The study of fertilizer effect on CH4 emssion from rice fields shows that the use of mineral fertilizer may reduce CH4 emission. But the quantity and type of organic manure are considered to be the dominate factor affecting CH4 emission,therefore the reduction of CH4 emission should be mainly achieved by scientific application of organic manure. Compared to the normally used organic manure,the fermented and "old"sludge from biogas pits may greatly reduce CH4 emission. Therefore we put forward a fertilization scheme combining sludge from biogas pits with mineral fertilizer to reduce CH4 emission from rice fields while having no influence on rice production. We propose that before supplied to field, "fresh" organic matter (green manure,rice straw and pig excrement)had better be fermented in biogas pits for fuel substitute and be dried by storing in the open air.Water management experiments show that in the field treated with constant moisture, when soil moisture lowers down to certain extent(26%<moisture<31%) ,CH4 emission drops suddenly,and the main CH4 producing area moves down to the deep soil. Even when flooded water was re-supplied to the dried field,CH4 emission was not rising for a reasonably long period. A frequent drainage with 3-day -interval in our experiment doesn' t significantly lower down the total -season methaneemission. Taking rice production and practical use into account, we think a frequent drainage with a suitable time table should be used to reduce methane emission. If soil moisture can be controlled,sunning field technique,which is commonly used in our rice agriculture, may also be a good technique for lowering methane emission.In order to reduce CH4 emission more efficiently and to increase rice production as well, we simulated a scheme in the late rice period (1992) combining fertilizer treatment which is the mixed use of fermented manure from biogas pits and mineral fertilizer, with water management which is the normal sunning ground technique,and we found that CH4 flux may be reduced by more than 50%. A more scientific and practical measures combining fertilizer and water management needs further investigation.As a main routine for CH4 transport,rice plant involves in CH4 production and oxidation processes. Therefore some varieties of rice plants may play active role in reducing methane emission from rice fields.