Table of Content

25 October 1993, Volume 4 Issue 4

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Articles

Investigation on the occurrence of extraordinarily serious sand storm in Ningxia Hui Nationality and Nei Monggol Autonomous Regions

Jiang Fengqi, Zhu Jiaojun

1993, 4(4):  343-352. 

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Based on the investigation of extraordinarily serious sand storm(ESSS) occurred on May 5th, 1993 in Ningxia Hui Nationality and Nei Monggol Autonomous Regions, the formation cause of this ESSS, its disastrous harms and moving patterns are analyzed. The results show that its occurrence is the comprehensive results of gale, aridity and desertification under the effect of macroclimates, and the losses or harms caused by it are very disastrous, Its moving patterns indicate that establishing shelterbelts or windbreaks and sand control engineering can prevent ESSSand avoid its harms. In view of the natural, social and economic characteristics of areas vulnerable to sand storm, the comprehensive strategies of preventing sand storm, managing desert and utilizing and developing sand land resources are put forward.

A disturbed ecosystem Ⅰ. Nutrient cycling in tussah-feeding oak plantation

Yang Sihe, WenShiyun, Don K. Lee, Wen Dazhi

1993, 4(4):  353-358. 

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Field experiments and laboratorial work were carried out to understand the nutrient cycling patterns in tussah - feeding oak plantation and the effect of disturbance on nutrient equilibrium. The results show that larger proportion of nutrient is stored in root and more nutrients can transfer from leaf to stem. The cocoon is the main form of the secondary productivity of tussah-feeding oak plantation. Its nutrient output level has a greater effect on the internal nutrient cycling in the tree. The decrease of nutrient storage in the tree is the main cause of the decrease of its productivity. Understanding the patterns of nutrient cycling is beneficial to control the disturbance and to enhance the stability of the ecosystem.

Litter dynamics of Pinus massoniana and Michelia macclurei mixed forest and its effect on soil nutrients

Zhang jiawu, Liao Liping, Li Jinfang, Su Yong

1993, 4(4):  359-363. 

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The annual litter amount of 55 years old Pinus massoniana and Michelia macclurei mixed forest is 6284kg. ha^-1, of which, leaf-litter accounts for 69.5％, 11.2％ higher than that of same years old pure P. massoniana stand. The amount of litter in mixed forest occupies 32.4％ of total in spring, and 19.1％ in summer. That of shrubs and herbs in mixed and pure stands is respectively 3.6 and 18％ of total. Compared with pure stand, mixed forest has a better soil nutrient status, the content of soil organic matter being increased 16.7％.

Plantation of Korean pine under secondary forest and its regulation

Li Xin, Dai Hongcai,Zhang Yiping, Guo Xingfen, Pang Yawen, Liu Haitang, Fan Zhuhua

1993, 4(4):  364-367. 

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The growing status of planted Korean pine under secondary forest is studied in this paper. The results show that its growth quality is better than that of natural and secondary ones. Optimal ecological conditions for the growth of planted Korean pine are sites with sparse bush cover, more than2m far from big tree and a canopy density of 0.5-0.6.

Relationship between ecological conditions and spruce growth on sandy land

Xu Wenduo, Zheng Yuanrun, Liu Guangtian

1993, 4(4):  368-373. 

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Based on fiedl survey and located observation, the relationship between ecological conditions and spruce growth is analysed. The daily height growth of spruce is of continuous growing type, its growth at day time is higher than that at night, being146-279％. Height increment in June is 65％ of annual increment. The annual height increment depends on the heat and moisture conditions in June. In normal years, the height increment is greater, and less in reverse. The height growth of spruce is closely related to soil moisture content, which is lower at the top of dune than at its bottom. Spruce on sandy land is a shade-tolerant species, the height growth of its seedlings being accelerated under shady condition. After 20 years, the height growth increment is maximum with increasing age when light intensity is 45％.

Ecological distribution characteristics of village system in different regions

Wang Zhiping

1993, 4(4):  374-380. 

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Using mapping and surveying methods, the factors affecting village system distribution in different regions are analysed and compared. The results show that villages located in piedmonts, low and coastal plains are respectively characterized by uniform, random and aggregation distributions, and those in mountainous and hill yregions are distributed aggregatively in valley floor, mountainous foot, piedmont fringe and billy land. Their size varies with different landforms. The distribution patterns of villate systems in Hebei province are affected by natural resources, water systems, farm productivity and social-economic conditions, and are divided into eight types of regions.

Biocycle of soil radioactivity in loess area

Zhang Zhongxian, Wang Nong, Hao Yuhuai, Liu Puling

1993, 4(4):  381-387. 

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Biocycle and equilibrium of radioactive substances in different soils are studied in this paper. The results show that the content of radionuclides in soil profile decreases gradually along with genetic horizons. The biological accumulation coefficients of different nuclides range from 1.06 to 1.44, and the content of radioactive substances in different plants is in order of fodder grass>crop≥shrub≥fruit tree>arbor. The concentration coefficient of plants for α radioactivity is less than 0.10 and that for β radioactivity is 0.5-1.0. Three equilibrium types(accumulation, consumption and medium) of soil radioactivity under different land utilizations are put forward.

Unsaturated hydraulic conductivity properties of meadow sandy soil in coastal area of North Belgium

Liu Zuoxin

1993, 4(4):  388-392. 

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Unsaturated hydraulic conductivity K(θ) and diffusivity D(θ) of meadow sandy soil in coastal area of North Belgium are determined in situ by internal drainage method, and their empirical formulae are obtained. Covariance analysis shows that there are no significant difference among K(θ) and D(θ) regression equations in differents soil layers of 0-30. 30-60 and 60-90cm, but there is which have a significant difference between these layers and 90-120 cm, layer which should be described by two sets of formulae. No visible difference between power and exponent functions has been found in this study.

Crust formation on sand surface and microenvironmental change

Ling Yuquan, Qu Jianjun, Hu Min

1993, 4(4):  393-398. 

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Investigation shows that in Shapotou region,the annual mean thickness of fallen dust(d<0. 063mm) is 0.144ram. Its suspended sal particles,calcium carbonates,trace elements and organic matters originated from lower plants,microbes and plant residues can promote the physical, chemical and biological changes of microenvironment. The amount and frequency of precipitation strongly affect the crust formation on sand surface and soil forming process. In sand dune with grain size of 0.250-0.125 mm,the permeating rate of precipitation is 1:7-1:10. Crust formation on sand surface can induce the change of moisture and heat status near earth surface,and hence, decrease the moisture content of sand layer to 2％ or below,which limits the function of vegetations in sand stabilization to certain extents.

Spatial pattern of hawthorn spider mite population and its application Ⅰ. Three-dimensional spatial pattern of adult mites in apple tree

Zhang Qingguo, Li Guiting, Xu Li

1993, 4(4):  399-403. 

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Three-dimensional spatial pattern of hawthorn spider mite adults and its aggregation and dispersion types are observed, and time series dynamics of its aggregation intensity are studied using patchiness index. The results show that all of the spatial pattern of adult mites an apple tree are aggregatively distributed as individuals or small colonies, and the aggregation intensity in lower crown is the highest. Based on spatial pattern of population, data transformation formulae about upper, middle and lower crowns are given.

Effect of Nile tilapia on nutrient levels of freshwater microcosms

Ruan Jingrong, Liu Quxia, Wang Shaomei, Rong Kewen

1993, 4(4):  404-409. 

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This paper studies the dynamics of Nand Pin freshwater microcosms with varying densities of Nile tilapia(Oreochromis niloicus). The concentrations of ammonia (NH₃-N), particulate phosphorus (PP) and total phosphorus(TP) in microcosms with Nile tilapia are higher than those in control, but the contents of or thophosphate(PO₄-P) and sediment phosphorus are lower. There are significant differences in measured values of some indices among different density treatments, but none of these indices are found to be regularly changed with stocking density of Nile tilapia. In the microcosms, PO₄-Pconcentration is significantly correlated with zooplankton and phytoplankton densities and primary productivity, and NH₃-Nconcentration is related to phytoplankton density. The top -down effect predicted by the trophic cascade hypothesis is not existed between phytoplankton density and TPconcentration, but on the contrary, there is a tendency of existing bottom-up effect. The variation of Pdistribution in the microcosms can reveal the main mechanism of accelerating nutrient cycling in the systems, and thus, enhancing their eutrophication processes by Nile tilapia.

Age, growth and fecundity of Clupanodon punctatus in Xipu Bay of Dongshan Island, Fujian Province

Zhang Qiyong, Hong Wanshu, Hu Weijiang, Yuan Qi, Jin Binming

1993, 4(4):  410-417. 

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1099 samples of Clupanodon punctatus were collected from Xipu Bay(a semi-enclosed bay with a seawall) of Dongshan Island, Fujian Province,during March 1991 to April 1992. Scales were used to determine their age and growth. The catched fish consist of 5 age classes, among which,class Ⅰ is predominant. The relationship between body length L(mm) and scale radius R(mm) can be expressed bey R=0.0151L-0.2806(r=0. 9944). Parameters of von Bertalanffy body length growth equation are:L_∞=196.48mm,k=0.417,l0=-0.508,and those of net weight growth equation are: W_∞=162.63g, k=0.241,l0=-1.608. Absolute individual fecundity F(eggs) ranges from 7575 to 72621(mean35310), and relative individual fecundities F/L(eggs·mm^-1) and F/W(eggs·g^-1) range from 64 to 445(mean243) and 220 to 1153(mean674) respectively. Ripe eggs are released at least two batches during spawning season, the individual fecundity of the first spawning batch being higher than that of the second one. The ecological parameters given show that the fish belongs to one of the r-selected species.

Degradation of trifluralin in soils and its affected factors

An Qiong

1993, 4(4):  418-422. 

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This paper deals with the dynamics of trifluralin degradation and its main affected factors in soils under field and pot experimental conditions. The results show that dealkyl -and nitro -reduced compounds are the main degradation products of trifluralin in soils, whose kind and amount depend on soil conditions. In different treatments, its t_1/2 is concentrated in 30-90 days, but more longer when organic matter content is higher or soil moisture content is ≤6％. The increase of soil moisture content and temperature can be promoted microbial activity, and is of advantage to biodegradation of trifluralin.

Microbial ecology in water area polluted by high concentrations of Cd and Pb

Zhang Chungui, Xu Huaxia, Jiang Qingnan, Zhang Suchun, Li Lin, Liu Qisong

1993, 4(4):  423-429. 

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The ecological distribution of microbes in water area polluted by Cd and Pb, their resistance and bioconcentration ability to these elements are studied with selective media and filter method. The results show that the variation of microbial biomass in waste water has no relation to the concentrations of Cd or Pb. The resistant microbial biomass is strongly affected by environmental temperature, its resistance to heavy metals is Pb>Cd and mould>saccharomycete>bacteria. The highest resistant concentration of Cd and Pb by mould is 20000 mg·L^-1,that of saccharomycete and bacteria is 5000mg Cd·L^-1 and 10000 mgPb·L^-1. The bioconcentration of Cd and Pb by resistant microorganism has a close relation to its resistance and the toxicity of Cd and Pb. The dominant microorganisms in Cd and Pb waste water are Erwuba, Alacligenes, Arthrobacter, Candida, Aspergillus and Cladosporinm.

Microbial purification of Cr(Ⅵ) containing electroplating wastewater

Li Fude, Tan Hong, An Muhui, Zhao Xiaohong, Wang Pin, He Zongying, Zhang Yongdi

1993, 4(4):  430-435. 

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Ahigh efficient strain SR Ⅰ is isolated from Cr(Ⅵ) containing electroplating sludge under anaerobic culture, and its purification effect on electroplating effluent is studied. In electroplating effluent, the purification rate of Cr(Ⅵ) by strain SR Ⅰ is stimulated by Zn²⁺,UO₂²⁺ and Sr²⁺, inhibited by Ag⁺, Cd²⁺ and SiF₆^2-, and not influenced by SO₄^2- CO₃^2- and Cl^-. The purification efficiency of strain SR Ⅰ is 99.6％ at 5-100μg Cr(Ⅵ)ml^-1, pH6-7 and 20-30C.

Early warning theory on regional eco-environmental issues and its application

Fu Bojie

1993, 4(4):  436-439. 

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Principles of early warning on regional eco -environmental issues are descussed in the paper. For this warning,the regional sustainable development ability(SDA)is used as a comprehensive index, which is weighed up by loading capacity, stability, buffer capacity and productivity. Natural resources,ecological degradation,environmental pollution and social -economic indices are selected to establish an index system for evaluating and early warning regional eco -environmental issues and, the eco-environmental quality of various provinces and districts in China is evaluated, put in order and early warned.

Behavior of airborne insects in their migratory process: a review

Zhai Baoping, Zhang Xiaoxi

1993, 4(4):  440-446. 

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This paper gives a review on the behavior of airborne insects in their migratory process and its ecological significance. Airborne insects are not simply passive drivers in the air,but can actively select their driving routes in some extents. They usually form a dense layer at the bights with higher temprature, stronger wind speed and better wind direction, and orient to a special azimuth to modify their displacements. Therefore, it seems that they have the ability to make the best use of kinetic energy of atmosphere to seek and find new habitats. Moreover, they are frequently concentrated by various scales of horizontal atmospheric convergence, which can accumulated the airborne migrants to an outbreak-density. But,whether or not the concentrated insects can form a outbreak population on crops will depend on the frequency,strength and lifetime of atmospheric convegence,the mechanism of landing(whether,when and where) and the re-emigration. Understanding the behavior of airborne insects in their migratory process is essensial for forecasting and controlling these insect pests.

Nutrient input of throughfall in a pine-spruce-fir forest of Changbai Mountain

Cheng Borong, Xu Guangshan, Geng Xiaoyuan, Zhang Guoliang

1993, 4(4):  447-449. 

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Nutrient elements in precipitation and throughfall are studied in a pine-spruce-fir forest of Changbai Mountain Natural Reserve. The amount of nutrient elements in throughfall is higher than that in precipitation, and their leached amount from canopy is in an order of K>Mg>Ca>N. From the viewpoint of nutrient return, throughfall plays a more important role in comparison to litterfall.

Biomass and productivity of southern evergreen broad-leaved forest in Heishiding Natural Reserve V. Herbivory

Chen Zhanghe, Chang Hongta, Wang Bosun

1993, 4(4):  450-453. 

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Annual herbivory and its monthly variation in southern subtropical evergreen broad-leaved forest in Heishiding Natural Reserve are studied. The annual herbivory is 0.217 t·ha^-1, i.e., 16.98％ of leaf biomass or 7.03％ of leaf area. About half of the foliage is more or less grazed. The consumed leaf is about 15％ of leaf grazed. Monthly variation of the herbivory shows that higher consuption percentage occurred from August to November(December), and lower one, from March to June. Different species of leaves show different sensitivity to herbivory. Small, harder and hairy leaves are less grazed, but thinner ones are generally consumed. Insects have some specificity to consume leaves.

Life table study on Lepidosaphes salicina Bersch

Ji Lanzhu, Yang Jinkuan, Shao Yuhua

1993, 4(4):  454-455. 

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Mean life tables for two generations of Lepidosaphes salicina Bersch., a main pest of shelter-forests in North China, are compiled by statiscal method. The unhatching rate of these two generations at egg stage is 66.5 and 36.0％, and their mortality at fixed nymph stage is 28.0 and 32.7％ respectively. The predation rate of 2nd instat nymph by Hemisarcoptes malus, an important natural control agent, is 36.3 and 41.6％, and the parasition rate of female adult by Aphytis procliaus is 2.2 and 7.2％ respectively. The population fluctuation trend index(Ⅰ) for these two generations is respectively 1.12 and 1.26.

Mechanism of artificial wetland treatment of Pb and Cd containing wastewater

Huang Ganquan, Yang Changfeng, Jin Lijun, Zheng Qiaofei

1993, 4(4):  456-459. 

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Through the studies on Pb and Cd contents in various compositions of artificial wetland and their speciation distribution in upper clayey layer, the mechanism of artificial wetland treatment of heavy metal-containing wastewater is approached. The results show that various compositions of artificial wetland all have the capability of removing Pb and Cd from wastewater, and upper clayey layer makes the largest contribution. The contents of Pb and Cd in substrates are decreased in order of upper clay soil>soil>sand>crushed stone. Taxodium ascenders has a stronger capability of enriching Pb and Cd, which is decreased in order of root>stem>cortex>stem xylem>leaf. Pb is mainly bound with Fe/Mn oxide(47.0％) and carbonate(39.3％), and Cd is mainly in exchangeable form(39.5％) and bound with carbonate(37.10％).