Di-Ammonium Phosphate
(DAP) 18-20-0-1
1. FEATURES
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High analysis source of Phosphorus.
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N:P ratio of 1:1 makes it an effective source of nitrogen.
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DAP releases free ammonium. Nitrogen in the ammonium form resists leaching and
is a slower release form of nitrogen.
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The free ammonium gives a higher pH reaction immediately around the granule.
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The low cost of nitrogen in DAP makes it a cost effective source of nitrogen if
Phosphorus is also required.
2. TYPICAL ANALYSIS
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%
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Total Nitrogen (N)
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18.00%
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Nitrogen (N) as Ammonium
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18.00%
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Total Phosphorus (P)
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20.00%
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Available Phosphorus (P)
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18.40%
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Phosphorus (P) as Water-Soluble
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17.80% min – 18.50%
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Phosphorus (P) as Citrate-Soluble
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2.00% min – 2.10%
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Phosphorus (P) as Citrate-Insoluble
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0.10% min – 0.30%
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Total Sulphur (S)
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2.20%
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3. PHYSICAL PROPERTIES
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Sizing
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2 - 4mm 90%
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Bulk Density
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0.92-0.95 tonnes/m3
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Appearance
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Brown to black granules
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Angle of repose
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31 - 33°
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4. MANUFACTURE
Ammonia gas is combined with phosphoric acid in a ratio of
1:1, granulated, dried and screened.
5. USES
One of the major cropping fertilisers used in
Australia
as a source of both phosphorus and nitrogen. The high phosphorus content makes
it a true high analysis fertiliser. DAP and DAP blends are used on a range of
crops in broad-acre farming, cereals, sowing pastures, dairy pastures, fodder
crops and also in horticultural crops, e.g. vegetables and tree crops.
6. STORAGE & HANDLING
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Does tend to take up moisture, both in storage and in the field
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Storage in a bulk shed is the preferred storage method. Covering with a tarp
will reduce any moist air uptake
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The use of augers may damage the fertiliser and increase any handling problems
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Do not leave exposed to moist air
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Either fill or empty (completely), the drill or airseeder fertiliser box
overnight.
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Cover seeding equipment with a tarp
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Tarp undercarriage of seeder or park it out of the paddock on a road or dry
ground
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Raise the tynes from the soil to stop moisture moving up the tubes
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7. RESTRICTIONS
For sowing there is little risk of affecting germination, even
at high rates. DAP does have free ammonia so the general rule of a maximum of
20kg/ha of nitrogen at seeding of cereals should be used.
When applying DAP, the fertiliser should be banded 5cm away
from the seed, either below or to the side. DAP is low in sulphur – 1.5%. It is
not recommended for high sulphur requiring crops such as canola, unless blended
with sulphate of ammonia.
Do not store in silos.
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