Sunflower Fertilizer Calculator
Work out the exact urea, DAP and MOP for sunflower from the recommended 60:60:30 kg/ha N-P₂O₅-K₂O dose, adjusted to your soil test and field size.
Half N + full P, K basal; rest N at 30–35 days. Spray 0.2% borax at ray-floret opening — boron at flowering is the classic fix for empty centres in the head.
Indicative planning figures based on published research averages. Local soil tests, varieties and weather change actual requirements — confirm with your agronomist or extension officer.
Farmers and agronomists use the free Sunflower Fertilizer Calculator to convert the official sunflower recommendation into exact urea, DAP and MOP quantities for their own field in seconds — no agronomy tables, no spreadsheet, and it works offline in the field.
About Sunflower Fertilizer Calculator
Sunflower's signature deficiency is boron at flowering: a single 0.2% borax spray on the heads cuts unfilled centres dramatically and routinely pays 10:1 — the calculator includes it. This calculator starts from the published recommendation of 60:60:30 kg/ha N-P₂O₅-K₂O (irrigated) or 40:40:20 kg/ha N-P₂O₅-K₂O (rainfed), adjusts it ±25% for your soil-test N, P and K ratings, scales it to your field area in hectares, acres or bigha, and converts the nutrients into real products — urea (46% N), DAP (18-46-0) and MOP (0-0-60) — including the number of bags to buy.
How to use Sunflower Fertilizer Calculator
- 1Enter your field area and pick the unit (hectare, acre or bigha).
- 2Choose the growing condition (irrigated / rainfed) and your soil-test ratings for N, P and K — leave Medium if you have no recent soil test.
- 3Read off the urea, DAP and MOP quantities and bag counts, then follow the split-application note for timing.
Why use Sunflower Fertilizer Calculator?
- ✓Official package-of-practices dose for sunflower — not a generic NPK guess
- ✓Soil-test Low/Medium/High ratings adjust the dose ±25% automatically
- ✓Converts nutrients to urea, DAP and MOP bags, with the DAP nitrogen credit handled correctly
- ✓Works in hectares, acres and bigha — and runs fully in your browser, even offline in the field
Frequently asked questions
What is the recommended fertilizer dose for sunflower?+
Irrigated: 60 kg N, 60 kg P₂O₅ and 30 kg K₂O per hectare; Rainfed: 40 kg N, 40 kg P₂O₅ and 20 kg K₂O per hectare. Half N + full P, K basal; rest N at 30–35 days.
Why are my sunflower heads empty in the centre?+
Poor seed set from boron deficiency and/or poor pollination. Spray 0.2% borax at ray-floret stage and encourage bee activity (avoid insecticide sprays in the morning during flowering).
Does sunflower deplete the soil more than other crops?+
It is a deep, aggressive feeder, so follow it with a legume and return stalks to the field; in rotation its 60:60:30 dose should be budgeted alongside the next crop's needs.
How does the calculator convert NPK into urea, DAP and MOP?+
DAP (46% P₂O₅) is sized to cover the phosphorus need; the nitrogen it also carries (18% N) is credited against the N requirement, and urea (46% N) supplies the balance. MOP (60% K₂O) covers potassium. Bag counts use 45 kg urea and 50 kg DAP/MOP bags.
Is this tool free, and does my data leave the device?+
It is completely free with no sign-up, and all calculation happens in your browser — nothing you enter is uploaded, so it also works offline in the field.
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