18-46-0 DAP Phosphorus Calculator
Calculate 18-46-0 DAP product per acre from a target phosphate rate, with the nitrogen credit, total pounds, bags and bulk tons.
How This Calculation Works
Product pounds per acre equals the target phosphate rate divided by the analysis percentage, times 100. For 60 pounds of phosphate per acre from 18-46-0, that is about 130 pounds of DAP per acre. That product also carries about 23 pounds of nitrogen per acre, which should be credited against the total nitrogen plan.
Field Calibration & Rate Reference Chart
| Analysis | Nutrient % | Target lb/ac | Product lb/ac |
|---|---|---|---|
| 46-0-0 Urea | 46 | 100 | 217 |
| 46-0-0 Urea | 46 | 120 | 261 |
| 34-0-0 AN | 34 | 100 | 294 |
| 28-0-0 UAN | 28 | 120 | 429 |
| 18-46-0 DAP | 46 | 60 | 130 |
| 11-52-0 MAP | 52 | 60 | 115 |
| 0-0-60 Potash | 60 | 80 | 133 |
| 10-10-10 | 10 | 60 | 600 |
| 19-19-19 | 19 | 80 | 421 |
| 6-4-0 Milorganite | 6 | 48 | 800 |
Common Questions
How much DAP do I need for 60 pounds of phosphate per acre?
Divide 60 by 0.46 to get about 130 pounds of 18-46-0 per acre. The 46 percent phosphate analysis means each pound of product carries 0.46 pound of P2O5. Multiply by acres for the field total.
Does DAP contain nitrogen?
Yes, 18-46-0 carries 18 percent nitrogen, so 130 pounds of product supplies about 23 pounds of nitrogen per acre. That nitrogen should be credited against the crop's total nitrogen requirement. Ignoring it can lead to over-application.
Should I band or broadcast DAP?
Banding places phosphorus in the root zone where it is most available and reduces fixation on high-pH soils. Broadcasting is faster and works on low-fixation soils with high phosphorus needs. Banding usually gives more crop response per pound.
Can DAP be applied with the seed?
DAP can be placed with the seed at moderate rates, but the ammonia it releases can injure germination at high rates, especially on sandy soils. Keep the seed-placed rate within the label guidance. A separate band is safer at high rates.