# Calculating the amount of fertiliser to apply

The content of each nutrient in a fertiliser is given as a percentage of N, P_{2}O_{5} and K_{2}O.

## ExampleWinter wheat grown on a P Index 2, K Index 1 soil and expected to yield 8 t/ha grain requires 200 kg N/ha, 65 kg P The surplus 35 kg P The deficit of 15 kg K |

Metric to imperial conversion tables are given in Appendix 8. If applying liquid fertilisers, manufacturers can supply tables which convert kg/ha of nutrient to litres/ha of product.

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