| Cover crop species | Cu rate (mg kg−1) | Average | ||||
| 0 | 5 | 10 | 20 | |||
| 1. Crotalaria (Smooth crotalaria) | 16.00cde | 18.33b | 20.33bc | 17.33d | 18.00e | |
| 2. Crotalaria (Showy Crotalaria) | 19.33bcd | 25.33ab | 21.00bc | 25.66abcd | 22.83cd | |
| 3. Calopogonio (Calapo) | 11.66ef | 26.00ab | 28.66ab | 26.66abc | 23.25cd | |
| 4. Pueraria (Tropical Kudzu) | 15.00de | 22.00ab | 17.66c | 19.66cd | 18.58de | |
| 5. Pigeonpea (black) | 8.00f | 22.33ab | 21.66bc | 24.00bcd | 19.00de | |
| 6. Lablab | 31.66a | 25.00ab | 27.00abc | 24.33abcd | 27.00bc | |
| 7. Black velvet bean | 22.00b | 29.66ab | 30.00ab | 32.00ab | 28.41ab | |
| 8. Gray velvet bean (Bengal bean) | 35.66a | 28.66ab | 35.00a | 33.33a | 33.16a | |
| 9 Jack bean | 21.00bc | 32.00a | 28.00abc | 32.33ab | 28.33b | |
| Average | 20.03b | 25.48a | 25.48a | 26.14a | 24.28 | |
| F-Test | ||||||
| Copper rate (Cu) | ** | |||||
| Cover crop species (C) | ** | |||||
| Cu X C | ** | |||||
| CVCu (%) | 8.77 | |||||
| CVC (%) | 15.10 | |||||