Here is some good information from Dr. Virk.
Liquid applicators are commonly used to apply different fertilizer solutions, and similar to the sprayers, they need to be appropriately calibrated to apply the desired application rate in gallons per acre (GPA). While the calibration process for liquid fertilizer applicators is similar to the sprayers, the actual rate for the fertilizer can vary significantly from water (especially at higher rates) due to the difference in the density between the water and fertilizer. Therefore, an adjustment factor must be used when calibrating liquid fertilizer applicators using water. This is not required when calibrating sprayers for pesticide applications because we use water as a carrier for pesticide applications, and the amount of pesticides (chemicals) mixed in the water is usually so small to affect the density of the solution. But if you mix and apply pesticides in a liquid fertilizer or solution other than water, an adjustment factor would need to be used to calibrate the application equipment properly.
The table below provides adjustment factors for some liquid fertilizer solutions, including a few commonly used nitrogen sources.
| Product | Density (lb/gal) | Specific Gravity | Adjustment Factor |
| 28-0-0 | 10.65 | 1.28 | 1.13 |
| 30-0-0 | 10.80 | 1.30 | 1.14 |
| 32-0-0 | 11.06 | 1.33 | 1.15 |
| 7-21-7 | 11.20 | 1.34 | 1.16 |
| 10-34-0 | 11.40 | 1.37 | 1.17 |
| 12-0-0-26 | 11.50 | 1.38 | 1.17 |
| 11-37-0 | 11.60 | 1.39 | 1.18 |
How to use an adjustment factor: Let’s work through an example to illustrate how to use an adjustment factor during calibration. A side-dress applicator needs to be calibrated to apply 32% UAN fertilizer at an application rate of 40 GPA. So at what rate (GPA) should the sprayer be calibrated using water to correctly apply 40 GPA of 32%UAN?
Using Table 1 above, 32% UAN has a density of 11.06 pounds per gallon and an adjustment factor of 1.15. So multiply the desired UAN application rate (GPA) by the adjustment factor to determine the water-only rate for calibration. For this example, it will be:
Water Calibration Rate (GPA) = 40 GPA (UAN Rate) X 1.15 = 46 GPA
This means that the sprayer must be calibrated to apply 46 GPA of water to apply 40 GPA of 32% UAN during field application. Remember that if the applicator were calibrated using water at the same rate as fertilizer, the actual applied rate of fertilizer would be lower than the target rate, again due to the density difference between the water and the fertilizer solution.