Table of Content

10 April 1992, Volume 11 Issue 02

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Quantitative Characteristics of Nitrogen Cycling in Agroecosystems of Miyun, Beijing

Hu Chunsheng, Han Chunru

1992, (2):  1-3,7. 

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Quantitative patterns and characteristics of nitrogen cycling in agroecosystems of Miyun county of Beijing suburb are studied and evaluated, Aseries of related parameters are obtained, and effective ways are suggested for improving the system and its nitrogen efficincy.

Relationship Between Leaf Water Potential of Eight Broadleaved and Coniferous Young Trees in Early Morning and Soil Moisture Content and Drought Resistance of These Trees

Guo Liansheng, Tian Youliang

1992, (2):  4-7. 

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The relationship between leaf water potential of eight broadleaved and coniferous young trees in early morning and soil moisture content is studied. Mathematical equations expressing their relationship are deduced from large amounts of determination data, and critical values of soil moisture content for the normal growth of young trees of different species are calculated. Comparing these values under the same soil condition with drought resistance of young trees of different species,some new results are obtained,which can be of practical significance in guiding afforestation.

Preliminary Study on Aggregation and Dispersion Behaviors of Wheat Aphids

He Liansheng, Ni Hanxiang, Li Guangbo, Guo Yuyuan, Jin Henian, Li Shimin, Guo Songjing

1992, (2):  8-13,17. 

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The aggregation and dispersion behaviors of Macrosiphum avenae and Rhopalosiphym padi are studied on wheat fields in Luohe county of Henan province, with the method of population spatial pattern investigation.The results show that these two species have the same seasonal aggregation peaks, i.e., in early April and mid-May, in their successive dispersion processes. Although the spatial pattern of the two aphid populations are similar among wheat plants, their aggregation and dispersion are obviously different among different parts of the plant,as the result of natural selection and adaptation. Basic principles are put forward for the rational control of wheat aphid.

Statistical Analysis on Lead Intake by Nutritive Organs of Vegetables

Cheng Hong, Dai Jun

1992, (2):  14-17. 

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This paper statistically analysed the Pb intake by nutritive organs of Chinese white cabbage (Brassica chinensis) and Chinese radish(Raphanus sativus),which showed that on the credibility of 95%, the intake rates between shoot and root and between leaf and root of cabbage are respectively 47.62?5.94(%) and 11.83?2.30(%); and those of radish are respectively 49.62?5.24(%) and 10.89?1.70(%). From regressive analysis, mathematical models of Pb intake between different organs are obtained with high statistical significance. These results have practical values in the detection and control of vegetable pollution.

Effects of Temperature, Salinity and Alkalinity on Embryo Development of Pond Smelt

Li Bo, Xie Yuhao

1992, (2):  18-21. 

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The highest and lowest critical temperatures for embryo development of pond smelt are respectively reported as 21℃ and 4℃, and favorible temperature as 10—15℃. After organ's formation, embryo develops stronger resistence to high temperature, and the body length of larvae hatched under high temperature is generally shorter. The critical salinity for embryo development is 2.5%, but larvae can live normally under a salinity of 4.5%. The 24hr, 48hr and 96hr TLMs of alkalinity for embryo development are respectively 47.8, 47.2 and 45.4. The toxicity of the same alkaline strengthens with the rise of pH.

Preliminary Study on Fargesia spathacea Forests in Shennongjia

Cui Xinhong, Mei Qian, Jia zihua, Liu shaozhou

1992, (2):  22-24. 

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Shennongjia is the east edge for the distribution of Fargesia spathacea, where the forests are largely distributed over mountain slopes at the altitude of 1200—2000m.Fargesia spathacea has a strong ability of asexual propagation and regeneration, its life-span being about 7—8 years. The regression equations between weight and height and between height and diameters are respectively Y=-95.667+1.131X and Y =23.172+0.576X. The weight percentage of 1,2 and 3 years plants can reach to 27.15%, 27.97% and 44.88% respectively. The total reserve of Fargesia spathacea in Shennongjia is about 500000 tons, which is rich in nutrients and provides ideal food resources for panda.

Host Suitability for Mango Funnel-Rolling Leaf Weevil

Dan Jianguo, Pu Tiansheng, Zhang Chong

1992, (2):  25-26. 

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Host suitabilities of Nepal Mango and its three varieties for mango funnel-rolling leaf weevil are evaluated in this paper. Detailed studies are also made on the life cycle of mango funnel-rolling leaf weevil and its food selectivity under different forage conditions.

Determination of Rational Applying Concentration of Insecticides Using Dynamic Modelling Method

Zhang Wenjun, Wang Shize, Liu Shaoyou, Zhang Yongjiang

1992, (2):  27-29. 

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Improved Weibull's dynamic models are used to simulate the population dynamics of wheat aphids and their natural enemies. Parameters and integrated indices are compared to analyze the effectiveness of different concentrations of rogor oxide in controlling aphids and preserving natural enemies and on wheat yield.The range of rational applying concentrations is determined. The research method has been proven to be simple, practicable and valuable in comprehensive control of insect pests.

Growth and Injury Threshold of Water Hyacinth in Silver-Bearing Waste Water

Chen Yuangao, Dai Quanyu, Pi Yu, Zhang Hang

1992, (2):  30-35. 

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The growth of water hyacinth and its relationship with environmental factors in silverbearing waste water are studied in Wuxi cine-film factory. Based on experimental results, the intrinsic growth rate K and environmental holding capacity r of water hyacinth in different months are determined, its growth curves are also fitted. In addition, laboratory static experiments are made for the injury of silver on water hyacinth. The injury threshold and critical doses of different forms of Ag on water hyacinth are determined.

Application of Niche Theory in Eco-Agricultural Construction of Central Hubei Hilly Region

Huang Yongju, Chen Yuhua

1992, (2):  36-40. 

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Optimal patterns of eco-agricultural construction in central Hubei hilly region are studied with the application of niche theory. The research indicate that on hilly non-irrigated land, ecological environments are improved and niche elements of crop field are sufficiently used by introducing paulownia and constituting niche unit "wheat-corn-bean" under it. In household ecosystems, the potential niches are more effectively used and its functions are improved after introducing methane-generating pit.

Ecological Significance of Xishuangbanna Dai Nationality's Holy Hill

Liu Hongmao, Xu Zaifu, Tao Guoda

1992, (2):  41-43,60. 

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Holy Hill is a traditional belief of Dai nationality in Xishuangbanna of southern Yunnan. Its ecological significance in conserving tropical vegetations and plant species diversities and improving environment are discussed. Based on current situations of Holy Hill in Xishuangbanna, some suggestions are given for its preservation.

A Review on Some Terms Related to Niche and Their Measurements

Yang Xiaowen, Ma Jisheng

1992, (2):  44-49,35. 

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Based on the review of definitions of niche, niche breadth and niche overlap, the advantages, disadvantages and applying conditions of 21 popular formulae measuring niche breadth and niche overlap are analysed in detail. As Hutchinson's conception of niche has three operational problems, an appropriate method for solving these problems--a multivariate statistical approach is introduced.Meanwhile, three reasons why niche overlap can't be used for measuring competition and three formulae for measuring competitive coefficierts are given.

Analysis of Factors Influencing Primary Productivity of Agroecosystems in Marketable Grain Base of Liaohe Plain

Liang Wenju, Yin Gongcheng

1992, (2):  50-53. 

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The formation of crop productivity is influenced by various factors such as natural, economic and social factors. In this paper, simple correlation analysis, partial analysis and path analysis are applied to deal with the effect of different factors, e.g., environmental resource, agricultural intensification level and natural disasters on the primary productivity of agroecosystems in marketable grain base of Liaohe plain, The results show that fertilizer and power energy are key constraints after precipitation and solar illumination. Moreover the areas of middle and low yielding fields are also of importance for the improvement of crop productivity.

Correlations Between Site Illumination Periods and the Growth and Development of Citrus sinensis

Zhang Mingfu

1992, (2):  54-56. 

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Cultivation of Citrus sinensis is wide-spread in various latitude areas in China. Based on observation and researches, it is found that within the same plantation, under identical management levels and at same age, the growth and development of Citrus sinensis are influenced by the length of illumination period caused by site factor variation. The nutritional and reproductive growths of Citrus sinensis are most favorable at an average diurnal illumination period of above 9.5 hours, secondarily of 8 hours and most unfavorable of below 6-6.5 hours.

Ecolomic Analysis on Three Optimized Diet Combinations and Egg-Laying Simulation Models

Li Yong, Ge Wenhua, Han Yang

1992, (2):  57-60. 

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Indices of feed rewarding rate, output value rate, direct expense coefficient, conversion efficiency of feed energy to egg energy and ecolomic benefits are used to calculate and analyze the experimental results obtained under three optimized diet combinations. The function En=at^bc^-et is applied in simulating and modelling egg-laying patterns under different diet combinations. The results can be of guidance in egg-laying hens management and in prediction of egg productions.

Leaf Shape Curve Equations of Broad-Leaved Trees——Mathematical Models Suitable for Leaf Area Calculation

Tian Xingjun

1992, (2):  61-63,74. 

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Based on observation and study, 3 curve equations for various leaf shapes,ellipse, oval and spindl, are advanced. These models provides scientific basis and available methods for calculating leaf areas of broadleaved trees.

Grade Classification of Ecological Destructions on Hainan Island

Xu Lianfeng

1992, (2):  64-68. 

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Destructions of forest and biological resources, water resource and soil resource on Hainan Island are analyzed in relation to its population, resources and development. Long-term forest destruction,slash-and-burn cultivation and other unreasonable land uses are considered to be the main causes of the ecological destruction. 8 dominant factors are selected and fuzzy cluster method is used for the grade classification of ecological destruction on Hainan Island. It is showed that ecological destructions of 28% counties are serious and 40% counties are above medium. Some suggestions about the ecological environmental protection on Hainan Island are proposed on the above bases.

Ecological Research in Modern Science and Technology

Liang Liuke

1992, (2):  69-71. 

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Problems concerning basic ecological theories and methodologies being become general scientific research method, and ecological research being penetrated into modern science and technology are discussed in the paper.