Table 4.
Index of the influence of petroleum products (IFpp) on the activity of soil dehydrogenases
| Dose Pp | Incubation time, days | ||||
|---|---|---|---|---|---|
| g kg−1 DM of soil | 15 | 30 | 60 | 90 | 180 |
| Biodiesel (Bd) | |||||
| 2 | 3.337a | 2.008a | 1.416a | 2.208a | 0.886d |
| 4 | 3.378a | 1.982a | 1.397a | 1.836b | 1.660b |
| 8 | 1.997b | 1.531b | 1.290b | 1.368c | 1.763a |
| 16 | 0.910c | 0.933c | 0.715c | 1.089d | 1.799a |
| Diesel (D) | |||||
| 2 | 1.857c | 1.533c | 1.328b | 0.828d | 0.966c |
| 4 | 2.278b | 1.559bc | 1.313b | 1.510c | 1.323b |
| 8 | 2.587a | 1.603b | 1.484a | 1.786b | 1.324b |
| 16 | 2.628a | 1.668a | 1.298b | 2.028a | 2.366a |
| Fuel oil (Fo) | |||||
| 2 | 1.806d | 1.333c | 1.208c | 0.742d | 1.138c |
| 4 | 2.221c | 1.535b | 1.248bc | 1.224c | 1.218b |
| 8 | 2.461b | 1.572b | 1.287b | 2.097b | 1.459a |
| 16 | 2.899a | 1.819a | 1.609a | 2.417a | 1.494a |
| Unleaded petrol (P) | |||||
| 2 | 0.855a | 0.915a | 0.997d | 0.426a | 0.836a |
| 4 | 0.640b | 0.774b | 1.102c | 0.386b | 0.622b |
| 8 | 0.582c | 0.698c | 1.286b | 0.336c | 0.534c |
| 16 | 0.588c | 0.622c | 1.374a | 0.259d | 0.500c |
The same letter means a homogeneous group in the columns for a petroleum product (Pp)