The recent eco-environmental problems concerned by the world and the present situations and future trends of eco-environment in China were wholly and systematically discussed in this paper. The measures for improving eco-environment of China were also proposed. 

The technological design, model construction and results run by models in the research of rural ecosystem development strategy in Jilin province were introduced. Through the preliminary analysis of the results, the future development of rural economy and ecological environment in Jilin were predicted. 

Basing on the compound ecosystem structural model, the way for planning of the Guquan Ecological Engineering Experimental Farm has been investigated through linear programming model.By comparison of six projects and analysis of thesensitivity of resources, the project programming and relevant measures for ratinal utilization of scarce resources were made out so that the experimental farm could maintain a benign ecolomic cycle. 

The authors carried out a comparative study of disinfection of anaerobic fermentation on Colon bacillus in hog dung and chicken manure. The results showed that the bacteria were very significantly disinfected during the course of the fermentation and that over 98% of escherichia coli in dungs were killed in 10 days. It showed the dungs treated by this way was beneficial to environmental sanitation.The results can also provide a good scientific data for better management of marsh pit system. 

The hydrolysis of Aldicarb ( AS ) and its toxic metabolites, Aldicarb sulfoxide ( ASO ) and Aldicarb sulfone ( ASO2 ) in aqueous media of pH 5.00, 7.00 and 9.00 were studied. Results showed that AS, ASO and AS02 were relatively stable under neutral and acidulous aqueous media. The hydrolysis rates of three compounds increased as the pH of media increased. At the temperature of 15℃ the half lifes of AS, ASO and ASO2 in the aqueous media of pH 5.00, 7.00 and 9.00 were 627, 510 and 354 days ( for AS ), 330, 267 and 192 ( for ASO ), and 1411, 399 and 100 days ( for ASO2) , respectively.

The water pollution control and environment protection in small size cities and towns of China is a complicated system engineering. Water resources and environment are used as resources in the processes of urbanization. Different ways of rational use and development of water resources will cause different ecological effects. The water resources in Tai Lake area have been polluted in certain degree by the development of industries run by villages and towns in recent years. The authors have studied the ways for water pollution control in small cities and towns.They emphasis that the combined benefits caused by multiple-path and integrated water pollution must be taken into consideration in pollution control,and that ecological assessment of water bodies must be carried out in the typical regions.

Agricultural ecosystem is a kind of man-made ecosystem, which is set up on the basis of the natural ecosystem. Its function is to meet the needs of the people for various agricultural products. In order to get more agricultural products with better quality from agricultural ecosystem on the basis of beniga cycle, it is necessary to analyse and understand its special characteristics.Agricultural ecosystem has four outstanding characteristics,which are very different from common natural ecosystems. These characteristics are the increase in the input and output of materials and energy, large input of auxiliary energy, the tendency of shortening food chains, the tendency of extending the chains of utilizing survivals. 

The combustion of fossil fuels and terrestrial, ecosystems, especially forest and their soils constitute the main source of carbon dioxide emissions. This may cause a long-term warming of the atmosphere. Several other man-made trace gases, e. g. CH4, N2O, halocarbons, accumulating in the Earth’s atmosphere, may also to, a global warming in the future. Although increased amounts of these individual trace gases may have a little greenhouse effect on the global warming, together they may rival the effects expected from the increasing level of carbon dioxide. As the development of industrial production and the increase of world population, the amounts of carbon dioxide and other man-made trace gases to atmosphere will, certainly,increase.The greenhouse effects caused by these events may significantly affect the global climate. However, these issues are not very well studied at present time.

A review was made on concepts of agroforestry, principles and findings in selection of plant species component and their arrangements in agroforestry systems, and functions and practical effects of agroforestry in providing a variety of agricultural products, energy, fodder, and mulching materials,improving ecological environment and soil fertility conservation of soil and water,enhancing economic efficiency in developping countries. A list of 57 species in 29 genera which were considered to have multiple functions and often used in research or successfully applied to actual agroforestry systems was given in the paper. The author suggested that it is necessary in China to make more investigations and deep researches on potential plant components and diversified agroforestry systems and on ecological functions of each component and the system as a whole, and to do multidis-ciplinary cooperative research. 

The results of field experiments and breeding rabbit experiments in the past two years ( 1086-1988 ) showed that the alternation of culture of "one grass and three crops"in the two yearswas new way to utilize dryland in the case of incorating the leguminous grass and animal husbandry into cropping system.A net income of 8295 yuan per hectare could be obtained from the new cropping system, which provided 2800 yuan more per hectare of net income and 180 kg more per hectare of nitrogen than the simple planting grain system( wheat and sweet potato). The improvement of soil fertility would ensure the later grain to grow well.Even though the rotation of "grain crop-leguminous grass" had one grain harvest less than the rotation of "grain crop-grain crop" ,the total grain yield per hectare of the former (20358.5 kg per hectare)was 1539.2 kg higher than the latter(l8819.3 kg per hectare).

The important parts of grey system theory——the principle and method of greyrelational grade have been introduced in this artical. The application of this method in grading the leading factors of soil ecosystem has been discussed. The re-suits showed that this method is handy and easy to operate. The analyzed results were in compliance with the actual results. It can be used as a supplement and perfection of analysing method for common factors. 

This article analyzed the general characteristics of fishing production in Hu-bei province.lt based water areas as its ecological environment and therefore a rational combination of fishing, grain-planting, live-stock and poultry-raising and fruit forestry v/ere formed . And as a result, these water areas have formed a system of a multifunctional and compound production . According to the theory of living-beings coexist and complement each other,a variety of material relations in this production system are being made more rational, systematic and standard.Several superior production models, such as the Plane-Distribution Model, the Vertical-Compound Model, the Chain-Food-Gaining Model and Space-Time-Fully-Loaded Model were also introduced. In this article an analysis is also made from the economic angle. All these models not only help to acquire benifits but also save expenses,They fit the situation of our country and its developing advantages.

In this paper the method of coefficient evaluated by function is applied to research of the unification of multiple purpose in the agricultural ecosystem, which unifies economic efficiency, social efficiency and ecological efficiency and solve the problem of transforming optimization of multiple purposes to optimization of single purpose in the agricultural ecosystem.

The dose-effects,time-effects on toad(Bufo bufo gargarizans)nuclei aberration test with a single intraperitioneal injection of Cyclophsphamide ( CP)and Formaldehyde ( FD ) were investigated. The experimental results showed that toad nuclei aberration rate existed a significant linear dose-response relationship in certain region. The results of data on time-effect showed that the nuclei aberration rate reached maximum 12 hr. after the toxic chemicals were injected.In addition,by comparison of nuclei aberration rate with micronuclei, frequency the author suggested that the nuclei aberration [test was more sentitive and more reliable screening system than micronuclei test in monitoring environmental mutagenes and ecotoxicity.Nuclei aberration test will probably become a new to-xicity index in the toxicity test of environmental pollutants, and a new research method for amphibian ecotoxicology.