[On nitrogen transformations and maturity during composting of pig manure].

The contents of T-N, the ratios of soluble NO3-N/soluble T-N and soluble organic-N/soluble T-N increased after co-composting for 63 days of pig manure and sawdust with or without additional leaves, while the ratios of soluble NH4-N/soluble T-N decreased. In this study, addition of leaves was beneficial for maturation of pig manure composting, and it could shorten the composting time from 42 d to 35 d. The ratios of soluble NH4-N/soluble T-N, soluble NO3-N/soluble T-N and soluble organic N/soluble T-N correlated with seed germination index (GI) significantly, and it could be used for maturity evaluation.