Table of Content

10 June 1986, Volume 5 Issue 03

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Primary Factor Causing Early-Spring Dieback of Poplar Plantations in Xinmin County——Interruption of Water Ascent in Xylem Caused by Insect's Laying Eggs Uder Bark

Tao Dali, Jin yue hua

1986, (3):  1-4. 

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Field observations indicate that stems are dried out from Tettigoniella viridis Linnaeus'laying eggs under the bark on lower part of the stem and that the damaged part dries out earlier than other parts.Similar symptoms are produced by cutting into the bark of potted plants to simulate the effect of insect damage.Fuchsin acid solution ascent is slowed down apparently in the stem sections damaged by the insect,It suggests that the interruption of water ascent in xylem resulted by insect's laying eggs is the primary cause of early-spring dietack of poplar plantation in Xinmin County of Liaoning Province.

Study on the Growth Character and Critical Age of Coilia Ectenes Taihuensis(Yuan et Lin)

Tang Yu

1986, (3):  5-9,13. 

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Asurvey from January 1983 to April 1984 shows that there exists a relationship between the length and weigth of Coilia Ectenes Taihuensis(Yuan et Lin).Its growth is very likely isometric.The von Bertalanffy's formula is applied to study the growth character and critical age of the fish.Its growth speed of length is gradually slow down with days passing by,but it has no turning-point.The fastest growth speed of weigth and its turning-point occurs at the 3rd year.Furthermore,the study shows that the fish with an age of 2.9 years old has the highest school biomass of one generation.Its critical age is an important reference for estimating fisheries resources

A Successful Man-made Forest Ecosystem——An Investigation on the Ecolomic Effects of Coastal Casuarina Windbreak at Nan San Tree Plantation

Long Siman

1986, (3):  10-13. 

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The investigation on ecolomic effects of coastal Casuarina at Nan San Island of south-western Guangdon province shows that the net association rate of the Casuarina plantation ecosystem is about 0.17—0.59%,104—225 m³/yr shifting sands can be fixated by each 100m windbreak.While the energy input compensating by man,it indicates that the integration effect is high.But,this ecosystem is fragile,and its structure is not stable.In order to further raise the ecolomic effects,managemental measures should be taken circumspectly.

Evaluation of Atmospheric SO₂ Pollution Status in Maoming City

Yu Mengbe, Yu Qingfa, Yang Ruilian

1986, (3):  14-17. 

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The contents of total and soluble sulfur of two plant species(Casuarina equiselifolia and Eucalyptus exerta)in more than thrity atmospheric SO₂ monitoring sites were determined.The results are:1.Three industrial areas in Maoming city are the main pollution sources.2.The sulfur content of leaves in all monitoring sites is 1—5 times higher than the controls,It shows that all of the monitoring sites are polluted by SO₂,but the extents of pollution are different.3.The variation of sulfur content of leaves is similar as that of daily average concentration of atmospheric SO₂.According to the content of sulfur pollutant and the injured extent of plants,it is suggested that the polluted status of Maoming city might be divided into three grades.The polt of these three grades is in agreement with that of isovalue line of atmospheric SO₂ concentration.

Preliminary Study on the Community-Structure of Grops in the North-China Plain

Dong Zhenguo

1986, (3):  18-22. 

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Principal conclusions in this study can be shown as follows:1.Winter wheat:when its yield is higher than 7500kg per ha,the period in which leaf-area index goes beyond 4.5 from-jointing stage to mulk stage is more than 40 days.2.Paddy rice:because of the leaf's inclination of this community is bigger in general,the optimum leaf-area index can be determined to be about 6.0.

A Research on the Population Density of East Asia Pincers Scorpion

Wang Jinmei, Song Shuxiang, Qi Zhongqi, Luo Haichao

1986, (3):  23-25. 

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The population density of East Asia pincers scorpion is related to season,temperature,humidity,habitat and biological characteristics.The distribution border of East Asia Pincers Scorpion shows the tendency of moving toward the south and it's quantity is decreased year by year.The quantity of youny scorpion is less than that of elders.It shows that the population of East Asia Pincers Scorpion is not exuberant.

On the Relationship Between Monsi Formula and Poission Distribution

Zhang Houxuan

1986, (3):  26-27. 

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The theoretical proof of Monsi formula must suppose that the distribution of leaf area in a stand is exactly obeyed on Poission distribution law.Using methematical methods,this paper shows the biological meanings of parameters in Poission distribution.It is indicated that Monsi formula is a special form of Poission distribution.And hence,the promise of Monsi formula has to be that plant stand possesses a property of spatial Poission distribution.Most of the stand in the nature doesn't possess this property,so the theoretical value doesn't meet the measured value of solar direct radiation,which shows a definite deviation.The quantity of this deviation maybe possess some significations for studying thermal and dynamic states in plant stand.

Evolution of Natural Environment in Compact Communities of Bagou Lowland

Xia Ling

1986, (3):  28-30,46. 

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Based on the evolution process of natural environment and human history in compact communities of Bagou,this paper discusses the relationship between human beings and their living environments.It's indicated that the evolution of Bagou lowland is under the intervention of artificial activities.In order to transform this region into cultural and recreative one,the author suggests that it's necessary to limit the development of industry,dredge the waterways and pools,improve the environments and control the speeds of population increments.

Studies on the Population Structure and Succession Trend of Evergreen Coniferous Broadleaf Forests on the North Slope of Jiugong Mountain

Huang Chengyi

1986, (3):  31-36. 

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In this paper,the population structure and succession patterns of two main types of evergreen coniferous-broadleaf forests on north slope of Jiugong mountain are investigated.The results show that these two types of mixed forests are exuberant or mature populations,which occupy on increasing position in.the stand and will evolve to an evergreen broadleaf forest——the climax community in tropic area of Central Asia.

Dryland-Ecosystem and Its Improvement in Dingxi District of Gansu

Lin Haiming

1986, (3):  37-40,56. 

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This paper discusses several problems existed in dryland-ecosystem of Din gxi district and their occurence.It's considered that the main problems are lower and unstable crop yields,serious water-and soil erosion and deficiency of fertilizer,forage and fuel.Their occurence is due to the unreasonable structure of agriculture,low utilization rate of natural resources and unbalance of material and energy flow in this ecosystem.Some corresponding countermeasures are put forward by the author.

Ecolomic Problems in Exploiting and Utilizing the Rural Natural Resources of Henan Province

Zhu Guixiang, Fan Wanxuan

1986, (3):  41-46. 

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Based on the present situation of rural natural resources of Henan,this paper discusses the problems induced by the unreasonable exploitation and utilization of natural resources and the experiences gained from following ecolomic laws.Countermeasures for solving such problems and developing ecologic agriculture are also put forward.

Improve Water-and Soil Conservation and Creat a Better Ecological Environment

Wu Youzheng, Pan Baolin

1986, (3):  47-50. 

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Serious ecological problems are induced by forest destruction over hilly areas of east and west Sichuan,among which,water-and soil erosion is the most serious one.The ecological environments of the whole Yangtze River Basin as well as these two areas are getting worse.It's suggested that measures for improving water-and soil conservation must be under taken to eliminate the threat of the destruction of ecological environment.