Abstract: Emission of ammonia during composting of dairy cattle waste and effects of organic materials added to adjust moisture content of the compost on loss of ammonia were studied.Results indicated that the emission of ammonia concentrated mainly in the early stage of composting,especially in the first 2 weeks,and the total N loss during the composting period was about 17%～50% of the total N in the dairy cattle waste.Addition of moisture regulating materials could reduce the N loss in varying degrees during composting.Sawdust showed the best restraining effect on ammonia emission,followed by rice hull and rice straw.Therefore,some steps should be taken to prevent the N lose.

Key words: dairy cattle waste, composting, emission of ammonia, moisture regulating material, sawdust, rice hull, rice straw