Select the currency that you want to use. Please note that the currency is NOT used in any of the calculations, it is simply used to change how the calculator displays the "Zinc Fertilizer Cost", the "Crop Price" and the axis/chart labels in the "Profit Increase" chart.

Select the type of zinc fertilizer that you want use in your calculations. There are three zinc fertilizers that the calculator can use, each containing a different percentage of zinc. The percentage of zinc in each fertilizer is indicated by the percentage in brackets.

Select the cost of the zinc fertilizer. This cost is the total cost for the zinc fertilizer, including any additional application cost if the zinc fertilizer is added in a separate application. If the zinc fertilizer is applied as part of an existing fertilizer application (for example, as part of a NPK blend), then there is no need to add an additional application cost.

Enter the application rate for the "Zinc Fertilizer Type" selected in Kilograms/Hectare. Once you have entered a "Zinc Fertilizer Application Rate", the calculator will display the equivalent zinc metal application rate to the right of the "Zinc Fertilizer Application Rate" you entered.

Enter what the crop yield is/was PRIOR to the zinc fertilizer application in the local currency per hectare.

Enter the revenue received for the crop per tonne.

The calculator displays the percentage increase in yield required to cover the application cost for the zinc fertilizer. If the yield increase from the application of zinc fertilizer exceeds this value, the application of zinc fertilizer results in increased profit for the farmer.