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Table of Content

    25 April 1993, Volume 4 Issue 2
    Articles
    Population ecology of Acanthopanax senticosus Ⅰ. Population structure
    Zhu Ning, Zang Runguo
    1993, 4(2):  113-119. 
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    In this paper,the age and performance structures of Acanthopanax senticosus population under three natural secondary forests and on cleared area are analyzed. It's shown that under fiatural secondary forests, the development of A. senticosus population is consisted with community succession, being a progressive population. The mean age of this population is positively correlated with community stability, and its maximum age and mean density are related to physical environment and disturbed level. The number of its individual plants varies with age, and its performance structure (height, weight and diameter class) has significant difference under forests and on cleared area, owing to the difference of habitats, disturbed levels and age stages.
    Fluctuation of forest community
    Peng Shaolin
    1993, 4(2):  120-125. 
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    The fluctuation of plant community means the seasonal or annual fluctuation of plant commumty but not of its characters caused by the seasonal or annual changes of ecological factors. The fluctuation possesses reversibility and direction. Positive fluctuation makes community advantageous, and negative one disadvantageous. The measuring formula of fluctuation intensity is built as follows: , When FIis positive, it means the positeve fluctuation, and when FIis negative, it means the negative one. The fluctuation of forest community has the following main types: that of growth rate, of hearing fruit and seedling, of seasonal development and of community structure. The fluctuation deffers from that of grassland.
    Structure and dynamics of Picea mongolica population on sand dune
    Xu Wenduo, Zheng Yuanrun
    1993, 4(2):  126-130. 
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    The size structure and distribution pattern of Picea mongolica population on sand dune and their rerlationship to eco-environment are studied by size structure in place of age structure. The results show that the population is charactrerized by increasing type in plots 1,2,3 and 5, and static type in plot 4. Regarding plots 1,2 and 3 as a plot, the population distribution pattern in contagious, which becomes random when young trees are getting matured.
    RLC circuit simulation of stomatal oscillation of Glycyrrhiza inflata under atmospheric drought condition
    Wang Genxuan, Zhao Songling
    1993, 4(2):  131-135. 
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    In this paper, the RLCcircuit model for transmission and transpiration of plant moisture is established. No difference can be found between the results of direct determination and model analysis on thresholds of initation, continuation and attenuation of stomatal oscillations of Glycyrrhiza inflata. The stomatal oscillation is initiated and its amplitude is being enhanced when the transpirational pulling force (F) is larger than the resistance(R). The amplitude and frequency of stomatal oscillation are not changed when F=R. The oscillation begins to be weakened when0<(R-F)<2√L/C, and doesn't appear when(R-F)>2√L/C. Under this experimental condition, the Rof G. inflata is 3.1×109MPa·m-3·s and the 2√L/C is 3.11-3.64×105MPa·m-3·s.
    Reduction pattern of wind-speed in farmland windbreak network region
    Zhu Tingyao, Zhou Guangsheng
    1993, 4(2):  136-140. 
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    Based on the principle of energy conservation, the pattern of momentum flux(or friction velocity) in farmland windbreak network region is analyzed using data obtained from wind tunnel experiment and field observation. The evaluation model on the ratio of friction velocities between windbreak network region and grassland is given: With this model, the relative wind speed in windbreak network region is also analyzed.
    N, P and K recyclings in an agroforestrial ecosystem of Huanghuaihai plain: with Paulownia elongata-intercropped wheat and maize as an example
    Wu Gang, Feng Zongwei, Wang Xiaoke, Liu Guohua
    1993, 4(2):  141-145. 
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    The studies show that in the whole community, Pis deficient, and Nand Kare basically balanced. N, Pand Kare accumulated in plant tissues and litters, but depleted in soil. Nand Pcontents in surface soil(0-20cm) are the main factors affecting crop growth, and Pcontent in20-80cm soil layer in the major one affecting Paulownia elongata growth. The absorption coefficients of N, Pand Kin the communities are respectively 0.078, 0.014 and 0.052, their utilization coefficients are respectively 0.95, 0.90 and 0.94, and their recycling coefficients are respectively 0.042, 0.05 and 0.063.
    Nutrient cycling in easily drought farmland ecosystem
    Fu Qinglin, Yu Jinyan, Wang Zhaoqian
    1993, 4(2):  146-149. 
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    Studies of nutrient cycling in farmland ecosystems with multiple cropping systems show that in fields Ⅰ(double cropping rice after wheat), Ⅱ(rice-soybean after barley) and Ⅲ(double cropping rice after rape), there are surplus in Ca and Mg, deficient in P, K, Fe and Mn, and greater extravagant in N. N, Pand Kin farmland ecosystems are imported by fertilizers and exported by agricultural products. Ca and Mg are controlled by water cycle. The remnant amount of Nis maximum (23—71kg·ha-1), and the residual rate of Fe is as high as 64—87%.
    Silicon supplying capacity of soil and interaction of silicon and nitrogen or phosphorus
    Zou Bangji
    1993, 4(2):  150-155. 
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    There is a positive correlation between available silicon content and pHvalue or clay content of paddy soil in Liaoning province. The silicon supplying capacity of soil in judged by available silicon content and related factors is different for various rice fields in Liaoning province. Soil with strong silicon supplying capacity mainly distributes in southern and partly in central or northern rice-planting belts, and that with weak silicon supplying capacity mainly distributes in rice-planting belts of eastern mountainous region and east Liaoning. Pot experiment with regression design shows that there is an obvious interaction of Si and Nor Si and P. With proper combination of N, Pand Si fertilizers, a maximum rice yield is obtained. N, Pand Si can all affect the ratio of rice/straw, and under the interaction of these three elements, the maximum rice yield will occur within the rice/straw ratio of 1.0—1.1.
    Geochemical distribution of some elements in soils of Liaohe River plain
    Fan Shihua, Yu Xuemin, Zhang Guilan, Guo Lei, Wu Yanyu
    1993, 4(2):  156-160. 
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    Geochemical distribution of 14 elements in soils of Liaohe River plain and factors affecting their distribution are investigated with correspondence analysis method. The results show that these elements could be classified into three groups: oxyphilic, sulphilic and leached elements. The mentioned distribution differentiations are caused by the geochemical properties of these elements. Soil type, parent material, soil physical composition and organic matter content are the factors influencing element distribution. Clay particles with size of more than0.01mm only influences leached element distribution. Clay particles of 0.01—0.001mm and organic matter are significantly related with sulphilic and oxyphilic elements respectively.
    Transformation and utilization of N and C in 15N-labelled rice straw by goat
    He Dianyuan, Xing Tingxian, Zhou Weijun, He Liehua, Liao Xianling
    1993, 4(2):  161-166. 
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    15N-labelled rice straw was used to feed three goats to study the digestion, assimilation, excretion and transformation patterns of Nand Ccompounds in it by goats. The results show that in two slaughtered goats, the digested, assimilated and transformed amount of 15Nis respectively 38.54 and 23.78% of 15Namount in diet, on an average of 31.16%. The 15Nin feces and urine excreted by three goats is respectively 34.78,33.88 and 33.18% of that in diet, on an average of 33.94%. For two slaughtered goats, their 15Nrecovery is 73.32 and 56.96%, and loss rate is 26.68 and 43.04% respectively. The 15Nrecovery of diet is coincided with amino acid digestion rate of it by goats. The digestion rate of carbohydrates in diet by three goats are respectively 76.40, 68. 66 and 65.19%, on an average of 66.93%.
    Correlation between forest litter and soll macroanimals
    Yin Xiuqin, Zhang Guirong
    1993, 4(2):  167-173. 
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    Correlation between iorest litter and soil macroanimals is studied with coniferous broad-leaved mixed forest and deciduous broad-leaved forest as an example. The results show that the individual number of soil macroanimals in forest litter varies with forest type and thickness and amount of litter. The decomposition rate of litter affects the species composition of soil macroanimals and their distribution. The content of mineral element in litter is well associated with that in soll macroanimals in litter decomposition is revealed, which provides a scientific foundation for forest management and preservation.
    Studies on Tetranychus cinnabarinus-Solanum melongena interaction system Ⅰ. Relationship between population dynamics of red spider and tannic acid fluctuation in plant leaves
    Wang Haibo, Wu Qianhong, Gao Wenda
    1993, 4(2):  174-177. 
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    Under infestation of Tetranychus cinnabarinus, Solanum melongena can initially regulate its relative level of secondary metabolism, inducing the synthesis of anti-insect secondary metabolite-tannic acid to restrict the increase of red spider population. Meanwhile, a secondary metabolism with a semi-cycle of two to three weeks is found in normal plant. The cause of this cycle and its effect on pest population are analyzed and discussed.
    Distribution of rust parasite and its occurred pattern in forest
    Yuan Zhiwen, Li Lianzhi, Yuan Jianyu, Jia Yun
    1993, 4(2):  178-181. 
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    In Liaoning province, rust parasite mainly distributes at Benxi, Fushun and Dandong districts. The investigation on its occurred pattern in forest shows that the dispersing peak of its conidia occurrs at 24 and 12 o'clock. The dispersing period is from the second ten days of June to last ten days of September, and the peak is in the last ten days of August. The amount of dispersed conidia is controlled by meteorological factors and particularly by rainfall. The incubation period of rust parasite is about one month. The infected level by larch brown rust decreases with annually increasing parasitic rate of rust, indicating the control effect of rust parasite on larch brown rust.
    Thermal balance of rapid infiltration eco-engineering during winter-operation and its application in system design
    Li Peijun, Sun Tieheng, Guo Zhixing, Zhou Yuwen, Fu Jinxiang, Yin Shijun
    1993, 4(2):  182-186. 
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    On the bases of pilot scale winter-operation experiments of rapid infiltration eco-engineering, the channels of heat supply and its loss in RIsystem during wastewater distribution, its melting, infiltration and exposure are discussed. The mathematical models on thermal balance under naked pond bottom and ice cover conditions are established, and the system design procedure of RIsystem is significantly extended. The effects of site, technology and operating conditions on thermal loss and purification functions of RIsystem are analysed, which provides theorititcal foundations for system design and winter-operation.
    Effect of water quality acidification and simulated acid rain on zooplankton
    Zhuang Dehui
    1993, 4(2):  187-191. 
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    In the experiments of water quality acidification and simulated acid rain, 17 species of zooplankton (including9 species of Rotifera, 6 species of Cladocera and 2 species of Copepoda) are found. The results show that the numbers of species (10-13) and individuals (223.0-334.5L-1) are larger at pH 5.0-8.3 and less (5—9 and 16.8—182.0L-1) respectively at pH3.0 and 4.5, indicating that there are significant effects on zooplankton community below pH 5.0. The occurrence frequency of various species show that Copepoda can be gradually replaced by Rotifera below pH 5.5.
    Relationship of crop yield to feeding injury by indirect insect and mite pests.Ⅰ. Leaf eating insect pests
    Sheng Chengfa
    1993, 4(2):  192-197. 
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    In the present paper, insect and mite pests of crops are divided into direct and indirect pests. The percentage reduction in yield is lower than that in organ or tissue consumed by indirect pests. Leaf eating insects constitute a large part of indirect pests. It is found that the most important factor affecting the relationship between leaf damage and crop yield was the crop. growth stage. The major crops examined here include cereals, cotton, soybean, cowpea, groundnut, potato, sunflower and sugarbeet. In general, the percentage yield reduction was highest when a given percentage of leaf area reduction occurred at the middle stage of crop growth. At this stage, the rate of yield formation approached the maximum and the leaf area index was at the maximal level. The other factors included percentage of leaf area lost, leaf position, feeding duration, crop varietal height, soil water and fertility, weather, and distribution of damaged leaves. Yield reduction would be decreased, or more even, yield increase would be occurred if some of these factors favoured the vegetative growth. This conclusion drawn from a variety of research fields is needed in improving crop loss assessment and developing IPMprogram for a region planted with different crops.
    Effect of elevated levels of atmospheric CO2 on plant-insect interaction
    Wu Kunjun
    1993, 4(2):  198-202. 
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    Carbon dioxide concentration in atmosphere is increasing more rapidly than before, which would en hance the photosynthesis and productivity of C3 plants such as rice, wheat, soybean, cotton etc., but reduce their nitrogen content and, therefore, their nutritive values for insect herbivores. Certain investigations showed that the phytophagous insects infesting these plant species responded to such CO2-induced changes with more consumption of plant materials to compensate their requirement for N-containing nutrients, which could result in heavier damage by them to their host plants.
    Defending strategy against main natural agrocalamities in Liaoning province: construction of forestry eco-engineering
    Jiang Fengqi, Zhou Xinhua
    1993, 4(2):  203-209. 
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    Based on the analysis of occurrence and damage of main natural agro-calamities in Liaoning province and the summarization of forestry eco-engineering constructions, this paper discussed the characteristics of forestry eco-engineering constructions in defending natural agro-calamities and, on the basis of this, a frame of its construction to defend the calamities in Liaoning province is advanced macroscopically, and its practicing methods are briefly described.
    A review on rm and relative parameters
    Ma Jisheng, Yang Xiaowen
    1993, 4(2):  210-213. 
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    The intrinsic rate of natural increase (rm) and capacity for population growth (rc) are two comprehensive parameters describing a population growth. Their conceptions and usage are now confusable. In this paper, the meaning of rm, rc and relative parameters, their usage range, advantages and disadvantages of various formulae, and relationship among them are reviewed. Some new opinions are put forward.
    Distribution pattern of saplings under forest in Jinyun Mountain of Sichuan province
    Li Xuguang, Xiong Limin, Zhang Jiqiang
    1993, 4(2):  214-217. 
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    In this paper, different methods are used to study the distribution pattern of saplings of Neolitesea aurata var. glauca, Castanopsis carlesii var. spinulosa and Symplocos lancifolia under evergreen broad-leaved and coniferous forest. The strength and area of their concentrated distribution are identified, and the relationship between distribution pattern and environmental factors are discussed. At the same time, the advantages and disadvantages of two methods (square grid method and transect plot method) used for studying the distribution pattern of plant population are analyzed.
    Detection of photosynthetic effective radiation (PAR) in tree canopy by Reinecke salt actinometer
    Chen Kai, Zhang Wencai
    1993, 4(2):  218-220. 
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    According to the principles of photochemical reaction and the ecophysioiogical characteristics of photosynthesis of tree leaves, the relative distribution of photosynthetic effective, radiation (PAR) in any position of tree canopy is detected by photochemical reaction actinometer with a solution of 0.01M Reinecke salt {ammonium reineckate, ammonium tetrathiocyanodiammonochromate, NH4[Cr(NH3)2(SCN)4] ·H2O}. The effective absorption wavelengths are as wide as 350—750nm and meet the demand for PARin tree leaf photosynthesis. The new technique is reliable, simple, convenient, and practical without any damage to the vegetative or reproductive organs of tree canopy. It is superior to the traditional methods (e. g. using photometer, radiometer, quantometer) in representativeness and repeatability. Therefore, it is appropriate for studying the photosynthetic eeophysiological phenomenon in tree population.
    Pest rodent economic thresholds of several crops
    Tian Jiaxiang, Hu Jiwu, Li Yuchun, Lu Haoquan
    1993, 4(2):  221-222. 
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    In this paper, the pest rodent economic thresholds of corn, soybean, peanut and sweet potato are determined. The daily appetites of each species of rodents are determined by saturated supply with seeds, stems and leaves of the crops as well as wild grasses. Taking daily appetite ratios as equivalent coefficients of damage intensities of each species of rodents, it is considered that oneApodemusagrarus equals to 0.599 Cricetulus triton and one C. barabensis equals to 0.468 A. agrarius. The rodent community capture rates are translated into equivalent ones of abundant species C. triton, and the regression equations of crop yield losses and rodent community densities (represented by the equivalent C. triton capture rates) are calculated. The dynamic economic thresholds are: corn272.70 L+1.26, soybean106.08L+2.35, peanut 223.56L+2.94 and sweet potato 3344.48L+0.27, and the statical economic thresholds are respectively 2.26,2.92,3.36 and 15.19.
    Leaf injury and superoxide dismutase activity in spinach leaves exposed to SO2 and/or simulated acid rain
    Liu Yanyun, Cao Hongfa
    1993, 4(2):  223-225. 
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    The studies show that under exposure to SO2 and simulated acid rain spinach leaf contains less chlorophyll, its MDAcontent and conductivity are increased, and leaf ageing is accelerated. The SODactivity is decreased with increasing pH, and lossed by 50% at pH3.6 for SO2 and simulated acid rain and at pH2.8 for simulated acid rain. The SODactivity of spinach leaves exposed to simulated acid rain is higher than that to SO2 and simulated acid rain.