Table 5.
The status of chemical properties in acidic soil into two soil sample years and parthenium biochar dosages (mean ± SD).
| Soil parameters | Soil sample | Parthenium biochar rates | LSD | |||||
|---|---|---|---|---|---|---|---|---|
| Years | PB0% 0 t/ha |
PB5.33% 12.5 t/ha |
PB8.0% 16 t/ha |
PB10.67% 19.5 t/ha |
PB13.3% 23 t/ha |
PB16% 26.5 t/ha |
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| pH (H2O) | First year | 5.44 ± 0.12b | 6.3 ± 0.5ab | 6.7 ± 0.5a | 7.1 ± 1.1a | 7.5 ± 0.6a∗∗ | 7.3 ± 0.6a | 2.06 |
| Second year | 5.45 ± 0.14d | 7.0 ± 0.2c | 7.6 ± 0.5b | 7.96 ± 0.2ab | 8.1 ± 0.2a∗ | 8.1 ± 0.15a | 1.58 | |
| Combined | 5.44 ± 0.12c | 6.7 ± 0.5b | 7.2 ± 0.7ba | 7.55 ± 0.8a | 7.8 ± 0.5a∗∗ | 7.8 ± 0.5a | 1.74 | |
|
| ||||||||
| pH (KCl) | First year | 4.8 ± 0.05b | 5.64 ± 0.5a | 6.1 ± 0.6a | 6.4 ± 1.0a | 6.8 ± 0.6a∗∗ | 6.8 ± 0.6a | 2.01 |
| Second year | 5.2 ± 0.7c | 6.3 ± 0.1b | 6.9 ± 0.5a | 7.3 ± 0.13a | 7.4 ± 0.1a∗∗ | 7.4 ± 0.1a | 1.78 | |
| Combined | 5.0 ± 0.5c | 5.99 ± 0.5b | 6.5 ± 0.7ab | 6.9 ± 0.8a | 7.1 ± 0.5a | 7.1 ± 0.5a∗∗ | 1.55 | |
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| EC (ms/cm) | First year | 0.09 ± 0.05d | 0.63 ± 0.04c | 0.76 ± 0.07c | 0.8 ± 0.2bc | 0.97 ± 0.16b | 1.34 ± 0.2a∗ | 0.58 |
| Second year | 0.15 ± 0.05d | 0.8 ± 0.15c | 1.37 ± 0.07b | 1.62 ± 0.1a | 1.75 ± 0.11a | 1.85 ± 0.1 | 0.57 | |
| Combined | 0.12 ± 0.04d | 0.71 ± 0.14c | 1.1 ± 0.34b | 1.2 ± 0.5b | 1.36 ± 0.4a | 1.6 ± 0.3a∗ | 0.35 | |
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| Ca (cmol+/kg) | First year | 11.95 ± 0.9c | 12.9 ± 0.3bc | 14.15 ± 0.3ab | 15.12 ± 1.8a | 13.9 ± 0.7ab | 14.9 ± 1.0a∗∗ | 3.17 |
| Second year | 11.14 ± 0.3c | 15.9 ± 0.6b | 17.9 ± 1.4ab | 18.45 ± 0.9a | 19.32 ± 1.5a∗ | 18.7 ± 1.2a | 4.8 | |
| Combined | 11.54 ± 0.7c | 14.4 ± 1.7b | 16.01 ± 2.2ab | 16.8 ± 2.2a | 16.6 ± 3.1a | 16.8 ± 2.2a∗∗ | 4.4 | |
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| K (cmol+/kg) | First year | 0.6 ± 0.05b | 1.75 ± 0.7b | 3.9 ± 1.5a | 5.3 ± 2.0a∗∗ | 5.2 ± 1.5a | 4.2 ± 0.6a | 4.63 |
| Second year | 0.72 ± 0.08d | 3.1 ± 0.5c | 5.3 ± 0.6b | 7.4 ± 1.0a | 7.8 ± 1.0a | 8.3 ± 1.1a∗ | 4.3 | |
| Combined | 0.64 ± 0.1d | 2.4 ± 0.9c | 4.6 ± 1.3b | 6.4 ± 1.8a | 6.5 ± 1.8a∗ | 6.2 ± 2.3a | 3.8 | |
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| Na (cmol+/kg) | First year | 0.21 ± 0.04c | 0.81 ± 0.2b | 0.5 ± 0.09a | 0.6 ± 0.04ab | 0.45 ± 0.1ac∗ | 0.43 ± 0.03ac | 0.6 |
| Second year | 0.24 ± 0.05c | 0.6 ± 0.08b | 0.74 ± 0.12ab | 0.8 ± 0.06ab | 0.92 ± 0.2a∗ | 0.83 ± 0.2ab | 0.53 | |
| Combined | 0.22 ± 0.04b | 0.7 ± 0.2a∗ | 0.62 ± 0.1a | 0.7 ± 0.1a∗ | 0.7 ± 0.3a∗ | 0.6 ± 0.2a | 0.39 | |
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| ||||||||
| Mg (cmol+/kg) | First year | 3.99 ± 0.9 | 5.4 ± 1.5 | 5.8 ± 2.0 | 5.0 ± 2.8 | 5.99 ± 1.3 | 4.8 ± 1.1 | NS |
| Second year | 3.8 ± 0.5b | 7.4 ± 1.5a | 8.7 ± 0.6a | 8.5 ± 1.2a | 7.9 ± 2.2a∗∗ | 7.6 ± 1.9a | 4.75 | |
| Combined | 3.9 ± 0.7 | 6.4 ± 1.8 | 7.3 ± 2.0 | 6.8 ± 2.7 | 6.9 ± 1.9 | 6.2 ± 2.0 | NS | |
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| OC (%) | First year | 0.8 ± 0.09d | 0.8 ± 0.1d | 1.1 ± 0.08c | 1.22 ± 0.04c | 1.47 ± 0.1b | 1.71 ± 0.1a∗ | 0.42 |
| Second year | 0.77 ± 0.1d | 1.4 ± 0.15c | 1.9 ± 0.07b | 2.2 ± 0.12b | 2.8 ± 0.2a∗ | 2.6 ± 0.1a | 0.52 | |
| Combined | 0.8 ± 0.1d | 1.1 ± 0.3c | 1.5 ± 0.4b | 1.7 ± 0.5b | 2.1 ± 0.7a | 2.2 ± 0.5a∗ | 0.63 | |
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| ||||||||
| Av. P (ppm) | First year | 13.6 ± 1.9e | 24.2 ± 1.5dc | 32.6 ± 3.4c | 38.8 ± 9.4bc | 49.2 ± 3.2b | 65.8 ± 7.5a∗ | 24.9 |
| Second year | 14.06 ± 1.5c | 58.1 ± 2.5b | 59.8 ± 2.9b | 62.7 ± 5.0b | 79.7 ± 2.8a | 80.7 ± 3.9a∗ | 16.9 | |
| Combined | 13.8 ± 1.5e | 41.1 ± 18.6d | 46.1 ± 15.1cd | 50.78 ± 14.7c | 64.4 ± 16.9b | 73.2 ± 9.7a∗ | 13.6 | |
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| CEC (cmol+/kg) | First year | 19.7 ± 1.3b | 21.1 ± 0.9b | 24.9 ± 2.1a | 24.8 ± 1.4a | 25.6 ± 0.9a∗∗ | 24.6 ± 2.5a | 5.9 |
| Second year | 20.6 ± 0.9d | 27.1 ± 1.5c | 28.3 ± 1.0b | 31.8 ± 1.0a | 32.7 ± 1.8a | 33.2 ± 1.7a∗∗ | 5.5 | |
| Combined | 20.2 ± 1.1c | 24.1 ± 3.4b | 26.6 ± 2.4a | 28.4 ± 3.9a | 29.2 ± 4.0a∗∗ | 28.9 ± 5.0a | 4.8 | |
Within rows, means followed by the same letter are not significantly different (p > 0.05); ∗significant at p ≤ 0.01; ∗∗ significant at p ≤ 0.05; NS, not significant; LSD, least significant difference; PB; parthenium biochar; SD, standard deviation.