Table of Content

25 December 1996, Volume 7 Issue s1

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Articles

Simulation of individual tree growth of Mongolian pine forest in sandy land

Jiang Fengqi, Zeng Dehui, Fan Zhiping, Zhu Jiaojun

1996, 7(s1):  1-5. 

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The Mongolian pine(Pinus sylvestris var.mongolica) is broadly introduced to sandy lands in north China,because of its good ecological adaptation. The Champan-Richards growth model is used to simulate the growth of diameter at breast height (DBH), height and volume of single tree in Honghuaerji and Zhanggutai regions. The results indicate that the quantitative maturity age of natural Mongolian pine forest in Honghuaerji is 100 years old and that of plantation in Zhanggutai is 46 years old, and that the fast-growing period is longer in Honghuaerji than in Zhanggutai.

Translation of short and long shoots after burning and its effect on survival of Larix gmelinii

Shan Jianping

1996, 7(s1):  6-10. 

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Studies on the characteristics of short and long shoots of Larix gmelinii and the effect of burning on them show that short shoot grows rapidly in early spring, and the growth of long shoot plays a key role in constructing the structure of branches and crown of Larix gmelinii. A long shoot can produce 10.5 short ones in the next year. Medium fire can give a serious injury on the branches and crown of Larix gmelinii. After burning, 37% short shoot buds on the first class swig are turned into long shoots, which accelerates the branches and crown structure. In the 3rd year after burning, the total number of short shoots is 98.46% of that before burning.

Rainfall interception by shelter forest crowns on Dougting Lake bater systems

YuanZhengke, Ouyang Hui

1996, 7(s1):  11-15. 

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The rainfall interception by crowns of 18 main shelter forest stands in Dongting Lake water systems is observed at fixed positions with rainfall through and siphon ombrometer.Mathematic model of rainfall interception varied With the rainfall outside forests and dynamic model of rainfall interception by crowns are established. The intercept ability of crows of most stands is stronger in July-August than in April-June, and varies with different time and stands. For different stands,their rainfall interception by crowns is varied evidently with the rainfall outside forests.

Afforestation with Alnus tinctoria to build fire prevention forest belt

Gao Guoping, Qu Yi, Yuan Hui

1996, 7(s1):  16-18. 

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Fire-resistance test with Alnus tinctoria forest belt in larch plantations shows that Alnus tinctoria is a fast growing and fire-resistance species, and its shade density after 5～6 years growing is more than 0.9. The combustibles are less in the belt than in broadleaved forest, being 0.8 kg·m^-2. It is quite safety during fire risk period of Spring and Autumn, and has a significant natural fire-resistance effect.

Preliminary study on classification of forest site in Lulang region of Tibet

Zhao Bin

1996, 7(s1):  19-22. 

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Through analysing the observed data from 66 standard plots in forest sites of Lulang, Tiber and selecting elevation,slope gradient and its direction, thickness of soil layer, soil texture, graved content and organic matter content as affecting factors, 8 types of forest site are classified with the method of principal component analysis. It is indicated that this method is available to the division of forest site types in mountain-gorge forest regions of Tibet.

Effect of vegetation harvesting on soil nutrients

Chen Rongjun, Richard T.Corlett, Ronald D. Hill

1996, 7(s1):  23-28. 

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The difference in N, P and K contents of hillside fields under different harvesting frequencies is investigated at Hong Kong, Heshan and Shenzhen study sites. There are significantdifferences in total and available nutrient contents among sampling locations. Soil nutrient contents on uncutting hills are significantly higher than those on often-cutting ones, and in the former case, soil N content is in the order of Hong Kong >Shenzhen >Heshan.Lower soil layers have a higher P content than upper often-cutting hill has a highernutrient content at Shenzhen than at Heshan. It is suggested that vegetation harvestingshould be done under optimal frequency and within optimal season to minimize its detrimental effect.

Effect of different cultivation modes on soil factors and wheat development on rice-harvested field along Huanghe River banks

Wang Xiaochun, Wang Huachen, Xu Xinfang, Yuan Jianping

1996, 7(s1):  27-32. 

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The study shows that a cultivation mode of gyrotilling and row-seeding is the optimal mode of seeding for high yield wheat on the field after rice harvesting along Huanghe River banks. Compared with zero-tillage and spread seeding, this cultivation mode makes soilhave a higher temperature, lower bulk density, higher moisture content and persistent high fertilizer efficiency. The population and individuals of wheat are well developed,spike density and tiller number are higher, and thousand-grain weight and yield are thehighest.

Hydrothermal regime of different texture soils and its effect on grain formation of winter wheat

Li Chaohai, Lu Daowen, Jing Ji, Hou Song, Xin Baoping

1996, 7(s1):  33-38. 

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Studies on the hydrothermal regime of three soils with different texture in East Henan Plain and the characteristics of grain formation of winter wheat show that during grainfilling stage of wheat, the average daily temperature at 0～5cm layer of clay loam, loam and sandy loam soils is respectively 18.3, 19.1 and 19.5℃. Their moisture content is in the order of clay loam>loam>sandy loam. The duration of grain-filling stage,thousandgrain weight and grain yield are respectively 38 days,45.5 g and 8253 kg·hm^-2 on clay loam soil;33 days,42.4g and 7617 kg·hm^-2 on sandy loam soill and 36 days,43.1 gand 7980 kg·hm^-2on loam soil.

Effect of rye grass intercropped peach orchard on soil thermal regime and its simulation study

Li Quansheng, Wu Jianjun, Yan Lijiao, Wang Zhaoqian

1996, 7(s1):  39-44. 

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Based on the data from field experiments, the effect of peach orchard intercropped with rye grass on soil thermal regime is analysed and simulated. Under cloudy condition, the average soil volumetric heat capacity in areas with and without rye grass intercropping is 2.54 and 2.53 J·cm^-3·℃^-1, soil temperature conductivity is 16.9 and 10.4 cm² ·h^-1,and average soil net heat flux is 136.6 and 167.6 J·cm^-2·d^-1 respectively. Under sunny condition, they are respectively 2.93 and 2.61 J·cm^-3·℃^-1, 16.3 and 5.8 cm²·h^-1, and 80.4 and 85.2 J·cm^-3·d^-1. Soil temperature at different depths is mostly in the form of first-order sine wave, its amplitude with depth shows an exponential function, the decay coefficient is greater in the area without intercropping than in rye grassplanted one, and the phase delay of soil temperature with depth is 0.4 h·cm^-1.

Comparative study on microclimate of Aneurolepidium chinense grassland under burning and grazing

Wang Renzhong, Zhu Tingcheng, E. A. Ripley

1996, 7(s1):  45-50. 

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The canopy temperature, soil temperature, soil humidity, air temperature and relativehumidity are measured at burned, unburned, overgraing and ungrazing plots of Aneurolepidium chinense grassland. The results show that at daytime, the canopy temperature atburned plot is about 2.5～5 ℃ lower than that at unburned one, but about 0.1～1 ℃ higher at night. The soil temperature at burned plot is about 5～7.5℃ higher than that at unburned one at daytime, but about 1～ 2.5℃ higher at night. No significant difference ofcanopy temperature is found between overgrazing and ungrazing plots, but soil temperature at overgazing plot is higher than that at ungrazing one. At the same plot, the temperature of lower canopy is higher than that of higher one at daytime, but lower at night.Soil surface layer has a higher temperature than the deeper layers at daytime, but has alower one at night.

Distribution of Oncomelunia hupensis in various silvi-agricultural ecosystems on river beach

Zhang Jialai, Liu Lide, Huang Runquan, Xiong Xiaojiao

1996, 7(s1):  51-56. 

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The study shows that the distribution of Oncomelunia hupensis is closely related with theunderground water level in forest land. O.hupensis has a maximum density,when the underground water level is 20～40 cm, and approaches to zero when the level is<1.55 cmor >75.7 cm. Its density in forest land is also affected by the flooding period of Changjiang River. Within a period of 100 inundated days, the longer the inundated time,the greater the O.hupensis density. Among 36 species of grass in herb layer, Lecnurks heterophgllas, Equisetum arvellse, Calystegia hederacea, Polygonum lapathifolium and Astragalas sinicus are negatively, and Roedria scandens and Oenanthe javanica are positively correlated with the density of O.hupensis.

Predatory selectivity of Harmonia axyridis on Hyalopterus amygdali and Erythroneura sudra

Yang Chuncai, Zhao Yiqin, Chen Debing, Wei Wengming

1996, 7(s1):  57-61. 

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Studies on the predatory selectivity of Harmonia axyridis show that it has a positive preference to Hyalopterus amygdali, but a negative one to Erythroneura sudra. When one of these preies exists alone, the functional response of H.axyridis shows the HollingⅡtype. When both of them exist simultaneously, but one′s density is less,the functional respones of H. axyridis on another prey still shows the Holling Ⅱ type.If one prey has a higher density. the functional response of H. aryridis shows the Holling Ⅱ type on E.sudra,but the Holling Ⅱ type on H. amygdali.

Spatial distribution pattern of bird cherry aphid and its sampling technique

Yang Yizhong, Dai Zhiyi, Han Juan, Chen Xiaobo

1996, 7(s1):  62-66. 

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Four aggregation indices I,Ca,m/m,Iδare used to analyze the spatial distribution pattern of Rhopalosiphum padi on winter wheat fields after earing. The results indicate that the distribution of aphids is in aggregative pattern during fifteen days after earing and beforeharvesting, and in uniform pattern from the fifteenth to thirtysixth day after earing. Thechange of spatial distribution pattern is related with the proportion of plants carrying aphids (q0). Their aggregative pattern is transformed into uniform one when the proportion of plants carrying aphids(q0) is more than 93%. Sample size requirements for estimating population means with fixed level of precision are also available to cereal aphids,and the pest control threshold can be estimated by the proportion of plants uncarrying aphids (p0).

Population supporting capacity of land resources in Hainan Island

Zhou Zaode, Tan Chuiwei

1996, 7(s1):  67-72. 

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With the aggregates of land resources as the object of study and based on the Fuzzy regional division of various types of productive forces, the potential land productivity,foodstructure and population Supporting capacity on Hainan Island are computed,with considering the input and transformation of material and energy of land resources.The resultsshow that the average biological production potential of 5 kinds of land resources is 5.25×10⁴ kg·hm^-2, equivalent to 2.36×10⁴ kg·hm^-2 standard grain. The population supporting capacity based on low, medium and high food structure programmes are 1.9573×10⁷, 1.5481×10⁷ and 1.2957×10⁷ population, or 52.5, 42.0 and 34.5 population perhectare,respectively. At present. the proportion of the population to that be able to provide for support is 34.2,43.3 and 51.8%,and by the year 2010,the proportion will be 44.5, 57.5 and 68.7%, respectively.

Application of grey multiple object state decision-making in afforestation of northwest Shanxi

Wang Yinggang, Cheng Li, Wang Xuemeng

1996, 7(s1):  73-77. 

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Optimal species of afforestation on different land types of northwest Shanxi are determinated with grey multiple-object state decision-making method. Caragana micophylla can be planted on hillside fields, Pinus tabulaeformis on shade slope land, Robinia pseudoacacia on light slope and Populus davidiana on flood land.

Ecological distribution of Trichoderma propagules in main vegetation soils of Yunnan

Zhang E, Zhou Bin, Yang Liyuan

1996, 7(s1):  78-82. 

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Studies on total soil fungi and abundance and distribution of Trichoderma in different vegetation soils of Yunnan show that relative amount of Trichoderma in forest soil occupies 3～15% of total fungal propagules, and varies with different sites, seasons and soil layers.Dominant species varies with different forest types. T. hamatum is widely distributed in all vegetation soils, especially in tropic rain forest soil. T. harzianum and T. aureoviride are frequently found in monsoon and semi-humid evergreen broad-leaved forest soils, respectively.

Rice field ecosystems in northern China Ⅱ. Study of symbiotic nitrogen fixation of Azolla in rice-Azolla combination systems

Su Fengyan, Li Weiguang, Wen Dazhong, Xu Qingde, Lin Jianqun

1996, 7(s1):  83-87. 

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The study on the quantities of symbiotic nitrogen fixation of Azolla filiculoides in rice-Azolla combination systems shows that the nitrogen fixation ability of Azolla varied with different periods of growing season. The highest nitrogen fixation rate is occured in early June.Its total quantity of nitrogen fixation is increased with increasing Azolla inoculation rates and rice row distances. Total quantity of nitrogen fixation of Azolla is 107.1 kg·hm^-2 in the system with alternating row rice planting of 50 and 10cm and an Azolla inoculation rate of 1500 kg·hm^-2, and is 36.0 kg·hm^-2 in the system with equal row riceplanting of 30cm and an Azolla inoculation rate of 325 kg·hm^-2.

Ecologic effect of Cu and Zn in seawater on Chaetoceros mulleri growth

Qu Keming, Yuan Youxian

1996, 7(s1):  88-92. 

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Studies on the ecologic effect of Cu and Zn on the growth of Chaetoceros mulleri show that when the ionic activities of Cu and Zn are less than 0～10^-7.80 and 0～10^-7.00 mol·L^-1respectively,the growth of C.mulleri is normal. Its optium requirement to the ionic activity of Cu is 10^-13.57～10^-10.53mol·L^-1, but for Zn,it is not essential at lower ionic activity. When the ionic activities if Cu and Zn are higher than 10^-7.80 and 10^-7.00 mol·L^-1 respectively,they will have a harmful effect to C.mulleri. Cu has a higher toxicity than Zn.

Embryonic development of Neosalanx oligodontis and its relation with temperature

Gong Shiyuan, Zhang Xunpu, Song Zhixiu, Zhu Ziyi

1996, 7(s1):  93-98. 

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When average water temperature is 14.2, 15.6,16.5,23.4 and 24.5℃,the incubationtime of Neosalanx oligodontis is 142, 119,108,68 and 61 hours in turn.Its embryonic development can be divided into ten stages. The relationship between temperature and incubation time is expressed as H=6861.1988 T^-1.4717,and that between accumulated temperature and incubation time is H=1.6081×10^-8A^3.0151.

Transformation, fate and ecological risk of priority organic pollutants in slow rate land treatment system of west Shenyang

Yu Dianchen, Liu Hailing, Zhang Lishan, Yin Zhaohua

1996, 7(s1):  99-104. 

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The transformation and residues of priority organic pollutants in SR-LTS (Slow Rate Land Treatment System) of west Shenyang were studied in this paper. The results show that total contents of priority organic pollutants in culticated soil of SR-LTS and traditional wastewater irrigation areas and underground water are one and four times higherthan those in control area, respectively. And there is a very similar distribution of priority organic pollutants in effluent, underground water of SR-LTS and traditional wastewater irrigation areas. It is suggested that organic pollutants in irrigating wastewater have an influence on soil and underground water. However, no obvious difference in priority organic pollutant contents in rice grain produced under the treatments of SR-LTS, traditional wastewater irrigation and clean water irrigation is detected.

Forest site study in the world-its present and future

Ma Jianlu

1996, 7(s1):  105-109. 

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The current situation of forest site study in the world is reviewed from the view point of vegetational,physiographical,combined multifactorial and numerical approaches. The historical background, basic principles, practical methods and application requirements of various representative schools or methods are analyed contrastedly, and the development trend of world forest site study is also discussed.

Effect of increased deposition of atmospheric nitrogen on forest ecosystem

Xiao Huilin, Zhuo Muning, Wan Hongfu

1996, 7(s1):  110-116. 

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Based on literature data, the effect of increased deposition of atmospheric nitrogen on forest ecosystem is discussed in this paper. During last decades,the deposition of atmospheric nitrogen is increased dramatically, and the relationship between nitrogen deposition and nitrogen emission is linear. In some areas, nitrogen deposition has exceeded the N requirement by forest ecosystem. The stimulation of plant growth and the damage to mycorrhizae by the increased nitrogen deposition, the exchange of absorbed excess NH₄⁺ forother nutrient canons in plant,and the competitive inhibition of the uptake of other nutrient cations by high level of NH₄⁺ in soil can lead to the deficiency of other nutrients in plant and the disorder of forest nutrition. The increase in nitrogen deposition will result in enhanced nitrification, promoted leaching of NO₃^- and concomitant base canons, accelerated soil acidifieation, and forced Al and Mn mobilization. A high level of nitrogen inplant due to the assimilation of large amount of excess nitrogen will increase the susceptibility of tree plant to the stress of cold, frost, fungal pathogens and possible insect attacks. The chronic increase in nitrogen deposition can induce the change in community through interfering with successional dynamics.

Basic theory and practice of agro-animal husbandry eco-engineering

Xing Tingxian

1996, 7(s1):  117-120. 

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The agro-animal husbandry eco-engineering is a complex agro-ecological, economic and technological system.It is composed of three subsystems:plant (crop industry), animal (livestock industry) and microbe (linking crop and livestock industry). The key is to set up an effective and economical livestock eco-engineering system which is mainly composed of"4,3,2,1" animal production model. The objectives of this model are toproduce as many and as fine crop -livestock products as possible from as less natural resources as possible in as short periods as possible, to obtain as high economic benefits as possible, and to achieve as optimum eco-balance as possible.

A theoretical methodology of landscape eco-classification

Wang Yanglin

1996, 7(s1):  121-126. 

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The basic principle of landscape eco-classification is discussed in this paper. Two-seriessystem of structural and functional classification is considered to be favorable to landscape eco-classification. In addition, bio-production, environmental service and cultural support are put forward as the basic functional types of landscape ecosystems. The study is expected to be beneficial to the development of emerging landscape ecology.

Ecological effects of pesticides on soil microorganisms

Gong Ping, Sun Tieheng, Li Peijun

1996, 7(s1):  127-132. 

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On the basis of reviewing the last decades'literatures on ecological effects of pesticides on soil microorganisms,following conclusions can be derived:(1) although some pesticidesmight cause temperate inhibition or stimulation on soil microbe or its activity, the effects would disappear quickly;(2) application of pesticides at their recommended concentrations does not have any adverse impact on soil microbial processes or activities, nor onmaterial cycling in soil or soil fertility; (3) most soil furpigants and fungicides can affectsoil microbial balance, and their effects are usually more intensive than insecticides and herbicides; and (4) long-term investigations indicate that no significant effects on soil microbial communities or activites could be observed in case of consistent use of pesticides,which might be partly due to their transformation and degradation by soil microorganisms.

Dynamics of litter decomposition in Hexi subtropical rain forest of Fujian

Shao Cheng, Zheng Wenjiao, Lin Peng

1996, 7(s1):  133-135. 

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The decomposition rate of litters and their variations of energy and nutrient release in Hexi subtropical rain forest of Fujian are determined with litter bags. The results show that the dry matter loss is faster from 8 mm than from 2mm mesh bages. The half-timeof decomposition in Zmm and 8mm mesh bages is 4.9 and 3.7 months, respectively. During decomposition, the N and P contents of residual leaf are higher than those of original one. The loss rate of 5 elements from decomposing litter is in the order of K>Mg>Ca>N>P. Residuals have a decreased caloric value.

Resistance of cotton nectariless character to bollworm and pink bollworm

Zheng Dongguan, Fang Qiying, Zheng Houjin

1996, 7(s1):  136-138. 

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Studies on the resistance of cotton nectarness character to bollworm and pink bollworm show that in experimental areas of Hefei, the number of bollworm eggs is decreased by 40～53.3%, that of damaged buds and balls by 50～70.3%, and the percentage of wormeaten seed by 43～57%. The similar effect is also observed for pink bollworm.

Distribution of microorganisms in saline-alkali soil at castern suburbs of Tianjin and activity of soil enzyme

Jin Suying, Cui Mingxue, Lin Jishang

1996, 7(s1):  139-141. 

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The study shows that the quantity of soil microorganisms and the activity of soil enzymes are related with crop kind and soil organic matter content. Rice soil has the highest quantity of microorganisms,and herbage soil has the lowest one. The number of microorganisms is much higher in 0～10cm than in 20～30cm soil layer. Protease and urease have a much higher activity in rice soil than in beer, herbage and wheat soils. Catalase activity isthe highest in beer soil, but the lowest in herbage soil.

Ecology of necton in Yuandang Lake of Xiamen

Lu Zhenbin, Du Qi, Huang Yijian

1996, 7(s1):  142-144. 

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After many years integrated management of Yuandang Lake in Xiamen,the nectons are increased from 1 to 43 species, among which, 29 are fishes, 8 are prawns,and 6 are crabs.Their monthly average biomass and density are respectively 34.43 g·net^-1 and 0.77 tail·net^-1, and their quantitative distribution is in the order of outer lake>innerlake>east Hudong bridge,the seasonal dynamics of species is in the order of bummers>autumn>winter>spring.Liza carinatus,Tilapia nilotica and Stolephorus commersonii are the dominants.