Table 1.
Biochar properties.
| Source |
Oil seed rape straw pellets |
Wheat straw pellets |
Miscanthus straw pellets |
Soft wood pellets |
|
|---|---|---|---|---|---|
| Biochar notation | OSR550 | OSR700 | WSP550 | MSP550 | SWP550 |
| Temperature (°C)1 | 550 | 700 | 550 | 550 | 550 |
| pH | 9.8 ± 0.5 | 10.4 ± 0.5 | 9.9 ± 0.2 | 9.8 ± 0.2 | 7.9 ± 0.3 |
| H:Ctot (molar ratio)1 | 0.32 ± 0.03 | 0.19 ± 0.02 | 0.4 ± 0.1 | 0.38 ± 0.04 | 0.39 ± 0.01 |
| O:Ctot (molar ratio) 1 | 0.12 ± 0.02 | 0.09 ± 0.02 | 0.1 ± 0.0 | 0.09 ± 0.03 | 0.09 ± 0.01 |
| Ash content [wt%]∗1 | 19 ± 2 | 21.9 ± 0.5 | 21 ± 1 | 12 ± 1 | 1.3 ± 0.4 |
| Electric conductivity [dS.m−1] 1 | 2.3 ± 0.4 | 3.1 ± 0.4 | 1.7 ± 0.4 | 0.8 ± 0.2 | 0.09 ± 0.03 |
| Total N [wt%]∗1 | 1.6 ± 0.2 | 1.3 ± 0.2 | 1.4 ± 0.1 | 0.8 ± 0.1 | <0.10 |
| Total P [wt%]∗1 | 0.29 ± 0.08 | 0.3 ± 0.1 | 0.14 ± 0.02 | 0.19 ± 0.04 | 0.06 ± 0.04 |
| Total K [wt%]∗1 | 2.9 ± 0.3 | 2.9 ± 0.4 | 1.6 ± 0.4 | 0.9 ± 0.1 | 0.3 ± 0.1 |
| Total pore volume [cm3.g−1]2 | 0.38 ± 0.02 c | 0.42 ± 0.01 b | 0.27 ± 0.01 e | 0.6108 ± 0.0003 a | 0.33 ± 0.01 d |
| BET [m2.g−1]2 | 416 ± 5 c | 461 ± 5 b | 299 ± 3 e | 490 ± 12 a | 358 ± 3 d |
| CEC [cmol.kg−1]2 | 22 ± 3 a | 23 ± 1 a | 21 ± 2 a | 22 ± 1 a | 11 ± 3 b |
BET: specific surface area determined by the Brunauer-Emmett-Teller (BET) method.
CEC: cation exchange capacity.
∗
Dry basis.
1
Data reproduced from UK Biochar Research Centre, values are means ± run to run variation (SD), (http://www.biochar.ac.uk/standard_materials.php; Accessed 17/08/2020).
2
Data determined experimentally in the present study, values are means ± standard deviation; n = 3; different letters indicate significant differences between biochars (p < 0.05; one-way ANOVA, Tukey's honestly significant difference (HSD) post hoc test).