It is know that tlic world environment is in a state of incessant change, ecosystems liavc developed and rcilislribulcd themselves on the chess-board of the changing racttl over Ilie past 3000 million years, but now they face a challenge which may well be unprecedented. This is because the world environment is being altered as a result of human activities on a larger scale and at a greater rate than at any time in the know past. This paper deals mainly with nature of global climate change, influences of global climate change on ecosystems of forest, wetland, coastal, island and arctic, biodiversity, distribution and existance of species, and main coumcrmca.sures for global climate change. 

The self-thinning rule, a universal biological law in an even-aged plant population, describes decreasing processes of population densities at -3/2 power of plant mean weight on log-log graph. In the paper, the author introduced the basic contents of the rule, discussed effects of site and shading on the rule, and proved theoretically that the power of the rule must be larger than an abs?lute value of -3/2 in the tree population. The author also noted the relations between the densities at the density-dependent mortality stage and at the early growth stage of population. The biological and cclolgical fas tors influencing the process of the self-thinning were discussed. 

Jiangxi Jihu Agricultural Development Project is one of the greatest projects in Jiangxi province, of wliich 60 million US dollors would come from the credit of the World Runk. Tin: main objective of the proposed project would focus on establishment of a large commercial scale pig, poultry, aquatic, forestry production and their product processing. The environmental impact of the projecton eco-cnvironmcnt has been studied. Organic materials will be the main pollutant from the project. Strategics suggested to protect the environment include; reasonable allocation of producticity, lying on the road of ecological agriculture; careful treatment of wastes and converting wastes into usable resources; proper use of feed and pesticides and strengthening environmental monitoring. 

Based in the assessment on the type, arrangement and present situation of the natural reserve construction in China and the biological dicersity conservation plan both at home and abroad, the natural reserve developing plan of China was put forward. And moreover, the detailed schemes for the preserved areas and national reserve construction were suggested. 

The concept of agro-ccolgical engineering, which was orignally proposed by the Chinese distinguished ccologisl , the late profcssot Shijun Ma, has been discussed. The special features and the enceent trends of the agroecological engincx;ring in China in comparison with those of the sustainable agriculture in some other countries has been reviewed. The existing problems and issues that need to be addressed in the devlopment of agro-ecological engineering in China along with some s|xx:ific suggestions for the study were proposed. 

The properties of paddy soil ecosystem and mutual impacts between crop system and soil condition were analyzed. Crop aaaptaomty and fertilizer supply, the main two factors determining the functions of the ecosystem, arc closely related to soil property. Based on regional variation of heat condition, soil hydrology and soil fertility, the rcgionalhation of paddy soil ecosystem in Taihu lake region has been discussed. 

On the basis of the data obtained from a lot of field experiments, the litter and its decomposition in a farmland shcltcrbclt network ecosystem with Popahis tomendost Carr. were studied. Tt is estimated that the annual Utter of the system was 0. 55t/ha with return rate of 35. 7%. The weight loss rates of litter in the farmland in 180, 360 and 540 days were 30. 5% ,54. 7% and 75. 2%, respectively, and its annual decomposition rate was 0. 86. Moreover, the decomposing rate of selected nutrient elements was in the order of N>P>K>Mg>Mn>Ca.

According to the characteristics of red-soil utilization in hilly area, ways for integrated utilization of organic materials has been studied and Satsuma orange -Plcurotus florida -Earthworm vertical ecological model has been set up. Results showed that this model had remarkable economical benefits and resulted in benign ecological cycle. It is concluded thct this vertical ecological system is of higher practical value in red soil hilly area. 

Effects of negative oxygen ions on the growth and development of cucumber (Cucunis sativus L. ) were studied. The results indicated that negative oxygen ions promoted the growth of vegetative organs at seedling stage, inhibited growth at the blossoming stage, lowered the node position of the first female flower, increased the percentage of fertile plant and yield of single plant and pro longed the time of fruiting. The output had been increased by 13. 1 % in comparison with control. On the basis of analyses of expcrimen tal results, it is suggested that the effect of negative oxygen ions on the growth and development of cucumber was related to promotion the synthesis of endogenous phytohormones and enhancement the activity of some enzymes.

The background values of Cr, Pb, Cd, As and Hg from 51 samples of the local native representative plants as Attea rdepidian chinense ,stioa, Artemisia frigila and caragtna have been analyzed. The results indicated that the orders of the four plants to sclcc-tively absorb these elements are almost the same. 

Because of the facts that the technologies and facilities arc advanced in the brick production, most fuels used arc by-product with low fluoride content, the surplus heat from chimney is recycled, fluoride in waste air was partly absorbed or adsorbed by bricks, the effect of fluoride pollution of brick-field on the agricultural environment in the suburbs of Slianghai is not serious. However, Since fluoride may be continuously accumulated and transfcrcd in the environment, attention should be paid to the technological reformation of the brick-field, and the environmental monitoring should be enforced in order to protect the agricultural environment from fluoride pollution. 

The production system of animal husbandry is a complicated system which contains live-stock and animal ecology, economy, management, resource and other factors. In the wake of the introduction of computer technolongy, various optimal models have been established in order to set the benign ecological system of animal husbandry. Obvious economic benefit has been achieved in the practical production, which shows its mighty future of application .The system method used in production of animal husbandry will open up a new way for settling all sorts of problems as the low energy turnover, low benefit in our country’s animal hushandry, it also will promote the development of the live-stock and animal harmoniously and steadily. Methods for establishing models and its application in animal husbandry have been reviewed. 

The ecological conditions of plastic greenhouse utilized bioencrgy and solar energy and its regulation were studied. The experimental results showed that room temperature changes similarly to the material temperature and air temperature outdoor , and that coefficients and regression equation of room temperature (y) to material temperature (X₁) and air temperature (X₂) were 0. 616, y=1. 22×1 - 5. 77 and 0. 62,y=1. 08×2+20. 6, respectively. Generally, room temperature began to increase 1-2 days after matcri al supply, sharply increase 3 - 5 days later, with the maximum 7-10days after material supply, and room temperature was still aprox. 10℃ higher than air temperature after 18-20 days. Because of the effects of sunshine and biocncrgy, day room temperature fluctuated significantly and night temperature remains steadily. Tn addition, horizontal differences in room temperature were very little but vertical differences were remarkable. Although air humidity was in the comdition of vaporization, indoor light intensity was sufficient for the growth of many crops and indoor light intensity in fine day was 46-60. 4 % of natural light intensity. Carbon dioxide concentration indoor was 5. 83 times higher than that of atmosphere. Moreover, Methods for regulating the condition of biocncrgctic greenhouse have been proposed, which include mulch with straw bed increasing temperature 11. 3-12.0℃, but mulch with straw bod only at noon in fine day decreasing 7. 3-10.8℃ and hanging black clothes indoor increasing 4-6℃.