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  • 1996 Volume 16 Issue 3
    Published: 30 July 1996
      

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  • Luo Chengping, Xue Jiyu
    1996, 16(3): 191-195.
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    The content of CO2 in the atmosphere has been increasing rapidly since industry revolution when the concentration of CO2 was 275 (±10)×10-6.It rose up to 316×10-6 in 1958,and 315×10-6 in 1988.The effects of CO2 content increasing in the air on agricultural production in China are predicted as follows:1)The primary productivity of crops would be going to rise beacause of strengthening photosynthesis;2)Crops would have a higher rate of water-use in the air with much more content of CO2;3)Roots,stems,leaves,flowers,fruits and seeds might be enhancedly growing;4)Global climate change,caused partly by the increasing CO2,would lead to series of transformations of agricultural productive conditions,such as light,temperature,water,soil and air etc..And so,the output of crops would be influenced.Owing to greatly different natural environment in China,the change of agricultural conditions might be quite different in various areas.In Northeast China the production might increase;in North China and in the middle and lower reaches of the Changjiang River the fluctuation of crop yield might beenlarged and more agricultural disasters might occur;in Northwest China irrigated agriculture might be threatened,while in South China agriculture might be less influenced.And so,some countermeasures for agricaltural production in China are put foward:1)to control the source of CO2;2)to reform agricultural system,and regulate the structure of agricultural ecosystem,and,3)to adjust the process of CO2 to influence agricultural production.

  • Song Lili, Zhang Changzhao
    1996, 16(3): 196-203.
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    Rice drought under non-irrigation conditions is evaluated by using the index of the longest drought period during early and late rice growth in this paper.The results indicate that in Guangdong the early rice drought becomes evident gradually from north to south,the most droughty areas are located in Leizhou Peninsula,the Pearl River estuary areas and the southeast coastregion of Guangdong on the contrary,the late rice drought becomes obvious from south to north,and the most droughty areas are located in northeast and northwest Guangdong and the coast region of Shantou.Rice drought,especially serious drought,is characterized by its frequent occurrance in successive years.For evaluation of rice drought disaster condition,or the losses caused by drought,the indexes of rice drought rate (the proportion of drought-impacted rice area to sowing area)and rice' damage rate (the prportion of drought-damaged rice area to droughtimpacted rice area)are used.The results show that the drought of early rice is more serious than that of late rice.The losses of rice Production caused by drought are going up.Some droughtrelief measures are suggested:1)make a long-term plan for irrigation and urban water suppy,and develop regional economy in the light of local conditions;2)energetically construct water conservancy project,increase the benefit of water conservancy facilities;3)improve the technique of cultivation and management,and SPread the scientific method of irrigation;4)control the soil erosion;and 5)scientifically make artificial precipitation.

  • Zhong Siqiang, Su Weijia
    1996, 16(3): 204-211.
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    The growth of longan (Euphoria stead.)and lychee (Litchi chinensis Sonn.)requires sufficient sunlight,and high temperature and humidity.The regions,where the annual average temperature is from 21℃ to 23℃,total accumulated temperature(10℃)from 7500℃ to 8200℃,averase temperature of January from 12℃ to 14℃,extreme minimum temperature 2℃,and the annual preciptation from 1200mm to 1800mm,are the most suitable to longan and lychee cultivation.The main meterological factors influencing mango (Mangifera indica Linn)growth are also temperature,sunlight and precipitation.The favorable temperature for mango blossoming and fruiting is from 20℃ to 25℃.Rainy day with high humidity and little sunlight is not beneficial to biossoming,fruiting and improvement of fruit quality.Consequently,the valleys where it is clear,warm and dry in the winter are suitable to mango cultivation.

  • Tu Yuexian, Yang Guiping
    1996, 16(3): 212-219.
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    Guangdong Province can be divided into four agroclimatic zones:the middle sub-tropical zone,the northern edge of southern sub-tropical zone,the southern sub-tropical zone and the northern edgeof tropical zone.Agricultural allocation should be in the light of local climatic conditions.In the middle sub-tropical zone,double cropping rice of late-maturing variety cannot be planted and typical southern sub-tropical fruit trees and corps cannot be cultivated on a large scale.In the northern edge of southern sub-tropical zone,double cropping rice of mid-maturing variety can be planted,tropical and southern sub-tropical fruit trees and corps can be distributed in some areas,but sugarcane cannot be cultivated in autumn and winter.In the southern sub-tropical zone,for double cropping of rice,mid-late or mid-maturing variety can be used,sugarcane can be cultivated in autumn and winter.In the northern edge of tropical zone,late-maturing variety of rice can be planted for double cropping,and tropical fruit trees and crops can be cultivated on low and flat land in winter.

  • Chen Xinguang, Zhi Shiqun, Li Yanxiong
    1996, 16(3): 220-225.
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    Based on the data of rainfall,longitude and latitude,and the elevation above sea level in North Guangdong a model for calculating yearly rainfall and monthly rainfall of January,April,July and october is developed in this paper.Using the model,the corresponding rainfall is calculated in each grid point of 5′×5′longitude and latitude,and the scattered chart for the rainfall in each grid Point is also made after macrotopography correction.

  • Zhang Weiqiang, Huang Zhenguo
    1996, 16(3): 226-235.
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    According to the data of altitude and 14C dating for 99 samples from the marine deposit at the coast of Taiwan,a curve of Holocene sea level changes along Taiwan coast is drawn in this paper,while that along the coasts of South China being taken as reference.The results indicate that:1)The sea level had been fast uprising before 5000 a B.P..The highest stand of sea level occurred about 5190 a B,P.,with an altitude of about+3.2m.2)The sea level has been fluctuating around its present position since 5000 a B.P..Four hash sea levels occurred 41201120 a B.P,3250±40 a B.P.,1970±40a B.P.,and 1300±120 a B.P.,resspectively,and the altitude of sea level has been decreasing gradually.3)From the comparison of sea level changes between the coasts of Taiwan,Fujian and eastern of Guangdong,eight cycles of sealevel changes or transgression during Holocene along the coasts of the Taiwan Strait can be determined.

  • Zhang Ruohang, Liu Qijun, Huang Guangjian
    1996, 16(3): 236-243.
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    The excess excavation of sediment has caused the rapid fall of river bed in the lower reaches of the Dongjiang River in recent years,with an average descent of 3.5~6 metre and the great change of relationship between water-level and discharge at the cross sections near the pumping station of the Dongjiang-Shenzhen Water Supply System (DSWSS),which results in a series of problems such as in ability of normal water supply to Hong Kong and Shenzhen by DSWSS in dry season,upstreem ascent of tide water and tide way,decrease in safety of the river banks and increase of the threat of floods and storm surge,and descent in comprehensive utilization efficiency of water resources of the Dongjiang River.Some relevant countermeasures for solving the problems including unified management of water resources of the Dongjiang River,strict control of sediment excavation in the lower reaches,construction of big downstream dam near thepumping station of DSWSS and tideproof sluice gates at the river mouthes,and reinforcement of dikes by casting rocks,are proposed in this paper.

  • Luo Mingang
    1996, 16(3): 244-250.
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    The off-shore islands of Guangdong have the advantages of estuarine,tourist and aquatic resources,and have some restrict factors such as shortage of land and water resources,and weak economic basis.It is considered that the development of the islands would be the first step for the development of the ocean and it should be linked to the developerment of the coastal areas.The selection of the industries should be based uPOn a long-term plan.Five dominant industries are suggested:1)Port transportation:to construct ten large ports which have berths for shipe of over ten thousand tons,and 17 medium and small scale ports,so that the totol handling capacity of the island harbours would be over 200 million tons.2)Port industry:to develop basical industries such as metallurgical industry,heavy chemical industry,thermal power industry and shipbuilding industry,forming three important port industry districts in Dahao island,West Zhuhai and Donghai island.3)Marine aquatic product industry:to develop marine cultivation and deep sea fishing,4)Tourist trade:to construct tourism areas with distinctive island features.5)Marine biological engineering:to develop the technique of marine biological artificial incubation,the processing of marine life and deeper processing of marine products such as health foods and medication.

  • Lan Zonghui
    1996, 16(3): 251-257.
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    The specimens of 65 species of bivalve molluscs which were collected along the eastern coast of Guangdong Province from July 1990 to July 1994 are reported in this paper.They belong to 43 genera,21 families and 6 orders.The result of species analysis indicates that 92.3% of the species are distributed in tidal zone and 7.7% below tidal zone.These species are divided into rock ecotype accounting for 33.8%,silt ecotype 32.3%,sand ecotype 23.1% and mud ecotype 7.7%.These lukewarm water species originating from the tropics and the subtropics have an advantage in quantity,and at the same time,there are a few species belonging to the strong tropics because of the influence of the warm currents in the South China Sea.Thus,these species form the bivalve molluscs fauna along the coast of eastern Guangdong as a part of the molluscs fauna of the northern marginal region in the Indo-West Pacific.The ways to develop the aquaculture of bivalve molluscs and make rational use of molluscs resources along the eastern coast of Guangdong Province are discussed.

  • Cao Honglin, Chen shupei, Qu Xiangyu
    1996, 16(3): 258-264.
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    Hebao Island is situated at the southwest part of Zhuhai,covering an area of about 11.82km2.On the island 442 vascular bundle species,of which 413 species are wild plants belonging to 319 genera and 122 families,have been identified of the 122 families,79.5% are those consisting of single or less than 5 species.Analysis of the flora indicated that 380 species are tropical and pan-tropical elements,making up 92.0% of the total species.The major tins of vegetation are as follows:Mamgrove and semi-mangrove;coastal sandy vegetation;shrubgrassland;evergreen scrub and evergreen monsoon forest.Four species are protected at national and provincial levels,they are:Stenochlaena palustris,Ixonanthes chinensis,Gmelina chinensis and Artocarpus hypargyreus.On the island there are many excellent decorative plants,such as podocarpus macrophyllus,Rhapis excelsa and Arundina graminifolia.The authors suggest to set up a forest park to protect and develop the vegetation of the island.

  • Xia Hanping, Ao Huixiu, He Daoquan, Liu Shizhong, Chen Longjiang
    1996, 16(3): 265-270.
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    Vetiver grass (Vetiveria zizanioides) is a very ideal hedgerow for the vegetative system of soil and moisture conservation,and being widely planted in tropical and sub-tropical regions.The pot and field trials indicated that this plant could efficiently ameliorate soil characteristics.It was capable of lowering acidity and the content of exchangeable Al of strongly acid soil by 0.5-0.7 and 0.3-0.6cmol.kg-1,respectively.Distinct increments of organic matter,total N,available N and K,and total porosity in the soils were found after vetiver was established for 29 months.The vetiver treatment averaged 60% and 93% less runoff and soil loss,and 4%-42% more soil moisture,than the control,respectively.Furthermore,this plant effectively improved the microclimates of fruit garden ecosystem,including an increase of relative humidity by approximately 4%-5%,and a decrease of air temperature by 1-3 degrees centigrade.

  • Zou Chunyang
    1996, 16(3): 271-275.
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    With the economic development,the land for non-agricultural use is expanding rapidly.As a result,the cultivated land decreases sharply.There exists contradiction between the urban planning and landuse planning.The reasons are:1)urban planning and landuse planning are produced and implemented by different departments of the government;2)urban population scale is undefined;3)many urban development plans are impractical.It is difficult to acquire identity of the quantitative forgets of urban planning and landuse planning.Some ideas to coordinate the two sides are given in this paper:1)the unification of the strategy of reStonal social-economic deyelopment;2)the coordination in distribution of citiy and town system;3)the consideration of the environmental capacity.As an example,the coordination between the urban planning and landuse planning in Sanys,Hainan Province,is analysed.

  • Liu Yi
    1996, 16(3): 276-282.
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    Lingnan culture is mainly distributed in Guangdong Province.From the angle of tourist development,Lingnan culture has three advantages:1)its open ideology,2)its incorperation with the culture of North China,and its compatibility to foreign culture,3)consisting of several subtypes in different areas with distinguishing local features.Many contents of Lingnan culturehave fairly high value for tourism,such as farming culture,food and drink culture,handicraf,arts and musics,customs of minority nationalities,festive folkways,ancient relics,and religion culture,etc.For the development of cultural tourism the restonal features of Lingnan culture should be stressed,a cultural tourism network should be established and improved.Five areas in Guangdong can be chosen as the focal points to develop:1)Central Guangdong with Guangzhou as its center,2)North Guangdong with Shaoguan as its center,3)East Guangdong with Chaozhou-Shantou as its center,4)Northeast Guangdong with Meizhou as its center,5)West Guangdong with zhanjiang as its center.