Fertiliser Calculator
Enter your stand count, your target rates and the products you actually have — get kilograms per hectare and per application.
Rates should come from your soil and tissue test. This calculator does the arithmetic: nutrient demand → product quantity → split schedule.
Fertiliser calculator
Per-stem annual demand converted into product per hectare and per application.
What the calculator does#
1. Nutrient per hectare (kg) = rate (g/stem) × population (plants/ha) ÷ 1,000
→ 200 g N × 1,667 plants = 333 kg N per hectare per year
2. Product per hectare (kg) = nutrient needed ÷ nutrient fraction in the product
→ 333 kg N ÷ 0.46 (urea) = 725 kg urea per hectare per year
3. Per application = product ÷ number of applications
(N and K are split; P and Ca are largely basal — see the schedule)Interpreting your soil test first#
| Test result | Adjust the programme |
|---|---|
| pH below 5.5 | Add lime before raising fertiliser rates — unavailable nutrients cannot be bought |
| P in the deficient band | Raise P to the rate in the preset; re-test in 12 months |
| K already high | Reduce K by 25–50% — excess K induces Mg and Ca deficiency |
| Mg low with high K | Add Mg independently; do not assume K covers it |
| Organic matter below 2% | Add compost and mulch; reduce reliance on soluble N |
| Tissue K below 3.2% at flowering | Raise the flowering and filling K splits |
| Tissue Zn below 15 mg/kg | Add a foliar Zn programme; check soil pH |
Split schedule logic#
| Timing | Share of N | Share of K |
|---|---|---|
| Basal at planting | 10% | 10% |
| Month 1–2 | 15% | 10% |
| Month 3–4 | 25% | 15% |
| Month 5–6 | 25% | 25% |
| Month 7–8 (flowering) | 15% | 30% |
| Month 9–10 (filling) | 10% | 10% |
The calculator compresses or expands this pattern to your chosen number of applications.
Next steps#
- Understand what the nutrients do: Nutrition reference.
- Execute the application: How to fertilise bananas.
- Fix the field size first: Planting density calculator.