Put on the appropriate personal protective equipment.

Measure out a ten metre by ten metre square (100 square metres).

Set the spreader to the estimated setting for the application rate required (see spreader's operator's manual).

Weigh out fertiliser and add to hopper (Weight A).

Fertilise 100 square metre area.

Weigh the fertiliser left over in the hopper (Weight B).

Calculate the amount required to fertilise 100 square metres (F100).

F100 = Weight A – Weight B

Calculate amount required to fertilise one square metre (F1).

F1 = F100 divided by 100

Calculate the amount required to fertilise one hectare (FH).

FH = F1 x 10000

Repeat steps one to nine until the setting you choose gives the required application rate.