| Cover crop species | Copper use efficiency (mg µg−1) |
| 1. Crotalaria (Smooth crotalaria) | 208.78bcd |
| 2. Crotalaria (Showy Crotalaria) | 180.40cd |
| 3. Calopogonio (Calapo) | 238.49bcd |
| 4. Pueraria (Tropical Kudzu) | 142.08d |
| 5. Pigeonpea (black) | 208.00bcd |
| 6. Lablab | 416.97a |
| 7. Black velvet bean | 294.12b |
| 8. Gray velvet bean (Bengal bean) | 276.12bc |
| 9 Jack bean | 484.06a |
| Average | 272.11 |
| F-Test | |
| Copper rate (Cu) | NS |
| Cover crop species (C) | ** |
| Cu X C | NS |
| CVCu(%) | 29.32 |
| CVC(%) | 28.62 |