Changes of organic carbon fractions and maturity index during composting of manure

In order to study the influence of manure composting on changes of organic carbon and its fractions,a 38 d composting experiment was conducted with two different proportions of cow manure,chicken manure,and fungus chaff as mixed media,each formula amended with or without fermentation activator.The maturity degree of composted materials was estimated by GI(integrated germination index) and the relationship between GI and organic carbon fractions was developed in this study.The results showed that fermentation activator promoted the decomposition of organic materials,reduced the contents of water-soluble organic carbon and organic acids by 41.85% and 85.18% respectively,and promoted the transformation of FA into HA,therefore accelerated the decomposing process of organic materials.High percentage of cow manure slowed down the decay of composting materials,resulting in longer time to reach their composting maturity.When GI0.8,the TOC,DOC and FA were less than 357.27 g·kg-1,7.00 g·kg-1and 6.45g·kg-1,respectively,and sharp absorbing peak of FTIR showed up at 1020 cm-1and 1427 cm-1during the late stage of decomposition,suggesting increased carbonate and nitrate contents and greatly dropped oxalic acid.These changes could be considered as the quantified standard in estimating maturity degree.Based on this standard,the treatment with the formula of cow manure:fungus chaff:chicken manure of 1∶1∶1 reached its maturity by 29 days with fermentation activator addition.