An agricultural scientist investigates how ammonium nitrate fertiliser, and the seeding density of barley plants, affect the total yield of barley.
She adds different masses of ammonium nitrate fertiliser to fields sown with different numbers of barley seeds per square metre, and measures the yield after harvest.
The table shows her results.
| Mass of ammonium nitrate fertiliser added in kg\text{kg}kg per hectare | Seeding density in seeds per m2\text{m}^2m2 | Yield of barley in tonnes per hectare |
|---|---|---|
| 0 | 150 | 5.2 |
| 0 | 300 | 4.5 |
| 50 | 150 | 7.8 |
| 50 | 300 | 6.4 |
| 100 | 150 | 6.1 |
| 100 | 300 | 5.3 |
Identify the mass of fertiliser and the seeding density that produced the highest yield of barley.
Describe the effect that changing the mass of ammonium nitrate fertiliser has on the yield of barley.
Explain the effect that changing the seeding density has on the yield of barley.
