Table 2. Effects of ridge tillage on grain yield and N use efficiency of waterlogged summer maize.
| Year | Hybrid | Treatment | Grain yield (Kg/ha) | Nitrogen translocation amount, NTA | Nitrogen translocation efficiency (NTE, %) | Nitrogen contribution proportion (NCP, %) | Nitrogen harvest index (NHI) | Nitrogen use efficiency (NUE, %) |
|---|---|---|---|---|---|---|---|---|
| (g/plant) | ||||||||
| 2014 | DH605 | W-V3 | 9,310 c | 0.22 c | 14.97 c | 13.50 c | 0.57 b | 47.89 c |
| W-V3+R | 11,495 b | 0.59 b | 32.24 b | 27.44 b | 0.63 a | 50.23 b | ||
| CK | 14,336 a | 1.29 a | 50.00 a | 51.39 a | 0.66 a | 55.89 a | ||
| ZD958 | W-V3 | 8,093 c | 0.20 c | 15.27 b | 13.25 c | 0.58 b | 45.76 b | |
| W-V3+R | 11,306 b | 0.96 b | 46.38 a | 46.83 b | 0.65 a | 53.01 a | ||
| CK | 13,916 a | 1.31 a | 48.16 a | 50.58 a | 0.65 a | 51.54 a | ||
| 2015 | DH605 | W-V3 | 8,311 c | 0.29 c | 16.33 c | 18.28 c | 0.52 b | 40.24 b |
| W-V3+R | 12,646 b | 0.43 b | 20.18 b | 21.51 b | 0.54 b | 51.01 a | ||
| CK | 14,175 a | 0.92 a | 37.96 a | 38.18 a | 0.62 a | 53.44 a | ||
| ZD958 | W-V3 | 8,137 c | 0.30 b | 20.81 c | 22.16 c | 0.54 c | 48.81 b | |
| W-V3+R | 13,107 b | 0.64 b | 33.14 b | 30.57 b | 0.62 b | 57.01 a | ||
| CK | 14,164 a | 1.13 a | 47.66 a | 47.51 a | 0.66 a | 58.19 a |
Note:
W-V3: waterlogging at the third leaf stage under conventional tillage; W-V3+R: waterlogging at the third leaf stage under ridge tillage; CK: no waterlogging under conventional tillage. Values followed by a different small letter within a column are significantly different at 5% probability level. Differences between treatments were calculated within the hybrids for each particular year.