Different methods were used to estimate N₂O emissions from croplands in China, characteristics of the emissions analyzed and potential mitigation options discussed in this study. Direct N₂O emissions from croplands estimated on the basis of field measurements and with the IPCC Phase Ⅱ methodology were 398 and 336 Gg, respectively for the year of 1995. By using the methodology, the input of N of four different sources Chinas croplands received in 1949,1955,1960,1965,1970,1975,1980,1985,1990 and 1995 was calculated with results showing that the skyrocketing of the consumption of synthetic N fertilizers was the main reason for the increase in N₂O emissions from croplands in China. Nitrous oxide emissions from paddy fields and uplands were identified. About 22% of the direct N₂O emissions from croplands in China were from paddy fields. Nitrous oxide emissions from paddy field during the rice growing season accounted for 9% of the total emissions from croplands. Therefore, paddy field is a non negligible source of N 2O. According to agricultural characteristics such as cropping system, fertilization and water management, options like modifying N∶P∶K ratios, narrowing the interregional differences in fertilizer N application rate, applying nitrification inhibitors and controlled release fertilizers may help reduce N₂O emissions from the croplands of China.

Patterns of information transmission between organisms and water, between vegetation and vegetation, and between vegetation and animal, and its role in maintaining the working order of the desert ecosystem are studied. The characteristics and process of the information transmission are also expounded, which is of significant importance for understanding the formation mechanism, evolution pattern, and developing trend as well as for setting up models for restoration and rebuilding of the degraded ecosystem.

Evaluation and comparison of the eco environmental quality of Hainan Island was carried out with the aid of remote sensing and GIS and in line with the principle of landscape ecology. The results show that the eco environmental quality is declining gradually from the center of the island outwards, with its rainforests diminishing in area and shrinking inwards, and that human disturbance goes deep into the rainforest ecosystem. Nevertheless, desertification and land degradation develops adversely in the island. 

Based on studies of the status quo of the biodiversity in the Qinling Mountains and its conservation and management, policies and strategies have been worked out for intensifying conservation of the biodiversity in the group nature reserves of the Qinling Mountains and stimulating development of the reserves. The main measures are: 1) to rationally divide and adjust function zones; 2) to intensify the internal management and to reinforce the patrol and monitoring of the natural resources; 3) to harmonize the relations with the neighboring communities by inviting them to take an active part in co management of the reserves; 4) to strengthen external cooperation and to make positive scientific study; 5) to raise peoples awareness of environment protection by means of propaganda and education;and 6) to exploit the natural resources appropriately so as to build up the self supporting capability of the reserves.

Results of an evaluation of the fishery environment in Changjiang River Delta showed that the major elements influencing water quality are petrol wastes, dissolved oxygen and non ion ammonia and the delta almost has half of its waters unfit for fishery production. To counter the situation, protective measures are brought forward herein in the hope that they can arouse serious concerns from the authorities related. 

Results of the sampling of representative soils in the Taihu Lake watershed between 1982 and 1999 show that decades of P fertilization at rates exceeding the removal rates by crops has resulted in widespread accumulation of P in agricultural soils. The increase in Total P and Olsen P is 0.1 g/kg on average and 4-5 mg/kg for most soils, respectively. Such a surplus has brought up the P level by a large margin in the soils of lands grown with cash crops, and the area of soils deficient in P has largely decreased. The increase in soil P, however, also enlarges the risk of P loss from soil to surface water. Soils differ from type to type in P adsorption capacity. Moreover, in this region, soils with low P adsorption capacity are often used to grow cash crops. As a result, excess P input increases the risk and the amount of soil P loss to water bodies.

A plot experiment on the soil derived from oil shale residue in Maoming, Guangdong showed that four herbaceous plants, Vetiveria zizanioides, Pennisetum americarum×P. Purpureum, Paspalum notatum, and Stenotaphrum secundatum, varied in Pb and Cd uptake and distribution. Generally, their concentrations were higher in the ground part than in the aerial. Fertilization reduced the concentrations of the two heavy metals in the plants. On the other hand, increased biomass may raise the uptake rate per unit area. Therefore, when plants are selected for purifying heavy metals in soils, it is advisable to take into account not only their heavy metal uptake ability, but also, or even more, their biomass.

The effect of lanthanum (La) accumulation on availability of soil nutrients in red soil was studied through indoor soil culture and pot culture experiments. The results showed that La accumulation decreased the content of soil available nitrogen and phosphorus, that there was significant negative correlation between the concentration of La and soil available nitrogen and phosphorus, and that La had no significant effect on soil available potassium.

The concentrations of lead and zinc in tailings in the Fankou disposal ground vary sharply with location in place and depth. The concentration of total zinc ranges from 703 to 19 657 mg/kg and that of total lead from 10 413 to 94 988 mg/kg. Normally the tailings contain as high as 151.6-841.7 mg/kg of available zinc and as low as 0.75-2.50 mg/kg of available lead, and are lack of other plant nutrients such as organic matter, total N, available P and readily available K. After be acidified, the pH value of the tailings is lowered down and the concentrations of available Pb and Zn rise, reaching as high as 175.8-2 828.0 mg/kg and 100.0 mg/kg, respectively, while the other plant nutrients fall almost to nil, making the tailings more infertile. In soils of the rims of the disposal ground and the coverings of the tailings, the content of plant nutrients is increased, which, however, also leads to higher concentrations of available Pb and Zn.

Based on the results of lab analysis, the effects of parent materials, leaching, geomorphologic conditions, organic matter, ferric oxide, soil texture, and pH on soil Chromium were analyzed. The law and the characteristics of the distribution of Chromium in the soil of Hainan Island were figured out. 

The UN Cartagena Protocol on Biosafety adopted in Montreal, Jan.29, 2000 and opened for signature in Nairobi, May 15-26, 2000 will exert a profound impact on international trade of genetic modified organisms (GMOs) and their products. The background of the drafting and negotiations of the protocol is expounded and the potential effects of various articles of the protocol on international trade of GMOs are analyzed. Based on the status quo of GMOs importation and domestic research and development of biotechnology in China, the tendency for importing foreign biotechnology and GM products after China accedes to WTO is explored. Meanwhile, strategies and countermeasures are brought forth to control and regulate importation of foreign GMOs in the course of implementing the protocol.

China is a large agricultural country and uses every year a tremendous amount and a huge variety of pesticides, which has resulted in serious ecological environment pollution. For a long time China has not been paying enough attention to the management of pesticides, leading to an imperfect pesticide management system. In the world, there are some countries, such as USA, Sweden and Japan, who have established fairly sound pesticide management systems and accumulated some successful experience in this aspect. These may serve as good reference for China in establishing its own pesticide management system.

A review is presented here of (1) the natural ecological environment of selenium; (2) the content, distribution, form and transformation of selenium in the global soils;(3) the key factors determining selenium content in plant and in food chain;(4) the relationship between selenium absorption and accumulation of plant and its genetic factors;(5) the major forms of selenium existing in plant tissues; (6) the relations between the forms of selenium with its bio availability and bio utilization rate;(7) the methods for regulating selenium level in food chain; and (8) the frontier issues for future research on selenium. 

In Northern China, the widespread Agro pastoral Zigzag Zone is rather fragile in eco geo environment, and very sensitive and extremely susceptible to disturbance and destruction with an apparent trend to degradation. This is also a region frequented by a variety of eco geo environmental disasters, such as land desertification, climatic disasters, endemic, etc. The mechanism of the formation of the fragile eco geo environment of the zone comprises inner geo dynamical mechanism and outer dynamical mechanism. The former refers to the tectonic movement in the geological history which has laid down the material basis for its specific patterns of land relief and fragile land surface, whereas the latter, the East Asia monsoon and irrational human activities. The joint effect of the two turns the potential fragility of the natural environment into real serious eco geo environmental disasters.