种植年限 | N (g/kg) | P (g/kg) | N/P (g/kg) |
2 | 28.47 ± 2.46a | 3.17 ± 0.10a | 8.99 ± 1.07a |
5 | 25.43 ± 1.07ab | 2.06 ± 0.04b | 12.33 ± 0.72a |
8 | 24.27 ± 1.46b | 1.87 ± 0.05c | 12.98 ± 0.82b |