2.6. Statistical analysis
Data were shown as mean ± standard deviation (SD). All parameters were determined in three replicates. Significant difference in the change of pH, organic matter and bacteria among the treatments over time was tested by using a two-way analysis of variance (ANOVA). Duncan's New Multiple Range Test was used to isolate any significant differences detected in the ANOVA (Duncan, 1955). All data were considered significant at P < 0.05.