Table of Content

10 October 1999, Volume 18 Issue 05

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Biomass Dynamics of the Pioneer Trema Orientalis Community in the Early Stages of Secondary Succession of Tropical Forest in Xishuangbanna

Feng Zhili, Tang Jianwei, Zheng Zheng, Song Qishi, Cao Min, Zhang Jianhou, Xie Jiwu

1999, (5):  1-6. 

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The biomass dynamics of the pioneer Trema orientalis community in the early stages of secondary succession of tropical forest in Xishuangbanna had been studied for 5 years by the standard tree regression(for trees)and clear cut method(for shrub,herb and inter layer plants). 1)The biomass distribution by organs was ranked as stems>branches>roots>leaves. 2)As the succession proceed, the percentages of stem and root biomass increased gradually, the percentage of leaves obviously decreased, and the percentage of branches fluctuated slightly; the dorminant species T. orientalis was replaced gradually by other species,that made the biomass distribution by species appeared to have a characteristics of relative dispersion;the biomass distribution by DBH class showed that biomass was mainly determined by the amounts of larger DBH class trees;the percentage of the tree biomass to the total community biomass gradually increased, the percentages of the shrub and herb layers remarkably decreased and the percentage of the inter-layer plants increased slightly.

Retention Capacity of Phosphorus and Nitrogen by Land/Water Ecotone Soil in Lake Baiyangdian

Yin Chengqing, Shao Xia, Wang Xing

1999, (5):  7-11. 

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Nutrient retention capacity by the land/water ecotone soil of Lake Baiyangdian was studied by means of simulation in situ. The results from column experiments suggested that the standard capacity for phosphorus adsorption be less than P14 mg穔g^-1 soil in order to meet the lake water quality regulation(P 0.1 mg稬^-1). Thus the 9,333 hectares of ecotone around the lake could retain 1,245 tons phosphorus in the upper 50-cm soil without degrading the water quality. The amount was nearly 24 times large as that of taken by annual reed harvesting. The maximum capacity for phosphorus was measured as P 774 mg穔g^-1 soil. The isothermal equation of phosphorus was also obtained. It was found that temperature had a significant effect on the transformation of nitrogen, and higher temperature would accelerated the nitrification rate. Nitrogen retention was conducted by the microbial activities in the soil and the uptake through aquatic vegetation. The research will benefit for better utilization of local ecotone and design of the planning project which aims to water eutrophication control.

Overall Effect of Mulch Bunch Planting Cultivation of Rain Fed Wheat

Du Shouyu, Tian Enping, Wen Ming, Feng Qian, Xu Zhiwen

1999, (5):  12-17. 

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The pedological,biological and economic effects of mulch bunch planting cultivation of rain fed wheat were studied systematically using methods combining experiment and demonstration. The results showed that compared with other cultivation methods such as open ground drill seeding,covering at seedling stage and open ground bunch planting, the mulch bunch planting cultivation had following merits:the water conservation of the soil of wheat field was improved,the productive efficiency of water increased,the soil moisture enhanced,the accumulated ground temperature lifted,the physical behavior and aeriation of the soil improved,the mineralization of organic matter quickened,N、P nutrient decreased significantly,the time from seeds to emergence of seedlings reduced,the tilling stage moved up,the young panicle differentiation and grain formation period shifted to an earlier date and the days undergone increased.So, the mulch bunch planting cultivation has effectively overcomed the growing defects of "one long and three short"with local conventional cultivation methods,achieved the results of bigger ears,more grains per ear and higher thousand kernel weight, and enhanced biological output and economic output.The mulch bunch planting cultivation has achieved a large increase in gross economic product value and net economic income through a small increase in input.

Sexual Behavior Observation of Fugu obscurus in Hasten Parturition under Different Water Temperature Conditions

Zhao Qingliang, Zhao Qiang

1999, (5):  18-20,28. 

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It is very important to recognize exactly the artificial insemination period in the artificial parturition process of Fugu obscurus. The sexual behavior feature of the parent fish treated with parturifacient should help us to seize the opportunity of artificial parturition. After treating with parturifacient, the sexual gland of the parent fish displaied a sexual behavior cycle that was excitedly quick swimming, pursuing and touching one another,and swimming of relative rest. The water temperature could affect the development speed of this sexual behavior cycle.

Ecological Effects of Submerged Macrophytes Restoration by using the Mesocosm Enclosure

Song Biyu, Wang Jian, Chao ming, Dai Mang

1999, (5):  21-24. 

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In order to study the eclological effects of submerged macrophytes restoration, the mesocosm enclosure experiments were conducted in an eutrophicated lake. According to main physico-chemical factors, content of phytoplanktonic chlorophyll-a and biodiversity of protozoan community, the restoration of submerged macrophytes made the water quality much better and the protozoan community diversity greater.

Ectotrophic Mycorrhizal Fungi and Their Ecological Distribution in Lushan

Chen Ye, Xu Zuguo, Fu Biao

1999, (5):  25-28. 

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A specific investigation on fungi in Lushan region in various seasons has been made. Totally 14 genera which include 31 species of ecto-mycorrhizal fungi have been found. The results showed that distribution of fungi was closely associated with type ofvegetation and type of soil as well as elevations.The investigation provided relevent evidence for further study of substance transformation and energy circulation in the forest ecosystems.

Research State of Soil Carbon Cycling in Terrestrial Ecosystem

Wang Yexu, Zhao Shidong, Niu Dong

1999, (5):  29-35. 

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Soil carbon pools and respiration play an important role in the global carbon budget, and they are also essential to understand the soil carbon cycling for the prediction of future atmospheric CO₂ concentration and understanding the structure and function of soil ecosystem. The key aspects in the research of soil carbon cycling were presented, including the different ways of estimate of soil carbon pools, the relationships between soil carbon cycling and global change, and the basic methods for the modeling of soil carbon cycling.

Approach to Sustainable Management on Pure Plantation of Pinus tabulaeformis in Western Liaoning Province

Du Xiaojun, Jiang Fengqi, Zeng Dehui, Shen Hui

1999, (5):  36-40. 

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Under the direction of Sustainable Development, some key issues of forestry in Western Liaoning Province were analyzed in this paper. "Planting Broad-leaved Trees and Accelerating Conifers"(PBTAC)was put forward as the effective approach to sustainable management on the Pure Plantation of Pinus tabulaeformis and the unique path of forestry sustainable development in Western Liaoning Province. The concept, aim, and notices of "PBTAC" were also analyzed and discussed.

On the Significance, Role and Manipulating of Neutral Insects in Paddy Ecosystem

Xu Jianxiang, Wu Jincai

1999, (5):  41-44,6. 

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The studies on neutral insects of agro-ecosystem in paddy field have been reviewed in this paper. The significance, role, and manipulating of neutral insects also have been discussed. Based on the effects of neutral insects on food-web of paddy field, the authors presented that we must pay more intensive attention to neutral insects and the effects of neutral insects on food-web must be taken into account in IPM of rice.

Habitat Renewal and Habitat Mitigation - on the Strategy of Natural Conservation

Li Xiaowen, Hu Yuanman, Xiao Duning

1999, (5):  45-51,24. 

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The conservation of species requires preservation of natural habitats,where the integrity of natural habitats has been severely disturbed and species goes extinct. All natural habitats are continuing to decline both inside and outside of reserves. Habitat change is partly a natural process(e. g. , succession), but human activities have accelerated the process so that natural rate of renewal is insufficient to maintain natural habitats. This paper provided concept, methods of habitat renewal, habitat mitigation and their implication to protection and exploitation of natural resource. We argue that our only resourse, in light of these scenarios, is to adopt a new conservation strategy that considers the importance of habitat renewal and habitat mitigation in addition to habitat preservation. Accordingly, in our management decision, we must not only choose the size of area to preserve,but also the size of area to balance habitat loss with habitat renewal or habitat mitigation. Finally, we explored the application of habitat renewal and habitat mitigation in regional sustainable development of Liaohe Delta wetland.

Applications of RS and GIS on Terrestrial Vegetation Ecology

Peng Shaolin, Guo Zhihua, Wang Bosun

1999, (5):  52-64. 

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The application of remote sensing and GIS on vegetaion ecology was reviewed in this paper.With the GIS, the information from remote sensing can be used in the studied on biomass,productivity,structure,evapotranspiration of vegetation,as well vegetation classification,mapping,monitoring,and management.In the fucture,the studies on energy flow and material cycling and in the ecosystem,structure and dynamics of vegetation,biodiversity monitoring,and globe change will be deepened with the application of RS and GIS.

Characters and Dynamic Model of Sorghum Root Growth and Development

Zhang Xiying

1999, (5):  65-67. 

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By taking soil cores at the different growth stages, the distribution, weight, and length of sorghum root system were studied, and models were established to simulate its total root length and weight increasing patterns. In addition,by comparing sorghum root system with maize root systems, the correlation of root systems with the high drought-resistance of sorghum was testified.

Slope Eco-engineering andits Current Developing State

Zhou Yue, D. Watts

1999, (5):  68-73,79. 

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Vegetation provides potential erosion controland slope protection,through its hydrological and me chanicalinteraction ofplants withlocalclimate and soil.Thetheoreticalunderstanding ofthese vege tative effectsis the base of slope eco - engineering.In the pastfew decades,theimportance of vege tation in protecting slopes has been stressed by many researchers.The greater awarenessthat vegeta tion can play a range ofrolesin slope protection has madeitincreasingly a valuabletoolin naturalen vironmentalprotection and civilengineering.and this knowledge hasled to aincreasing application ofvegetation types world - wide.Thoughitisstilla kind ofyoungtechniques,anincreasing amountofexperience ofslope eco - engineering of vegetation is gathering from the past practices,and thelagernumber ofsuccessful examples ofits applicationsis showing its greatfuture.

Eco-Agricultural Types and Benefits in Qinba Mountain Region

Chen Changfa

1999, (5):  74-76. 

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Ankang District lies in Qinba hinterland where is a region of transition in the North-South of China.The conditions of agro-ecology are different from the North and the South.The artical traversed experiment and investigation, and announced three types of Qinba mountain area’s ecological agriculture as follows: agriculture of planting and breeding by the chief of biogas; ecological manor of synthesize use of soil resources;stero agriculture’s developments of plough.