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  • 1983 Volume 2 Issue 1
    Published: 15 March 1983
      
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  • THE UTILIZATION AND TRANSFORMATION OF THE NORTH CHINA PLAIN
    Jiang Dehua
    1983, 2(1): 1-11. https://doi.org/10.11821/yj1983010001
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    The North China Plain occupies an important position in the country. However, natural hazards of drought, flood, salinization-alkaliiation as well as-wind hazard frequently take place over a long period of time. Besides, there are more than 100 million mu of low-yield land, hence agricultural production is unstable and not high, and living standard of the local people is impossible to raise rapidly. So long as what is beneficial is promoted and what is harmful is avoided and superiority is given into full play, great potential of production can be tapped. Therefore, it is possible to build the region gradually into an important base for commodity grain, cotton, oil-bearing crops, soyabean and fruits as well as an integrated agricultural region.Favorable conditions for decision making are as follows; land resource, heat and temperature coditions as well as manpower in the region are sufficient, flourishing industry and developed urban areas and transportation are favorable for agricultural develop-ment; in a certain sense, it has a solid foundation for production due to the long history of agricultural development; and some achievements and experience have been obtained by the state on the development, utilization and management of the region.The strategic thinking on the management and transformation of the North China Plain should be: under the unified leadership, draw an overall plan to undertake integrated management; cope with more difficult points after the easy ones being tackled; carry on work in units and areas in a combined way; persist in realizing the goal for a long time to come; and finally stress practical results. In the respect of conquering natural disasters, problems should be solved in the order of flood drainagesalt control-drought resistance-fertility fosterage so as to improve natural ecological environment step by step.Mean-while, agricultural production structural system should be established accor-dingly. In order to ensure fundamentally the realization of the objective on disaster elimination and production increase, from a long-term point of view, water transfer from south to north, the regulation of the three major rivers-the Huanghe, Huaihe and Haihe as well as soil conservation in the upper reaches are all principal measures related to the development of agricultural production of the North China plain.
  • A STUDY OF REGIONALIZATION OF COTTON CULTIVATION IN CHINA
    Xu Peixiu, Mei Fangquan, Tang Zhifa
    1983, 2(1): 12-22. https://doi.org/10.11821/yj1983010002
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    A scientific division of China's cotton cultivated area is favourable to the country's cotton production in accordance with the principle of adopting suitable measures to local conditions, practicing reasonable allocation and guiding production according to various types.According to ecological and srio-economic conditions, basic characteristics of cotton production and current state of allocation, China's cotton cultivated area can be divided into five major cotton regions and twelve cotton subre-gions. They are: 1) the Huanghe Valley cotton region (including four subre-gions: North China plain, Huang-Huai plain, Fen-Wei-Luo Plain, and Beijing-Tianjin-Tangshan area); 2) the Yangtze Valley cotton region (including five subregions. the Lower Yangtze Valley, the Middle Yangtez Valley, the Upper Yangtze Valley, the Nanyang-Xiangyang basin, and the Southern Red Earth Hilly area); 3) the Northwestern In terior cotton region (including three subregions. south Xinjiang, East Xinjiang,and North Xinjiang-Hexi Corridor); 4) the early-maturing cotton region; and 5) South China cotton region.The North China Plain is a famous cotton area of our country, Possessing the optimum ecological conditions very suitable for the cotton cultivation with great potential in increasing production.South Xinjiang and the Huang Huai Plain are also cotton-production areas known for their optimum ecological conditions, but the current status of cotton development is handicapped by the Relatively low level of economic and technical conditions, yet they have great potentialities.The Lower and Middle Yangtze Valley Plain is a large high-yield cotton-cultivated area distrbuted intensively with cotton fields.It is suitable to cotton cullivation but with limited potential in development.The Fen-Wei-Luo Plain, North Xinjiang,and Nanyang-Xiangyang Basin are also main cotton production areas but they have less potential.The Upper Yangtze Valley, the Southern Red Earth Hilly Area, South China, and Northern Early-Maturing Cotton Regions are ecologically less suitable to cotton production; Cotton field there are small in acreage and distributed separately.From strategic point of view of allocation, the future development of China's cotton-producing areas should take into account the following measures, i.e.to consolidate and improve cotton concentrated areas of Lower and Middle Yangtze Valley Regions,to actively construct the cotton producing area of North China Plain, to develop gradually new cotton area of the Huang-Huai Plain, to create conditions to explore high-quality cotton area in South Xinjiang,to adjust and diminish cotton acreage of the regions where ecologically unfavorable to cotton cultivation and to concentrate properly the dispersedistributed cotton acreage, so as to establish a rational alloction system of cotton development.
  • DETERMINATION OF THE MAIN SOURCE OF THE YANGTZE RIVER
    Shih Mingding
    1983, 2(1): 23-34. https://doi.org/10.11821/yj1983010003
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    Usually a river has several headwaters on its source, but how to define the main source of a river lacks a univerally accepted principle or criterion. Some rivers define their main sources according to their lengths, and others define their main sources according to the traditional habit of the people.Under normal conditions, the traditional habit of the people coincides with the general flow direction of the river course, that is, if we make a survey from the plan map of a river network it looks like a natural extention of its way from lower reaches to upper reaches. However, the quantity of water in a river usually doesnot define the main source.The source region of the Yangtze River headwaters is situated in the hinterland of Qinghai-Xizang plateau, which is an unlraveled region, so thah a consensus of opinions about where the main source of the Yangtze River rises is not yet attained.After thorough investigation, among the various headwaters of the Yangtze River, the Tuotuohe River is the longest (including the glacier on headwaters) by length, and the Dangqu River is slightly shorter. As to the criterion of unanimous direction of streams, Garqu River is the smoothest, and the Tuotuohe River next; by the discharge of water, Dangqu River ranks the biggest and Tuotuohe River the second gumming up the above considerations, the Tuotuohe River is both the longest and with approximately the same direction of streams.For this reason, we consider that the Tuotuohe River should be the main source of the Yangtze River.In accordance with the above standpoints, We have computed the length of the rivev section from the headwaters of the Tuotuohe River to Yibin of Sichuan province to be 3174 km; and the length of that section from Yibin to the river mouth about 2806 km.Since the main channel of Middle and Lower Yangtze Rivers swing bank-to-bank frequently, and the section of river mouth has extended for a considerable distance to the East China Sea, the length of the Yangtze River is about 6300 km.
  • A PRELIMINARY ANALYSIS OF THE PROCESSES OF SEDIMENT YIELD IN SMALL CATCHMENT ON THE LOESS PLATEAU
    Chen Yongzong
    1983, 2(1): 35-47. https://doi.org/10.11821/yj1983010004
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    The main regions of sediment yield lie on the both sides of Huang He from Hekouzen to Lunmen, and in the upper and middle reaches of Jinhe, Lohe and Wehe river on the Loess Plateau. The sediment yield is concentrated in the period from July to September, or in one or two rainstorms.The delivery ratio approches to in the watersheds on the Plateau. Sediment yield in a small catchment is the result of both physical factors and human activities.Soil erosion is proportional to the addition of precipitation and the depth of runoff and increases with the gradient of the ground surface, while the runoff flow erosion decreases on the slope of over 25°-28°. Clayly loess is present in the south part of the Plateau and coarse loess in the north. Scrub is better for soil conservation than other vegetations. The sediment yield has been increasing in the last 30 years in the lower reaches of the Huanghe. The artificial increase is about 23-35% of the mean transporting sediment.The pattern and intensity of soil erosion vertically change from the top to bottom in the small catchment. Rill erosion dominates in the intergully, and gully bank is an area of multi-functions of water erosion, gravitational and cavern erosions. The sediment output in gully bank is abnut 59% higher that in the Loess region of gullied-hilly, and most sediment yield from the gully bank is in the Loess gullied-table areas.
  • THE CHANGES OF SONGHUA-LIAO RIVER SYSTEM
    Yang Binggeng, Sun Zhaochun, Lü Jinfu
    1983, 2(1): 48-56. https://doi.org/10.11821/yj1983010005
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    Since the Neogene,the ancient Songhua-Liao River system have undergone several changes with the alternation of fluvial and lacustrine formation on a large scale.In the early Miocene, ancient NenJiang-West Liao R. formed a centripetal interior drainage; and in the Late Miocene, Daan-Dabusu Lake and Panshan-Tienzuang tai Lake were formed.During the Pliocene, a fluvial and lacustrine climax had reached ever since the cenozoic time Subsequently, in the Tai-Kang Stage,the hydrographic not had become centripetal interior drainage once more.At the end of the early Pleistocene or the early stage of the Middle Pleistocene, Songhua R. had cut through the divide near the neighbourhood of Shanxing, and sabsequently the Liao R.also had cut through the Tieling-Faku Hill.Thus the centripetal interior drainage of the ancient Songhua R.Liao R. become the recent exterior drainage.
  • ON THE CLIMATOLOGICAL CHARACTERISTICS OF THE NATURAL SYNOPTIC SEASONS IN ASIA
    Zhang Jijia, Sun Zhaobo, Chen Songjun
    1983, 2(1): 57-64. https://doi.org/10.11821/yj1983010006
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    A series of five-day mean cirulation at the 500mb level over Asia and the mean temperature fields in China were expanded by the method of empirical orthogonal functions.The results from analyses of the annual variation of some first time co-efficients of EOF enable us to come to a conclusion that a year may be divided into six NSS, namely, spring, early summer, summer, autumn, early winter and winter The average division and duration of each NSS are then determined.A synoptic-statistical analysis was also made for the primary characteristics of circulation within NSS.
  • PRELIMINARY STUDIES ON FORAMINIFERA IN SURFACE LAYER OF SEDIMENTS ALONG THE NORTH COAST OF THE BOHAI BAY AND ITS HABITAT
    Li Yuanfang, He Xixian
    1983, 2(1): 65-73. https://doi.org/10.11821/yj1983010007
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    About 100 samples from surface layers of deposits located along the north Coast of Bohai Bay have been qualitatively and quantitatively analyzed,A total of 82 benthonic foraminiferal species belonging to 40 genera has been identified. They are mostly salt-brackish water and shallow water species.According to the distribution of foraminifera two foraminiferal assemblages can be distinguished. 1) The littoral assemblage living in the enviroments such as the river mouths, coastal plains, beach, lagoon etc. The representative species are Ammonia confertitesta Zheng, Elphidium hughesi foraminosum Cushman, Cribrononion porisuturalis Zheng, Pseudononionella variabilis Zheng, Quinqueloculina seminula var jugosa Cushman, Nonion akitaense Asano etc. They are called the Ammonia confertitesta and Elphidium hughesi foraminosum assemblage east of Nanbao, and the Ammonia Confertitesta and Pseudononionella variabilis assemblage west of Nanbao,2)The near coast shallow sea assemblage, the representative species are Ammonia confertitesta Zheng, Elphidium magellanicum Heron-Allen and Earland, Quinqueloculina akneriana rotunda(GeRke),Cribrononion incertum (Williamson), Elphidium advenum (Cushman), Buccella frigid (Cushman) etc. It is called the Ammonia confertitesta and Elphidium magellanicum assemblage, Difference between the two foraminiferal assemblages clearly shows that the distribution of foraminiferas was associated with water depth, salinity and different types of deposits,A section has been made which is perpendicular to the coastline and passes across Shegang barrier beach. By analysing the relationships between habitats and the amount of foraminiferal shells at each sites along the section, we can judge that the amount of foraminiferal shells is latger in the shoreline of lagoon-swamps, and smaller at barrier beach, even zero on the top of the barriers, but it increases again towords the sea.Those foraminiferal assemblages and their distributions provide an important basis for explaining foraminiferal palaeoecology in this area.
  • THE FLUCTUATION OF AUTUMN RAIN IN SOUTH-WEST CHINA
    Feng Liwen, Guo Qiyun
    1983, 2(1): 74-84. https://doi.org/10.11821/yj1983010008
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    It is found in this paper that the variations of runoff from the hydrometric station, Yichang, in the upper reaches of the Changjiang river in September and October reflect the variations of autumn rain in South-west China, Therefore, it is possible to utilize the data of runoff from the period 1882-1980 at Yichang to research into the fluctuation of autumn rain in Southwest China.The fluctuations of autumn rain in this region have cyclic character, the major cycle in September is about 3 year and 17 year, but it is about 13 year in October. The fluctuations of the autumn rain may be divided into many spells, some of them are above normal, but other are below normal. These spells are related with the condition of subtropical ridge in pacific in September and with Indian low in October.
  • A PRELIMINARY STUDY ON THE DISTRIBUTION CHARACTERISTICS OF MERCURY IN SOME TRO-PICAL AND SOUTH-SUBTROPICAL SOILS OF CHINA
    Hong Jihua, Zhang Shen
    1983, 2(1): 85-92. https://doi.org/10.11821/yj1983010009
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    The level and distribution status of mercury in some soils of the Tropics and South-subtropics in China were described in this paper. The results obtained may be summarized as follows.1.The distribution frequency of mercury content in the soils studied is a lognomal one.The geometric mean is a value of 100 ppb,2.The accumulation of mercury was observed in the topsoil and the content of mercury decreases with the depth of the profile. The level of mercury in underlying igneous rocks is lower than that of each soil sample derived from them.3.The mercury content of these soils increases with the content of organic matter.4.All of the topsoils contain a little methylmercury, the level relates to the content of the total mercury in sample.5.The contents of mercury in the landscapes of geochemistry are as follows: The soil derived from superagual landscape>eluvial landscape>tran-seluvial landscape.
  • TABLES FOR QUICK COMPUTATION OF THE PENMAN ESTIMATE OF POTENTIAL EVAPOTRANSPIRATION
    Wang Yixian
    1983, 2(1): 93-107. https://doi.org/10.11821/yj1983010010
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    This paper contains the following four main parts.1.A brief survey of the definition of potential evapotranspiration Et,and the relation between the potential evapotranspiration Et and the open water evaporation Eo.2.Historical review of the study of evaporation.3. The factors δ/δ+v and v/δ+v have been considered as "weighingfactors" which specify the efficiency of conversion of net radiation into energy of vaporizing water. It was considered that these weighing factors are function of mean air temperature alone, but recent study indicated that these factors are quite related to altitude. We take these factors as the functions of mean air temperature and the altitude of meteorological stations.4. For the purpose of quick calculation, We provide 6 tables for calculating the Penman estimate of potential evapotranspiration. i. e. 1) table of δ/δ+v and diagram of v/δ+v at different altitudes and for different mean airtemperatues,2) table of conversion from different mean air temperatures and relative humidities to saturation deficit, 3) table of (0.56-0.08√ed),4)table of (0.10+0.90n/N), 5) table of (0.248+0.752n/N, and 6) Table of conversion from U10 to 0.26 (1+9.8×10-3U2).
  • IMPACTS OF WATER TRANSFER FROM SOUTH TO NORTH ON THE WATER QUALITY OF THE HUANGPU RIVER
    Tang Qingwei
    1983, 2(1): 108-114. https://doi.org/10.11821/yj1983010011
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    This paper gave a preliminary analysis of the characteristic and vari ation regularity of runoff of the Yangtze river in low-flow period (from Dec. to Mar.), and the effects on the quality of the water of the Huang pu river after the intrusion of sea water.Although rich in water resource the Yangtze river hasn't much discharge during the low-flow period. The total runoff in low-flow period occupies only fifteen per cent of the annual total runoff. The mean monthly discharge in low-flow period of normal year of 50% frequency is below 15000 M3/sec. The mean monthly discharge of 75% frequency of dry year in Jan.and Feb, is less than 10000 M3/sec. Salinity varies with the quantity of the flow which comes from upstream. It becomes highly sensitive in river-mouth area when the discharge in Da Tong station is 10000 M3/sec. The salinity in river-mouth area will increase repidly if the discharge in Da Tong station is less than 10000 M3/sec. As a result, serious impacts will happen to the water supply both of Shanghai city and the industrial and agricultural bases in river-mouth area. For the planning of water supply in the Yangtze river basin,it is necessary to keep the discharge through Da Ton station above 15000 M3/sec, or at least not less than 10000 M3/sec.