Table of Content

10 August 1987, Volume 6 Issue 04

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Development of Laticifers of Brazil Rubber Trees under Different Ecological Conditions

Zhao Zhongqi

1987, (4):  1-3. 

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The laticifers of the Brazil rubber trees(Hevea brasilinsis)were investigated.The resultsindicated that there was significant decrease of the rows and the density of the laticifers ofthe phloem of Brazil rubber trees with increase of the latitude or altitude.There weremuch more rows of laticifers and the denser laticifers at the western and southern sides ofthe phloem than at the northern side at the same height of the rubber tree.

Industrial Energy Intensifing of Agroecosystems in China:Ⅰ.the Development of Ecological Agro-techniques for the Improvement of Energy Intensive Agriculture in China

Wen Dazhong

1987, (4):  4-8. 

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The approaches to improving energy intensive agriculture in China were discussed.The conceptof ecological agro-techniques was defined in the paper.The achievements and problems of deve-loping ecological agro-techniques recently in China were discussed.

Effect of Weeds on Wheat Growth and Nutrient Balance under Rice-wheat Rotation System

Ding Ruixing, Liu Dehui, Sun Yuhua, Xu Jianwei

1987, (4):  9-13. 

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The occurrence and development of weeds in farmland under rice-wheat rotation system andtheir effects on the nutrient balance were studied during 1980—1985.A rice-wheat rotation systemcreated a better condition for propagation of weeds.The biomass of weeds was closely related tothe amount of inorganic nitrogen applied to the soils.The amounts of N,P and K absorbed bythe weeds from soils were 13.1—26.3kg/ha,1.1—2.9kg/ha and 9.1—31.8kg/ha respectively,corresponding to 57—112%,38—81% and 55—230% of the amounts of N,P and K absorbed bywheats,respectively.On the basis of the study some measures for controling weeds were proposed.

Seasonal Changes and Distributions of Nitrogen in Leymus Chinensis-soil system

Hu Tianming, Zhu Tingcheng

1987, (4):  14-18. 

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This study was carried out in a natural grassland dominated by Leymus chinensis during 1983—1984.The total N content of the system was 540.75 gm^-2,the most of which(98%)was presentin the soil.The soil layer of 0—15cm contained 50% of the total N.There were no significantchanges in soil-N over the growing season(May—October,p=0.005).The nitrogen reserve inroots showed a“T”-pattern in distribution and decreased exponentially with soil depth,andhad a tendency to accumulate at soil surface with time.The aboveground parts of LeymusChinesis contained only 0.16% of the total N in the system(540.75gm^-2).The ratio of below-ground to aboveground part was 5.55:1 in terms of nitrogen reserve.The minimum of ratioappeared in August.The proper time to fertilize and cut the grasses was suggested.

Root Distributions of Dominant Trees in Broad-Leaved Korean Pine Forest of Changbai Mountain

Xu Zhenbang, LiXin, Dai Hongcai, Zhang Yiping, Guo Xingfen

1987, (4):  19-24. 

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The distributions of root systems of the dominant tree species in different types of the Koreanpine forest were investigated.The data of the length and biomass of the dominant trees:Ko-rean pine,linden,ash in Oak-korean pine forest,Korean pine broad-leaved forest and broad-leaved korean pine forest were given,The main characteristics of the root distributionsin soils of the trees were discussed.

Relationship between the Variety Group Distributions of Sheep and Goat and Climatic-ecological Conditions

Bi Bojun

1987, (4):  25-29,32. 

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The relationships of the population distributions of sheep and goat in Liaoning province withthe climate and ecological conditions were studied.The results indicated that it was closelyrelated to the drought degree in the growing season,annual rainfall,annual sunshine hoursand annual evaporation capacity:Based on the above four climatic factors,using the methodof fuzzy mathematics,the boundary line of distribution between two groups of sheep and goatwas determined,the different climatic-ecological regions of sheep and goat were assessed.

Comparative Study of Bacteria From Rhizoshere of Echhornia Crassipes and Water

Zheng Shizhang, Huang Jingjuan, He Min

1987, (4):  30-32. 

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This article is a report of observation on the types and numbers of bacteria from Huangtian-dang,Shuzhou.The results show that the bacteria found in the rhizosphere of Echhornia crassipes are different from those in the water body in terms of types and numbers,especially for Pseudomonas.

Analysis of Factors Affecting Urban Ecology in the Cities of Suzhou, Wuxi and Changzhou

Xu Guiqing

1987, (4):  33-37. 

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Lying on the Taihu plain are the three large-and medium-sized cities:Suzhou,Wuxi andChangzhou.The population and the land exploitation of the three cities are under rapid de-velopment along with the development of regional industry and agriculture.Nevertheless,owingto the disproportionate development of certain enterprises and services related to urban construc-tion,a series of problems of urban ecology have appeared.The relationships of the degra-dation of the urban ecological situation with the factors,such as population,land exploitation,hydrology and microclimate,were discussed.In order to improve the urban ecological situationof the three cities the following measures were suggested,readjustment of resional ecologicalenvironment by using the rich water resources in the region,rational distribution of thelarge-,medium-and small-city systems,and construction of traffic system and green landsin the city proper.

Relationships of Soil Ecosystem with the Population Dynamics of Field White Grub and General Tactics for Their Control

Luo Yizhen

1987, (4):  38-41,52. 

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Based on the soil ecosystemic concept the trophic structure of soil faunal communities and phy-sical environment that significantly effect the faunal composition,spatial distribution and popu-lation fluctuations of the dominat species,Field White Grub were discussed.The naturalenemies of the grub in soil including predators,parasitoids and pathogens,played a majorrole in the natural control of the grubs.A general control programm was suggested.

Stress Ethylene Production from plants Injured by Environmental Pollutants and its Ecophysiological Significance

Chen Youqiang

1987, (4):  42-45. 

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This paper reviews the researches on the formation of stress ethylene from plants injured byenvironmental pollutants,suggests the pathways of biosythesis of stress ethylene in plant andthe possible role of stress ethylene in plant eco-physiology.It might be possible that the degreeof environmental pollution could be determined by measurment of the amount of stress ethyleneproduced by the injured plants.

Investigation of Benefits from Closing Hillsides to Facilitate Afforestation in Kazuo County

Zhu Rendong, Pei Shuchun

1987, (4):  46-48. 

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Through over 30 year efforts,the forest-covered land in the Kazuo county increased from 2.1% of the land covered by forest in the 50′s to 31.3% of land covered by forest now.Throughclosing hillsides to facilitate afforestation the area of regenerated forest stands reached up to3.33×10⁴ ha,making up 52.1% of the total forest land.The closing of hillsides to facilitateafforestation includied four major practices,i.e.closing hillsides to livestock grazing and fuelgathering,combination of closing with tending and planting trees,combination of closing andplanting trees,and combination of closing with tending shrubs and planting grasses.Thepractice of closing hillsides to facilitate afforestation is a efficient way to accelerate recoveringforest vegetation.