Work out fertiliser requirement instantly with clear inputs, formula shown and shareable results.
Divides the nutrient target by the fertiliser's nutrient content to give the product rate, then scales to the area and cost.
Fertiliser rate
Product rate (kg/ha) = nutrient target (kg/ha) / nutrient content fraction; urea at 46% N needs 2.17 kg per kg of N
It contains 46% nitrogen, so one divided by 0.46 gives 2.17.
Fertiliser labels use P2O5 and K2O; multiply P by 2.29 and K by 1.2 to convert to oxide basis.