East Xizang region belongs to Sino-Himalayan forest sukingdom of Horaltic Kindom.(Fig.1).The species of wild spermatophytes in this region amount to 2318 (Tab, 1),constituting 44.79% of the total number in Xizang.32.66% of them, e.g.757 species are the endemics to China, among which 49% (371 species) are distributed only in South Hengduan Mountains, such as Abies ern-estil, A.forrestii, Larix potaninii,Picea brachytula var.complanata, P.liki-angesis var.hirtella, Pinus densata, They are dominats of subalpine coniferous forest in East Xizang.There are 425 endemic species to Xizang, e.g.18.33% of the total number.Among them 340 species represent the region's endemics, including 50 species of Compositae, 21 of Rosaceae, 20 of Gramineae, 16 of Papaveraceae and so on.Altogether 1182 species are attained including the endemics of Xizang and of the 0 her parts of China, that is, 50.99% of the total number of species.From this percentage we may see that flora in East Xizang is a young and quite flourishing species-endemism.The elements of East Asian distribution pattern occupy an important place in the flora of East Xizang and consist of 753 species, constituting 31.7% of the total number.Among them 311 species belong to East Himalayas and 195 to the whole Himalayas.There are a lot of common alpine Plants Himalayas, such as Cassippe selaginoides.Diplarche multiflora, Saxifraga (22 species), Rholdod-endron (20), Primula (24), Gentiana (10), Pedicularis (16).It appears that the flora of East Xizang region, asapart of Sino-Himalayan forest flora of Horaltic Kingdom, is closely related to East Asiatic flora.The so-called relationship between East Xizang flora and Mediterranean-Central Asian flora is really next' to nothing.East Xizang region is subdivided into 2 subregions:A.Hengduan Mountains subregion with 64 endemic species of 37 genera of 21 families, including monotypic genus Salweenia of the primitive tribe Soph-oreae in Leguminosae.It was very probably a member of Gondwanaland flora which hed survived after finding a refuge in the midstream valleys of Nujiang River (Salween) and Lancang River (Mekong)B.Bomi-Gyaca subregion with 276 endemic species of 90 genera of 30 families includes Quercus tungmainsis, Brassiopsis Karmalaica, Agapetes praeclara, Aconitum (12 species), Corydalis (14), Pedicularis (14) and so on.The monotypic genus Parapteropyrum tibeticum is found in this sudregion and appears to be the definite Tethysian element during the drawing back of Tethys sea.

This paper discussed the spectrum structure and time profiles of greenness for wheat, corn, soybean and cotton in North-China according to spectral data observed in Yucheng, Shandong provinces in 1981 and 1982.It was proved that primary informations for interpreting the four crops containing in modes of greenness made up of reflectivity of visible region (0.4-0.7μm) and near-infrared region (0.8-1.1μm).The combination of any band in the visible region does not produce more informations for interpreting the four crops, nor does the combination of any band in infrared region.Graphic transformations and time profiles of the greenness which have unique features for four crops were depicted, and their roles in interpretation were shown.We presented three new models of greenness.G6, G7 and G3, with which we can approach cholorophyl contents for wheat, corn and soybean respectively.More informations for interpreting crops can be obtained when the models have been ingeniously combined and rationally used.Different time profiles of greenness will be got when division of band is different.The above mentined charati-cristics' should be considered in choosing optimum band for resource satellite of China.

The research in the Loess Plateau of China, has had a very long history.The changes of the natural environment are very obvious and the effects on-the neighbouring North China Plain have been great.Since the founding of the people's Republic of China, alor with the vigorous development of our national economy, science and culturt, the historical-geographical scholars of China have studied the loess Plateau from many aspects and have gained great success.Progress in research work, on the whole, may be divided into two stages: 1.from the 1950's to the early 1960's, 2.from the late 1970's until now.In the first stage the experts have written several theses of high quality.In the second stage more historical-geographical scholars have taken part in the research activities, the atmosphere has been more lively, and its effect has been more widespread.After liberation, the historical-geographical scholars of China have made gceat achievements in scientific research.These include research on climatic changes, the developments and the changes in the distribution of agriculture and livestock farming, the relationship between the form of land utilization and the flood of the lower reaches of the Yellow River, vegetation changes, the formation of loess and the causes of its erosion, changes in the morphological characteristics of rivers and lakes, the desert's changes in the historical period of the Loess Plateau of China, The research work has produced good results in the harnessing of the Yellow River and the Loess Plateau of China, in agricultural regionalization and in the development of agriculture, forestry and animal husbandry.Professors Zhu kezhen, Tan Qixiang, Hou Renzhi, Shi Nianhai, Xin Shuzhi and others have made great contributions, A large number of the middle-aged and young people have also made further advances.In order to carry on thoroughly historical-geographical research on the Loess Plateau of China, the experts should cooperate with those who specialize in all the subjects concerned.We must concentrate our attention to the study of important subjects such as: forestry changes, the influence of man's activities on soil erosion and desertification, and try to make breakthroughs.We should attach special importance to historical documents and simultaneously strengthen field investigation and adopt new techniques.We should widen the application of basic theory and spread the main research achievements of historical geography among the people.

This paper mainly deals with the eastern route water transfer from the Changjiang to the Hai-River-Plain north of the Huang-He.The first-stage project of the east route water transfer was approved by the Chinese state Council in Mar.,1983.After the completion of this project, about 50m³/s of water discharge would be diverted to the Dongping Lake on the south bank of the Huang-He.In consideration of the second-stage project of the eastern route water transfer, the following problems are discussed in this paper.1.Water shortage in the Hai-River-Plain north of the Huang-He;2.Conjunctive use of local water in the Hai-River-Plain and imported water from the Changjiang River.3.Impacts of water transfer upon the environment in the plain north of the Huang-He;4.Rational utilization of the Huang-He's water resources.To sum up, the authors of the present paper would like to point out that the no-rthward water transfer from the Changjiang to the plain north of the Huang-He is Ikiely to be advisable.

西南师范学院亚热带生物与地理研究所、四川省生态学会和四川省地理学会于1983年12月5日至11日在重庆北碚联合举办了中国亚热带学术讨论会。出席会议的有46个单位112人。大会收到57篇论文和一批专辑、专著。

The fringing reefs of Hainan Island are one of the most developing fringing reefs in China. There are many coral reefs discontinuously distributed around the island. In the eastern and southern coasts, the fringing reefs develop on a large scale. In the western and northwestern coasts, the fringing reefs have some different characteristics. The bases of the fringing reefs are different from place to place, such as basaltic, granitic, limestones of ordo-vician system quartziferous conglomerate of Devonian system or loosing slope wash and alluvium etc.The climate of Hainan Island belongs to the tropical monsoon island climate. The mean annual temperture of air is 25.4℃,and the mean annual tem-perture of sea-water 26.7℃ in the southern coast, whereas the air temperture is 23.4℃ and the temperture of the sea-water 24.2℃ in the northern coast. The mean salinity of the surface sea-water is about 32-33‰ which is slightly lower than the mean value of the South China Sea (34‰). Generally speaking, the quantity of evaporation is greater than that of rainfall. The whole area is subjected to NE monsoon and SE wind. As usual, The NE monsoon is the prevailing wind in winter and the SE wind prevails in summer. Spring and autumn are the alternative seasons of the wind. In a word, the coastal climatic and hydrographic coditions are suitable for the growth and development of coral reefs, but the seasonal change moderates the growth of the coral reefs.The fringing reefs of Hainan Island can be divided into the following five zones:1. The protogenous reef zone. This zone is situated in the lower tide zone. It forms a slope, on which many kinds of corals, algae and reef-like creatures are developed. This zone can also be subdivided into upper zone and lower zone according to the combination of the hydrodynamic conditions and the coral species. The depth of these zones is approximately 5m. The lower limit for the living corals is about 10m deep.2. The reef flat zone. This zone is situated in the tidal zone. It has a broad and flat relief, on which the turdidites are accumulated and there live a few living corals. This zone can also be subdivided into marginal shoal, inner and outer subzones.3. The beach. This zone is situated in the tidal zone.The beach is a slope. Upward it becomes the berm of the upper-tide zone.4. The coastal biogenic berm. This zone is situated in the upper-tide zone and is the highest place of the fringing reef. The berm is composed of the biogenic shingly sand accumulation.5. The lagoon and swampy zone. This zone is situated in the upper-tide zoneand distributed in the side of the coastal biogenic berm or between twoberms. It is composed of biogenic sand and shingle.In terms of the coast characteristic, the environment of reef formation and the conditions of the development of coral reefs, the reefs of Hainan Island can be divided into the following four types. 1. Straight fringing reefs, 2. gulf fringing reefs, 3. lagoon fringing reefs, and 4. offshore-isle fringing reefs.Because of the different environments of the reef formation, the scale of fringing reefs, coral species and contents of terrigenous materials differ between southeast and northwest coasts of Hainan Insland.By the determination of the isotope C, there were several periods of higher sea-level around Hainan Island in the last 8000 years, and in the period of 5000 years B.P. the sea level was the highest (about 2-4m. above the present sea level).

The purpose of this study is to make a functional classification of the cities and towns in Sichuan, Yuannan, and Guizhou provinces in Southwestern China on the basis of the National Statistical Data of 1979, according to the method formulated by Howard J. Nelson in 1955,The rsult shows that,the correct way of using H.J. Nelson's method of quantitative analysis is to revise it by taking the actual conditions into account. The results of the functional classification are as follows. There are 18 multiple-functioned cities from the total 22 ones with administrative municipality; among them 3 are provincial capitals, 12 are prefectul centres and the other 3 are economic-cultural centres without political-administrative function over some administrative areas, Chungqing with a population of about 2 millions is one of this kind of economic-cultural centres, the biggest city in Southwestern China, another two are small cities with a population of around 200 thousands each. Moreover, there are 12 cities with distinctively specialized industries, such as metallurgy, coal mining, manufactures, textile, chemical,paper-making, salt-making, and sugar-making industries etc.The statistical data for the functional classification of the administrative towns and rural centres (district, commune or township centres under the county) are inadequate. The administrative towns are usually the prefectuml or county centres (but there are more than one half of the county centres withou town-administration in the three provinces),A few of them are district centres, or towns of prominent commercial-industrial, purely industrial, mining or suburban characters. The proportion of the labours in industry is small, about one-third of the total, but it is about one half in the cities with administrative municipality,Usually there are several dozens of rural centres in every county, but only one or two of them (including county centres) have town-administrative offices. The commercial function of the rural centres is more prominent than that of the administrative towns.

The Ningbo-Shaoxing Plain, a well-known area of water network in China, has been in the historical periods a lake group consisting of 217 major lakes, a lake group which played an important role in the development of the human society of the region, and which was decidedly influenced in its vicissitudes by the enhanced activities of man. Owing to the special regional physical and socio-historical conditions, there has existed from the beginning a relation of mutual dependence and contradiction among man and the land and water in the region, and the lake group, evolving without intermittence in such contradiction and conflict, has experienced a process of fluctuation from hilly areas to the plain and vice versa. The lacustrine fluctuation essentially a migration of water bodies, reflects man's readjustment of the physical environment, with a purpose of utilizing, under the situation of the high-speed growth of the population, the land resources of the region to the maximum. The fluctuation in which both borizontal and vertical movements took place, has resulted in the change of the property of the lakes and their morphological improvement, which were realized, along with the migration of water bodies, mainly in vertical movement.In consequence of the vices of feudalism existing long since, and of the mistakes in agricutural policy in certain respects after liberation, the proper exploitation of the water resources of Ningbo-Shaoxing Plain has not been fully resolved, and the lacustrine fluctuation of the region is still to be treated in further researches.

This paper deals with accumulation and dispersion of the water-salt in the soil at the hillock, slope and low land. The salt is intensely accumulated under the condition of the water-salt at the slope.The salt isn't usually accumulated at the hiuock. Although the soil is in the dynamic type of the water-salt by the film water and capillary water at the hillock the soil salinization may also happen when the degree of mineralization of ground water is comparatively high. Although the salt in the water condition the low land is easily accumulated, the salinization do not happen at the trough-shaped low land and some dish-like low land, due to the presence and formation of the low mineralization zone.This paper also deals with the variation of the salt contituents at the hillock, slope and low land.

The muddy coast of the southern Zhejiang Province belongs to deposited coastal segment. The source of sediments is quite in abundance.It is supplied by the Oujiang, the Fiyuenjiang and the Aujiang Rivers.In addition, it is also supplied by the littoral current. In the recent 30 years, the mean progra-dation-rate of the shores and beaches toward the sea reaches about 20-30m per year. The vertical distribution of the sediments also proves that the sediments of the offshroe facies of. the modern intertidal zone developed on the basis of the shallow sea facies of the prime subtidal zone.The changes of the shores and beaches and erosion and accretion of this region are very complicate from hydrological and sedimental points of view. In general, there is a tendency of deposition above the medium tidal level, but below that level, the sediments are not deposited easily because the hydrody-namic forces are relatively string and also because of the littoral current.

"Southern Jiangsu" covers the part of Jiangsu Province South of the Yangtze R. roughly by Maoshan divided Mountains, It is into two parts, the western hilly country and the eastern Taihu plain.In the late Pleistocene, when the sea level was lower, the coastline nearly coincided with present isobath of 115m in East China Sea, The land at that time tended to slope gently from SSW to NNE,In the early and middle Holocene, when the climate of the whole world became warmer, the sea level rose rapidly, and the sea water flowed into the depression of the Taihu through the Wusong R., a branch of the Yangtze, and further into the depression of the Zhaohu and the Gehu through the lod Longxe R., Two bays were formed, which later changed into two lagoons. This process is proved in this article by the petrologic character and fossils of the sedimentary rocks in to profile shown by a number of holes drilled around the Taihu and Zhaoge lakes.According to historical records, in the late Holocene, the Taihu and Zhaoge lake areas were freshened through the stages of lagoon and transformed into networks of waterway. And finally they have the present landforms.

This paper presents four non-linear regression equations about the distribu-tion-of solar energy in China. Two of them (equation (4) and (5)) are those for the estimation of the monthly values of the global solar radiation Q and the direct solar radiation S'.

This paper sums up evaporation study in China under three headings. (1) measuring evaporation, (2) calculating evaporation., (3)potential and actual evaporation. With reference to the progresses of this field in the world, achievement of the last three decades in China is gathered, and prospect is presented.Much work on measuring evaporation was undertaken during the period from mid 1950's to mid-1960's. The research on evaporation from water tank and/or pan was carried out in some evaporation stations which were established under the guidance of the Ministry of water Conservancy and power and its local authorites. A number of measurements were made with accuracy, and on the basis of data some formulas were obtained. The detemination of evapotranspiration from agricultural field was performed in some experimental stations due to the need of scheduling irrigation. The water balance method was applied to the detemina tion of evapotranspira tion. Mo.it of the results by using it were not very satisfactory, because of the accuracy of measurement of water ele ments and limitation of observation aites.A type of lysimelers, which is mainly used for the relation of rain to infiltration and fluctuation of groundwater, was installed by organizations of the Ministry of Geology, but it is quite difficult to have good results of evapotranspiration under natural conditions. More comprehensive studies on evaporation which include various methods with exception of eddy correlation method were carried out by some institutions, but desirable results did not reach because of difficulties of both theory and practice. In view of deficiencies of evaporation studies in the past, a great effort has to be made towards the experimental direction.On the contrary,much more work has been done in calculating evaporation. Various formulas were produced to meet the urgent need of evaporation information, and some maps of evaporation distribu tion were presented by some authors. The articles on evaporation calculation are still increasing. There is a motley collection of results. It is a good idea to compare the calculation values with experimental data in order to judge which is better or worse.As for potential and actual evaporation, first of all, a variety of definitions of potential evaporation was analysized. In common sense it was regarded as evapotranspiration which occurs under the condition of sufficient water or when water is not a limiting factor in evaporation process. Differences of definition appeared when otherlimiting factors were added to specify potential evaporation under a particular condition. The variance of it was not justified in our country so far, therefore it is difficult to use the estimation of potential evaporation by existing formula. Once actual evaporation was looked over, it was kept in mind that our knowledge about it was too little. In order to improve it experimental study in representative catchments and development of models should be put into action.

The Changjiang's course at its estuary is divided into two brauches by the Chongmitg Island. According to the historical records of channel changes in the reaches of the Changjiang's estuary, the feasibility of the project of sealing up north branch is discussed in this paper. The author indicates that the project the would be advisable to realize as it would, be help-ful to mitigate channel siltatiou and sea water intrusion in the area of the Changjiang's estuary after completion of the project of nouth to uorth water transfer from the Chang-Jiang's downstream.

Zhong Hua Geographical Society, was one of the earliest geographical society in China, It was established in Shanghai 1931. It had some eighty menbers. The chief task of this society was to publish the "Geographical Quarterly". From 1931-1936, this review had been published 2 volumes (8 issues, 124 articles)This review contained geographical theory, human and economical geography, physical geography, Chinese and foriegn geography, historical geography, geographical teaching method, travel records, local geography, book reviews and geographical activities.This periodical was the first magazine to introduce Marxism theory to the geography study in China. In this aspect, some ten papers dealt with the theory. Such as "The Development of Human geography and Schools" (Vol.1, No.1, by Chu Tunan), in this paper, the author introduced the chief opinion of the new social geography. "The New Stage in the Study of Geography" (Vol.2 No.1&.2), "An Easy Explanation of Transitional Period Geography" (Vol.2 No.4, by Li Changfu), "An introduction to the Chinese Historical Geography" (Vol.2 No.3, by Chu Tunan) and some other articles also discussed Marxism theory for the geography researches.As the Japanese invasion to China in 1937, the activities of the society had to be ended.

中国科学院地理研究所经济地理部于1984年4月24日邀请香港中文大学地理系B·泰勒博士作了题为“香港城市规划系统”的报告。泰勒博士首先指出香港的城市问题是香港目前最严重问题之一。城市问题就是空间不足、人口密集。

竺可桢研究会业已成立。为了开展对竺老各方面的研究,包括目前正在着手的他的年谱和传记的编写,亟需调查研究有关竺老生平的各种史实,征集有关他的手迹照相等文物。

This paper deals with distributive regularity of brine with high-boron content (B₂O₃ is higher than 400 mg/1). This paper is based on the data of more than 90 saline lakes obtained from Qinghai-Xizang field obtervations and laboratory studies.The component,water-chemical properties and formative con-ditiont of the brine are also discussed in this paper. It has been discovered that boron not only coexists with Li⁺,K⁺,Mg²⁺,but also is well interrelated to them; but then, the content of boron is inversely proportionate to that of magnestium in carbonate-type's brine. The reason why there is difference of water-chemical components between the brine of Chaidamu Basin and Northern-Xizang is explained here. We also inquired into the material source of the brine rich in B³⁺, Li⁺, K⁺, R⁺, Cs⁺, F⁺, As³⁺, and the contributing factors of high-boron brine.

Taking the middle and lower reaches of the Yangtze River as a typical example, this paper deals with the problem about the formation and evolution of braided,channel with stable island.Two fundational requirements are necessary for the formation of braided channel with stable island. 1. Sediments are deposited in the centre of a river, 2. Deposited sediments become some srable deposit bodies with a cetrain shape.In order to attain these requirements it is necessary that various conditions of the river itself, including geological, geomorphological and boundary conditions, coming water and coming sediments should be combined in a certain way, In the middle and lower reaches of the Yangtze River these conditions are as follows.1. The geomorphological condition with alternate wide and narrow seetions. This brings about the difference of stream power along the river and then the difference of depositing places. Besides, the free shift of the channel in lateral direction is also confined.2. Different geologic structures along the river. It is discovered from the data of natural conditions and experimental researches that crustal subsidence favours the widening of the channel and the formation of central bars or islands, while crustal uplift cuts down the channel and forms straight and single channel.3. The moderate erodibility of the channel boundary makes the channel moderately widened and sediments deposited in the centre of the river.4. For the properties of the coming sediments there must be a suitable proportion between the rolling and suspended materials, i.e. the former occupies 13.7% and the latter 25.7%. This makes the deposited sediments become a stable island. From a lot of historical records and real measured material, we obtainthe evolutional law of the braided channel with stable island as follo'ws.1. At first a lot of piecemeal central bars are formed in the river, then they gradually combine with each other, develop and become islands, and then move down-stream; or side bars are formed and cut by the flow and become central bars, and then the above sequence goes on repeatedly.Thus is the general law of the formation and development of the braided channel with stable island.2. After the braided channel with stable island is formed, the status of every branching channel changes alternatively itself, some develop and others weaken or even die off, then new branching channel is formed again.3. The period in which the alternation between the main channel and the branching, channel is performed is relatively long, from decades to hundreds of years, so the braided channel possesses relatively stable property.The internal-mechanism of the formation and evolution of braided channel with stable island can be explained by the hypothesis that a river has a tendency to minimize its rate of energy dissipation. Depending on the concrete conditions of a river and its changes, it can adjust itself to achieve this purpose. The concrete conditions of the Yangtze river are just the case to force the channel to become a braided one with stable island by means of automatic adjustment.

Energy resources are the important material basis to realize the socialist four modernizations and to raise the living standards of the people.Studying the problems of the energy resources has been one of the three strategical measures to quadruplicate the annual gross industrial and agricultural output by the year 2000. It is very important to make a study of the current situations and rational utilization of energy resources in China.The article begins with a discussion of the concepts and types of energy resources, then emphasizes the reserves, the distributions, the characteristics and the problems of development, and closes with the prospect of the energy resources in China.The total reserves of the energy resources are large, yet their per capita average value is lower in China. Moreover, as the energy resources are not proportionately distributed, remote transport is very expensive and raises the cost.The article analyses the characteristics and problems, (a) the energy industry develops rapidly, (b) the coal is the chief item in the energy resources, (c) energy resources are in great proportion spent in industry, (d) the rural districts mainly spend biological energy resources, thus destroying agricultural ecology, and (e) low utilization and high waste of the energy.The article puts forward some suggestions. (a)to make technological transformations and economize on energy resources, (b) to establish a comprehensive energy system and use all energy resources and export second energy, (d)to develop both water and fire electricity,especially water electricity,and(e) to accelerate the developing of new energy resources.At last,the article points out that China has large energy resources,a fairly developed industry and technology. The urgent matter for today is to design a plan of energy resources development with a foresight and sagacity.

As a part of the study of Keshan disease and kaschin-Beck's disease are associated with geographical environment, We have collected 236 soil samples from various natural zones in China and analysed their selenium content by fluorence spectropotometry.The frequency of se-content in the soils mainly shows a logarithmicnormal distributions, so geometric average is adopted in this research work. The results obtained are as follows.1. The average Se-content in the soils in China is 0.16 ppm, that is, lower than the mean Se leve in the soil of the world.2. The geographical distribution of the Se content in the soils shows a beltformal regional differentiation. The belt, that consists of dark-brown forest soil, black soil, drab soil, dark Loessial Soil, purple soil, Alpine-and Sub-alpine meadowsoil,is a low selenium zone of soil running from northeast to southwest in China. The average Se contents in the soils in this belt range from 0.06 to 0.12PPm. So there are other two belts in the Northwest and the Southeast on both sides of the low selenium zone, and their average Se contents in the soils range from 0.11 PPm to 0.32 PPm. This situation of the soil Se geographical distribution is similar to that for the grains and also for the human hairs.3. In the Northwest belt with arid and semiarid features, the Se contentsof soils in the eluvial landscape in the mountains are lower than that in the subordinate landscape in the basins and the flood-fan deltas. It indicates that the activity of selenium in alkaline environment is higher. In the red-Yellow soil zone in the Southeast, on the contrary, the Se contents of soils on mountains and hills are higher than in the fluvial plains. It indicates the Se-accumulation in the re-yellow soil.4. Within the low selenium zone, the Se contents in the Black soil and Dark-brown forest soil are higher than in the drab soil, dark loessial soil and purple soil. The Se contents in the soils on the mountains, hills and high plains are lower than the Se contents in the cultivated fluviogenic soil on the plains and fluvial terraces.5. The low selenium soil zone corresponds to the regionswh ere the keshan disease and Kaschin-Beck's disease in man and white Muscle disease in animal occur. The difference of the soil Se contents between the disease region and the nondisease region is significant statistically. It Shows that the low selenium content in the soils is the one of the basic factors leading to low Se content in the grains and therefore the occurrence of the disease in low selenium regions.Finally, the paper also discussed the factors, which influence the distribution of Se in soils, and the possibility of increasing the Se content in the grain by improving the soil to prevent the disease.

At present the study of channel geometry of alluvial streams is almost restrieted with empirical method in the realm of plain trar.t which ma nly carries suspended load.In this paper, according to the field data, using the ratio of threshold velocity and bankful velocity as index (Fig.1), the alluvial streams can be divieded into two main categories with different sizes of bed material, one is the river reach of gravel bed which is under the condition of threshold of motion, the other is the reach with sand bed which is with a live bed. The latter can be further divided into two sub-kinds, one is the reach of cobble bed which mainly carries bed load and the other is the reach of sand bed which mainly carries suspended load. There are two schools in the design of canals, tractive-force theory and regime theory, which are not two opposite ones but are the summary of two different kinds of motion of bed material t It is consistent with those of natural streams. The same law governs the motion of bed material of natural streams and canals.The downstream relations of hydraulic geometry of the said three types of river reaches are analysed with unified method in this paper. At the present time there are two approaches in the study of hydraulic geometry of rivers,one is the empirical approach propoed by Leopold et al.,and the other is a theoretical one. The latter is a method by solving simultaneous equations of the relations of the hydraulic and sediment variables. In this paper the two approa ches are combined together, using the equable distribution of variance among width, depth, velocity and stream power per unit bed area as a supplementary equation, and the equations for the downstream hydraulic geometry of alluvial rivers of the three types are obtained.For the threshold condition, equations (16) to (10) are of downstream hydraulic geometry, which are similar to the results of Li et al.For the bed load condition, equations are (24) to (27) are of downstream hydraulic geometry by using Dou's bed load formula; equations (29) to (32) are slightly different if other bed load formula is used such as Engelund-Hansen formula used in this paper.For the suspended load condition, equations are (37) to (40) are of downstream hydraulic geometry, which are similar to the results of Dou[11] and Langbein[12].Comparing the results of this paper with the field data, and other authors'results which are shown in figure 2 and table 4, the agreement is satisfactory.

On the basis of the summer (June-August) precipitation data of China in the recent 31 Years (1951-1981), we divide into Drought-Flood years and months, and select the last four years (1978-1981) as an example.In 1978, the Southern provinces of China were in severe drought. In 1979, except for some local regionas in drought or flood, generally they were in normal year. In 1980, Southern China was wet and Northern China dry and in 1981 Western China wet and Eastern China dry. By using steamline field, potential equivalent temperature and moisture, we discuss the relationship between the interannual variation in summer monsoon and Drought-Flood. We here mainly analyse low latitude 700mb surface of the southern and northern hemisphere for 1978-1980, so as to understand some relationships between different original cnrrents of summer monsoon and Drought-Flood. The results are as foollows. 1. In the severely drought year of 1978, the position of subtropical high was by east and by north and meridional cirulation prevatiled China was under the influence of intense SE current, The cold air was so weak that drought was persistent in the southern part of China. 2. In 1980, the streamline field was apparently different from that of 1978. The situation of subtropical high was by forward west and permanent stable. Three different currents influenced China, east of 110°E It was the SW current from the ahead ridge, SW current was also present coming from the Bay of Bengeal and the crose equator current, These three systems of thermal and moist currents were convergent at the southern part of China. Simaltaneously the northern cold air moved southward continuously, so that rainfall was persistent in Jianghuai river, and thus became anomalous climate of Southern flood and Northern drought in China.3.During 1979, the subtropical high normally moved from south to north.Both thermal and moist sw current (coming form northwest Pacific Ocean and the Bay of Bengal) stretched forward to China and rainfall was nearly normal.Therefore the interannual variation of summer monsoon and the sitation and strenght of subtropical high are closely associated with the low latitude circulation of the southern and northern hemisphere.

By way of stepwise discriminant analysis, this paper analyses and inquires into the general method of agricultural regionalization, including fundamental ideas and structure of pattern.

In 1957, Dr. Zhu Kezhen led a group of scientists conducting investigations on the Hainan Island and the Peninsula of Leizhou. The findings of this group were summarized in a report by Dr. Zhu in the same year. His observations may be briefly stated as follows.1. The development of tropical land will inevitably lead to conversion of the natural ecosystems (biogeozenes) to more productive systems to better serve the society.2. Much attention was paid to the plantation of tropical economic crops. With respect to rubber, the selection of suitable land, shelter belt, vegetal cover, soil conservation and high yielding cultivars adapted to the environment of Hainan were strongly recommended. About the same applied to other tropical crops as well, but, in addition, research on plants naturally growing in the region was stressed.3. Self-sufficiency in staple food production should be the minimum goal, while the extension of sugarcane and pineapple cultivation to meet the need of other regions of China was advocated. Distribution of crops in conformation with the physical environment was advised,and along with this, diversification was suggested. Efforts were called to establish sustained production systems. Measures to increase food production as stipulated included better land management, higher yield and increased multiple cropping. Development of irrigation and expansion of fertilzer supply were mentioned as the key to higher yield of food crops.Livestock production was viewed as a means both to provide meat and other animal products and to supply manures for crops. Green manures and local resource of liming materials were also regarded as important to raising crop productivity.4. Deforestation and other vegetation destruction was seriously worried about for its inducement to soil erosion and its harmful effect on water resour-es. Importance was tacitly accorded to forestation, as witnessed by much discussion in the report on tree species adaptable to various types of terrain. In connection with forestation, firewood production end again shelter belt establishment were reted as useful and indispensable. Nature reserve was also tacitly highly valued, since it was strongly recommended in his other reports.Since 1957, significant progress has been made in scientific research on tropical environment of the world. Simultaneously, considerable changes have taken place in Hainan. A no small fraction of rubber plantation has gone around to attain fairly high productivities mainly consequent upon the adoption of measures stated in 1. There has been a growth in agricultural production, but still part behind self sufficiency in staple food. Remarkable achievements have appeared in scene in planting quick growing trees in some coastal tracts. Irrigation has developed on a moderate scale, although leaving much to be desired.Changes may be noted in all other aspects, but not impressive.A tragedy is that annual forest depletion surpasses annual forest growth. The need to reverse the tendency is becoming more and more urgent. In view of the recent advances in scientific knowledge of the tropics and developments in the situation of Hainan, the majorty of Dr. Zhu's observations in 1957 still hold good today.Recently numerous investigations have been undertaken on the problems of the development of Hainan. In the Symposium on Hainan in Guangzhou in 1983, organized by the China Association for Science and Technology, a number of proposals were presented. I agree with most of them. But their implementation would require many years and heavy overhead expenditures. In my opinion, Leucaena leucocephala may serve as cheap alternatives for the solution of many problems.It will supply fuelwood, timber,wood pulp, fertilizers and animal feed, control soil erosion, slow down deforestation, improve soil properties, and help to make reforestation less difficult.Its potentialities are not fully understood.

The Data Base for Administrative Units of the People's Republic of China has stored standard codes and coordinates of more than 2300 counties. It is divided into four data files, that is, arc records, coordinates data, polygon records and chaining from arcs to polygons, and it includes more than 30 routines, which are used for the establishment and management of the data base, as well as for statistical analysis and for making thematic maps. This data base is based on minior microcomputer and suitabe for statistical analysis and mapping within the whole country, province or region. In the last two years it has been used in various statistical mapping such as population mapping, etc, and the efficiency is much better than by using traditional method.This paper describes the aims, functions and utilizations for designing the data bank, its content, data capture method, data organization, and its application

In this paper, natural calamities recorded in literatures and modern meteorological observation data are adopted to study the climatic changes of Guangdong province during the 16-20th century and its tendeney in the future climate.During the recent 500 years, the history of the climate of Guangdong province can be divided into 4 cold periods (-1537 year, 1636-1729 year, 1831-1894 year and 1950-now) and 3 warm periods (1538-1633 year, 1730-1830 year and 1895-1949 year). They are shown in the table, The coldest periods were 1636-1729 and 1831-1894, There ware two cold periods, the cold period of the 17th century was the longest, with a duration of 93 years. And the other cold period occurred in the 19th century, which continued for 63 years. It was colder than that of the 17th century.In the 3 warm periods, the warm period of the 20th century is the warmest, in addition, the cold period of the 20th century (modern climate) is warmer than that of the l6-19th century.The climate of Guangdong was dry in the 16-17th century and was humid in the 18-19th century. The climate now is more humid than the 16-19th century and similar to the climate in the 18th century. It is possible that the climate of Guangdong will become warmer by the coming century.In the winter seasons at present, the lowest temperature was raised by 3.2℃, and the January mean temperature was raised by 1,8℃ approximately higher than that of the 16-19th century.

The South-to-north water transfer is a magnificent project in China, which brings excess water from the Yangtze River in the south to the arid areas of North and Northwest China. The proposed East Transfer Route would pass through and supply water to the Huang-Huai-Hai plain,The liuang-Huai-Hai plain is a weakly or easily salinized region. Owing to the influence of the pacific monsoon, this region has always been suffered from disasters of drought, flooding, salinization and alkalization throughout the history. Under this specific natural condition and human activity, sail salt-water movement is significantly characterized by seasonal changes. Soil is in the process of modern salinization,only varying in degrees of salt accumulation with location and times. Therefore, in the design and implement of the South-to-north Water Transfer, attention should be paid to the control of soil salinization. Alter the water is transferrer, the irrigation area in the Huang-Huai-Hai plain will be enlarged. There will be a beneficial effect on improving water condition of this region, leaching soil salt and promoting agricultural production. At the same time, the present salt-water balance of the region will be changed. The districts with poor natural drainage and without artifical drainge system might be confronted with secondary soil salinization.If the four lakes in the south of the Huang-He are used as regulation reservoirs in the South-to north Water Transfer project, then the elevation of the original storage level of the lakes will have a definite effect on the drainage of the main channels in the west of the four lakes and on soil salinization.From a long-term point of view, it is necesary to dig deep trough or to deepen the bottom of the lakes to meet the requirment of storage capacity and storage level of the lakes. In addition, the channel of drainage flooding and controlling seepage should be excavated along the west side of the four lakes, to reduce and control groundwater level of the region along the lakes, at the same time, pumping drainage station should be established at the outlet of the main drainage channel, to settle drainage outlet and increase capacity of drainage flooding.The conveyance of water for a long period of time in the main canals, especially in the stretches where the level of transported water is higher than the land surface, would lead to the formation of high-water-table zones on both sides of the canals, owing to a large amount of seepage of canals. The groundwater runoff in the left side of the main canals would impede in varying degrees and block the drainage of underground runoff and might lead to a general increase of the level of groundwater and aggravate soil salinization along the canal. Both an adequate engineering drainage system of controlling or intercepting seepage and an agricultural technique should be considered. At the same time, a scientific management system for the supply of transferred water should be worked out. So long as more attention is paid and appropriate and reasonable measures of water management, agricultural and engineering system are adopted, soil salinization could be prevented or controlled.