Urease activity as an index for assessing the maturity of cow manure and wheat residue vermicomposts

The establishment of a reliable index is an essential need to assess the degree of stability and maturity of solid wastes vermicomposts. The objective of this study was to investigate the effects of vermicomposting process on some chemical (pH, EC, OC, TN, lignin and C:N ratio) and biochemical properties of the cow manure (CM) and wheat residue (WR). Results demonstrated that during vermicomposting process of CM and WR urease activity was highly correlated with the time of vermicomposting (r=-0.97^∗∗ for CM and r=-0.99^∗∗ for WR), and well able to show the stability of organic waste. The urease activity showed significant correlations with the C:N ratio during the vermicomposting of CM and WR (r=0.89^∗ and r=0.93^∗∗ respectively) therefore it can be considered as a reliable indicator for determining the maturity and stability of organic wastes during vermicomposting process.