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In the process of Collybia velutipes and Coprinus fimetarius inoculation at 3, 4 and 5 per cent level to urea-treated barley, oat and rice straws for 30 d, C fimetarius grew faster than C. velutipes on urea-treated straws and degraded more lignln, ADF and NDF and decreased PH as well as DM during the solid substrate fermentation. C. velutipes and C.fimetarius were best suited for 5 per cent urea treated rice straw degrading 34.42 and 40.03 per cent lignin respectively. Rice straw was a better substrate for C. fimetarius and C. velutipes tban the other straws in respect of bioconversion performance.