"How much fertiliser?" has an exact answer — but it is a calculation, not a universal number. The official balance method weighs crop offtake for the planned yield against what the soil can supply: nutrient reserves, humus mineralisation, organic inputs and uptake coefficients. Supply rules the result: low P/K soils need rates above offtake, rich soils justify negative balances or no P/K at all, and pH decides what actually reaches the root (acid soils lock up phosphorus, alkaline ones block zinc and iron).
On top sits the Nitrates Directive cap system — up to 20.4 kg N/da for wheat on heavy soils at intensive yields, 14.4 for maize, 12.0 for sunflower, and 17 kg N/da for organic nitrogen. Every input of that balance except offtake comes from soil analysis — which is exactly what Zemedelko's zonal satellite analysis delivers, with an AI read-out that does the balance for your field.