Experimental procedure
Chemical analysis
Physicochemical properties of the experimental raw materials (dry matter basis)
Sequential P fractionation
The compost samples were analyzed for pH and EC in 1:10 (w/v) water extracts (He et al. 2009). NH4
+-N and NO3--N were extracted with 2 mol L-1 KCl from fresh samples and were then determined by the indophenol
blue method and cadmium reduction method. The moisture contents of the samples were determined after dried at 105°C for 24 h. Ash content was determined by combustion at 550°C for 8 h. OM was determined by subtraction of ash content. Total organic carbon was calculated as 58% of OM (Zmora-Nahum et al. 2005). TN was measured by Kjeldahl method (Bremner 1996).DOC, CHS extracted with 0.1 mol L-1 NaOH, and CFA from the NaOH extraction at pH 1.0 were determined by potassium dichromate oxidic method (Pereira et al. 2006). CHA was calculated as the difference in CHS and CFA. Activities of urease and AlkP were measured according to Cang et al. (2009).