| Cover crop species | Cu rate (mg kg−1) | Average | |||
| 0 | 5 | 10 | 20 | ||
| 1. Crotalaria (Smooth crotalaria) | 30.33a | 28.67b | 31.33a | 27.67a | 29.50ab |
| 2. Crotalaria (Showy Crotalaria) | 29.00a | 29.00b | 31.33a | 27.66a | 29.25ab |
| 3. Calopogonio (Calapo) | 27.33a | 28.67b | 30.33a | 26.00a | 28.08b |
| 4. Pueraria (Tropical Kudzu) | 30.67a | 29.00b | 31.33a | 26.00a | 29.25 |
| 5. Pigeonpea (black) | 30.00a | 31.00ab | 30.33a | 26.00a | 29.33ab |
| 6. Lablab | 29.00a | 31.00ab | 29.00a | 26.66a | 28.91ab |
| 7. Black velvet bean | 29.00a | 33.00a | 29.00a | 27.00a | 29.67a |
| 8. Gray velvet bean (Bengal bean) | 29.67a | 32.67a | 29.00a | 27.66a | 29.75a |
| 9 Jack bean | 28.67a | 29.33b | 28.00a | 26.33a | 28.08b |
| Average | 29.37a | 30.25a | 29.96a | 26.78b | |
| F-Test | |||||
| Copper rate (Cu) | ** | ||||
| Cover crop species (C) | ** | ||||
| Cu X C | ** | ||||
| CVCu(%) | 5.05 | ||||
| CVC(%) | 4.07 | ||||