Cotton Fertilizer Calculator
Work out the exact urea, DAP and MOP for cotton from the recommended 150:75:75 kg/ha N-P₂O₅-K₂O dose, adjusted to your soil test and field size.
Give full P and K at sowing. Split N three ways — one-third at sowing, one-third at squaring (~35–40 days) and one-third at flowering (~65–70 days). Avoid late N: it extends vegetative growth and invites bollworm.
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 Cotton Fertilizer Calculator to convert the official cotton 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 Cotton Fertilizer Calculator
Bt and hybrid cotton remove far more nitrogen than desi types, and over-fertilized cotton grows rank foliage at the cost of bolls, so the dose is matched to the variety class and water situation. This calculator starts from the published recommendation of 150:75:75 kg/ha N-P₂O₅-K₂O (irrigated bt/hybrid) or 100:50:50 kg/ha N-P₂O₅-K₂O (irrigated desi) or 80:40:40 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 Cotton Fertilizer Calculator
- 1Enter your field area and pick the unit (hectare, acre or bigha).
- 2Choose the growing condition (irrigated bt/hybrid / irrigated desi / 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 Cotton Fertilizer Calculator?
- ✓Official package-of-practices dose for cotton — 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 cotton?+
Irrigated Bt/hybrid: 150 kg N, 75 kg P₂O₅ and 75 kg K₂O per hectare; Irrigated desi: 100 kg N, 50 kg P₂O₅ and 50 kg K₂O per hectare; Rainfed: 80 kg N, 40 kg P₂O₅ and 40 kg K₂O per hectare. Give full P and K at sowing.
When should I stop applying nitrogen to cotton?+
Apply the last nitrogen split at flowering (roughly 65–70 days after sowing). Nitrogen applied later mostly feeds vegetative growth, delays boll opening and increases pest pressure rather than adding yield.
Does Bt cotton need more fertilizer than desi cotton?+
Yes. Bt/hybrid cotton carries a much heavier boll load, so packages of practices recommend roughly 150:75:75 kg/ha N-P2O5-K2O for irrigated Bt against about 100:50:50 for irrigated desi types.
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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