DAP is the default seeding starter across Australian broadacre cropping, and for good reason: at 18-46-0 it is the most concentrated way to place phosphorus and a useful slug of nitrogen in the same pass. Here is what to check before you commit a few hundred tonnes of it.
What a tonne of DAP actually delivers
| Per tonne | |
|---|---|
| Nitrogen (N) | 180 kg |
| Phosphorus (P2O5) | 460 kg |
| Elemental P | ~201 kg |
| Total nutrient units | 64 |
That 64 units is the number worth comparing across suppliers — not the price per tonne. Two products at the same price per tonne are not the same buy if one carries fewer units.
Working out your tonnage
| Target P2O5 | DAP rate | N also applied | 300 ha | 800 ha |
|---|---|---|---|---|
| 25 kg/ha | 54 kg/ha | ~10 kg/ha | 16.2 t | 43.2 t |
| 35 kg/ha | 76 kg/ha | ~14 kg/ha | 22.8 t | 60.8 t |
| 45 kg/ha | 98 kg/ha | ~18 kg/ha | 29.4 t | 78.4 t |
| 60 kg/ha | 130 kg/ha | ~23 kg/ha | 39 t | 104 t |
Do not overlook the third column. The nitrogen in DAP is real nitrogen and should come off your in-season plan — growers routinely pay for it twice.
Four things to check before you commit
1. Your soil pH, because it may favour MAP
DAP creates an alkaline zone as it dissolves. On alkaline and calcareous soils — much of South Australia and the Yorke and Eyre Peninsulas — MAP 12-61-0 and its acidic reaction zone often performs better. Full comparison in DAP vs MAP.
2. Seed safety
That alkaline zone also releases free ammonia, which can hurt germinating seed in close contact — worse in dry conditions, on sands, and with small seeds like canola. Separation between seed and fertiliser matters more than the rate.
3. Granule quality
If you spread wide rather than band, uniform hard granules are what deliver the rate you paid for — irregular ones scatter and stripe. Ask about size range and hardness, not just the analysis. Same logic as high tower granulation.
4. The Certificate of Analysis
Ask for the CoA for the batch you are actually receiving, not a generic sheet. Our technical data sheets are free to download with no registration, and the CoA for your delivered batch is what governs.
Packing and delivery
DAP 18-46-0 is supplied in bulk, 1 tonne bulka bags, or 25 kg and 50 kg bags. Which suits depends on how you unload and how long you will store it before spreading — set out in the packing guide. Delivered Australia-wide; for export a 20ft container takes 20–27 MT depending on packing.
What to send for a quote
- Analysis — the grade you want, or your soil test and we will match it
- Tonnage — and whether it is one delivery or several
- Packing — bulk, 1 t bulka bags, or 25 kg / 50 kg bags
- Delivery address — or destination port for export
- Unloading — what you can unload with on the day
Those five and the quote comes back complete rather than approximate. More on how a quote is built up in what drives your quote.
Send the tonnage, your nearest town and how you will unload. You get a written delivered price and the data sheet with it.