| Treatments | RI | RII | RIII | Mean |
| T1 = Control (no urea) | 77.3 | 80.6 | 72.5 | 76.8 |
| T2 = Recommended urea soil applied (130 kg・ha−1) | 91.6 | 88.5 | 87.1 | 89.1 |
| T3 = 1% urea at 35 days after sowing | 89.6 | 90.5 | 88.6 | 89.6 |
| T4 = 1% urea at 60 days after sowing | 90.2 | 92.6 | 87.2 | 90.0 |
| T5 = 1% urea at 85 days after sowing | 92.6 | 89.6 | 88.8 | 90.4 |