, stability and renewal situation of land. The third is the sustained index of land environment. On the evaluation research of area level, we should lay particular emphasis on statistic indexes. With a case of Guangxi Zhuang Autonomous Region in China, the evaluation index system of sustainable land use in county area has been built in this thesis. Using the weighted average method to calculate the means of sustainable land use in each county, according to the land using situation, all counties in the autonomous region have been divided into three types. (1) Sustainable Pattern contains 18 counties, which have higher land resource productivity, stronger sustained abilities of land environment .The economic benefits of land using in these counties are obviously higher. These counties have gotten highly intensive farming, and they are all in the good circumstance. (2) Basically Sustained Pattern contains 48 counties, which productivity of land resource is of middle level. In part of counties and cities, the stock of land resource inclines to lower level, but their land using potentialities are still greater. Through changing land using pattern, these counties can rapidly enter in a good circumstance. (3) Critically Sustained Pattern contains 14 counties, which are mostly in the karst mountain areas. They have less stock of land resource, lower productivity and more extensive cultivation. The productivity of land renewing has been hindered, so it urgently need to be renovated. At last, the writers have explored the basic ways of sustainable use of land resource in Guangxi, China — (1) Retain the stock of land resource and strictly manage farmland uses. (2) Strengthen the value accounting of land resource, and control the farmland occupation of non agricultural construction. (3) Depend on technology advanced, optimize the land using structure, and promote the productive level. (4) Carry out land management all round, and improve the ecological environment of land resource. (5) Enhance evaluation researche and land monitoring, and promote the sustainable utilization level of land resource.
Sustainable use of natural resources is different from sustainable development. As the most important natural resource, sustainable use of land resource is the essential guarantee of sustainable development. The nature of sustainable use of land resource is to retain the quantity and productivity of land resource from generation to generation.The evaluation of sustainable use of land resource is an important method to ensure land use to get onto the sustainable track. Furthermore, building index system is the key of the evaluation. In view of tendency of the evaluation indexes chosen so widely, the evaluation indexes should include only three kinds in the researches on the evaluation of sustainable use of land resource. The first is the stock and structure index of land resource, viz. Areas quantity structure of land resources. In China, it is especially paid attention to the per person index of land quantity and rate between cultivated land and farmland. The second is the productive index of land, which includes the productivity, potentiality, stability and renewal situation of land. The third is the sustained index of land environment. On the evaluation research of area level, we should lay particular emphasis on statistic indexes. With a case of Guangxi Zhuang Autonomous Region in China, the evaluation index system of sustainable land use in county area has been built in this thesis. Using the weighted average method to calculate the means of sustainable land use in each county, according to the land using situation, all counties in the autonomous region have been divided into three types. (1) Sustainable Pattern contains 18 counties, which have higher land resource productivity, stronger sustained abilities of land environment .The economic benefits of land using in these counties are obviously higher. These counties have gotten highly intensive farming, and they are all in the good circumstance. (2) Basically Sustained Pattern contains 48 counties, which productivity of land resource is of middle level. In part of counties and cities, the stock of land resource inclines to lower level, but their land using potentialities are still greater. Through changing land using pattern, these counties can rapidly enter in a good circumstance. (3) Critically Sustained Pattern contains 14 counties, which are mostly in the karst mountain areas. They have less stock of land resource, lower productivity and more extensive cultivation. The productivity of land renewing has been hindered, so it urgently need to be renovated. At last, the writers have explored the basic ways of sustainable use of land resource in Guangxi, China — (1) Retain the stock of land resource and strictly manage farmland uses. (2) Strengthen the value accounting of land resource, and control the farmland occupation of non agricultural construction. (3) Depend on technology advanced, optimize the land using structure, and promote the productive level. (4) Carry out land management all round, and improve the ecological environment of land resource. (5) Enhance evaluation researche and land monitoring, and promote the sustainable utilization level of land resource.
2002, 12(1): 68-72.
Abstract:
Some techniques and methods for deriving water information from SPOT-4(XI) image were investigated and discussed in this paper. An algorithm of decision tree (DT) classification which includes several classifiers based on the spectral responding characteristics of water bodies and other objects, was developed and put forward to delineate water bodies. Another algorithm of decision tree classification based on both spectral characteristics and auxiliary information of DEM and slope (DTDS) was also designed for water bodies extraction. In addition, supervised classification method of maximum likelyhood classification (MLC), and unsupervised method of interactive self organizing dada analysis technique (ISODATA) were used to extract waterbodies for comparison purpose. An index was designed and used to assess the accuracy of different methods adopted in the research. Results have shown that water extraction accuracy was variable with respect to the various techniques applied. It was low using ISODATA, very high using DT algorithm and much higher using both DTDS and MLC.
Some techniques and methods for deriving water information from SPOT-4(XI) image were investigated and discussed in this paper. An algorithm of decision tree (DT) classification which includes several classifiers based on the spectral responding characteristics of water bodies and other objects, was developed and put forward to delineate water bodies. Another algorithm of decision tree classification based on both spectral characteristics and auxiliary information of DEM and slope (DTDS) was also designed for water bodies extraction. In addition, supervised classification method of maximum likelyhood classification (MLC), and unsupervised method of interactive self organizing dada analysis technique (ISODATA) were used to extract waterbodies for comparison purpose. An index was designed and used to assess the accuracy of different methods adopted in the research. Results have shown that water extraction accuracy was variable with respect to the various techniques applied. It was low using ISODATA, very high using DT algorithm and much higher using both DTDS and MLC.
2002, 12(1): 73-79.
Abstract:
"West Jilin Province" in this paper means Zhenlai, Baicheng, Taonan, Da'an, Tongyu, Fuyu, Songyuan, Qian'an, Changling, also includes Gongzhuling, Shuangliao, Lishu, Siping and Nong'an which have been suffered from desertification. In west Jilin Province there are three sand zones passing through, they are Xiang(Xianghai) Wu(Ulan Tug) sand zone, Hai Feng sand zone, and Tao'er River right bank sand zone. The desertification area of west Jilin Province is 819 100 ha, making up 12.5% of the total land area. Among desertification types, in Jilin Province light desertification is the major, then is medium dersertification, hevey desertification is the least.According to the comparison of the interpretation results of the Landsat images of the 1980s and the 1990s by remote sensing and GIS techniques, it can be seen that the desertification area in west Jilin Province basically didn't change on the whole, only increased 6130 ha, making up 0.8% of the desertification area, change scale is less than 1%. Evidently, desertification is controlled mostly, but some areas are continuing deterioration.The desertification process of China can be divided into three types according to origin nature, they are sandy steppe desertification, fixed sand area(sand land) activation and dunes transfer invasion.Reasons of desertification of West Jilin Province are analyzed, they include natural factors(such as material source factors, chimate factors) and artificial factors(such as destroying grass to reclaim, steppe decreasing greatly, illegally feeling shelter forest stands, constructing reservoir to influence eco environment etc.). Some suggestions are put forward as follows: establishing the social project for ecological reconstruction of degenerated land; intensifying planning and management of land use, reverting farmland into forestland or pasture in a planned way. The key desertification control is to depend mainly on policy and management, then control techniques.
"West Jilin Province" in this paper means Zhenlai, Baicheng, Taonan, Da'an, Tongyu, Fuyu, Songyuan, Qian'an, Changling, also includes Gongzhuling, Shuangliao, Lishu, Siping and Nong'an which have been suffered from desertification. In west Jilin Province there are three sand zones passing through, they are Xiang(Xianghai) Wu(Ulan Tug) sand zone, Hai Feng sand zone, and Tao'er River right bank sand zone. The desertification area of west Jilin Province is 819 100 ha, making up 12.5% of the total land area. Among desertification types, in Jilin Province light desertification is the major, then is medium dersertification, hevey desertification is the least.According to the comparison of the interpretation results of the Landsat images of the 1980s and the 1990s by remote sensing and GIS techniques, it can be seen that the desertification area in west Jilin Province basically didn't change on the whole, only increased 6130 ha, making up 0.8% of the desertification area, change scale is less than 1%. Evidently, desertification is controlled mostly, but some areas are continuing deterioration.The desertification process of China can be divided into three types according to origin nature, they are sandy steppe desertification, fixed sand area(sand land) activation and dunes transfer invasion.Reasons of desertification of West Jilin Province are analyzed, they include natural factors(such as material source factors, chimate factors) and artificial factors(such as destroying grass to reclaim, steppe decreasing greatly, illegally feeling shelter forest stands, constructing reservoir to influence eco environment etc.). Some suggestions are put forward as follows: establishing the social project for ecological reconstruction of degenerated land; intensifying planning and management of land use, reverting farmland into forestland or pasture in a planned way. The key desertification control is to depend mainly on policy and management, then control techniques.
2002, 12(1): 80-85.
Abstract:
The economic development in China and the rising of the living standard need to speed up the urbanisation. The development of small towns is an important way to Chinese urbanisation. Land use plays a very important role in the development of small towns. However there are many problems in the development of small towns, esp. in land use. The paper first discusses the land problems in the development of small towns. Such as much cultivated land lies idle, under utilization and waste of land, increasing illegal use of land, unstable contractual relationship for land use. The relationship between the development of small towns and land use is also studied. Then the guidelines for the land system innovations of small towns are put forward. Namely the sustainability of social and economic development, the balance between land reservation and land utilization, the provision of service to village, agriculture and farmer, the management of land resource and land assets, the parsimonious and legal use of land. The basic framework of land system innovations of small towns is put forward finally. It include the land replacement policy for small towns and the permanent tenancy of farmland, the overall plan for land uses and other plans in harmony, the establishment of a flexible system of land supplies, using land with payments, the transfer of agricultural land and refining the land law related to the construction of small towns.
The economic development in China and the rising of the living standard need to speed up the urbanisation. The development of small towns is an important way to Chinese urbanisation. Land use plays a very important role in the development of small towns. However there are many problems in the development of small towns, esp. in land use. The paper first discusses the land problems in the development of small towns. Such as much cultivated land lies idle, under utilization and waste of land, increasing illegal use of land, unstable contractual relationship for land use. The relationship between the development of small towns and land use is also studied. Then the guidelines for the land system innovations of small towns are put forward. Namely the sustainability of social and economic development, the balance between land reservation and land utilization, the provision of service to village, agriculture and farmer, the management of land resource and land assets, the parsimonious and legal use of land. The basic framework of land system innovations of small towns is put forward finally. It include the land replacement policy for small towns and the permanent tenancy of farmland, the overall plan for land uses and other plans in harmony, the establishment of a flexible system of land supplies, using land with payments, the transfer of agricultural land and refining the land law related to the construction of small towns.
2002, 12(1): 86-89.
Abstract:
Taking South Lake and Jingyue Pool in Changchun as examples, we determined particulate Hg in ambient air and Hg concentration in precipitation. Results indicated that particulate Hg in air and Hg concentration in precipitation in both sites in nonheating period were lower than that in heating period, which is influenced by coal combustion. The annual particulate Hg concentrations of South Lake and Jingyue Pool were 0.254ng/m3 and 0.109ng/m3. The yearly average Hg concentrations in precipitation were 0.268μg/L(South Lake) and 0.108μg/L(Jingyue Pool). The higher particulate Hg concentration in air and Hg concentration in precipitation in South Lake than that of Jingyue Pool indicated that mercury deposition was influenced by anthropogenic sources(especially from coas combustion). Hg concentration in precipitation is related with particulate Hg in the atmosphere. Dry deposition fluxes were estimated by using dry deposition model on the base of particulate Hg concentrations in the atmosphere, they were 35.5μg/(m2.a) for South lake and 15.3μg/(m2.a) for Jingyue Pool. Combined with precipitation amount, wet deposition fluxes were estimated in these two sites, 152.2μg/(m2.a) for South Lake and 61.2μg/(m2.a) for Jingyue Pool. Atmospheric Hg deposition fluxes were 160.2g/a for South Lake and 328.62g/a for Jingyue Pool.
Taking South Lake and Jingyue Pool in Changchun as examples, we determined particulate Hg in ambient air and Hg concentration in precipitation. Results indicated that particulate Hg in air and Hg concentration in precipitation in both sites in nonheating period were lower than that in heating period, which is influenced by coal combustion. The annual particulate Hg concentrations of South Lake and Jingyue Pool were 0.254ng/m3 and 0.109ng/m3. The yearly average Hg concentrations in precipitation were 0.268μg/L(South Lake) and 0.108μg/L(Jingyue Pool). The higher particulate Hg concentration in air and Hg concentration in precipitation in South Lake than that of Jingyue Pool indicated that mercury deposition was influenced by anthropogenic sources(especially from coas combustion). Hg concentration in precipitation is related with particulate Hg in the atmosphere. Dry deposition fluxes were estimated by using dry deposition model on the base of particulate Hg concentrations in the atmosphere, they were 35.5μg/(m2.a) for South lake and 15.3μg/(m2.a) for Jingyue Pool. Combined with precipitation amount, wet deposition fluxes were estimated in these two sites, 152.2μg/(m2.a) for South Lake and 61.2μg/(m2.a) for Jingyue Pool. Atmospheric Hg deposition fluxes were 160.2g/a for South Lake and 328.62g/a for Jingyue Pool.
2002, 12(1): 90-96.
Abstract:
Based on comparative studies on four regional floras from northwest, west, south and southeast of Yunnan respectively, the formerly suggested two biogeographical lines, i.e. the "Tanaka Line" and the "Ecogeographical Diagonal Line", both going from northwest to southeast of Yunnan, and their significance are discussed. In family and generic levels, similarity coefficients among the four compared floras are more than 93% and 60% separately, which indicate the close floristic affinities among them. The highest similarity coefficient, i.e. 98.7% in family level and 78.6% in generic level separately, is found between the regional flora of northwest Yunnan and the flora of southeast Yunnan although these two regions are the most distant away each other among the compared regional floras. The flora of northwest Yunnan is also the most similar to the flora of southeast Yunnan in floristic composition. These support the idea of "Ecogeographical Diagonal Line". In specific level, the relatively high similarity coefficient is between the regional flora of west Yunnan and the one of south Yunnan. The floristic affinities among these regional floras and some distribution patterns could be explained by the geological history and tectonic theory of Yunnan.
Based on comparative studies on four regional floras from northwest, west, south and southeast of Yunnan respectively, the formerly suggested two biogeographical lines, i.e. the "Tanaka Line" and the "Ecogeographical Diagonal Line", both going from northwest to southeast of Yunnan, and their significance are discussed. In family and generic levels, similarity coefficients among the four compared floras are more than 93% and 60% separately, which indicate the close floristic affinities among them. The highest similarity coefficient, i.e. 98.7% in family level and 78.6% in generic level separately, is found between the regional flora of northwest Yunnan and the flora of southeast Yunnan although these two regions are the most distant away each other among the compared regional floras. The flora of northwest Yunnan is also the most similar to the flora of southeast Yunnan in floristic composition. These support the idea of "Ecogeographical Diagonal Line". In specific level, the relatively high similarity coefficient is between the regional flora of west Yunnan and the one of south Yunnan. The floristic affinities among these regional floras and some distribution patterns could be explained by the geological history and tectonic theory of Yunnan.
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