| Treatment combination | Average yield (kg ha−1) | Adjusted yield (kg ha−1) | Gross benefit (ETB ha−1) | Total variable cost (ETB ha−1) | Net benefit (ETB ha−1) | Marginal rate of return (%) |
| I2 × 14 cm | 1728.0 | 1555.2 | 10886.4 | 5288 | 5598.4 | 157.8 |
| I2 × 10 cm | 2045.0 | 1840.5 | 12883.5 | 5850 | 7033.5 | 255.3 |
| I3 × 10 cm | 2873.5 | 2586.3 | 18104.1 | 6850 | 11254.1 | 422.1 |