Table of Content

25 April 1991, Volume 2 Issue 2

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Articles

Preliminary analysis of correlative characteristics of turbulence on leeward side of open windbreaks

Wang Zhengquan, Gong Weiguang, Luo Chuanwen

1991, 2(2):  97-102. 

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In this paper, autocorrelation, space correlation, and integral scale of turbulence were discussed, using theory of turbulence statistics and field observation data. On leeward side of windbreaks, near X=1H-5H, turbulent correlations were not close due to the small scale of turbulence. The time scale of eddy is about 2—3 sec. (1.5m) and 3—8 sec. (5m), and space scale is 10—20m. The turbulence correlations were higher with the distance from windbreaks and the scale of turbulence increased. The time and space scale of eddies are about 15—20 sec. and 70—80m at the range X=20H-X=30H, respectively. Meanwhile, autocorrelation of turbulence confirmed the 2/3 power law.

Application of GIS in dynamic simulation of forested landscapes

Shao Guofan, Zhao Shidong, Zhao Guang

1991, 2(2):  103-107. 

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Linking a forest dynamic model to a relevant Geographical Information System(GIS) through the transformations between data files in the model and database in GIS, the simulation of forested landscape dynamics can be carried out. It is proved that this modelling approach has mainly three advantages of flexible data input, time-save running and more capable run output including tables, figures and maps. The components and structure of GIS, the choice and running of forest dynamic models, and a case study using this method in Changbai Mountain of China are also introduced in this paper.

An approach to the index system for productivity of agricultural eco-economic system

Zeng Benxiang

1991, 2(2):  108-112. 

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This paper is aimed at applying the eco-economic theory to the agricultural practices, and the principles and methods to build an index system which will estimate the productivity of agricultural eco-economic system were investigated. Aseries of indices (including six integrated indices) are established. The author calculates these indices in several agricultural eco-economic systems and sets up some standard values to correctly estimate our objective system. According to comparasive research, some results to Qutou Farm can be shown: 1) Its productivity is much lower than standard values. 2) There are significant differences in productivities among all parts of the farm. 3) The farm's productivity has been pacing up and down for a long time.

Ecological techniques on broad water body (ETBWB) and effects of Azolla raising and its application

Li Zhuoxin, Luo Xianchi, Xu Tianxiang, Jiang Yongtang

1991, 2(2):  113-120. 

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To economically and productively develop production in reservoir or lake, the ETBWBis designed for comprehensive coordination of the relationship among the main elements in ecology and production of the broad water body (BWB) on its surface, in its shallow and deep layer as well as the aerial part above it, and for realizing a "Azolla-chicken-fish" production, in which the production is done under a stereo-constructive and optimized combined system. Its content, characteristics and effectiveness are involved by the following aspects: a "floating tray" technique for Azolla raising on the surface and a series of new measures concerned the Azclla culture were developed, some promissing Azolla species as a new feed resource suitable to fish and chicken are screened out and got a good yield as high as 495—547t·ha^-1·yr^-1; feeder fishes were raised in net pen from water surface down to 2.5m, a forecasting technique for reasonable use of the Azolla feeding fishes was developed, fish output was increased by 37.5—117.6%; in water filter feeder fishes were cultured and fed by the fish excrement from the net pen, thereby, the filter feeder fishes's yield was increased to 4.29 times; in the space above the net pen, a technique of poultry house for chicken farming was developed, in which chickens were fed with the Azolla, the body weight of the chickens increased 2.5—7.5% and concentrated feed was saved by 10—20%; manure of the chickens was applied to Azolla and fishes. Thus, a new industrywith less consumption of the land, feed, labour and energy about the BWBdevelopment was formed.

Parameters of energy flow in paddy field community

Yang Xianguo, Chen Changming

1991, 2(2):  121-126. 

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In this paper, communities in paddy field were studied on the basis of combination of field survey with laboratory analysis from the view point of dynamics of energy flow. Data of species number, biomass, heat value, respiration loss, productivity, assimilation efficiency and ingestion of communities in late rice field were obtained. According to above data, parameters of energy flow of communities in late rice field were evaluated.

Field experiment on vertical distribution of winter wheat roots

Lu Zhenmin, Xiong Qinxue

1991, 2(2):  127-133. 

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It is important to study root distribution for simulating its water absorption in different layers of soil, but there are a few data can be used for this work. This paper gives some field experimental results taken at the Beijing Datun Experimental Station, which provide some idea to the user. The parameters of the root discussed in this paper are root length, root weight, actual area of root surface and root diameter. The results show that the vertical distribution of root length, root weight and area of root surface are logarithmly related to the soil depth, and the accumulated root length, root weight and area of root surface are hyperbotically related to it:V=>Z′/ 0.0011+0.0090Z′ LV′=Z′/ 0.0016+0.0087Z′ where V′ is accumulated root weight, LV′ is accumulated root length. Test with the data taken from other surfaces shows that these types of distribution are suitable to other cases too.

Establishment of a field management system with coupling cotton bollworm (Helitothis armigera) dynamics and cotton plant development

Zhai Lianrong, Li Dianmo, Ding Yanqin

1991, 2(2):  134-140. 

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Based on detailed studies of Heliothis armigera foraging behaviour in cotton field, its population dynamics and simulation model of cotton growth and development, a management system has been established. The latest research achievements in this area are combined in the system. The dynamical effects of the 2nd and 3rd generations of cotton bollworm on the growth and development of cotton plant can be given separately and compositely. As a management system, it can produce suitable schemes of artificially removing squares in different egg levels of the 2nd generation. And, by comparing the final yields of cotton in different spraying tactics, the optimal one can be given. The overcompensation mechanism in cotton plants has been especially emphasized in the system. Field experiments had shown that artificially removing early squares can increase cotton yields, and if without or within a certain extent of the damages of plant growing points, the foraging by cotton bollworm had same effect, but with less degree. The system can differentiate clearly the effect of these two different "stimulations" on cotton growth and final yields.

Mathematical models for occured areas of emigration of Nilaparvata lugens and Cnaphalocrocis medinalis and their distribution in Eastern China

Zou Yunding

1991, 2(2):  141-145. 

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The relationship between emigration activities of brown planthopper (Nilaparvata lugens Stal) and rice leaf roller (Cnaphalocrocis medinalis Guenée) and solar height angles is analysed Models of occured areas of emigration and their distribution are developed. Solar height angles at occured areas of emigration of two species can be evaluated by solar height angle formula at noon: h_θ=90°-φ+σ_θ……. Regression analyses are made on T's and solar height angles, and the predictive models are developed.

Fouling organisms in Daya Bay Pearl Culturing Farm

Zheng Chengxing, Huang Zongguo, Li Chuanyan, Lin Sheng, Wang Jianjun, Yan Songkai, Zheng Dongqiang

1991, 2(2):  146-152. 

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From September 1987 to August 1988, two groups of panels were tested in Daya Bay Pearl Culturing Farm at surface(0m), middle(2.5m) and bottom(4—5m)layers, The panels were PVC and concrete for monthly, seasonal and yearly intervals. 228 panels were recovered and 3818 specimens and 150 fouling species were obtained. This paper repots the species composition, attaching season, attaching amount(thickness, coverage area and wet weight) and seasonal variation of the fouling organisms in this culturing farm.

Study of large scale landscape monitoring information system and its establishment

He Hongshi, Liu Zhenguo, Xu Jun, Song Aijun

1991, 2(2):  153-158. 

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Landscape monitoring information system(LMIS) was established on AST/386 microcomputer and remote sensing image processing computer using ASSAMBLE, FORTRAN, Quick BASIC, PASCAL, DBASE-Ⅲ PLUS and Cliber Compiler as its working software. LMIS has three levels of menus to execute its all functions. LMIS pays more attentions to landscape analysis and image processing, as well as landscape monitoring of a large region.

Study on the accumulation amount of silver in wastewater and its utilization by water hyacinth

Dai Quanyu, Chen Yuangao, Pi Yu, Zhang Heng, Xu Genrong, Zhang Xiuying, Dai Wenning

1991, 2(2):  159-167. 

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The accumulation amount of silver in wastewater and its utilization by aquatic plants uch as water hyacinth (Eichhornia crassipes) had been studied during 1987—1989. At abroad, Wolverton detected 113 ppm(DM)silver in roots of water hyacinth in chemical wastewater, but this research detected 12251.3 ppm (DM) with an accumulation coefficient F_x of 102194 in from 80 to 160 ppb Ag concentra ion of wastewater, its ash content is 4.125%, and accumulation coefficient F_x' is 343750. It was succeeded to recover the silver from aquatic plants, whose amount is 105g from about 6kg ashes. This study offered a profitable experience in purifying wastewater containing precious metals and recovering them.

Assessment of water system in Changde City based on microbial communities

Shen Yunfen, Gu Manru, Feng Weisong

1991, 2(2):  168-173. 

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In this paper, the structure and function of microbial communities in water system of Changde City were analysed asing PFUbio-monitoring method, and three functional parameters were put forward on the basis of MacArthur-Wilson's model. Besides, two structural parameters are determinated as well. Meanwhile, water quality of 16 stations for four seasons from 1986—1987 is analysed, and the chemical combined pollution index（p）is advanced. The results show that biotic parameters(HI, Seq, Gand T_90%) are closely correlated with the chemical combined pollution index（p）. The species diversity indices（d） could also reflect the pollution level to a certain extent. It is demonstrated that PFUbio-monitoring method is really a new rapid, accurate and economic way.

Action intensity of nitrogen-fixing and denitrifying bacteria in chernozem polluted by heavy metals

Wang Shufang, Hu Liansheng, Ji Youhai, Wang Yulan, Yao Deming

1991, 2(2):  174-177. 

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In this paper, the action intensity of nitrogen-fixing and denitrifying bacteria in chernozem polluted by heavy metals is determined with gas chromatographic method at the same time. An exact and fast new method for defining critical indicator of soil microorganisms polluted by heavy metals such as Cd, As, Pb and Cu is provided.

Prospects for soil ecological study

Zhou Likai

1991, 2(2):  178-180. 

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Soil ecological study is from the viewpoint of ecology and on the basis of further revealing the essential attribution of soil and its unique development patterns, to expound the distinctive role and function of soil as the key link of terrestrial ecosystem and whole biosphere, to study the optimum soil condition needed for constructing a terrestrial ecosystem with high productivity and little trouble with pollution, and to work out corresponding effective measures. The aim of these is to further give full play to soil's productive potentiality and improve mankind's existence environment. The main contents of soil ecological study should include: relationship of soil fertility with state factors; role of soil pool in matter flow and energy transformation; soil productivity; establishment and maintenance of relative equilibrium position of soil and problems of methodology.

Dissipative structure, hierarchy theory and ecosystems

Wu Jianguo

1991, 2(2):  181-186. 

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Dissipative structure is a far-from-equilibrium new metastable state in the non-linear re gion of an cpen system, derived from and maintained by constant negentropy flow from the environment. The theory of dissipative structure, with other thermodynamic concepts, may be used to interpret ecological phenomena. Ecosystem is dissipative system and, therefore, it may be more appropriate to analyze and tackle problems such as ecological balance in terms of the theory of dissipative structure. Hierarchy theory has been developed to dea' with complex systems. The theory asserts that the organization of a system lies in the differences among its process rates. Ecological systems are medium-number, hierarchical systems. The theory of dissipative structure and the stratified stability hypothesis lay the foundation for the development of hierarchical structure of ecological systems. Hierarchy theory provides an objective conceptual framework and a practical guideline for studying the behavior and other characteristics of ecosystems. It is breaking new ground for developing unifying ecological theories. The purpose of the paper is to review and examine dissipative structure and hierarchy theory in the context of ecosystems. The relevance and applicability of the two theories in ecology are also discussed.

Morphological characteristics of Ⅱ Frankia strains under different ecological conditions

Yang Huifan, Liu Huichang, Zhu Baoqin

1991, 2(2):  187-190. 

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Frankia strains were isolated from nodules of newly recorded actinorhizal tree species grown at different localities of China. The species are Alnus mandshurica(Call.)Hand-Mazz., Hippophae rhamnoides var. porcera Rehd., Elaeagnus oxycarpa Schlecht., E. multiflora Thunb., E. stallipila Rehd., E. gonyanthes Benth., E. bockii Diels., E. moorcroftii Wall., E. crispa Thunb., E. viridis var. delavayi Lec. and E. mollis Diels. Using optical and electronic microscopes, morphological characteristics of Frankia strains were studied and collections of illustrative plates were photographed.

Catalytic wave oscillopolarographic determination of traces of lead in crops

Suo Yourui, Huang Yali

1991, 2(2):  191-193. 

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Asensitive polarographic catalytic wave system (Pb-0.24M HCl-0.6% NaAc-0.4% KI-0.4% ascorbic acid) for determining traces of lead in crops was proposed. The peak potential is-0.34V (vs. S. C. E.). The wave for the determination of lead within the range of 0—30μg/25ml is available. The detection limit of Pb is 0.002μg/ml. Eighteen metal ions and acid radicals are not interferential. The waves are clear and steady. The recovery is 92.6—107% and the variation coefficient is less than 3.41%.