TABLE 7.
Effects of nitrogen application on harvest index, yield, and yield components of maize.
| Cultivars | Nitrogen rate | Kernels per ear |
1,000-kernel weight (g) |
Grain yield (t ha–1) |
Harvest index (%) |
||||
| 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | ||
| ZH 311 | N 0 | 366.66 d | 337.96 d | 271.87 g | 266.75 g | 5.94 e | 5.48 e | 0.44 cd | 0.46 c |
| N 120 | 437.96 b | 411.18 b | 283.38 e | 280.07 e | 7.24 d | 6.55 bc | 0.44 bcd | 0.45 cd | |
| N 240 | 468.39 a | 448.11 a | 291.68 d | 290.78 c | 8.24 a | 7.46 a | 0.43 d | 0.44 d | |
| N 360 | 458.34 a | 431.63 a | 285.04 e | 284.56 d | 7.97 b | 6.75 b | 0.43 d | 0.42 e | |
| Mean | 432.84 A | 407.22 A | 282.99 B | 280.54 B | 7.35 A | 6.56 A | 0.44 B | 0.44 B | |
| XY 508 | N 0 | 283.47 f | 281.07 e | 279.55 f | 277.23 f | 5.20 f | 4.64 f | 0.47 a | 0.49 a |
| N 120 | 325.17 e | 338.60 d | 300.37 c | 291.76 c | 6.10 e | 5.71 e | 0.46 ab | 0.48 ab | |
| N 240 | 379.06 d | 361.58 c | 310.25 b | 299.45 b | 7.11 d | 6.25 d | 0.46 ab | 0.46 bc | |
| N 360 | 400.41 c | 377.02 c | 316.61 a | 303.58 a | 7.46 c | 6.47 cd | 0.46 abc | 0.45 cd | |
| Mean | 347.03 B | 339.57 B | 301.70 A | 293.01 A | 6.47 B | 5.77 B | 0.46 A | 0.47 A | |
| F value | Years (Y) | 36.60** | 156.60** | 437.75** | 2.69ns | ||||
| Cultivar (C) | 787.57** | 1224.54** | 559.01** | 71.81** | |||||
| Nitrogen (N) | 287.96** | 640.70** | 642.14** | 7.02** | |||||
| Y × C | 11.03** | 49.00** | 1.60ns | 0.07ns | |||||
| Y × N | 1.96ns | 2.12ns | 15.06** | 5.83** | |||||
| C × N | 9.40** | 59.60** | 21.60** | 0.62ns | |||||
| Y × C × N | 2.81ns | 14.27** | 2.00ns | 0.12ns | |||||
Values followed by different lowercase letters are significantly different with p < 0.05; within cultivars, values with different uppercase letters are significantly different with p < 0.05 according to the least significant difference test. **p < 0.01; *p < 0.05; nsNot significant. The bold values are the mean value of one cultivar in different N treatments.