Table of Content

10 June 1994, Volume 13 Issue 03

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An Eco-Model of Grass Cultivntion and Goose Rearing on Sandy Lands

Xing Tingxian, Fang Rejun, Hu Minqiang, Chen Huiping, Tan Zhiliang, He Liehua

1994, (3):  1-6. 

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A gooes-grassland-pool eco-model was established on sandy lands in northern China by growing grass and rearing goose. Matter transference in the grass-goose feces-soil circulation and its effect on soil fertility were investigated.The optimun,goose grazing capacity was determined, and the ecological and ceonomic benefits were evaluated. Soil fertility,and hence, and quality of grass can be improved by goose feces.

Ecological Characters of Vertical Distribution and Aestivotion of Wireworm Population(Pleonomus conaliculatus Fald.)in Wheat Field and Their Relationship to Its Control

Luo Yizhen, Niu Shanguang, Long Yan

1994, (3):  7-10. 

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The seasonal dynamics of vertical distribution and diapause syndrome of aestivation of wireworm in wheat field were investigated during 1988-1990.According to the population percentage in upper soil layer,its activity peaks were present in early spring and early summer,which synchronized phenologically with the growing stage of wheat and seedling stage of corn,respectively.During seedling stage of wheat in autumn,wireworm population in upper soil layer was the lowest of the year.Aestivation occured at the older,fully developed larvae stage,which was sensitive to higher temperature stimulus.The duration of aestivation persisted through autumn to early winter.Control measures were conducted in wheat field in accordance with these ecological characters and proved successful.

Planting of Fast-Growing and High-Yield Poplar Forest with Taking Advantage of Forest Edge Effects──A New Model of Complex Agroforestry Ecolomic System

Xu Hongru, Liu Jinsheng, Fan Xuewen

1994, (3):  11-16. 

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The experimental results show that it is practicable to plant fast-growing and high-yield poplar forest with taking advantage of forest edge effects. The reasonable structure is:8m of effective belt width and 2m?2m or 2m?3m of spacing between trees and tree rows.Significant effects are acquired from it,with an annual average tree growth of 21-33m³穐a^-1.Such a complex agroforestry operation can also be carried out within tree belts,with the economic benefits completely redeeming the initial aforestation investment.

Experimental Population Ecological Study of Adoxophyes cyrtosema Meyrick

Li Jianrong, Zhu Wenbing, Li Longshu

1994, (3):  17-20. 

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This paper deals with the development of Adoxophyes cyrtosema Meyrick under the influence of different temperature,light,citrus variaties and shoot conditions. The results indicate that temperature is the most im-portant factor.The range of active temperature is at 8-36℃, 20-32℃ being the optimum. The optimum light duration is about 12 hours. The same-year spring shoots are the best nutrition source,and Citrus sinen-siscv. hamlin is the most favourable host for this leaf roller.

Selection of Drought-Resistant and Salt-Tolerant Plant Species in the Taklamakan Desert

Liu Jiaqiong, Qiu Guoyu, Shi Qinghui, Li Fengqin

1994, (3):  21-24. 

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The drought-resistances of 16 representative sand-fixing plant species in the Taklamakan Desert area are analysed by comprehensive evaluation method,and the salt-tolerances of 6 plant species are observed through pot experiment irrigated with different salt concentration water.The 16 drought-resistant plant species can be ranked by their resistance to drought as:Tamarix hohenackeri>Haloxylon ammodendron>T. austromon-golica>H. persicum, Caragana korshinskii, Artemisia arenaria, Calligonum leucoladum,C. rubicundum>C.angustifolia>Halimodendron holodendron>Atraphaxis pungens, C. roborovskyi>Populus euphratica>Elaeagnus angustifolia>Populus simonii; while the 6 salt-tolerant species can be ranked as:Tamarix hispida>T. ramosissima>Nitraria sibirica>Haloxylan ammodendron>Halimodendron haloden-dron>Ammodendron argenteum. The habitat adaptability of different sand-fixing plants are also discussed.

Phenol-Degradation Capacity of Abacterial Eichhornia crassipes

Zhao Dajun, Zheng Shizhang

1994, (3):  25-29. 

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Experiments were carried Out to study the phenol-degradation capacity of abacteriaI Eichhornia crassipes. In solutions with different phenol concentration(10,100,150,200,360,800μg·ml^-1),30.2-0.3g dry weight dabacteriaI Eichhornia crassipes can degradate phenol by 20-40% within five days, although the plant may die soon.The amount of phenol absorbed is different for different original phenol concentrations. Comparative study by two methods of measuring phenol degradation—4-amitoantipyrine chloroform excraction methed and ultraviolet spectrophotometry method──proves that the former is more dependable than the later in the special ocassion.

Efrects of Regeneration and Invigoration Technique on the Ecological Environment and Growth Behavior of Bashania fangiana

Zhou Shiqiang

1994, (3):  30-34. 

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Regeneration and invigoration technique is proven beneficial to increase the light intensity and 0-5cm soil temperature required for the growth and development of Bashania fangiana,and to increase the floristic composition and biological productivity of herb ground covers.It is predominantly effective to the growth of base diameter and plant height of 1-3 years seedlings and to the reduction of group leaf area index. The efficiencies of this techniques are different with different forest types and different management policies.

Dry Land-Paddy Soil Shifting and Eco-Environmental Evolution of Soil at Liushu Town of Yingkou City

ZhaoYi, WuYanming

1994, (3):  35-40. 

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Liushu town is situated at the lower reach of Liaohe Rlver and was seriously affected by salt and flooding calamities,After the shifting from upland to paddy soil cultivation,the salt content of soil haa been greatly reduced by leaching of irrigation water.Sampling analysis indicates that 5450kg· ha^-1 of salt is discharged from surface soil annually, which will reduce the salt content of saline meadow soil by 0.1─0.2% within 2─4 years. Salt composition is also changed from NaCl type to sulphate mixed type. The cl and Na content has been greatly reduced.and soil properties have been improved,which provide a reliable garantee for the progressively high and stable yield of crops.

Effect of Pholoperiod on the Growth and Survival of Silver Carp, Bighead Carp and Common Carp fry

Wang Jiqiao, Zhao Deshu, Zhang Jingquan

1994, (3):  41-44. 

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The growth rates of tested fish fry increase, with increasing photoperiod. In ponds,the daily instantaneous growth rates of common carp, silver carp and bighead carp are 5.57,4.02 and 9.90 times higher under 14-15h sunlight than under 0h sunlight,respectively,and ih net chambers,they are respectively 0.6,3.7 and 3.3 times higher.The minimum and optimum photoperiod;for fry growth are 3-6 and 12h,respectively. It seems that common carp fry is more tolerant to short photoperiod than silver carp and bighead carp fry.There is no significant relationship between photoperiod and survival rate of fry.

Role of Rhizosphere in Environmental Science

Chen Nengchang, Tong Qingxuan

1994, (3):  45-52. 

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Rhizosphere is the joint among biosphere,pedosphere,hydrosphere and atmosphere. As an interface of soil-plilnt system,it plays an important role in controlling the translocation of pollutants, in food-chain. removing pollutants from wastewater,and producing greenhuse gases to atmosphere. Better understanding the small-scale processes of Water and chemical movement in the rhizophere of crops is critical to minimize the increasing problem of agricultural non-point source pollution.Further studies on the rhizosphers chemistry and ecology of pollutants are guarantees to improving environmental quality.

Nutrient Balance in Farmlaud Ecosystem Under Major Rice-Based Cropping Systems in Subtropical Zone of China

Fu Qinglin, Meng Cifu

1994, (3):  53-56,34. 

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Investigation shows:(1)fertilizers are the main way of N,Pand Kinput in the rice areas,return back as crop residues is also one of the important nutrient resources,and biologicaInitrogen fixation is one of the important nitrogen resources. Harvest is one of the important output ways for N,Pand K,and loss of nitrogenous gases is another important output way for Nin the rice areas;(2)rice-based cropping system in eastern and central China tends to be more inorganic agriculture than that in southern and southwestern China.The degree of organic agriculture in southern China is the highest in the three rice areas;(3)the inputs and outputs of N, Pand Kunder major rice-based cropping systems in subtropical zone of China are basically balanced and most of their input to output ratios are 0.7-1.5.

Ecological Effects of Multi-Layer and Multi-Species Shelterbelt

Peng Jinzhao

1994, (3):  57-61,67. 

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This paper summarizes the experiences of Guangxi Daguishan forest farm in establishing a high efficient and rational structured multi-laver and multi-species shelterbelt network.The ecological effects of this network in preventing forest fire and pest infestation,in promoting large-area fOrest growth, better cycling and sustained cropping,and in creating favorable ecological environment for forest regeneration are discussed.

Preliminary Study on Interspetific Associalion and Combined Population Patterns of Stipa bungeana Steppe Community

Li Linghao, Shi Shibin

1994, (3):  62-67. 

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study of interspecific association and combined population patterns of Stipa bungeana steppe community is carried out by means of x²-test, variance ratio methOd and Kershaw's covariance analysis. The results show:(1) among45 species pairs in10 species,6 pairs are positively associated,5 pairs are negatively associated,and the rest 34 pairs are not associated;(2)according to the above results,10 species could be divided into three groups:the association being negative among groups and highly positive with each group;(3)the com-petition fOr living space and resources among Stipa bungeana,Artemisia frigida,Carex rigetcen is the basis for the formation of interspecific relation in the community,and the separation of the 3 species constitutes the basis of the spatial patterns of the whole community.

Effects of Soil Acidification on Enzyme Activities and Nutrient Elements in Rice Nursery Soils

Tang Yong, Liang Chenghua, Zhang Zhongyuan, Li Huanzhen

1994, (3):  68-69. 

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Studies of soil acidification in rice nurserv soil show that the activity of soil urease is decreased,the activitv of phosphatase in alkaline soil is increased and that in neutral soil is decreased after acidifing soils to pH4.5.The volatilization rate of ammoniacal nitrogen in the soils is decreased obviously by acidifing the soil,especially in alkaline soils. The available phosphate in alkaline soils is increased,but that in neutral soil is decreased slightly as the soil is acidified.The amount of positive trace elements in soil are increased differently in acid conditions.Thus acidifing dry nursery soils in early spring can improve available nutrients for rice in the soils.

Allelopathic Effect of Wheat Straw Mulching on Seedling Growth and Development of Summer Corn

Zhang Yuming, Ma Yongqing

1994, (3):  70-72,75. 

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Wheat straw contains water soluble toxic substances,which inhibit seed germination and seedling growth of corn. In this paper,the allelopathic effect of wheat straw mulching on corn seedling growth at different time with different quantities is presented. The results show that mulching with different amounts os wheat straw has different effects on corn seedling growth,4.5ton per hactare of wheat straw yields the best growth of corn seedlings. When the straw is mulched after 5 days of planting,the biggest inhibition on corn seedling growth would happen.When the straw is mulched at the day or after 15 days of planting, the best positive effects would be obained.

Ordination Axes Partitioning and Its Application

Zhang Jintun

1994, (3):  73-75. 

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Ordination axes partitioning,a new method for classification of plant communities, is described in this paper.It is based on the first m ordination axes of Detrended correspondence analysis and is a polythetic technique. The outcome of its application to the classification of Vitex negundo var. heterophylla is identical tothat of fuzzy equivalence clustering and group-average clustering. It is concluded that ordination axes partitioning is a simple,effective methedology in vegetation study.

Overview on the Role of Theory and Model in Ecology

Wu Jianguo

1994, (3):  76-79. 

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In ecology,theory should be considered not only as a conceptual framework for research,but an ultimate preduct of ecological studies as well. Model may serve as the basic unit for many theoretical and applied studies. Theory and model can be used to generate new hypotheses,to clarify and test existing hypotheses,to identify key components in complex systems,to suggest critical experiments,to synthesize knowledge across disciplines and seales,and to make assesa,ment or optimization for decision-making processes.Models become indispensable when we deal with both spatial and temporal dynamics of systems simultaneously,and when the scales of the phenomenon become large. Ecologists should keep themselves up-to-date of the state-of-the-art in their field,and try to equip tbemselves with advanced methdsand approaches.Empirical and theoretical ecology are interdependent and interactive. Minimizing the gap between theoreticians and empiricists will certainly help promote the development of the science of ecology.