Research Article
Evaluation of In-Season Nitrogen Management for Summer Maize in North Central China
Table 4
Maize grain yield, crop N uptake, nitrogen use efficiency (REN and AEN), HI, and HIN of different N treatments.
| | Sites | Treatments | Grain yield (kg ha−1) | Crop N uptake (kg N ha−1) | REN (kg kg−1) | AEN (kg kg−1) | HI (%) | HIN (%) |
| | Hengshui | N0 | 7384.0b† | 178.8c | — | — | 54.5a | 60.2a | | N120 (0/120) | 7877.3ab | 207.1b | 23.6d | 4.1b | 54.2a | 59.9a | | N120 (30/90) | 8181.3a | 230.6ab | 43.2b | 6.6a | 54.8a | 60.7a | | N120 (60/60) | 8231.1a | 246.7a | 56.6a | 7.1a | 54.5a | 60.6a | | N180 (0/180) | 8037.3ab | 212.3b | 18.6d | 3.6bc | 53.3ab | 60.5a | | N180 (45/135) | 8088.0ab | 217.4b | 21.5d | 3.9b | 54.7a | 62.9a | | N180 (90/90) | 8181.3a | 239.1a | 33.5c | 4.4b | 52.3ab | 60.6a | | N240 (0/240) | 8073.8ab | 239.5a | 25.3d | 2.9c | 50.1b | 57.1a |
| | Xinji | N0 | 6157.8c | 103.2d | — | — | 57.6a | 70.1a | | N120 (0/120) | 6298.6c | 124.1c | 17.5e | 1.2d | 51.7b | 63.9ab | | N120 (30/90) | 6907.5b | 153.4a | 41.9a | 6.2ab | 55.8a | 67.3ab | | N120 (60/60) | 6769.2b | 146.8ab | 36.3b | 5.1b | 55.8a | 65.2ab | | N180 (0/180) | 6677.2bc | 137.3b | 19.0e | 2.9c | 51.3b | 64.0b | | N180 (45/135) | 7228.3ab | 150.7ab | 26.2c | 5.9b | 56.2a | 68.8ab | | N180 (90/90) | 7434.5a | 154.1a | 28.3c | 7.2a | 56.6a | 67.4ab | | N240 (0/240) | 6911.9b | 155.4a | 21.8d | 3.1c | 50.2b | 62.4b |
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† Within each column, mean values followed by different letters are significantly different (P < 0.05).
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