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  • 1986 Volume 6 Issue 4
    Published: 30 October 1986
      
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  • ON THE COMPATIBILITY OF GENERAL RUN-OFF C3ENERATION MODEL IN THE SOUTH CHINA
    SHEN Tsanhsin, LAU Maynan
    1986, 6(4): 289-298.
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    The process of runoff generation is determind by physiogeographical environment, surface configuration and human activities. A long time, the author studied many models of runoff generation of small watersheds in South China. The studies revealed that it is unsuccessful to calculate the water yield of small drainage according to formulas basing on "formation at the natural storage" or "formation in excess of infiltration" models. In other words, both the ideas are not compatible to use in the storm flow region in Hainan Island, the bulkhead Pearl River delta, the confined groundwater region as well as the Karst areas in Guangdong Province. In Karst region, specially where the soil covering in thin, a large quantity of surface water infiltrates through the fissures and the sinkhole of limestone layer, and shifts into groundwater as soon as it has rained out. It may be said that the models as advanced by R.E. Horton cannot be applied generlly to many places in South China. In terms of aforemetioned condition, the author sets the new idea as "different physio-geographical region has different process of runoff generation and should be created suitable model for runoff forecast." The researches dealing with some 60 usual models over the world show that the infiltration equations which base on R.E. Horton's theory cannot be applied in South China. The author cited the example of the new model for Karst region in South China and prediction of water yield in some stations. The result is very satisfactory. Then, he proves his "Idea of landscape flow genertion" is truthfulness also.
  • WATER BALANCE OF THE DYKEPOND SYSTEM OF THE ZHUJIANG DELTA AND ITS ECOLOGICAL FUNCTION
    Wu Houshui
    1986, 6(4): 299-308.
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    The water balance of the dyke-pond system of the Zhujiang Delta has its uniaue pattern. Its simplified pattern can be expressed as follows:
    (rK+rL)-(EK+EL+f)=(C1+C2)+(W1+W2+W3)
    where rk represents the precipitation on the dyke, rL, the precipitation on the fish pond, Ek, the evapo-transpiration of the dyke, EL, the surface evaporation of the fish pond, f, water from fish pond flowing to the area outside the dyke-pond system, C1, water absorbed by plants and becoming a constituent part of the plants, C2, water absorbed by the planktons and becoming a contituent part of the planktons, W1 water detaind by the plants, W2, variation of the water contain in soil, and W3, variation of water leve of the pond. The variation patterns and characteristics of the dyke-pond system and its two subsystems (the dyke subsystem and the fish pond subsystem) have been analyzed and the ecological function of water balance of the dyke-pond system has been discussed on the basis of the measured data. It is considered that the reason why dyke-pond system possesses a good agricultural ecological function has a direct bearing to its unique water balance module. Finally, some measures to further improve the agricultural ecological condition in the studied area have been put forward from the viewpoint of water balance.
  • THE INFLUENCE OF URBAN DISTRICTS ON THE PRECIPITATION IN GUANGZHOU
    HUANG Weifeng, SHEN Xuepin
    1986, 6(4): 309-315.
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    The influence of city on the precipitation is a controversial issue. The study, carried by the authors, shows that the urban effect causes an increase of 4-6 present in rainfall of Guangzhou urban districts. The Guangzhou urban heat island effect increases the number of thunderstorm-day. the day-time precipitation and precipitation intensity, and decreases the number of fine day. The influence occures Bnainly in summer and autumn. The authors suggest that the increase of urban precipitation result from the synthetci effect of various factors. Cities in low latitudes, such as Guangzhou, the effect of urban heat island is the main factor.
  • PRELIMINARY EXPLORATION OF SURFACE WATER AND AIR POLLUTION IN GUANGZHOU AND WAYS OF ITS CONTROL
    Zhang Shengcai
    1986, 6(4): 316-320.
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    The essay studies the pollution of surface water and air in Guangzhou and suggests five major measures to control and abate the air and water pollution in the area.
  • RICEFIELD FISHING IN SOUTHEAST ASIA
    Kenneth Ruddle
    1986, 6(4): 321-330.
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    Ricefied capture and culture fisheries have a long history in much of lowland Sou th, Southeast and East Asia, where they play an important role in rural nutrition. However, over most of those regions, with the noteable exception of China, ricefield fisheries have declined in importance over the last twenty years. Their decline has been hastened by the introduction of high yielding rice varieties and their associated agrochemical, and water regime requirements. This paper surveys the mian ricefield fishery systems in Southeast Asia, with particular reference to Indonesia, examines the main contraints under which they operate and outlines the main research needs for their future development.
  • PRELIMINARY COMMENT ON THE FISHERY OF SHAOGUAN CITY
    HE Yashou
    1986, 6(4): 331-336.
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    Rich in fish resource, the Shaoguan City is a region with good coditions for fishery, where there are vast waters. Influnced by some unfavorable factors, yet the mean fish output per unit area in shaoguan City is low, especially in most of reservoirs. Hence, for reforming the structure of agriculture in broad sense, impriving the fish supply to the market in mountainous areas, some tasks such as to fully develop the areal predominance by utilizing all available waters, to top the productive potentialities by raising the per unit yield are demended immediately. The problem that natural fishery resources are being damaged by the polluted rivers should be solved. The author suggests that to speed up the construction of hatching pond to improve the breeding and fishing technique in reservoirs as well as to popularize the family fish farming be the key to the fishery prosperity in Shaoguan City.
  • DISTRIBUTION OF SEDIMENTS AND SUBMARINE TOPOGRAPHY OF QIONGZHOU STRAIT
    YE Chunchi
    1986, 6(4): 346-353.
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    Qiongzhou Strait is one of the largest straits in China. Dominanted by both the EW-trending and NW-trending structural system, the shoreline there is zig-zag in plan shape. Of the sediments on the Strait, sands and gravals, composed of quartz grains and basalt fragments, are distributed on the deep trough where current velocity is relatively high; the finer sediments are accumulated on low-energy areas, such as the bays along coasts and the outer edge of the west mouth of the Strait. A deep trough, 51 km in length and 2.7 km in width, is lying along the bottom of the Strait. On the both sides of the axis of the trough, there is a series of EW-trending depression and eminence features. In the mouths of the Strait, because of the ncreasing of cross-section areas, tidal currents spread and their velocity is reduced. Therefore, two tidal deltas, comprising shoals and troughs which arrange alternatively and radially, are respectively formed in the east mouth and west mouth. On the west delta, the sediments are clayey sands or sandy clays. Contrastly, the sediments on the east delta, being mainly medium or coarse sands, are coarser.
  • A STUDY ON THE WOODS-RUBBER-PEPPER INTERCROPPING
    LIN Shaolong
    1986, 6(4): 354-359.
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    Based upon the principle of ecological interaction, the woods-rubber-pepper artificial ecosystem has been designed by agronomists of Guilingyang state-farm in Qiongshan county, Hainan Island. Making full use of land, sunlight, air as well as water, the woods-rubber-pepper community is superior in ecological stability and achieves good economic benefit. The advantages of woods-rubber-pepper artificial ecosystem can be explained as follows; 1.the micro-climate and the soil structure, are improved. 2.both the rubbers and peppers are growing well. 3.the economic benefit of rubber and pepper intercropping is higher than that of unified rubber plantation. The issues such as spacing in rows and stocks, wind-break, pruning, tending of woods plan of operations in the woods-rubber-pepper community have been presented by the author.
  • PROMOTE THE TROPICAL FRUIT PRODUCTION IN SOUTHWEST OF HAINAN ISLAND
    XIE Guogan
    1986, 6(4): 360-366.
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    To expand the production of tropical fruit in order to make full use of natural resources is a major task for economic development in Hainan Island. The southwest part of Hainan Island lies in tropical zone, abundant in sunshine, with high temperature, middle precipitation, droughty winter and spring. Apart from this favorable climate, in the region there is a large amonnt of uncultivated land for planting fruit trees. The author suggests that the southwest of the island be the commodity production base for tropical fruits. Take the natural and socio-economic conditions, as well as domestic and international market into full account, the tropical fruits such as mango, cashew, winter water melon, banana, coco are suitable for market-oriented production now. To promote the tropical fruit productivity, it is suggested: 1.devote major efforts to foster a great deal of horticulturist. 2.construct a large quantities of nursery. 3.widely spread improved varieties and advanced techniques. 4.improve the public service in order to link up production and marketing. 5.for support the tropical fruit production, a agile and efficient administrative system be set up.
  • THE SUPERIORITY AND RATIONAL EXPLOITATION OF LAND RESOURCES IN SHENZHEN
    WEN Changen
    1986, 6(4): 367-377.
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    Shenzhen, the biggest special economic zone in China, has favourable conditions consisting of superiority in geographical location and abundance of land resources. This paper deals with the land use in Shenzhen City. The landform of Shenzhen is mainly characterized by platform with slight slope. The area with a slope less than 20 degrees acounts for 66.25% of the total. The land resources, being not only favourable to urban construction and cultivation, but to animal husbandry as well, has potential superiority to exploit. The current problems of land use in Shenzhen may be enumerated as follows: 1.The type and level of land use vary greatly from place to place. 2.The cultivated land decreases rapidly while the capital construction of city is booming, much land has been wasted because of ill city planning. 3.The scattered woodland covers a large area with poor economic benefit. For rational development of land resources in Shenzhen, the author suggests that; 1.To promote the economic benefit of land, the structure in land use must be adjusted. 2.More attention be paid to planning of land use, which contains some measures such as: strictly contrel non-agricultural land use, energetically develop tourism, fully exploit coastal area and sea area, correctly handle the relation between resources exploitation and environment protection, establish a unified organization for management of land use. The most important task for economic development in SEZ is the exploitation of land resources. While take up the capital construction, we should rationally use each piece of land, in order to achieve the best benefit of land resources. The demands of construction of Shenzhen is to set up a favourable investment environment, to establish a base of agricultural products for export, to promote the growth. of both economic and ecologic benefits.