Some conclusions were drawn from plot exper-iments.（1） Average methane ecission flux ,which was single cropping paddies applied with four kinds of biogas pit sediment and only chemical fertilizer separately,was in the range of 0.569-2.188mg/m²·h.There was not singnificant difference between the two treatments.Average methane emission flux ,which was single cropping paddies treated with manures,was 44.18mg/m²·h .The result of the latter was higher than that of the former,it showed that applied biogas pit sediments and chermical fertilizers can reduce obviously menthane emission fluxes from cropping pdddies.（ 2） Peak stage of methane emis-sion fluxe frorn each treatment paddy appeared from tillering stage to early jointing stage,it showed that this was the key peried for controlling the total methane emission from pad-dies.（ 3） The Tnethane emission flux was significantly and pos-itively correlated with the contents of readily mineralizable carbon（RMC）and CH₄-C in the soils and organic fertilizers before flooding,it suggested that RMC was the important fac-tor for forming methane form paddies.（4）There were not ob-vious differences among the rice yields of each treatment paddy.

In this paper we have summarized the mea-sures for the control of methane emissions from paddy fieldand reduction of methane emissions by agricultural tech-niques. The result shows: (1)among the four different kinds of biogas manure applied as basic manure ,methane emission fluxes in three treatments were reduced by 24 -62%,whichwas 11-56% less than the treatment with chemical fertilizer applied only.Owing to one of the biogas manures (i .e. horse blogas manure )was insufficiently composted ,the decrease in methane emission was not significant (2) The alternation ofnitrogen fertilizer such as using ammonium nitrate and ammo-nium sulfate to replace urea as top application,the methane e-mission fluxes was decredxed by 26%and 46%.separately .(3)The intermittent wet-dry irrigation technique from rice tillering stage to early jointing stage can decrease significantly Tnethane emission flux without any effect on rice yield.( 4)Se-mi- arid cultivation technique can obviously inhibite the emis-sion of mehtane in paddy field.

In this paper,many aspects in drinking watersource region,at outskirts of large city,has been studied sys-tematically,suca as the socio-economic development situa-tion,pollution origin ,water quality and hydrologic condition within tidal river network,techniques for pollution treatment,water environment management and so on .On the basis ofthese a comprehensive survey and analysis was made,the ad-vanced computer software and systematic engineering ap-proach were adopted, and the management model for waterenvironment was established. which should meet the demands of given environmental conditions,reach the goal of obtaining the maximum ecological environment benefit.The manege-ment model consists of seven systematic sub-models provides a practical technical system from data collection to controllingcountermeasure,This study resolved the problem of how toharmonize economy development and environmental protec-tion, from the aspects of theory and practice.

Some eco-physiological parameters for Sparti-na alterniflora and S. anglica in salt-marsh ecosystem in Bin-hai County of Jiangsu Province were observed and measured for a year. Rexults showed: maxium aboveground biomass was found in September,with 1714g (dry wt ) /m² and 419g (DW)/m² for S. alterniflora and S .anglica respectively Seasonal pat -terns of chlorophyll exhibited slope"Z" and flat "W" for S .al-terniflora and S .anglica respectively .The assimilation rates of photosynthesis for both species were higher in June than in september .Energy contents of plant material for two Spartina species varied from 12.56kJ/g to 20. 10kJ/g.

The listing of stressed plants checklist and di-vision of conservation sequence is one of the most important issues in plant diversity conservation .In this paper,the evalua-tion and gradation indexes for rare and endangered plants were studied,the method of expert system was introduced and an expert system for evaluating and grading rare and endangeredplants was established.The established expert system can,to acertain extent,simulate human experts’ thinking process .It will be helpful to turn the qualitative division into a combina-tion of qualilative and quantitative division for prior conserva-tion class of stressed plants.so as to make more objective andaccurate evaluation of the extent of stressed plant species andreasonable determination of the conservation level of plant species.

The screened criteria of diverhity,repretesenta-tiveness,rarity,naturalness,suitability of area and both intrin-sic fragility and threat of hurman interference were expounded,compared and analyzed in accordance with the status of naturereserves in China,The reldtively systematic and practical criteria, standards and method of ecological evaluation for naturereserves were established .It can be used in quantitative evalu-ation of the nature reserves in the natural ecosystems . 

In China the trend of environmental pollutionof industrial wastes on rural environment is slowing down tosome extent,but the environmental effects of township andvillage industrial enterprisexare progressively increasing .The trend of continuous rural environmental quality degradation isnot effectively controlled.In order to strengthen the manage-ment of rural environrnental quality,this paper emphatically discussed four principles that should be observed in rural envi-ronmental quality regionalization .Based on the theory of ana-lytical hierarchy process,rural environmental quality regional-ization index system with 28 indexes was presented with re-spect to natural eco-environment ,human exploitation in tensi-ty,and environmental status. This simple and practicable index system can be used in regionalization practice at different lev-els and localities .

In this paper,the models of environmental quality assessment widely applied now have been analysed.On the basis of this,the multi-grade fuzzy comprehensive evalua-tion-grey relational preponderance analysis complex model of environmental quality assessment was established After such model is applied to the comprehensive assessment on the land-scape eco-environmental quality of Huangshan Mountain .some satisfactory results were achieved. 

In this paper,the author made a quantitative study on a spacial pattern of Paulowina-wheat intercropping a-groforestry system wiht the mathematical methods of GreyControl System taking 10 years as a rotation period with dif-ferent spacial density treatments,the author derived a model decision optimum spacial pattern of Paulowina-wheat agro-forestry system ,by using a multi-objective Grey Sitution De-cixion. It is concluded that:(1) with priority given to agricul-tural production,the optimum spacial pattern is 5×40m ;(2)with priortty given to forestry production,the optimum spaLcial pattern is 5×5m and (3) with priority given to agricultural and forestry production,the optimum spacial pattern is 5×20m. 

With the method of analytic hierachy process(AHP),a comprehensive appraisal system for best environ-mental protection practical control techniques was proposed This system has been used in the appraisal of electroplatingwaste water control techniques around Nanjing district.The results inditated that the appraisal results is quite close to the practical. 

The profile of ozone formation was studied in NO₂-air .NO₂-air .NO₂-rice -air .and NO₂-SO₂-rice-air systems in order to clarify the effect of SO₂or/and rice. The average stability concentration of ozone in NO₂-SO₂-air system was about 7%higher than that NO₂ -air system ,and about 14% higher than that in NO₂ -rice-air system.

The pot experirments showed that the distribu-tion of pb,Zn,and Cd in three polluted soils were obviouslydifferent. In ore tailing particle of mine drainage pollut soils ,the majorities of Pb,Zn,and Cd were found to be in residualfraction, But in soil adding heavy Tnetals, most of Pb wasweak acid extractable or bound to organic matter and the ma-jority of Zn or Cd was exchangable,Soybean seedlings biocon-centrate Zn or Cd more powerful in soil adding pollutants than that in ore tailing particle and mine drainage pollution soils . 

The soils sampled from different areas in Zhe-jiang province were acidified by simulated acid rain,leaching of active Al and changing of Al species in the acidefied soils were studied .The results indicated that acid rain could pro-mote release of active Al from acid soils .When soil pH value wax>5.significant fraction of active Al in soil would be mononuclear Al species .However,when soil pH value was<5.the Al in soil would be Al￣(3-) species .The active Al in acidi-fied soils was transformed from solid Al(OH) of soil. 

Based on the new goals and tasks proposed in “The Dicision of Strengthening Rural Economic Development ”formed in the Eighth Plenary Session of the Thirteen central Committee of the Communist Party of China and in considera-tion of the pressures from the fast rural economic development upon the environment,the present status of the whole country’s rural environment in 1990s asanalysed in detail,and it is also indicated in the paper that intensification of the rural environmentdal protection is an objective demand for rural eco-nomic development.So we should follow the demand and focus on the rural environtnental protection,Through the analyses of that rural eco-environment and natural resources are destroyed and polluted by the industrial and agricultural productions. It is pointed out that the present status of the rural environment is not optimistic and it should be emphasized from now on,Al-so the basic countermeasures are put forward to deal the rural environmental problems.

Along with the rapid development of economy,Chinese agriculture is facing both the challenges from en-vironment and development. So the technological system for sustainalbe development of agriculture with Chinese characteristics,which are based on the econolomical economic princi-ple,should be established through applying the approach of system engineering,carrying on the essence of Chinese traditional agricultural techniques and adopting modern agricultural techioues .The sustainable development should be realized on the basis of sound cycling of economy and ecology and har-monized development of environmental protection and economic development,and exploitation and regeneration of natural resources.

Groundwater is contaminated as a result of an-thropo- genically induced perturbation of physical,chemical and biological processes occurring from soil surface through the unsaturated zone to subterranean water-bearing layer .The management of water and its dissolved organic contaminants from soil surface through the unsaturated zone to groundwater supplies requires an accurate conceptual understanding and a quantitative description of all relevant physical,chemical and biological processes and properties in the unsaturated zone.some conceptual problems and opportunities for modelling un-saturated zone water flow and solute transport processess are reviewed.Alternatives to classical modelling approaches are also outlined.

In this paper,some concepts and mithods in the energy flow analyxis of agro-ecosyxtems were discussed.Supplementary energy replace ratio concept was proposed to clrify people s comprehension and understanding to some concepts. It is suggested to replace energy input-output ratiowith supplertientary energy replacement ratio in the energyflow analysis.The calculations of industrial supplementary en-ergy among various systems or at different periods of same system were discussed.

On the basis of the agricultural utilization practices for fly ash in the past and its research achievements both in China and abroad,the ways for agricutural utilization of fly ash have been dixcussed ,which include:directly applying to agricultural land as soil amendment,using fly ash to manu-facture fertilizer and to create more land by filling pit with it.New concepts in the proxpect of fly ash agricultural utilization are proposed. 

Thestructure,andfunction,energy input-output ratio,biomass and etc. of hilly land ecosystem in ShanyiVillage of Zhejiang Province were investigated and studied.The results indicated that sound economical.environrmentaland social benifits have been achieved through rnany years’ e-cological construction in the hilly land ecosystem . 

The energy conversion efficiencies of three em-banked fish pond ecosystems ,namely,fine fodder,grass and fertilizer for fish culture,were analyzed in the seashore,and the economic efficiency of grass-fed system was anlalyzed .The results showed that attention should be paid to solar ener-gy utilization in low input’s embanked fish pond ecosystem a-long the coastal areas .The encrgy conversion efficiency of thegrass- fed system was the highest among three fish culture models,and the economic efficiency was better.The technique of planting grass for fish culture shoud be popularized in or-der to raise the utilization efficiency of natural resources along the coastal area. 

The toxicities of cycloprothrin dissolved in wa-ter with toluene and acetone as cosolvent separately on paramecium were tested .The results show the LC₅₀ of cyclo-prothrin to paramecium caudutum is about 16.3mg/ l,while it is dissolved in water with toluene as cosolvent,or 24.0mg /l Whilt it is dissolved in water with acetone as cosolvent,It is suggested that acetone is better than toluene when cyclopro-thrin is applied.