A student investigated the water-retaining properties of four different soil mixes (P, Q, R, and S) to find which is most suitable for growing tomato plants in pots during a dry, sunny summer.
The table below shows the results of their investigation:
| Type of soil mix | P | Q | R | S |
|---|---|---|---|---|
| Dry mass of soil mix / g | 400 | 400 | 800 | 800 |
| Volume of water retained / cm3\text{cm}^3cm3 | 12 | 28 | 48 | 32 |
| Total mass of soil mix after water was added / g | 412 | 428 | 848 | 832 |
Explain which soil mix would be best to use for agricultural pots containing tomato plants to be grown during a dry, sunny summer.
