| Soil fertility category | Site | X2 | P-value | |
| Intervention | Non-intervention | |||
| Good | 44 | 36 | 0.80 | 0.371 |
| Moderate | 39 | 46 | 0.576 | 0.448 |
| Poor | 17 | 18 | 0.029 | 0.866 |
| n | 100 | 100 |
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