Table of Content

25 January 1990, Volume 1 Issue 1

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Articles

Current situation of applied ecology and its development

Shen Shanmin

1990, 1(1):  2-9. 

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Applied ecology can be defined as a discipline which studies and coordinates the relatio nship between mankind as the one hand and organism, resource and environment as the other. It has become a wide discipline containing over hundred branches. Its current weakness and existing problems mainly are:shorts of scientific strictness, Jack of technical ability and applied techniques, and in the course of its fast expansion, being less of the disciplinary boundary of itself. In the future, application of mathematics and computer techniques in ecological research and practice, ecological experiment, macroscopic ecological research, and study of ecological engineering techniques and their development will be the most active fields in the research of applied ecology.

Ecological behaviour of priority organic pollutants in land treatment systems of municipal wastewater and their control strategies

Gao Zhenmin, Li Yutai

1990, 1(1):  10-19. 

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Ecological engineering land treatment system(LTS) is suggested as a good pratical technique series with multiple functions and goals in protection of water bodies and purification of municipal wastewater into renew resource under the guideline of ecological principles, and hence, it is a vital area in study of applied ecology. Through optimization of site selection, rational design, good operation and sound managenment as required, it would be able to play an important role in protection environment and promoting economic development. It should be stressed that priority organic pollutants and eco-environmental problems caused by them might be the limiting factor for implementation of ecological engineering LTS in practice. In this paper, a comprehensive review was given on the basis of combination of theory with practice, which covers some essential topics such as purification function, ecotoxicological effects and ecological risk evaluation, etc. However, the main aim is to provide a solid foundation for the effective control and manipulation of priority organic pollutants with LTS.

Simulators of weather environment of ecosystems

Shen Zuorui, Guan Zhihe, T. P. Mack, Lin Erda

1990, 1(1):  20-25. 

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Weather is of paramount importance among environmental elements for both natural and managed ecosystems. System analysis makes it increasingly imperative to simulate weather in research projects related to ecosystems. In this paper, a summary firstly introduces mathematical principles of an American weather generator (WGEN), which is constructed with Markov chain——gamma distribution as a model to produce daily precipitation data and weakly stationary process——harmonic analysis as tools to build another model generating daily maximum temperature, minimum temperature and solar radiation for a given location. Then, WGEN derives ALWGEN and BJWGEN for Alabama and Beijing, respectively, after the model parameters are estimated by procedures of conventional statistics or the grey target bleaching. Taking the paper size into account, however, the concrete procedures are not demonstrated here; and also, the model verification and validation by Monte Carlo bootstraping are mentioned only without detailed description.Finally, a brief discussion on applications of the weather simulators is made. Risk analysis in IPM programs, decision making in ecosystems management, ecologically planning of agricultural areas, are all need weather simulators really for the present or potentially for the future.

Growth tediousness as an explanation of over-compensation of crops for insect feeding

Sheng Chengfa

1990, 1(1):  26-30. 

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The over-compensation of crop plants for insect feedings arouses great interests, but little attention has been paid to the explanation of the phenomenon. This paper presents a concept of tediousness in growth of crops which is found frequently in plant height, leaf area, number of branches or tillers, number of reproductive organs, duration of growth stages and the ratio of biomass to economic yield. The tediousness increases with the increasing input of subsidiary energy. Essentially, the tediousness in growth is an ecological strategy of an organism to adapt itself to the fluctuating environment, increasing the stability of reproduction and decreasing the risk of extinction. However, this inherent property causes a waste of energy and is a burden on the higher crop yields when the environmental conditions are improved or when the crops are supported and protected by human being. The reduction of tediousness with practices of crop growing and breeding has increased the crop yields. Insects can reduce the tediousness in some instances, which is proposed as a basic explanation of the over-compensation of crops for insect feedings.

A new mathematical model of interspecific competition: an expansion of Lotka-Volterra competition equations

Sun Guowei, Cui Qiwu

1990, 1(1):  31-39. 

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The classical Lotka-Volterra competition equations are the direct extension of the classical Logistic equation of single population growth. Because they have no necessary theoretical basis and oversimplify the process of interspecific competition, it is not suitable for Lotka Volterra competition equations to be a general theoretical model of interspecific competition. Based upon the theory of nutrition kinetics, a new kind of competition model is constructed as follows: dX₁/dt=μ_c1*X₁ * 1-(X₁+a₁₂X₂)/X_m1^*/1-(X₁+a₁₂X₂)/X_m1^′ dX₂/dt=μ_c2*X₂ * 1-(X₂+a₂₁X₁)/X_m2^*/1-(X₂+a₂₁X₁)/X_m2^′ They are the extension of Cui-Lawson model of single population growth which is as follows: dX/dt=μ_c^*X * 1-X/X_m^*/1-X/X_m^′ The new competition model has more complex and extensive behaviours than Lotka Volterra competition equations, and under specific condition, it turns into Lotka-Volterra competition equations. Therefore, the new competition equations are more general, and are the expansion of classical Lotka-Volterra competition equations.

Determination of dominant factors of site with linear model theory: division of farmland shelterbelt sites in Hilly Areas of Chaoyang

Jiang Fengqi, Zhou Xinhua, Yang Ruiying

1990, 1(1):  40-45. 

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It is a developing tendency to divide site quantitatively with considering comprehensive polyfactor. The grading combination of the dominant factors of site in some regions is a simple, precise and effective method, the key of which is the determination of dominant factors of site. The relationship between dominant height of main tree species (populus spp. and Ulumus pumila) and site factors such as landforms, soil fertility, etc, has been analysed with the linear model theory in 17 townships of Chaoyang, Jianping, Kazuo and Beipiao Counties in the west Liaoning province. The landform, position of slope and soil depth are considered as dominant factors of site in hilly areas. The farmland shelterbelt site was divided into 3 classes in the region according to geomorphic unit. Then, combining the gradations of slope position and soil depth with 3 classes, 6 sub-classes were classified. At last, the suitable tree species were selected for each site types, and its suitability was evaluated quantitatively.

Chinese ginsen and forest-ginsen system management in Northeast China

Chen Dake, Zhu Ning, Wang Fengyou

1990, 1(1):  46-52. 

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Panax species is a valuable medicinal plant survived from the Tertiary Period, Wild Chinese ginesn(panax ginseng Meyer)mainly grows under Korean pine/broadleaved mixes forests in Northeast China.In this paper, its natural distribution, growth and environment conditions and the construction and management of forest-ginsen system are discussed. The results demonstrate that the establishment of forest-ginsen system is benefitial to the development of forest silviculture. This kind of forest produces high economic, social and ecological benefits.

Secondary succession of soil animal community and its development process in tropical artificial forest

Liao Chonghui, Chen Maoqian

1990, 1(1):  53-59. 

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Secondary succession of soil animal community in tropical littoral eroded land and its development process might be divided into three stages: aggradation, transition and steady state. The last stage will be arrived after about 20 years.The succession dynamics for various animal groups are.a)Individuals of hygrocolous microfauna increased quickly during aggradation stage, and decreased slightly during transition stage; b) Unstable groups of insects decreased gradually; c) Termites increased to a highest level in the earlier aggradation stage, then decreased and kept at a lower level;d) Earthworns appeared in the later stage of aggradation, then developed quickly and became a dominant group.

Vertical distribution of stomatal resistance in wheat canopy

Lu Zhenmin

1990, 1(1):  60-66. 

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Based on the measurement in the field, this paper gives the difference of stomatal resistance of different layers of leaves in the canopy and different parts of the leaf.The influnce of environmental factors, especially soil moisture, on the difference is discussed. The result shows that the difference of stomatal resistance in different parts of leaf of the canopy is very pronounced. The largest stomatal resistence was found near the tip of the leaf. And then, it decreased gradually from the tip to the base of the leaf. The abaxial stomatal resistance was smaller than the adaxial. Seventy percent of total water and CO₂ was transported by two leaves of the upper part of the canopy. The resistance was increased from the top to the bottom of the canopy. And the resistance was also influenced by leaf area index and environmental factors. For example, when soil water supply was limited, the sensitivity of the stomatal resistance to it was different in different parts of canopy.The stomatals in the lower part were more sensitive than those in the upper part. Finally, this paper gives a model which can be used to calculate the stomatal resistance with conventional meteorogical data and leaf area index.

Transferring and cycling of organic and inorganic nitrogen in micro-agroecosystem

Wu Shanmei, Ni Miaojuan

1990, 1(1):  67-74. 

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¹⁵N labelled technique was used for understanding the transferring and cycling of nitrogen in micro-agroecosystems with soil-ryegrass-rabbits-rice compartments and soil rice compartments. Preliminary results showed that the utilizational rate of (NH₄)₂SO₄ by ryegrass was 59.36% for the above ground portion and 9.79% for roots. As ¹⁵N labelled ryegrass was comsumed by rabbit, the ¹⁵N labelled recovery rates in feces and urine collected were 11.78% and 17.95% respectively. Rabbit excrement-nitrogen was integrated with inorganic fertilizer nitrogen in different proportions as 1:0, 0.5:0.5, 0.3:0.7 and 0:1 for rice culture. Results showed that the uptake of nitrogen by rice plant was 67—70% from the soil and 30—33% from fertilizers.The utilizational rates by rice plant were increased with the proportion of inorganic nitrogen. They were 36.94%, 40.52%, 40.73% and 43.91% for treatment 1—4. The yield of rice grain decreased with the proportion of inorganic nitrogen, however. The functional effects of organic fertilizer on the ecosystems were:(l) promoting the ear and root development of rice plant;(2) increasing the transferring ability of nitrogen from straw to rice grain, especially in 0.5:0.5; (3)maintaining inorganic fertilizer nitrogen in soil; (4)decreasing losses of nitrogen to air and waters. In treatment 0.3:0.7, the utilizational rate of organic fertilizer nitrogen was enhanced, and no considerable increment of utilizational rate of inorganic fertilizer nitrogen was found in the study. According to the complexity of food chain and the nitrogen recycling indexes in different microecosystems, it is considered that the maturity and stability of the ecosystem were higher in treatments 1:0, 0.5:0.5, and 0.3:0.7, but lower in the treatment 0:1 which consists of rice plantation and relaying on inorganic fertilizers only.

Study on the variation of landscape pattern in the west suburbs of Shenyang

Xiao Duning, Zhao Yi, Sun Zhongwei, Zhang Guoshu

1990, 1(1):  75-84. 

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Spatial pattern of landscape is a central issue in landscape ecology research. The main reason of variation of landscape pattern owes to the external disturbance. There are three remarkable variations of landscape pattern:(a)a landscape element becomes a new matrix in place of former matrix;(b) landscape proportions among several landscape elements changed; (c) a new landscape element is arisen in the landscape system. Landscape pattern was studied in this paper with following quanta indexes:(1) number and size of patches, (2) transition matrix of patches, (3) dominance indexes of patches, (4) the diversity index of landscape.The results show that in the west suburbs of Shenyang, landscape is becoming more and more fragmentary throughout 30 years. There are many patches plot or island-liked in the landscape. Landscape matrix has changed, the west suburbs of Shenyang is urbanized remarkably. Economical benefits of land use has increased. With the population growth, average land area per person has constantly decreased. The unused land hardly left. This means that the capacity of land will be saturated, predicting land crisis is coming.

Geochemical characteristics of basaltic sol in Zhejiang province and its significance in resource ecology

Wu Cifang, Zhu Xicheng

1990, 1(1):  85-89. 

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Soil developed on basalt has its distinctive geochemical superiorities: the energy transforming rate (ETR) of its ecosystem could be 1.39—3.46 times higher than that of soils from other parent materials, and its structure and K-supplying are not so bad, being an important soil resource not been paid attention to for Jong time. But, for soils formed under different geochemical developmental stages, the difference of their ETR could be 77.86%.Among these soils, weakly ferrallitic one has greater potentiality for exploitation and utilization. The enrichment of Fe₂O₃ and its transformation characteristics in soil and the soil geochemical variations induced by various positions of geological stratums and various types of basalts give a significant influence on agro-ecological processes. Therefore, it is considered that geochemical study is an effective way for the studies of resource ecology.

Reactions to HF exposure by some sensitive plants

Chen Shuyuan, Gao Xuping, Xu Hebao, Xie Mingyun

1990, 1(1):  90-93. 

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In this paper, physiological reactions to HF exposure by Polygonum chinensis L., Fagopyrum cymosum Meisn and Metasequoia glyptostroboides were studied with top opened field chamber. During the process of HF exposure, stomatal resistance (S.R.), transpiration intensity (T.I), electric conductivity (E.C.) and amount of chlorophyll were measured. It was found that the S.R. of polygonum chinensis L. was higher than that of Fagopyrum cymosum Meisn. What is more, the S.R. of polygonum chinensis in green leaf was higher than that in red leaf. In addition, the difference in sensitivity to HF among different plants was also appeared in tendency and value of E.C. change. Sensitive plants showed much higher E.C. It is considered that to select and determine the appropriate physiological index is one of the important work in biological monitoring of atmospheric pollution.

Investigation on the emission of nitrous oxide by plant

Chen Guanxiong, Shang Shuhui, Yu Kewei, Yu Adong, Wu Jie, Wang Yujie

1990, 1(1):  94-96. 

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Studies of the different pathways of N Joss from plant-soil system are highly important for increasing the efficiency of soil N and decreasing the environmental contamination. This paper is the first report on the N₂O emission from some plants (e. g. soybean, maize, rice and alder), and points out the emission rates of N₂O being related to the plant species or their organs. Possible implications of the N₂O emission from plants are discussed.