On the basis of a great deal of information collection, the methane emission amount from China’s different agricultural emission sources are estimated in detail with the calculation method recommended by IPCC. The methane emission amounts from rice paddies, domestic ruminant animals and agricultural residue are obtained. 

The latest progress of greenhouse gasmethane researches is summarized, including its contribution to global warming, emission mechanisms and prioities of methane research. It is estimated that China contributes 10. 48% of world total anthropogenic methane emission, with over half of that comes from agriculture. On the basis of experimental results, the technological options for reducing methane emission from rice paddy and domestic ruminant animals are proposed. 

The field experiments conducted over the past three years indicate that the methane emission fluxes from the rice paddies vary drasticaly with various agricultural measures. During the three late rice growing seasons from 1990 to 1992, CH₄ emission fluxes from the experimental fields were 10. 83, 25.18 and 19. 85 mg/m²·h, respectively. Semi-dry cultivation reduced the CH₄ emission fluxes by about one third, sunning field, applying ammonium sulfate and intermittently flooded irrigation might also make the CH₄ emission fluxes decreased significantly. The principal reasons for high CH₄ emission fluxes are heavy application of organic fertilizer and long-term flooding. The key of controlling CH₄ emission lies in regulating irrigation water. As long as a proper irrigation scheme is adopted, an increase of organic fertilizer may not be followed by an increase of CH₄ emissions. 

The methane emission fluxes from rice after wheat and single rice field have been measured in Beijing area from 1990 to 1992. CH₄ emission flux for single rice was about 8. 5-10. 0 mg/m²·h and for rice after wheat was 17. 5 mg/m²·h. The amount of organic base fertilizer added was the major factor affecting methane emissions (dry-seeded rice field and rice field without organic matter input have lower emission than other treatments). The use of scientific irrigation (intermittent irrigation) with suitable amount of organic base fertilizer could either increase rice yield or reduce methane emission, but it was also observed the increasing emission of another greenhouse gas N₂O under the stage of dry and moisture water management. 

The advances in the research of methane emission from rice paddies and related soil properties and environmental factors are reviewed. It is pointed out that any strategy to be employed for reducing methane emission from rice paddies should not cause reduction of rice yield and increase of other greenhouse gas emissions. During drought conditions, the role of rice paddies acting as methane sink should be estimated.

The characteristics of methane release as well as biological mechanism in paddy soil were studied by methods of soil column and in situ field. The results showed that the amounts of methane released were up to maximum during vigorous tillering stage of both early and later rice, then gradually decreased. Both organic and inorganic ferilizers stimulate the release of methane from paddy soil, however, organic manure induce more methane release than urea. The most active part of methane formation was the root system undisturbed and combined closely with soil. More than 80% of methane was released by rice plant i methanogenic bacteria adhered to root surface. The result also showed that the amounts of methanogenic bacteria, anaerobic celluloclastic and methane-oxidizing bacteria as IVFA in rhizosphere soil were higher than that in non-rhizosphere soil. 

The major anthropogenic emission soure-ces of methane and their flux are introduced. The concentration of methane in the atmosphere and its contribution to the greenhouse effect are also analyzed, the anthropogenic emission of methane in Shanghai area is estimated. 

The effect of different cultivation conditions on the release of methane, the amounts of methanogens and methane-oxidizing bacteria in rice paddy soil are reported. After rice seedlings was transplanted, the amount of methane released from rice plant was gradually increased with rice plant growth and reached to the maximum at flourishing tillering stage. After this stage it was gradually decreased. The amount of methanogens in rice paddy soil was 2-3 orders of magnitude lower during the earlier stages than that during the latter stages in earlier rice. However, the amount of methanogens was slighly higher during the middle stage than that during the earlier and latter stages. The predominant methanogenic bacteria isolated from rice paddy soil belonged to Methanobacterium and Methanosarcina. The amount of methane-oxidizing bacteria was about 103-104/g dry soil during the earlier stage and 108/g dry soil during the latter stage in earlier rice. Then, it was kept at about 108/g dry soil in latter rice. Four strains of methane-oxidizing bacteria were isolated and belonged to faculative heterotrophic methylotrophs.

Methane is an important greenhouse gas. According to the estimation of IPCC, the methane emission from rice paddies was about 20% of the total methane e-mission. Studies from China, one of major rice producing countries , showed that the methane emission flux from rice paddies in China varied from 7. 8 to 60mg/m²· h. The methane emission from rice paddies actually consists of two processes, the formation of methane in paddy soils and the release to the atmosphere. Methanogen providing anaerobic condition in water logged paddy (soil Eh value below -200mv) plays a key role for the methane formation. The methane emission from soil to the atmosphere is mostly through rice plants, only small amounts of methane is released across the water-air interface via bobbles or molecular diffusion. Therefore, the methane formation and emission is mainly a biological process. Some physical and chemical conditions of paddy soil, paddy water and atmo Sphere, such as temperature, pH, flooding period and application of organic manure and chemical fertilizer, greatly influence this process. With the understanding of the mechanism of methane emission from rice paddies, the methane emission rate can be reduced along with a good rice production. 

The methane release fluxes from paddies in complete rice growth period have been monitored in Wali County of Beijing City from 1990 to 1992. Different fertilizers were applied in the fields in order to test the effect of organic and chemical fertilizer on methane emission. The results show that average methane emission rate was 17. 6mg/m²·h under common managementl and exhibited a strong seasonal variation with maximum emission flux around Aug 15. The methane emission during the climax period accounted for more than 65% of the total methane emission in the whole year. Experimental results also show that animal manure enhances methane emission?ammonium sulfate suppresses the methane emission during its effective period. Intermittent irrigation seems to be one of the effective ways to reduce the methane emission from paddy fields. 

Ruminant animal is one of the major atmo-Spheric methane emission sources. In this paper, the advance in the research of methane emission flux form ruminant animal both in China and abroad, and its world total emission amout is briefly reviewed. The preliminary conclusion and current existing problems in metnane emission research are discussed.

In this paper, the experimental design for monitoring methane emission flux from rice paddy in Guangzhou area with automatic sampling and analyzing system is introduced. 

In this paper, the general situation of research programme selection on stable global climate policy is introduced,and the slow and rapid changes of world long-range perspective are analyzed.