Table of Content

    15 July 1980, Volume 35 Issue 3 Previous Issue    Next Issue
    Lin Chao, Li Changwen
    1980, 35 (3):  187-199.  doi: 10.11821/xb198003001
    Abstract ( )   PDF (1039KB) ( )   Save
    The mountain regions north of Beijing occupies the western part of Yen Shan which, runs eastward to Shanhaiguan and forms the northern border of the North China Plain. The climate belongs to the semi-humid warm temperate type, with a cold winter and a hot summer. Average annual precipitation is about 800 mm in the front ranges and decreases to abont 500 mm in the sheltered valleys. Deciduous forest of a semi-xerophytic type is the common vegetation. Drap soil is developed under this climatic and botanical environment.Field investigations revealed that a great variety of landscape exists in this mountain region. A system of classification of land types has been attempted. This classification is based on the knowledge of physical geography and especially on the ana-lysis of the physical factors controlling the differentiation of the landscape.Firstly, altitudinal zonation has to be considered. Although the altitude is not very high, from about 50 m in the foothills to over 2,000 m at the summit, vertical zona-tion of natural landscape is clearly manifested. Three vegetation-soil zones may be distinguished:1. The lower part of the mountain below 1200 m is covered by shrubs and grasses of semi-xerophytic and meso-xerophytic types. Small patches of Pinus tabulaeformis and Quercus dentala, Fraxinus bungeana may be found here and there in sheltered and protected areas. This is a secondary growth, the result of interference of human activities since historic times. Deprived of the protection of forest cover, erosion is very intensive in this part of the mountain. Mass wasting, such as mudflows, are com-mon features which cause great damage to property and loss of life.2. Above 1200 m and up to 1850 m is the second zone. It is rather well covered by a deciduous forest, dominated by various species of oak (Quercus aliena, Q. varia-bilis, Q. accussima), birch (Betula platyphylla, B. duhurica) and poplar (Popular davidiana). Shrubs and grasses form the undergrowth of the deciduous forest, but they are different in species from those in the lower mountain. Brown forest soil is the typical soil. Due to the protection of the forest cover, mudflowa seldom occur in this zone.3. Above 1850 m to the top of the mountain the deciduous forest is superseded by mountain meadow which is underlaid by a layer of black meadow soil. It constitutes a distinctive zone by itself. The meadow is used for pasture during the summer.Next to altitudinal zonation, lithology deserves special attention. Lithological character is an important factor in the formation of landforms, soils and vegetation. For example, we found granite and limestone form very different landscape in this part of Yen Shan. Granite usually forms rounded or undulating landforms, covering with a thick layer of regolith and a mixed forest of pines and oak. Brown forest soil is developed whereever granite occurs. In limestone area karstic landforms are found, with only a thin veneer of weather materials. Cypress (Biota orientalis) usually takes the place of pines. Drap soil is usually developed wherever limestone occurs. Loess which appears in different altitudes forms a typical landscape by itself, characterized by flat or undulating top and vertical slope under water erosion. The typical soil is drap soil, most of the loess covered land is cleared for cultivation. Alluvial deposits along the valley constitute another type of landscape. The new deposits beside the river channel forms flood plains, while the older deposits further away from the river forms terraces. The flood plains and the terraces are the most fertile land in the mountain region and become the centre for agriculture and settlement. However, the occurrence of summer flood may be a hazard to the crops and inhabitants in the valley.Mountain landscape is further diversified by the erosion of miming water. Moun-tain slopes are intensively dissected and form mesorelief and microrelief. Slopes may be gentle or steep, convex or concave. The effect of aspects of slope is also quite evident. In the upper par
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    Zhong Gongfu
    1980, 35 (3):  200-209.  doi: 10.11821/xb198003002
    Abstract ( )   PDF (1427KB) ( )   Save
    The system of "Mulberry-Dyke-Fish-Pond" is a peculiar farming method develop-ed by the working people as a result of making full use of land and water resources in their longtime farming practice in the Zhujiang Delta. It is an interrelated system which brings into full play the production potential and makes reasonable use of land-water resources. It promotes the development of different branches of agriculture and its related processing industry. "Mulberry-Dyke-Fish-Pond" is a complete scientific ecosystem.Mulberry-Dyke-Fish-Pond is characterized by its complex and diversified cycle. Mulberry-growing, sericulture and fish-breeding are interrelated. They promote each other and their circulating operation is complex and diversified. In terms of the food chain, the whole operation follows the following pattern: mulberry leaves are fed to silk-worms, silkworm ’excreta to fish and mud from the fish pond is used as good manure for mulberry trees. This circulating process begins with mulberry-growing, then moves on to sericulture and ends up with fish fanning. In this closely related process, eachlinks has either positive or adverse effect on the other. There is a popular saying in Shunde which goes something like : The more luxuriant the mulberry trees, the stronger the silk-worms, the fatter the fish, the richer the pond, the more fertile the dyke and the more the cocoons. This illustrates to the full the circulation relation of Mulberry-Dyke-Fish-Pond. In this system the mulberry tree is the producer making use of sun-light energy to produce mulberry leaves, the silk-worm is the first consumer eating mul-berry leaves, the fish is the secondary consumer having silkworm excreta (and pupas) ae food, the plankton in the pond is the reduction agent bringing the organic sub-stances such as N, P, K back to the pond.The producing cycle of mulberry-growing, sericulture and fish farming has as its base the circulation of substance in soil, water and living beings between pond and dyke. The relations of mulberry trees, silkworms and fish to dyke, pond and atmo-sphere are those of substance-energy exchange and transformation between living beings and environment. Any change in morphology, productivity, quality etc. during the growing process of mulberry trees, silkworms and fish is the result of interaction between mulberry trees, silkworms, fish and environments such as temperature, light, water, air, soil etc.With an interdependent relationship between the living beings and environment, the Mulberry-Dyke-Fish-Pond is a complete ecosystem in which substance circulates and energy exchanged and transformed. It is a scientific farming method as well. In various cycles, big or small, the mulberry is the base and the fish pond is the key link. The pond can feed fish as well as the dyke. "With the pond being taken good care of, there can be high yield in fish, and that also promotes the output of other crops.The role of the Mulberry-Dyke-Fish-Pond is:(1) Bringing into full play the potential of the local resources. Located in the southern sub-tropical zone, each year large quantities of mulberry leaves are collected, enough to feed eight to nine batches of silkworms, hence eight to nine batches of co-coons. Make use of the fish fry from the middle and lower parts of the Xijiang Eiver in the development of pond fish farming. Make use of river water and tidal water for self-control drainage and irrigation all the year round. Use mud from rivers and ponds as an impotant manure. Use silkworm excreta to feed fish. Thus the land is being made full use of.(2) Abundant sources of income and huge economic gains. The average income from every mu of mulberry trees (including that from mulberry leaves, cocoons, fish, vegetables, dry-land crops and mulberry branches) is 400- 500 yuan. If cocoons are exported, income will be even more, about four times more than that from rice, three times more than that from sugarcane.(3) A large labour force can be accommodated and needed to do both’ heavy and light workg.
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    Liu Yinhan
    1980, 35 (3):  210-218.  doi: 10.11821/xb198003003
    Abstract ( )   PDF (616KB) ( )   Save
    The division of natural zones is decided by the features of all round natural conditions.Since the formation of natural zones is mainly controlled by zonal factors, taking climatic conditions into consideration, heat, water, soil, vegetation and the characteristics in agricultural production should be regarded as criteria in the division of natural zones.Because these phenomena are mirrored in the soil, vegetation and agricultural dif-ferentiation, Shaanxi province can be divided into following eight natural zones:(1) Sub zone of semidesert steppe-brown desert steppe soil;(2) Zone of dry steppe covered by wind-blown sands-light chestnut soil;(3) Zone of dry steppe-light-textured heilu soil;(4) Zone of forest steppe-gray forest soil and argillaceous heilu soil;(5) Zone of semi-arid deciduous broad-leaf forest and forest steppe-drab soil;(6) Zone of mixed forest of coniferous and broad-leaf trees-burozem and drab soil;(7) Zone of deciduous broad-leaf forest and evergreen broad-leaf forest-Cinnamon Yellow soil and Brown Yellow soil;(8) Sub Zone of evergreen broad-leaf forest-Yellow earth. Of course clear boundary lines do not always exist, since one natural zone may shade into another.
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    Han Chin
    1980, 35 (3):  219-231.  doi: 10.11821/xb198003004
    Abstract ( )   PDF (872KB) ( )   Save
    The Tarim Basin below the confluence of the Yarkant, Hotan and Aksu Rivera has been one of our chief irrigated agricultural areas ever since two thousand years ago, whereas more than one million mows of virgin lands have been turned into farm-lands during last twenty years.
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    Gu Tinmin, Gong Dewen, Shen Jianzhu, Chen Enjiu
    1980, 35 (3):  232-241.  doi: 10.11821/xb198003005
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    In the past, most of the climatic regionalizations in China only showed dry and humid degree of the atmosphere.
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    Deng Tangxin
    1980, 35 (3):  242-250.  doi: 10.11821/xb198003006
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    During the investigations on the Guxiang mud-rock flow in Xizang from 1964 up to 1965, we also observed the distribution, damage, types, activity and forms of snow avalanche, and its roles in the physical geographic processes of high mountains.The main contents in this paper are as follows:1. The distribution and activity of snow avalanche.2. The favorable conditions for snow avalanche.3. The types of snow avalanche.4. The role of snow avalanche in the physical geographic processes of high moun-tains:(1) The geologic and geomorphologic functions of snow avalanche;(2) The function of snow avalanche in nourishment of glaciers;(3) The influence of snow avalanche on plant cover;(4) The relationship between snow avalanche and mud-rock flow.5. The influence of snow avalanche on constructional works in mountainous regions.
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    Wu Chen
    1980, 35 (3):  251-258.  doi: 10.11821/xb198003007
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    During the 1976 Tangshan great earthquake with magnitude 7.8, the large scale of water and sand eruption had occurred on the ground surface of Tangshan district. On the basis of field survey and aerial photo interpretation, it is evident that the spatial distribution of water and sand eruption, including the eruption density, morphological character and various extending orientation and their figuration, was associated not only with the sand bodies of macro-geomorphic units, but also with the micro-geomorp-hic types, especially the ancient river channels. Accordingly, we concluded that the distribution of water and sand eruption is controlled by alluvial sand bodies, and the nature of water and sand eruption is determined by geomorphic types.As for the occurrence of water and sand eruption, beside shock-force with re-levent energy, a thicker layer of shallow buried and water saturated fine silt, which was covered or uncovered by clayey loam, is a necessary condition. Since some geo-morphic types, such as river flood plain, mid and perpheral portions of alluvial fan, marine plain and shallow buried ancient river channel, comprise above described sedi-mentary structure, and a strong earthquake give a forcefull shock to those geomorphic types, water and sand may easily erupt from underground to surface. Therefore, in seismological research, the geomorphologists should accurately demarcate the above men-tioned geomorphic types, whereas the engineers should pay particular attention to shock-proof measures on such geomorphic types.
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