Table of Content

15 May 2002, Volume 13 Issue 5

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Eco-environment and nutrient accumulation of sharptooth oak stands in southern slope of Mt. Qinling

LIU Guangquan, NI Wenjin, LIU Huifang, G. Gravenhorst

2002, (5):  513-518. 

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Based on the date from chemical analysis of 10785 botanical and 1489 edaphic samples,the amount of nutrients accumulated in soil layer (0～60 cm) of sharptooth oak stands,the total biomass of the stands and their contents of accumulated nutrients,and the amount of litter and its contents of accumulated nutrients in southern slope of Mt.Qinling were calculated.To a certain extent,the biomass and the nutrient accumulation of the stands were increased with stand densities and stand ages from thin to high or from young to old,similar to the utilization efficiency of the stands to soil nutrient elements and the trunk canopy ratio.The tree composition of the stands much more influenced nutrient accumulation contents than the biomass.The more broad leaved tree of species composition, the higher nutrient accumulation contents of stands.In the same region biomass and its nutrient contents of the stands with similar site factors and stand factors had not remarkably difference among different forest types,but had a difference among various forest types and species composition.In different region,biomass and its nutrient contents of the stands with similar site factors and stand factors had a difference with the sequence of south slope>north slope,middle section>east section or west section.The utilization efficiency of soil nutrient elements by the stands was decreased from lower to higher elevation,from the south to north slope,from middle to east and west section.

Species structure of natural secondary forest in the Wudaohe farm

HUANG Qingfeng, KANG Xingang

2002, (5):  519-522. 

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The analysis of soil thickness and slope gradient in natural secondary forest of the Wudaohe forest farm showed that the area of the secondary forest whose soil thickness was lower than30 cm and slope gradient was higher than25? was 2390.1hm²,covering83.5% of its total area, while the area with soil thickness of higher than or equal to 30cm and slope gradient of lower than or equal to 25? was only 474.2hm², covering16.5% of the total.It is suggested that the secondary forest is ecologically fragile,and this forest farm should develop a mulriple forest including waterhead protection forest,lumber stand and economic forest.It was shown by analytic hierarchy process (AHP) that the suitable ratio of three forest types is 72.7%,18.6%,8.7%,respectively.

Vegetation and its relation with climate conditions near the timberline of Beitai,the Xiaowutai Mts., Northern China

YU Pengtao, LIU Hongyan, CUI Haiting

2002, (5):  523-528. 

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On the basis of field investigations,the timberline range of Beitai,the Xiaowutai Mountains was carved up, and the changes in the makeup and diversity of plants with the altitude were discussed.The results showed that the timberline with gradual changes in the northern slope of Beitai ranged from 2620～2800m.In timberline,herbaceous plants were rich,and the diversity was higher than that in coniferous forest and sub alpine meadow zones.The turnover rates of species were gradually hoisting from the centre of timberline to sub alpine meadow and forest zones,and highest at the edge of timberline. Betula,Picea meyreri and Larix principis-ruprechtii species were the ecological indicator for research on environmental changes.Climate indication significance of these arbor species distributed in and near the timberline was also discussed.

Evaluation on degradation of Karst forest community and human disturbance

YU Lifei, ZHU Shouqian, YE Jingzhong, WEI Luming, CHEN Zhengren

2002, (5):  529-532. 

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Fire,reclamation,herd,and cut led to degradation of Karst forest in Guizhou Province.Five indexes as height,dominance,percentage of asexual individual,biomass,and percentage of shade tolerant for evaluating community degradation were selected.Degraded communities were divided into six degraded grades (A～F).Community structure and function fluctuated normally in climax (A) under nature force or light human disturbance.While effect of disturbance was preponderated over the range of community fluctuation,climax community degraded evidently,and degraded degree of communities increased gradually.Degraded grades of communities were consistent to succession stages of degraded community.In degraded process,the key factor was decrease of biomass and shade tolerant species.Degraded communities due to fire,herd,and reclamation were distributed in grades C～F,and degraded community due to cut was in grades B～C. Amount of asexual individual was influenced by disturbance type,and the amount in degraded communities due to fire and cut was more than that due to reclamation and herd.Degraded degree of different disturbed community was in order of cut community<cleared community<herded community<fired community.

Dynamic characteristics of nutrient elements in Castanea henryi plantation at beginning of fructification and its simulation

CHEN Hui, HE Fang

2002, (5):  533-538. 

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The dynamic variation of nutrient elements in Castanea henryi plantation was analysed and simulated by means of a system analysis,and the models of four compartments including aboveground,root,soil and litter were constructed. Evaluation on the nutrient pools of N,P,K,Ca and Mg in the four compartments at the beginning of fructification showed that soil compartment had highest content of N,P,Kand Ca which was up to 311.47,11.64,218.90 and 87.56 kg穐m^-2,respectively.The highest Mg occurred in litter compartment, up to 7.563 kg穐m^-2.Based on the compartment model,the fluxes and rates of the five nutrient elements between the compartments were calculated,and their changing trends in compartments in5 years were forecasted.The results showed that the most suitable amount of annually compensating the five elements was 20(N),8(P),5(K),10(Ca) and 5(Mg) kg穐m^-2,respectively.This nutrient compensation promoted the nutrient flows,and normalised the growth and metabolism of the tree.The research could provide with important basic data for nutrient management of this type of plantation at this stage.

Effect of returning corn straw into soil on soil fertility

WU Zhijie, ZHANG Haijun, XU Guangshan, ZHANG Yuhua, LIU Chunping

2002, (5):  539-542. 

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Three year field micro plot experiment was conducted to study the effect of applying corn root stubble, corn straw, and the ordure of cattle fed with corn straw to improve soil fertility in northern Liaoning province. The results showed that chemical fertilizers could significantly increase the corn production, while organic fertilizers mainly improved the soil physical and chemical properties so as to increase soil fertility.In comparison with no fertilizer treatment, combination of chemical fertilizers and organic materials could increase soil organic matter by 3.06%～27.78%.The increments of soil organic matter by using different organic materials were in order of 100% corn straw > 50% corn straw > mixture of cattle ordure and soil > cattle ordure > 33% corn straw > corn root stubble.For maintaining and increasing soil organic matter, corn straw was better than mixture of cattle ordure and soil, and secondly better than cattle ordure if they contained the same carbon content.In addition, comparing with applying chemical fertilizers only, combination of chemical fertilizers and organic materials increased soil labile oxidization organic matter by 10.91%～20.67%, increased extractable humic acid by 1.43%～14.28%, raised slack/stable ratio of bonded humus by 0.07～019, and raised HA/FAratio by 0.07～024. Meanwhile, this combination improved the soil nutrient status of N, P, and K, and the status of soil moisture and porosity, which demonstrated the increase of activity of soil organic matter and the improvement of soil fertility.So directly adding straw into soil without removing after harvest in autumn should be actively recommended, and the amount of corn straw added into soil should be 30 to 50 percent of the total production of corn straw.

Quantification of dry matter accumulation and distribution among different organs of winter wheat

QIAO Yuhui, YU Zhenrong, P. M. Driessen

2002, (5):  543-546. 

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Based on the field experimental data, dry matter accumulation and distribution among different organs of winter wheat were studied to modify the dry matter distribution of the winter wheat growth model. The calculating method of distribution and transition coefficient was introduced, and a function table between distribution coefficient and relative development stage was established. Meanwhile, the model was verified based on the experimental data, and the result was reasonable.

Effects of drought, CO₂ concentration and temperature increasing on photosynthesis rate, evapotranspiration, and water use efficiency of spring wheat

LIAO Jianxiong, WANG Genxuan

2002, (5):  547-550. 

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The effects of drought, CO₂ concentration and temperature increasing on development period, photosynthesis rate (P_n), evapotranspiration (ET), and water use efficiency of spring wheat were investigated. The results showed that elevated CO₂ concentration (550, 700μmol·mol^-1 ) could lengthen heading ripening period, but high temperature (average diurnal temperature increase 4.8℃), which made heading ripening period shorten and speeded the seedling under treatment of both high CO₂ concentration and high temperature, affected growing period more than high CO₂ concentration. The combined effects of elevated CO₂ concentration and temperature enhanced P_n, stomatal resistance (r), leaf water use efficiency (WUEl), and whole canopy water use efficiency (WUE), while transpiration rate (E) were not significantly affected. The effects on ETdepended on soil moisture. High CO₂ concentration and high temperature enhanced ETunder high (75%～85% field water capacity)and middle(55%～65% field water capacity)soil moisture, but decrease ETunder low soil moisture (35%～45% field water capacity).

Energy balance,water use efficiency and surface resistance in a maize fiel

MO Xingguo, LIU Suxia, LIN Zhonghui

2002, (5):  551-554. 

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The characteristics of land surface/air energy translation was analysed on the basis of the observation data collected over a maize field in the North China Plain.The results indicated that the energy balance processes of land surface were greatly affected by the features of underlying face.Latent heat fluxes were the main component of land surface/air energy exchanges.Daily sensible heat fluxes were turned to be negative in the late growth period of maize.Among factors regulating surface energy translation,bulk canopy resistance was seasonally changed with high values in the early and late stage and with low value in the mid stage,and the lowest value of 25 s穖^-1.This trend was closely related to soil cover fraction and leaf senescence condition.Water use efficiency (WUE) was not changed with evapotranspiration.The low WUEin the early stage means that the energy resources were not fully utilised, and the high WUEin the late stage means that enough soil water content was the key for high and stable yield

Bioavailability of exotic zinc and cadmium in purple soil

ZHU Bo, QING Changle, MU Shusen

2002, (5):  555-558. 

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Correlation analysis between seven forms and available amounts (extracted by DTPA) of Zn and Cd, and their path analysis from soil to lettuce ( Lactuca sativ L.)were conducted to evaluate bioavailability of zinc and cadmium and their contributions to the plant.The results showed that exchangeable Zn and Cd were significantly correlated to available Zn and Cd ( r=0.954 and 0.953) at significance level of 0.01,and path coefficients of exotic Zn and Cd to tissue Zn and Cd were 1.267 and 1.168 respectively,indicating the high bioavailability of exchangeable Zn and Cd in purple soil.Exotic Zn and Cd made the most contribution to the plant, while the path chain coefficients of CAB Zn, MnO Zn, and Cd to the plant by indirect action of exchangeable forms were 0.856,0.592,0.723,respectively,showing that they may make some other contributions to tissue Zn and Cd through exchangeable forms.Therefore, exchangeable Zn and Cd are not only highest available,but also are bioavailable bridges and main paths from purple soil to the plant

Chemical depletion of cumulative phosphorus in soils

ZHENG Chunrong, CHEN Huaiman, ZHOU Dongmei, TU Cong, QIN Shengwu, GU Yichu

2002, (5):  559-563. 

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Cumulative phosphorus was defined as the phosphorus which was unavailable for plants and accumulated in soils fertilizer application. In this paper, chemical depletion of cumulative phosphorus in soils was studied by methods of batch equilibrium, kinetic, and anionic exchange resin membrane. The results showed that desorption amount of cumulative Pincreased with time increasing, and the desorption process was consonant with second order kinetic equation. Release rate of Pin different treatments was in order of PK>NPK>NK. The amount and rate of Preleased from red soil were higher than those of Fluvio aquic soil. Desorbed Pwas significantly correlated with soil available Pand Puptake by Plant. The maximum utilization of cumulative Pin soils was about 45% of total phosphorus.

Dynamic tendency of arid oasis under the influence of water resources decreaseA case study of Ejina oasis in Heihe River Basin

WANG Genxu, CHENG Guodong, SHEN Yongping

2002, (5):  564-568. 

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The runoff changes of arid inland river seriously influenced on the formations and changes of oasis in the lower reach. By the oasis patches dynamic modeling, the vegetation water interrelated analysis, and the estimation of water demand by the ecological system, the dynamic tendency of the Ejina oasis in the lower reach of Heihe River Basin under difference water resources allocating were studied. The results showed that the lowest water demanded for preserving the present oasis area was about 5.7×10⁸m³ based on rational usage of the water resources. Considering the water demand of people and livestock, and the water lose in the water transport process, the incoming runoff through the Langxinshan section should be about 6.0×10⁸m³ to preserve the present oasis area before 2015. To regain the oasis area to the level at the primary of 1980s, the demand incoming runoff should be about 8.9×10⁸m³, and the runoff through the Zhengyixia section should be 10.9×10⁸～13.1×10⁸m³.

Induction of sesquiterpene cyclase gene expression and antioxidant enzyems regulated by exongenous salicylic acid in leaves of Capsicum annuum

HE Shuilin, LIN Wenxiong, CHEN Rukai

2002, (5):  569-572. 

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An analysis of the induction of sesquiterpene cyclase gene expression and antioxidant enzymes in Capsicum annuum by exongenous salicylic acid (SA) pointed out that the sesquiterpene cyclase gene expression in detached pepper leaves was induced by 0.5～4mmol·L^-1 of exongenous SA,whereas the enzyme activity and accumulation of cyclase mRNAwere much lower,and it took a longer time (36h) for the gene to be induced to express after SAtreatment,comparing to other elicitors such as UVand fungi treatment.The activities of SODand PODwere enhanced,while the CATactivity was inhibited to some degree. Consequently,H₂O₂ content was increased in SAtreated pepper leaves.H₂O₂ accumulation was related to the integrated influences from antioxidant enzymes.

Comparison of leaf tissue turnover for Leymus chinensis and Phragmites communis after grazing

LIU Ying, WANG Deli, WANG Xu, BA Lei, SUN Wei

2002, (5):  573-576. 

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Leaf tissue turnover of Leymus chinensis and Phragmites communis after grazing was studied by application of theory and method of tissue turnover in this paper. The results showed that the number of living leaf of P. communis was larger than that of L.chinensis, but the length of living leaf of L. chinensis was larger than that of P. communis during the whole growth period. Both of the leaf appearance rate and the leaf elongation rate of L. chinensis and P. communis were largest at first, and then they decreased gradually. The rate of leaf wither and leaf senescence were in the converse trend. The leaf lifespan of P. communis was shorter than that of L.chinensis. The velocity of leaf tissue turnover of P. communis was faster than that of L. chinensis. There would be a great loss if the leaf tissue of L. chinensis were not used in time. The quality of grasslands could be improved by different utilization ways and periods.

Effect of light on the growth and stem flowering rate of mat rush

SHEN Weiqi, Zhang Guoping, Gui Wenguang

2002, (5):  577-580. 

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Stem length and whether it flowered are two key elements for mat rush quality. The results indicated that different photoperiod and light intensity significantly affected these two ones. In the early growing stage, day extension significantly increased stem flowering rate, lower light intensity by shading reduced the number of tillers, stem length, stem flowering rate and the number of florets per cyme. In the middle and late growing stage, shading within some degree could increase stem length and reduced stem flowering rate. It is suggested that light was one of important ecological factors to result in flowering transition and to affect the quality of mat rush.

Effects of habitat fragmentation on nesting site selection of red-crowned crane

WAN Dongmei, GAO Wei, WANG Qiuyu, WANG Haitao, LIU Mingyu

2002, (5):  581-584. 

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During April and May of 1985,1995 and 1998, red crowned crane's nesting and variation of breeding population quantities in Shuangtaihekou National Natural Reserve in Liaoning,and also the habitat fragmentation there were investigated. Associated with previous data of the reserve, red crowned crane's nesting habitat had been seriously fragmentated into 91 patches from one integrated reed wetland.The area of the smallest patch was 0.37km²,and the minimum distance of two nests was 304m.Compared with records of previous data,the minimum area of nesting habitat reduced by 0.72km².However,the breeding population quantities of red crowned crane had maintained at about 30 pairs for a long period.The red crowned crane adapted to the changed environment by the ecological adaptation strategy of reducing area of nesting habitat.

Evaluation on the impacts of environmental changes and Three-Gorge Engineering on the population of Yangtze voles (Microtus forits) in the Dongting Lake region

ZOU Shaolin, GUO Cong, LIU Xinping

2002, (5):  585-588. 

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The relationships between the populaton of Yangtze voles ( Microtus fortis ) and the evolvement of the Dongting Lake beaches were analyzed based on historical data,and the impacts of the Three Gorge Engineering on beach environment and water level of the lake were assessed according to the regulation scheme on downward discharge flux of the Three Gorge dam.The results indicated that the population of the voles has been increasing since 1950's,owing to the continuous enlargement of the lake beach and prolonging successional emergence of the beach.The emergence date of the beach in Autumn would be earlier,its emergence area would be going up,the population of the voles would be also expanded at the initial post construction stage,which would still increase with the continuous expansion of beach area in a middle and long period after the establishment of the dam.More voles would thus move to the farmland,and heavily harm crops.

Relationship between rare earth accumulation and rape sclerotiniose

ZHANG Jian, CHENG Heyuan, JIN Wangzhi, LI Guoliang, ZHANG Zili

2002, (5):  589-592. 

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Field plot experiment with long term application of rare earth fertilizers showed that 0.5～10% of adsorption capactiy and 0.6kg·hm^-2 of rare earth application had no remarkable effect on natural incidence of rape sclerotiniose,ratio of diseased plants,natural disease index,expanding rate of diseased spots,yield of single plant,and 1000 seed weight.

Relationship between population dynamic of freshwater leech Whitmania laevis and chemical factors of water

TAN Enguang, PAN Zhigang, HUANG Liying

2002, (5):  593-595. 

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The population size of freshwater leech Whitmania laevis had been observed every month in Guangzhou kaleyard slot from 1994 to 1998, and ten chemical factors of water were measured.The relationship between the population dynamic of W. laevis and chemical factors was studied by stepwise regression analysis method.The results showed that the population size dynamic of W. laevis was different every year.The maximum of population size appeared in April,May, and June,and the total population size of three months was accounted for 57.14～71.18% of whole year.The major chemical factors that effected on the annual population size were different every year,and the factors included pHvalue,PO₄^3-,Na⁺,Ca²⁺,and Mg²⁺.Fe³⁺ was the chief chemical factor effecting on population size during the 5 years observation.The behavior of leech W. laevis was also described in this paper.

Effects of copper mine tailings on seed germination and seedling growth of five legumes species

LIU Dengyi, TIAN Shengni, YANG Shiyong, XIE Jianchun

2002, (5):  596-600. 

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Through solution culture and soil culture experiments,effects of Tongling copper mine tailings on seed germination and seeding growth of five legumes species were studied in this paper.The results showed that the seeds of five legumes species could germinate in the normal and acidified tailings extracted solution,but germination percentage was lower than that under control.It indicated that tailings extracted solution had inhibition effect on seed germination,however,acidified tailings extracted solution promoted absorbing water of the seeds in early stage.In five amelioration substrates between tailings and soils,the tailings also inhibited seed germination of the five species.No dead seedlings of Glycine max, Phaseolus angularis, P.calacaratus were found within 70 days.

Potential of purifying SO₂ of main tree species and their planting quota in Shenyang area

HAN Yang, LI Zhenzhen, LIU Rongkun

2002, (5):  601-604. 

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The total potential of purifying SO₂ of main tree species was studied by using the combination of field measurement and fumigation experiment in this paper.The integrated value of purifying SO₂ including total bimass,absorption intensity of SO₂,and absorption transformation periods of sulfur by trees was 4.39?10⁶ kg,which was accouted for 3.66% of total sulfur released per year in Shenyang.It indicated that the maximum daily potential of purifying SO₂ of trees might be 12.19kg穔m^-2.Supposed that the average annual absorption capacity for sulfur of tress in Shenyang was 0.70 kg per tree and the average annual absorption capacity for sulfur of broad leaved trees was 1.35kg穞ree^-1,88.88 million broad leaved trees would be required to purify the annual released SO₂ thoroughly.This number was equivalent to 12.9 times of existing trees.On the conditions of strengthening environmental protection and decreasing 20% of annual released sulfur,if the broad leaved trees was double of the present number,SO₂ content in air might be below 0.06 mg穖^-3 and Shenyang would become a standardizing city with clear air.

On forest ecosystem health and its evaluation

CHEN Gao, DAI Limin, FAN Zhuhua, WANG Qingli

2002, (5):  605-610. 

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Definition and connotation of forest ecosystem health were introduced, and existing ideas and methods of health evaluation were analyzed in this paper.Furthermore, forest ecosystem health was discussed from the aspects of the management objective approach, ecosystem approach, and integration approach. Widespread application of ecological indicators is the main means of evaluation on forest ecosystem health at present, and some material forest health evaluation methods, especially EMAPand FHM, were introduced and summarized to impel the relative researches in China.

A review on the water physiological characteristics of Tamarix and its prospect

ZENG Fanjiang, ZHANG Ximing, Li Xiaoming

2002, (5):  611-614. 

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It is very important to study and grasp the water physiological characteristics of Tamarix in order to use properly and scientifically manage it. Based on the multiply studies on the water physiological characteristics of Tamarix (P Vcurves,predawn water potential and water potential daily course and transpiration rate) for many years, a preliminary comment was given on the experimental methods used at home and abroad. The aims of this paper is to understand the ecological characteristics of Tamarix as fast as possible and provide theoretical bases for the restoration and re establishment of Tamarix in the arid and semi arid region.

Spatial heterogeneity and forest regeneration

HAN Youzhi, WANG Zhengquan

2002, (5):  615-619. 

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The research on spatial heterogeneity is meaningful for forest regeneration dynamics,which is a critical part in the forest ecosystem dynamics.Traditionally,forestry scientists are mainly concentrated their attention to the studies on the process of regeneration.However forests are spatiotemporal heterogeneous.In regeneration,there exists an ecological dynamic process at temporal scale, but also a heterogeneous pattern at spatial scale.Almost of the factors influencing forest regeneration,including both botic and abotic environment,both natural and human disturbances,and both characteristics of tree species and response of tree species to different disturbance agents,are spatially heterogeneous.Discussion on spatial heterogeneity and its effect on regeneration is indispensable for the understanding of the pattern,process and mechanism of forest regeneration.Main research contents and viewpoints of spatial heterogeneity in forest regeneration were summarised on the basis of available literature,and sources of spatial heterogeneity in the process of regeneration were analysed.The response of species to spatial heterogeneity,small scale spatial heterogeneity and regeneration dynamics,spatial heterogeneity of lights in stand and regeneration pattern,and correlative relationships between the scales of soil heterogeneity and regeneration heterogeneity were reviewed.

Advances in the ecological risk management of pollution point sources of toxicants in aquatic environment

SHANG Huihua, JIN Hongjun, CUI Yuxia

2002, (5):  620-624. 

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Progress in this field in developed countries and China was reviewed and the prospects were also presented in this paper. Based on the water quality standards and discharge standards,the chemical-specific approach in common use could not effectively control complex discharges containing toxic organics. Therefore, applying this traditional approach only was not a valuable measure. Toxicity based approach could be used at the same time to supply the gap for the control of complex discharges containing toxic organics effectively based on the requirements of ecological risk management. Toxicity identification evaluation (TIE) for identifying the key toxicants causing the effluent ecotoxicity was a core of the ecological risk management of point sources of toxics. The prospects were also described for the development of TIEmethodology and the application of toxicity based approach to the ecological risk management of point sources of toxicants in aquatic environment in China.

Advances of studies on ecological risk of herbicide atrazine and its determination and remediation

LI Qingbo, HUANG Guohong, WANG Yanhong, LIU Xiaoyi

2002, (5):  625-628. 

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With wide application of chemical such as pesticide in farming, the coming problems of ecological risks and environmental pollution were increasingly serious. Residual material of atrazine was founded in the surface water, underground water, and atmospheric sedimentation, and it resulted in the global ecological influences. For atrazine could exit in soil for a long time and enrich in organism, it would bring about potential threaten on the safety of food. The results from experiments on animal indicated that atrazine had biological activity. So, there is an increasing demand for further studying on its ecological risks. In this paper, some viewpoints of the researches on atrazine were introduced. With the development of analytical techniques, the opportunities were created to study on the ecological risks of atrazine, and people should attach serious importance to the bioremediation techniques.

Application of continuous-flow culture in microecological research

CAO Yusheng

2002, (5):  629-631. 

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The application of continuous flow culture in microbial ecology and its advances were reviewed.Continuous flow culture can be used to build in vitro models simulating ecosystems composed of normal bacteria such as human or animals intestinal and buccal bacteria,to examine the interactions between normal bacteria and pathogens,to investigate the physiological and biochemical traits of bacteria and their metabolic products,and to develop microecological preparations.

Establishment and applications of the spatial database of land resources information in Anshun,Guizhou Province

ZHOU Bin, YANG Bailin, LIN Qinyuan

2002, (5):  632-634. 

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For the purpose of managing and processing land resources and environment information, a spatial database of land information in Anshun City, Guizhou Province, which involved present data and the investigated information by remote sensing, was established under the supporting of PAMAP GIS^TM 4.2. The spatial database could provide the functionality of querying for spatial data and its associated attributes, conversion between the different data formats,mapping the digital terrain, fast and accurate analysis on soil resources, land assessment and management application, and soil erosion risk mapping. The establishment of this spatial database was expected to play an important role in territorial planning, agricultural sustainable development, spatial assessment of ecological environment, and so on.

Benefit of sediment reduction by biological measures in the watershed scale

DONG Cuiyun, HUANG Mingbin, ZHENG Shiqing

2002, (5):  635-637. 

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Based on the measured data and the model of plotted watershed hydrology, the benefit of sediment reduction by biological harnesses of soil and water conservation was studied in the watershed scale. The result indicated that the erosion modulus in Wangdonggou watershed, which were 1869t穔m², 1050t穔m², 383t穔m², and 504t穔m² in the periods of the sixth, seventh, eighth, and ninth five year plans, respectively, were gradually reduced by comprehensive measures. Taken out the effect of rainfall, the sediment reduction by biological measures of soil and water conservation was increased by 24.1% and 22.4% in the periods of eighth and ninth five year plans compared to that in the seventh five year plan.

Effect of agrochemicals and bio-control productions on soil nematode community dynamics

ZHANG Wanmin, DUAN Yuxi, CHEN Lijie, LIANG Chen

2002, (5):  638-640. 

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Dynamics of soil nematode communities amended with agrochemicals and bio control preparations were investigated in a soybean field. The results showed that the frequency of plant non parasitic nematodes were obviously higher in soil amended with bio control preparations (Doufeng 1) than with urea and herbicide, however, that of plant parasitic nematodes exhibited an inverse trend.

Eco-environment and nutrient accumulation of sharptooth oak stands in southern slope of Mt. Qinling

LIU Guangquan, NI Wenjin, LIU Huifang, G. Gravenhorst

2002, (5):  513-518. 

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Based on the date from chemical analysis of 10785 botanical and 1489 edaphic samples,the amount of nutrients accumulated in soil layer (0～60 cm) of sharptooth oak stands,the total biomass of the stands and their contents of accumulated nutrients,and the amount of litter and its contents of accumulated nutrients in southern slope of Mt.Qinling were calculated.To a certain extent,the biomass and the nutrient accumulation of the stands were increased with stand densities and stand ages from thin to high or from young to old,similar to the utilization efficiency of the stands to soil nutrient elements and the trunk canopy ratio.The tree composition of the stands much more influenced nutrient accumulation contents than the biomass.The more broad leaved tree of species composition, the higher nutrient accumulation contents of stands.In the same region biomass and its nutrient contents of the stands with similar site factors and stand factors had not remarkably difference among different forest types,but had a difference among various forest types and species composition.In different region,biomass and its nutrient contents of the stands with similar site factors and stand factors had a difference with the sequence of south slope>north slope,middle section>east section or west section.The utilization efficiency of soil nutrient elements by the stands was decreased from lower to higher elevation,from the south to north slope,from middle to east and west section.

Species structure of natural secondary forest in the Wudaohe farm

HUANG Qingfeng, KANG Xingang

2002, (5):  519-522. 

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The analysis of soil thickness and slope gradient in natural secondary forest of the Wudaohe forest farm showed that the area of the secondary forest whose soil thickness was lower than30 cm and slope gradient was higher than25? was 2390.1hm²,covering83.5% of its total area, while the area with soil thickness of higher than or equal to 30cm and slope gradient of lower than or equal to 25? was only 474.2hm², covering16.5% of the total.It is suggested that the secondary forest is ecologically fragile,and this forest farm should develop a mulriple forest including waterhead protection forest,lumber stand and economic forest.It was shown by analytic hierarchy process (AHP) that the suitable ratio of three forest types is 72.7%,18.6%,8.7%,respectively.

Vegetation and its relation with climate conditions near the timberline of Beitai,the Xiaowutai Mts., Northern China

YU Pengtao, LIU Hongyan, CUI Haiting

2002, (5):  523-528. 

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On the basis of field investigations,the timberline range of Beitai,the Xiaowutai Mountains was carved up, and the changes in the makeup and diversity of plants with the altitude were discussed.The results showed that the timberline with gradual changes in the northern slope of Beitai ranged from 2620～2800m.In timberline,herbaceous plants were rich,and the diversity was higher than that in coniferous forest and sub alpine meadow zones.The turnover rates of species were gradually hoisting from the centre of timberline to sub alpine meadow and forest zones,and highest at the edge of timberline. Betula,Picea meyreri and Larix principis-ruprechtii species were the ecological indicator for research on environmental changes.Climate indication significance of these arbor species distributed in and near the timberline was also discussed.

Evaluation on degradation of Karst forest community and human disturbance

YU Lifei, ZHU Shouqian, YE Jingzhong, WEI Luming, CHEN Zhengren

2002, (5):  529-532. 

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Fire,reclamation,herd,and cut led to degradation of Karst forest in Guizhou Province.Five indexes as height,dominance,percentage of asexual individual,biomass,and percentage of shade tolerant for evaluating community degradation were selected.Degraded communities were divided into six degraded grades (A～F).Community structure and function fluctuated normally in climax (A) under nature force or light human disturbance.While effect of disturbance was preponderated over the range of community fluctuation,climax community degraded evidently,and degraded degree of communities increased gradually.Degraded grades of communities were consistent to succession stages of degraded community.In degraded process,the key factor was decrease of biomass and shade tolerant species.Degraded communities due to fire,herd,and reclamation were distributed in grades C～F,and degraded community due to cut was in grades B～C. Amount of asexual individual was influenced by disturbance type,and the amount in degraded communities due to fire and cut was more than that due to reclamation and herd.Degraded degree of different disturbed community was in order of cut community<cleared community<herded community<fired community.

Dynamic characteristics of nutrient elements in Castanea henryi plantation at beginning of fructification and its simulation

CHEN Hui, HE Fang

2002, (5):  533-538. 

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The dynamic variation of nutrient elements in Castanea henryi plantation was analysed and simulated by means of a system analysis,and the models of four compartments including aboveground,root,soil and litter were constructed. Evaluation on the nutrient pools of N,P,K,Ca and Mg in the four compartments at the beginning of fructification showed that soil compartment had highest content of N,P,Kand Ca which was up to 311.47,11.64,218.90 and 87.56 kg穐m^-2,respectively.The highest Mg occurred in litter compartment, up to 7.563 kg穐m^-2.Based on the compartment model,the fluxes and rates of the five nutrient elements between the compartments were calculated,and their changing trends in compartments in5 years were forecasted.The results showed that the most suitable amount of annually compensating the five elements was 20(N),8(P),5(K),10(Ca) and 5(Mg) kg穐m^-2,respectively.This nutrient compensation promoted the nutrient flows,and normalised the growth and metabolism of the tree.The research could provide with important basic data for nutrient management of this type of plantation at this stage.

Effect of returning corn straw into soil on soil fertility

WU Zhijie, ZHANG Haijun, XU Guangshan, ZHANG Yuhua, LIU Chunping

2002, (5):  539-542. 

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Three year field micro plot experiment was conducted to study the effect of applying corn root stubble, corn straw, and the ordure of cattle fed with corn straw to improve soil fertility in northern Liaoning province. The results showed that chemical fertilizers could significantly increase the corn production, while organic fertilizers mainly improved the soil physical and chemical properties so as to increase soil fertility.In comparison with no fertilizer treatment, combination of chemical fertilizers and organic materials could increase soil organic matter by 3.06%～27.78%.The increments of soil organic matter by using different organic materials were in order of 100% corn straw > 50% corn straw > mixture of cattle ordure and soil > cattle ordure > 33% corn straw > corn root stubble.For maintaining and increasing soil organic matter, corn straw was better than mixture of cattle ordure and soil, and secondly better than cattle ordure if they contained the same carbon content.In addition, comparing with applying chemical fertilizers only, combination of chemical fertilizers and organic materials increased soil labile oxidization organic matter by 10.91%～20.67%, increased extractable humic acid by 1.43%～14.28%, raised slack/stable ratio of bonded humus by 0.07～019, and raised HA/FAratio by 0.07～024. Meanwhile, this combination improved the soil nutrient status of N, P, and K, and the status of soil moisture and porosity, which demonstrated the increase of activity of soil organic matter and the improvement of soil fertility.So directly adding straw into soil without removing after harvest in autumn should be actively recommended, and the amount of corn straw added into soil should be 30 to 50 percent of the total production of corn straw.

Quantification of dry matter accumulation and distribution among different organs of winter wheat

QIAO Yuhui, YU Zhenrong, P. M. Driessen

2002, (5):  543-546. 

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Based on the field experimental data, dry matter accumulation and distribution among different organs of winter wheat were studied to modify the dry matter distribution of the winter wheat growth model. The calculating method of distribution and transition coefficient was introduced, and a function table between distribution coefficient and relative development stage was established. Meanwhile, the model was verified based on the experimental data, and the result was reasonable.

Effects of drought, CO₂ concentration and temperature increasing on photosynthesis rate, evapotranspiration, and water use efficiency of spring wheat

LIAO Jianxiong, WANG Genxuan

2002, (5):  547-550. 

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The effects of drought, CO₂ concentration and temperature increasing on development period, photosynthesis rate (P_n), evapotranspiration (ET), and water use efficiency of spring wheat were investigated. The results showed that elevated CO₂ concentration (550, 700μmol·mol^-1 ) could lengthen heading ripening period, but high temperature (average diurnal temperature increase 4.8℃), which made heading ripening period shorten and speeded the seedling under treatment of both high CO₂ concentration and high temperature, affected growing period more than high CO₂ concentration. The combined effects of elevated CO₂ concentration and temperature enhanced P_n, stomatal resistance (r), leaf water use efficiency (WUEl), and whole canopy water use efficiency (WUE), while transpiration rate (E) were not significantly affected. The effects on ETdepended on soil moisture. High CO₂ concentration and high temperature enhanced ETunder high (75%～85% field water capacity)and middle(55%～65% field water capacity)soil moisture, but decrease ETunder low soil moisture (35%～45% field water capacity).

Energy balance,water use efficiency and surface resistance in a maize fiel

MO Xingguo, LIU Suxia, LIN Zhonghui

2002, (5):  551-554. 

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The characteristics of land surface/air energy translation was analysed on the basis of the observation data collected over a maize field in the North China Plain.The results indicated that the energy balance processes of land surface were greatly affected by the features of underlying face.Latent heat fluxes were the main component of land surface/air energy exchanges.Daily sensible heat fluxes were turned to be negative in the late growth period of maize.Among factors regulating surface energy translation,bulk canopy resistance was seasonally changed with high values in the early and late stage and with low value in the mid stage,and the lowest value of 25 s穖^-1.This trend was closely related to soil cover fraction and leaf senescence condition.Water use efficiency (WUE) was not changed with evapotranspiration.The low WUEin the early stage means that the energy resources were not fully utilised, and the high WUEin the late stage means that enough soil water content was the key for high and stable yield

Bioavailability of exotic zinc and cadmium in purple soil

ZHU Bo, QING Changle, MU Shusen

2002, (5):  555-558. 

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Correlation analysis between seven forms and available amounts (extracted by DTPA) of Zn and Cd, and their path analysis from soil to lettuce ( Lactuca sativ L.)were conducted to evaluate bioavailability of zinc and cadmium and their contributions to the plant.The results showed that exchangeable Zn and Cd were significantly correlated to available Zn and Cd ( r=0.954 and 0.953) at significance level of 0.01,and path coefficients of exotic Zn and Cd to tissue Zn and Cd were 1.267 and 1.168 respectively,indicating the high bioavailability of exchangeable Zn and Cd in purple soil.Exotic Zn and Cd made the most contribution to the plant, while the path chain coefficients of CAB Zn, MnO Zn, and Cd to the plant by indirect action of exchangeable forms were 0.856,0.592,0.723,respectively,showing that they may make some other contributions to tissue Zn and Cd through exchangeable forms.Therefore, exchangeable Zn and Cd are not only highest available,but also are bioavailable bridges and main paths from purple soil to the plant

Chemical depletion of cumulative phosphorus in soils

ZHENG Chunrong, CHEN Huaiman, ZHOU Dongmei, TU Cong, QIN Shengwu, GU Yichu

2002, (5):  559-563. 

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Cumulative phosphorus was defined as the phosphorus which was unavailable for plants and accumulated in soils fertilizer application. In this paper, chemical depletion of cumulative phosphorus in soils was studied by methods of batch equilibrium, kinetic, and anionic exchange resin membrane. The results showed that desorption amount of cumulative Pincreased with time increasing, and the desorption process was consonant with second order kinetic equation. Release rate of Pin different treatments was in order of PK>NPK>NK. The amount and rate of Preleased from red soil were higher than those of Fluvio aquic soil. Desorbed Pwas significantly correlated with soil available Pand Puptake by Plant. The maximum utilization of cumulative Pin soils was about 45% of total phosphorus.

Dynamic tendency of arid oasis under the influence of water resources decreaseA case study of Ejina oasis in Heihe River Basin

WANG Genxu, CHENG Guodong, SHEN Yongping

2002, (5):  564-568. 

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The runoff changes of arid inland river seriously influenced on the formations and changes of oasis in the lower reach. By the oasis patches dynamic modeling, the vegetation water interrelated analysis, and the estimation of water demand by the ecological system, the dynamic tendency of the Ejina oasis in the lower reach of Heihe River Basin under difference water resources allocating were studied. The results showed that the lowest water demanded for preserving the present oasis area was about 5.7×10⁸m³ based on rational usage of the water resources. Considering the water demand of people and livestock, and the water lose in the water transport process, the incoming runoff through the Langxinshan section should be about 6.0×10⁸m³ to preserve the present oasis area before 2015. To regain the oasis area to the level at the primary of 1980s, the demand incoming runoff should be about 8.9×10⁸m³, and the runoff through the Zhengyixia section should be 10.9×10⁸～13.1×10⁸m³.

Induction of sesquiterpene cyclase gene expression and antioxidant enzyems regulated by exongenous salicylic acid in leaves of Capsicum annuum

HE Shuilin, LIN Wenxiong, CHEN Rukai

2002, (5):  569-572. 

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An analysis of the induction of sesquiterpene cyclase gene expression and antioxidant enzymes in Capsicum annuum by exongenous salicylic acid (SA) pointed out that the sesquiterpene cyclase gene expression in detached pepper leaves was induced by 0.5～4mmol·L^-1 of exongenous SA,whereas the enzyme activity and accumulation of cyclase mRNAwere much lower,and it took a longer time (36h) for the gene to be induced to express after SAtreatment,comparing to other elicitors such as UVand fungi treatment.The activities of SODand PODwere enhanced,while the CATactivity was inhibited to some degree. Consequently,H₂O₂ content was increased in SAtreated pepper leaves.H₂O₂ accumulation was related to the integrated influences from antioxidant enzymes.

Comparison of leaf tissue turnover for Leymus chinensis and Phragmites communis after grazing

LIU Ying, WANG Deli, WANG Xu, BA Lei, SUN Wei

2002, (5):  573-576. 

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Leaf tissue turnover of Leymus chinensis and Phragmites communis after grazing was studied by application of theory and method of tissue turnover in this paper. The results showed that the number of living leaf of P. communis was larger than that of L.chinensis, but the length of living leaf of L. chinensis was larger than that of P. communis during the whole growth period. Both of the leaf appearance rate and the leaf elongation rate of L. chinensis and P. communis were largest at first, and then they decreased gradually. The rate of leaf wither and leaf senescence were in the converse trend. The leaf lifespan of P. communis was shorter than that of L.chinensis. The velocity of leaf tissue turnover of P. communis was faster than that of L. chinensis. There would be a great loss if the leaf tissue of L. chinensis were not used in time. The quality of grasslands could be improved by different utilization ways and periods.

Effect of light on the growth and stem flowering rate of mat rush

SHEN Weiqi, Zhang Guoping, Gui Wenguang

2002, (5):  577-580. 

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Stem length and whether it flowered are two key elements for mat rush quality. The results indicated that different photoperiod and light intensity significantly affected these two ones. In the early growing stage, day extension significantly increased stem flowering rate, lower light intensity by shading reduced the number of tillers, stem length, stem flowering rate and the number of florets per cyme. In the middle and late growing stage, shading within some degree could increase stem length and reduced stem flowering rate. It is suggested that light was one of important ecological factors to result in flowering transition and to affect the quality of mat rush.

Effects of habitat fragmentation on nesting site selection of red-crowned crane

WAN Dongmei, GAO Wei, WANG Qiuyu, WANG Haitao, LIU Mingyu

2002, (5):  581-584. 

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During April and May of 1985,1995 and 1998, red crowned crane's nesting and variation of breeding population quantities in Shuangtaihekou National Natural Reserve in Liaoning,and also the habitat fragmentation there were investigated. Associated with previous data of the reserve, red crowned crane's nesting habitat had been seriously fragmentated into 91 patches from one integrated reed wetland.The area of the smallest patch was 0.37km²,and the minimum distance of two nests was 304m.Compared with records of previous data,the minimum area of nesting habitat reduced by 0.72km².However,the breeding population quantities of red crowned crane had maintained at about 30 pairs for a long period.The red crowned crane adapted to the changed environment by the ecological adaptation strategy of reducing area of nesting habitat.

Evaluation on the impacts of environmental changes and Three-Gorge Engineering on the population of Yangtze voles (Microtus forits) in the Dongting Lake region

ZOU Shaolin, GUO Cong, LIU Xinping

2002, (5):  585-588. 

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The relationships between the populaton of Yangtze voles ( Microtus fortis ) and the evolvement of the Dongting Lake beaches were analyzed based on historical data,and the impacts of the Three Gorge Engineering on beach environment and water level of the lake were assessed according to the regulation scheme on downward discharge flux of the Three Gorge dam.The results indicated that the population of the voles has been increasing since 1950's,owing to the continuous enlargement of the lake beach and prolonging successional emergence of the beach.The emergence date of the beach in Autumn would be earlier,its emergence area would be going up,the population of the voles would be also expanded at the initial post construction stage,which would still increase with the continuous expansion of beach area in a middle and long period after the establishment of the dam.More voles would thus move to the farmland,and heavily harm crops.

Relationship between rare earth accumulation and rape sclerotiniose

ZHANG Jian, CHENG Heyuan, JIN Wangzhi, LI Guoliang, ZHANG Zili

2002, (5):  589-592. 

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Field plot experiment with long term application of rare earth fertilizers showed that 0.5～10% of adsorption capactiy and 0.6kg·hm^-2 of rare earth application had no remarkable effect on natural incidence of rape sclerotiniose,ratio of diseased plants,natural disease index,expanding rate of diseased spots,yield of single plant,and 1000 seed weight.

Relationship between population dynamic of freshwater leech Whitmania laevis and chemical factors of water

TAN Enguang, PAN Zhigang, HUANG Liying

2002, (5):  593-595. 

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The population size of freshwater leech Whitmania laevis had been observed every month in Guangzhou kaleyard slot from 1994 to 1998, and ten chemical factors of water were measured.The relationship between the population dynamic of W. laevis and chemical factors was studied by stepwise regression analysis method.The results showed that the population size dynamic of W. laevis was different every year.The maximum of population size appeared in April,May, and June,and the total population size of three months was accounted for 57.14～71.18% of whole year.The major chemical factors that effected on the annual population size were different every year,and the factors included pHvalue,PO₄^3-,Na⁺,Ca²⁺,and Mg²⁺.Fe³⁺ was the chief chemical factor effecting on population size during the 5 years observation.The behavior of leech W. laevis was also described in this paper.

Effects of copper mine tailings on seed germination and seedling growth of five legumes species

LIU Dengyi, TIAN Shengni, YANG Shiyong, XIE Jianchun

2002, (5):  596-600. 

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Through solution culture and soil culture experiments,effects of Tongling copper mine tailings on seed germination and seeding growth of five legumes species were studied in this paper.The results showed that the seeds of five legumes species could germinate in the normal and acidified tailings extracted solution,but germination percentage was lower than that under control.It indicated that tailings extracted solution had inhibition effect on seed germination,however,acidified tailings extracted solution promoted absorbing water of the seeds in early stage.In five amelioration substrates between tailings and soils,the tailings also inhibited seed germination of the five species.No dead seedlings of Glycine max, Phaseolus angularis, P.calacaratus were found within 70 days.

Potential of purifying SO₂ of main tree species and their planting quota in Shenyang area

HAN Yang, LI Zhenzhen, LIU Rongkun

2002, (5):  601-604. 

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The total potential of purifying SO₂ of main tree species was studied by using the combination of field measurement and fumigation experiment in this paper.The integrated value of purifying SO₂ including total bimass,absorption intensity of SO₂,and absorption transformation periods of sulfur by trees was 4.39?10⁶ kg,which was accouted for 3.66% of total sulfur released per year in Shenyang.It indicated that the maximum daily potential of purifying SO₂ of trees might be 12.19kg穔m^-2.Supposed that the average annual absorption capacity for sulfur of tress in Shenyang was 0.70 kg per tree and the average annual absorption capacity for sulfur of broad leaved trees was 1.35kg穞ree^-1,88.88 million broad leaved trees would be required to purify the annual released SO₂ thoroughly.This number was equivalent to 12.9 times of existing trees.On the conditions of strengthening environmental protection and decreasing 20% of annual released sulfur,if the broad leaved trees was double of the present number,SO₂ content in air might be below 0.06 mg穖^-3 and Shenyang would become a standardizing city with clear air.

On forest ecosystem health and its evaluation

CHEN Gao, DAI Limin, FAN Zhuhua, WANG Qingli

2002, (5):  605-610. 

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Definition and connotation of forest ecosystem health were introduced, and existing ideas and methods of health evaluation were analyzed in this paper.Furthermore, forest ecosystem health was discussed from the aspects of the management objective approach, ecosystem approach, and integration approach. Widespread application of ecological indicators is the main means of evaluation on forest ecosystem health at present, and some material forest health evaluation methods, especially EMAPand FHM, were introduced and summarized to impel the relative researches in China.

A review on the water physiological characteristics of Tamarix and its prospect

ZENG Fanjiang, ZHANG Ximing, Li Xiaoming

2002, (5):  611-614. 

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It is very important to study and grasp the water physiological characteristics of Tamarix in order to use properly and scientifically manage it. Based on the multiply studies on the water physiological characteristics of Tamarix (P Vcurves,predawn water potential and water potential daily course and transpiration rate) for many years, a preliminary comment was given on the experimental methods used at home and abroad. The aims of this paper is to understand the ecological characteristics of Tamarix as fast as possible and provide theoretical bases for the restoration and re establishment of Tamarix in the arid and semi arid region.

Spatial heterogeneity and forest regeneration

HAN Youzhi, WANG Zhengquan

2002, (5):  615-619. 

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The research on spatial heterogeneity is meaningful for forest regeneration dynamics,which is a critical part in the forest ecosystem dynamics.Traditionally,forestry scientists are mainly concentrated their attention to the studies on the process of regeneration.However forests are spatiotemporal heterogeneous.In regeneration,there exists an ecological dynamic process at temporal scale, but also a heterogeneous pattern at spatial scale.Almost of the factors influencing forest regeneration,including both botic and abotic environment,both natural and human disturbances,and both characteristics of tree species and response of tree species to different disturbance agents,are spatially heterogeneous.Discussion on spatial heterogeneity and its effect on regeneration is indispensable for the understanding of the pattern,process and mechanism of forest regeneration.Main research contents and viewpoints of spatial heterogeneity in forest regeneration were summarised on the basis of available literature,and sources of spatial heterogeneity in the process of regeneration were analysed.The response of species to spatial heterogeneity,small scale spatial heterogeneity and regeneration dynamics,spatial heterogeneity of lights in stand and regeneration pattern,and correlative relationships between the scales of soil heterogeneity and regeneration heterogeneity were reviewed.

Advances in the ecological risk management of pollution point sources of toxicants in aquatic environment

SHANG Huihua, JIN Hongjun, CUI Yuxia

2002, (5):  620-624. 

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Progress in this field in developed countries and China was reviewed and the prospects were also presented in this paper. Based on the water quality standards and discharge standards,the chemical-specific approach in common use could not effectively control complex discharges containing toxic organics. Therefore, applying this traditional approach only was not a valuable measure. Toxicity based approach could be used at the same time to supply the gap for the control of complex discharges containing toxic organics effectively based on the requirements of ecological risk management. Toxicity identification evaluation (TIE) for identifying the key toxicants causing the effluent ecotoxicity was a core of the ecological risk management of point sources of toxics. The prospects were also described for the development of TIEmethodology and the application of toxicity based approach to the ecological risk management of point sources of toxicants in aquatic environment in China.

Advances of studies on ecological risk of herbicide atrazine and its determination and remediation

LI Qingbo, HUANG Guohong, WANG Yanhong, LIU Xiaoyi

2002, (5):  625-628. 

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With wide application of chemical such as pesticide in farming, the coming problems of ecological risks and environmental pollution were increasingly serious. Residual material of atrazine was founded in the surface water, underground water, and atmospheric sedimentation, and it resulted in the global ecological influences. For atrazine could exit in soil for a long time and enrich in organism, it would bring about potential threaten on the safety of food. The results from experiments on animal indicated that atrazine had biological activity. So, there is an increasing demand for further studying on its ecological risks. In this paper, some viewpoints of the researches on atrazine were introduced. With the development of analytical techniques, the opportunities were created to study on the ecological risks of atrazine, and people should attach serious importance to the bioremediation techniques.

Application of continuous-flow culture in microecological research

CAO Yusheng

2002, (5):  629-631. 

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The application of continuous flow culture in microbial ecology and its advances were reviewed.Continuous flow culture can be used to build in vitro models simulating ecosystems composed of normal bacteria such as human or animals intestinal and buccal bacteria,to examine the interactions between normal bacteria and pathogens,to investigate the physiological and biochemical traits of bacteria and their metabolic products,and to develop microecological preparations.

Establishment and applications of the spatial database of land resources information in Anshun,Guizhou Province

ZHOU Bin, YANG Bailin, LIN Qinyuan

2002, (5):  632-634. 

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For the purpose of managing and processing land resources and environment information, a spatial database of land information in Anshun City, Guizhou Province, which involved present data and the investigated information by remote sensing, was established under the supporting of PAMAP GIS^TM 4.2. The spatial database could provide the functionality of querying for spatial data and its associated attributes, conversion between the different data formats,mapping the digital terrain, fast and accurate analysis on soil resources, land assessment and management application, and soil erosion risk mapping. The establishment of this spatial database was expected to play an important role in territorial planning, agricultural sustainable development, spatial assessment of ecological environment, and so on.

Benefit of sediment reduction by biological measures in the watershed scale

DONG Cuiyun, HUANG Mingbin, ZHENG Shiqing

2002, (5):  635-637. 

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Based on the measured data and the model of plotted watershed hydrology, the benefit of sediment reduction by biological harnesses of soil and water conservation was studied in the watershed scale. The result indicated that the erosion modulus in Wangdonggou watershed, which were 1869t穔m², 1050t穔m², 383t穔m², and 504t穔m² in the periods of the sixth, seventh, eighth, and ninth five year plans, respectively, were gradually reduced by comprehensive measures. Taken out the effect of rainfall, the sediment reduction by biological measures of soil and water conservation was increased by 24.1% and 22.4% in the periods of eighth and ninth five year plans compared to that in the seventh five year plan.

Effect of agrochemicals and bio-control productions on soil nematode community dynamics

ZHANG Wanmin, DUAN Yuxi, CHEN Lijie, LIANG Chen

2002, (5):  638-640. 

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Dynamics of soil nematode communities amended with agrochemicals and bio control preparations were investigated in a soybean field. The results showed that the frequency of plant non parasitic nematodes were obviously higher in soil amended with bio control preparations (Doufeng 1) than with urea and herbicide, however, that of plant parasitic nematodes exhibited an inverse trend.