MAP — Mono-Ammonium Phosphate (12-61-0)
The soluble, high-phosphorus grade for drip and nurseries — a phosphorus starter you feed through the water, not a field basal.
- Composition
- 12% N, 61% P₂O₅
- Form
- Fully water-soluble
- Price
- Premium (non-subsidised)
- Best for
- Drip fertigation & nurseries
Overview
MAP supplies 12% nitrogen and 61% phosphorus — the highest phosphorus content of any common fertiliser — and it is fully water-soluble. That solubility, not the concentration alone, is the point: MAP is made for drip fertigation and nursery feeding, where it delivers a strong phosphorus start without clogging the system.
On an open field, granular DAP does the phosphorus job far more cheaply, so MAP is not a broadcast fertiliser. Its place is high-value vegetables and fruit under drip, and raising healthy transplants, where soluble phosphorus at establishment pays for the premium.
What it is and when to reach for it
- A soluble, high-phosphorus fertiliser for fertigation and nursery raising — reach for it for a phosphorus start under drip.
- It is a premium top-up, not a field basal: on open fields DAP delivers phosphorus for a fraction of the cost.
- Its slight acidity helps keep drip lines clean, which is part of why growers pick it for fertigation.
How to use it well
- Fertigation: apply small doses through the drip early in the crop for root and establishment support, per the crop’s schedule.
- Nursery: dissolve and water in at low concentration to raise sturdy, well-rooted transplants.
- Being fully soluble it mixes cleanly with other solubles, but do a jar test before combining with calcium-based products.
Common mistakes
- Broadcasting it on a field — an expensive way to buy phosphorus that DAP supplies far cheaper.
- Mixing it in the tank with calcium nitrate, which can form an insoluble precipitate — keep them in separate stock tanks.
- Relying on its 12% nitrogen alone and under-feeding nitrogen over the season.
Organic alternative
Bone meal
For organic phosphorus at establishment, bone meal worked into the nursery mix or root zone is the slow-release stand-in.
Crops it is used on
Open a crop for its full nutrient schedule.
Common questions
What is the difference between MAP and DAP?
Both are ammonium phosphates, but MAP is more concentrated in phosphorus (61% vs 46%) and fully water-soluble, which makes it suited to drip fertigation and nurseries. DAP is a granular field fertiliser, cheaper and applied at sowing. MAP is also slightly acidic, DAP slightly alkaline.
Can MAP be used in drip irrigation?
Yes — being fully water-soluble it is one of the standard fertigation grades, valued for delivering soluble phosphorus without clogging. Apply it in small doses through the season and avoid tank-mixing it directly with calcium nitrate, which can cause a precipitate.
Is MAP worth it over DAP for a field crop?
Usually not. On an open field, granular DAP supplies phosphorus for far less money. MAP earns its premium only where you are fertigating high-value crops or raising nursery transplants and need soluble phosphorus.
Composition and doses follow ICAR / Soil Health Card guidance; prices are the notified subsidised rates for the season shown and are guidance, not a quote. A soil test for your field always beats a general rate. See our editorial policy.