An ecology student investigated the effect of soil pH on the rate of decomposition of oak leaf litter over a 45-day period. The results are shown in the table below.
| Soil pH | Mass of leaf litter at start (g) | Mass of leaf litter after 45 days (g) | Decrease in mass (g) | Percentage decrease in mass (%) |
|---|---|---|---|---|
| 4.0 | 15.0 | 13.8 | 1.2 | 8.0 |
| 5.0 | 15.0 | 11.7 | 3.3 | 22.0 |
| 6.0 | 15.0 | 8.4 | 6.6 | 44.0 |
| 7.0 | 15.0 | 5.1 | 9.9 | 66.0 |
| 8.0 | 15.0 | 12.3 | 2.7 | 18.0 |
Explain which soil pH was the most suitable for the decomposition of the oak leaf litter.
