| Cover crop species | Cu rate (mg kg−1) | Average | ||||
| 0 | 5 | 10 | 20 | |||
| 1. Crotalaria (Smooth crotalaria) | 5.37d | 5.87bc | 5.66c | 6.50a | 5.85ef | |
| 2. Crotalaria (Showy Crotalaria) | 5.56cd | 5.66cd | 5.96bc | 6.23ab | 5.85ef | |
| 3. Calopogonio (Calapo) | 5.53cd | 5.40d | 6.20ab | 6.03bc | 5.79f | |
| 4. Pueraria (Tropical Kudzu) | 5.76cd | 6.36a | 6.30a | 5.70d | 6.03c | |
| 5. Pigeonpea (black) | 5.83bcd | 6.26a | 6.23ab | 5.76cd | 6.03c | |
| 6. Lablab | 5.50cd | 6.40a | 6.43a | 6.27ab | 6.15bc | |
| 7. Black velvet bean | 6.30ab | 6.17ab | 5.73c | 5.83cd | 6.00cde | |
| 8. Gray velvet bean (Bengal bean) | 5.97bc | 6.20ab | 6.46a | 6.23ab | 6.21b | |
| 9 Jack bean | 6.60a | 6.20ab | 6.43a | 6.43a | 6.42a | |
| Average | 5.82b | 6.05a | 6.15a | 6.11a | ||
| F-Test | ||||||
| Copper rate (Cu) | ** | |||||
| Cover crop species (C) | ** | |||||
| Cu X C | ** | |||||
| CVCu (%) | 2.49 | |||||
| CVC (%) | 2.17 | |||||