Table 3.
Mineral nitrogen (kg N ha-1) in the top 40 cm of soil treated with different N fertilizers.
| SEASON 2019A (Short rain) | SEASON 2019B (Long rain) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Soil depth(cm) | Rate(kg N ha-1) | Days after planting | |||||||||
| 0 | 35 | 70 | 91 | 125 | 0 | 35 | 70 | 91 | 125 | ||
| 0–20 | 0 | 4.1 ± 1.1 | 9.9 ± 2.8 | 2.4 ± 0.8 | 2.9 ± 2.2 | 6.3 ± 0.8 | 39.0 ± 3.8 | 5.7 ± 1.0 | 26.1 ± 3.1a | 14.4 ± 0.5 | 31.5 ± 0.8 |
| 30N BSF | 3.2 ± 1.6 | 6.9 ± 3.6 | 5.7 ± 1.4 | 5.4 ± 2.4 | 6.7 ± 1.3 | 42.1 ± 4.2 | 11.4 ± 5.2 | 37 ± 8.7a | 19.9 ± 3.3 | 23.5 ± 16.5 | |
| 60N BSF | 2.2 ± 0.1 | 4.8 ± 0.2 | 3.4 ± 1.5 | 8.1 ± 1.0 | 6.3 ± 1.0 | 43.2 ± 7.7 | 23 ± 9.9 | 63.0 ± 14.5a | 15.4 ± 1.4 | 23.4 ± 13.1 | |
| 100N BSF | 4.2 ± 1.1 | 9.3 ± 3.0 | 4.2 ± 1.6 | 2.5 ± 2.2 | 6.7 ± 0.6 | 36.2 ± 7.9 | 6.4 ± 3.1 | 50.1 ± 6.1a | 27.5 ± 4.7 | 54.4 ± 7.1 | |
| 30N SAFI | 1.9 ± 1.1 | 4.4 ± 2.6 | 5.1 ± 1.9 | 6.0 ± 0.9 | 5.8 ± 1.0 | 38.1 ± 4.9 | 4.0 ± 0.1 | 28.9 ± 8.5a | 17.9 ± 2.0 | 36.6 ± 4.5 | |
| 60N SAFI | 1.8 ± 0.2 | 4.0 ± 0.2 | 11.3 ± 5.7 | 0.82 ± 0.1 | 5.4 ± 1.8 | 69.6 ± 10.2 | 3.9 ± 0.01 | 62.7 ± 15.0a | 12.6 ± 5.6 | 59.2 ± 10.3 | |
| 100N SAFI | 5.7 ± 1.7 | 12.9 ± 3.4 | 7.2 ± 1.0 | 4.8 ± 1.8 | 5.9 ± 1.6 | 46.5 ± 23.3 | 5.4 ± 1.6 | 47.1 ± 7.1a | 16 ± 1.1 | 31.6 ± 1.8 | |
| 30N UREA | 1.7 ± 0.8 | 3.7 ± 1.9 | 7.3 ± 1.2 | 5.5 ± 2.2 | 7.1 ± 2.1 | 46.2 ± 1.3 | 6.8 ± 1.6 | 23.6 ± 4.7a | 14.5 ± 2.4 | 41.5 ± 3.5 | |
| 60N UREA | 2.6 ± 1.3 | 5.9 ± 3.1 | 6.1 ± 0.7 | 8.1 ± 0.7 | 7.5 ± 1.2 | 25.4 ± 5.0 | 5.2 ± 1.6 | 45.1 ± 8.3a | 32 ± 15.5 | 49.5 ± 23 | |
| 100N UREA | 6.1 ± 0.5 | 13.3 ± 0.7 | 6.6 ± 1.1 | 8.2 ± 3.9 | 13.0 ± 3.9 | 39.9 ± 11.4 | 13.3 ± 2.9 | 51.1 ± 7.8a | 24.4 ± 5.5 | 62.6 ± 7.6 | |
| ns | ns | ns | ns | ns | ns | ns | * | ns | ns | ||
| 20–40 | 0 | 3.4 ± 1.3 | 7.8 ± 2.9 | 6.4 ± 1.7 | 5.9 ± 0.8ab | 3.6 ± 0.8a | 16.0 ± 6.3 | 19.1 ± 9b | 35.9 ± 15 | 11.6 ± 3.6 | 12.3 ± 1.2ab |
| 30N BSF | 2.0 ± 1.1 | 3.9 ± 2.0 | 11.4 ± 0.4 | 5.0 ± 0.4b | 3.1 ± 0.4a | 17.5 ± 4.2 | 27.9 ± 11ab | 44.5 ± 16.4 | 15.2 ± 6.2 | 9.1 ± 2.6b | |
| 60N BSF | 1.2 ± 0.4 | 2.5 ± 0.7 | 6.2 ± 0.8 | 5.9 ± 0.5ab | 3.1 ± 0.6a | 18 ± 11.2 | 42.5 ± 19ab | 37.5 ± 10.8 | 17.1 ± 6.8 | 9.1 ± 2.0b | |
| 100N BSF | 2.1 ± 0.1 | 4.1 ± 0.1 | 7.8 ± 3.3 | 5.3 ± 0.2ab | 4.6 ± 0.6a | 19 ± 4.4 | 34.5 ± 11ab | 49.6 ± 8.1 | 11.0 ± 2.7 | 15.9 ± 5.0ab | |
| 30N SAFI | 1.2 ± 0.4 | 2.5 ± 0.7 | 7.5 ± 1.6 | 4.5 ± 0.3b | 3.0 ± 0.2a | 32.5 ± 12.0 | 16.5 ± 8.3b | 65.6 ± 1.5 | 10.2 ± 0.4 | 7.5 ± 1.0b | |
| 60N SAFI | 0.8 ± 0.4 | 1.8 ± 0.7 | 7.4 ± 1.6 | 5.1 ± 0.2ab | 3.6 ± 0.5a | 38.9 ± 15.4 | 32.4 ± 14ab | 42 ± 8.3 | 11.1 ± 6.8 | 9.4 ± 1.6b | |
| 100N SAFI | 2.4 ± 0.9 | 4.6 ± 1.7 | 7.3 ± 2.8 | 6.4 ± 0.6ab | 2.8 ± 1.3a | 13.4 ± 6.0 | 8.2 ± 2.1b | 35.9 ± 11.2 | 12.4 ± 4.6 | 6.5 ± 0.1b | |
| 30N UREA | 2.1 ± 0.9 | 4.0 ± 1.6 | 12.1 ± 2.5 | 5.1 ± 0.1ab | 5.9 ± 0.8a | 9.6 ± 2.8 | 12.4 ± 2.1b | 36.8 ± 13.8 | 16.1 ± 6.4 | 20.5 ± 4.1ab | |
| 60N UREA | 1.1 ± 0.3 | 2.3 ± 0.5 | 9.9 ± 2.4 | 7.5 ± 1.3ab | 3.9 ± 0.5a | 19.7 ± 8.7 | 89.5 ± 22ab | 48.1 ± 14 | 12.7 ± 3.5 | 26.1 ± 5.5a | |
| 100N UREA | 2.4 ± 1.0 | 4.6 ± 1.8 | 15.5 ± 5.2 | 8.9 ± 1.6a | 6.2 ± 0.5a | 35.6 ± 6.5 | 149.3 ± 69a | 108.2 ± 41 | 26.2 ± 6.9 | 20.6 ± 1.5ab | |
| ns | ns | ns | * | * | ns | * | ns | ns | ** | ||
*p < 0.05, ns, not significant; 30N, 60N, and 100N, application rates of fertilizers at rates equivalent to 30, 60, and 100 kg N ha-1 supplemented with 60 kg P ha-1 and 50 kg K ha-1; 0, control treatment; BSF, black soldier fly frass fertilizer; SAFI, commercial organic fertilizer.