Table 1.
Effect of biochar addition on physicochemical properties of the final composting products.
| CK | 2.5%BC | 5%BC | 10%BC | |
|---|---|---|---|---|
| GI (%) | 72.01 ± 4.26d | 81.38 ± 13.9b | 91.45 ± 19.43a | 75.12 ± 16.16c |
| Mg (mg/g) | 5.12 ± 0.22b | 5.51 ± 0.22b | 5.45 ± 0.13b | 6.41 ± 0.40a |
| Cd (mg/g) | 0.022 ± 0.0003b | 0.021 ± 0.0008b | 0.022 ± 0.0002b | 0.0251 ± 0.0015a |
| E4/E6 | 4.31 ± 0.04a | 3.98 ± 0.25ab | 3.58 ± 0.09b | 3.56 ± 0.08b |
| pH | 7.24 ± 0.03b | 7.25 ± 0.02b | 7.3 ± 0.04b | 7.4 ± 0.01a |
| EC (mS/cm) | 2.86 ± 0.21a | 3.01 ± 0.2a | 2.83 ± 0.17a | 2.8 ± 0.14a |
| TN (%) | 2.79 ± 0.29a | 2.77 ± 0.07a | 2.9 ± 0.07a | 2.61 ± 0.14a |
| DON (mg/g) | 0.69 ± 0.26a | 1.03 ± 0.4a | 0.86 ± 0.28a | 0.8 ± 0.02a |
| NO3 −-N (mg/g) | 0.41 ± 0.08d | 1.03 ± 0.12c | 1.62 ± 0.01a | 1.27 ± 0.02b |
| NH4 +-N (mg/g) | 0.29 ± 0.03a | 0.35 ± 0.02a | 0.32 ± 0.03a | 0.3 ± 0.01a |
| TC (%) | 26.25 ± 1.59a | 28.12 ± 0.56a | 30.39 ± 0.53a | 30.00 ± 2.51a |
| OM (g/kg) | 153.45 ± 0.50c | 155.86 ± 0.61ab | 157.24 ± 0.46a | 155.06 ± 0.3b |
| DOC (mg/kg) | 28.15 ± 1.56a | 23.53 ± 1.48ab | 22.6 ± 2.95ab | 20.72 ± 2.26b |
Data are means ± SE (n = 3). Different letters indicate significant difference among different treatments (p < 0.05). GI, germination index; E4/E6, the ratio of the optical density of humic acid at 460 nm to that at 660 nm; EC, electrical conductivity; TN, total nitrogen, DON, dissolved organic nitrogen; NO3−-N, nitrate nitrogen; NH4+-N, ammonium nitrogen; TC, total carbon; OM, organic matter; DOC, dissolved organic carbon. CK, compost without biochar; 2.5%BC, compost added with 2.5% (w/w) biochar; 5%BC, compost added with 5% (w/w) biochar; 10BC%, compost added with 10% (w/w) biochar.