Changes in physical-chemical and microbial properties of rice straw through vermicomposting

Vermicomposting is a popular technique used for waste treatment (e.g. cow dung, pig manure and chicken excrement). In order to evaluate the feasibility of vermicomposting used for rice straw treatment, three kinds of rice straw and dung mixture (straw∶dung=1∶1, dry weight) were set up: rice straw plus cattle dung(RCD), rice straw plus pig manure(RPM) and rice straw plus chicken excrement(RCE). The physical-chemical and microbial properties of end products obtained through composting and vermicomposting were analyzed respectively. The results indicated that vermicomposting decreased the microbial biomass carbon (MBC) in the end products of RCD and RPM significantly after thirty days, while increased the microbial respiration quotient (qCO2), dehydrogenase and alkaline phosphatase activities in the end products of RCD, RPM and RCE, especially for RCD. The total solid loss (TS loss) in the RCD, RPM and RCE were increased through vermicomposting by 6.45%, 4.22% and 3.82%, respectively. Vermicomposting decreased the pH in the end products of three straw and dung mixture. The vermicompost obtained from RCD, RPM and RCE increased the contents of total nitrogen (TN), total phosphorus (TP) and total potassium (TK), while reduced C∶N ratio compared with compost. The vermicomposting effects used for rice straw was followed with the order: RCD>RPM>RCE. The best dung suitable for vermicomposting was cattle dung followed by pig manure and chicken excrement.