| Aerobic composting was one of the most effective ways to transform livestock and poultry wastes to high quality organic fertilizer. Whereas it generally produced odors (such as NH3) during the period of composting, which not only caused the environmental contamination, but also resulted in the loss of nitrogen and reduced the agricultural value of mature composting.In this research, co-composting of swine manure and rice bran experiments were carried out to study the changes of nitrogen forms, the characteristic of NH3 emission as well as the influences of C/N on NH3 emission and composting maturity . The effects of adding calcium superphosphate, zeolite on nitrogen loss, the appropriate dosage of additions were also studied. The results obtained were as following:(1) The maximum of NH3 emission occurred at mesophilic and thermophilic phases especially during 07d of composting, this was a well period to reduce the loss of nitrogen. There were positive relations between NH3 emission and water soluble NH4+-N(n=8,r=0.8723*) as well as pH (n=8, r=0.7857*). Thus reducing composting materials pH, transforming NH/-N to other forms of nitrogen could reduce NH3 emission.(2) Effect of C/N ratio on NH3 emission during composting was significant. The amount of nitrogen loss with initial C/N ratio of 17.6, 24.0, 32.4 and 40.3 were 32.19%, 20.80%, 13.65% and 7.66% respectively. The results indicated that the high initial C/N ratio could reduce nitrogen loss. Moreover the C/N ratio also affected the degradation and the quality of composting. The low C/N ratio of 17.6, due to the higher soluble salts, caused harmful effects on seed germination index (GI); but the high C/N ratio of 40.3 would reduce the nutrient content of compost and the disposal amount of swine manure. So the C/N ratio of 2530 was appropriate for swine manure composting .(3) The results showed that there were not significant effects on the temperature and GI by adding calcium superphosphate on compost. But calcium... |
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