VRAFY Formula Library
See how the VRAFY Formula Library lets you choose from an expansive list of formulas, and customize each one to your needs.
Written by Sawyer Hansen
Updated at January 30th, 2026
Table of Contents
The Formula Library is our key to building successful prescriptions. These formulas allow us to use yield data, soil data, or both in an equation to help your soil meet your goals and produce more yield. It's a simple 3 step process, select the group that you want to run prescriptions out of, select your formula, and create your prescriptions. Prescriptions are downloadable as a shapefile, and can be added to your Operations Center account to view them later, or send them straight to a machine.
Customizing your prescriptions
Use the Variables and Preferences to customize the formulas to match exactly what each of your fields need.
Variables (Vars)
The Variables allow you to customize the prescription by setting your target build rates, product blend percentages, yield adjustment factors, and select the season of which data you would like to use. Some formulas have an extensive set of variables, others just have 2 or 3. To change the variable from the default, just select the Flat button on the slider, then enter your desired variable.
Phosphorus Formulas
Our phosphorus formulas have multiple variables in them for phosphorus to account for Bray 1, Olsen, or Mehlich 3. If you're soil data is all in Mehlich 3, the P1 and P Olsen variables should be left empty.
Preferences (Prefs)
Set the boundaries of your prescriptions using the preferences tool.
Switch Rates
What a switch rate does, is it defines the minimum value that a prescription formula will produce.
For Example, a switch rate with Rate 1 at 25 and Rate 2 at 50 will run the formula, if the value comes back between 0-25 it will produce a 0 rate. In areas that the formula provides a value between 25-50, the final prescription will produce a value of 50. Areas that the formula provides a value above 50 will kick out the formula prescribed rate.
Maximum Rate
The Maximum rate will cap your final prescription to the chosen rate here.
Average Rate
If you've ran your prescription and like the variability, but need the prescription to match what you have budgeted for that field, enter the average rate that you have budgeted and the prescription will keep the same variability, but the average rate will match your desired output.
Cost $
Enter your cost per applied unit of product. This would be your DAP in cost per pound. For example if your DAP costs $800/ton, you would enter $0.40 in the cost box. This will then add a cost column to your prescription report showing you exactly how much a prescription will cost you in fertilizer dollars, and give you a cost per acre breakdown.
Flat Credit
Enter a flat credit if you're planning to apply additional fertilizer at another time. Enter the flat credit in a value of this prescription's units.
Example
If you apply 10 gallons of 10-34-0 with your planter, you may want to enter a flat credit for your MAP 11-52-0 Application.
10 Gallons of 10-34-0 contains roughly 40lbs of P205
40lbs of P is equivalent to 77lb of MAP 11-52-0
In this case, you want to enter a flat credit of 77 to account for your 10gal of 10-34-0
Formula Groups:
01 pH Balance
These formulas are for balancing your pH, whether you need to raise your low pH areas with lime, or if you need to lower your pH with sulfur.
Supported Products:
- Ag Lime
- Pel Lime
- AMS
- Elemental Sulfur
02 Crop Removal +
Crop Removal + formulas run on your yield data only. The variables allow you to change your yield adjustment percentage so you can fertilize for 120% of yield, or 90% of yield if you so need to.
Supported Products:
- MAP 11-52-0
- DAP 18-46-0
- MESZ 10-40-0-10S-1Zn
- Potash 0-0-60
- Custom P Blend/Product
- Custom K Blend/Product
03 Crop Removal + Build
The Group 03 formulas allow you to set a build target for your soil and add additional crop removal nutrients needed. These work great for balancing out your field nutrients by applying more nutrients where you need to build, and fewer nutrients where your soil is sufficient. Add on top of this the yield removal from either a single year's crop or 2 crop seasons, and these formulas will help you maximize your nutrient efficiency.
Supported Products:
- MAP 11-52-0
- DAP 18-46-0
- MESZ 10-40-0-10S-1Zn
- Potash 0-0-60
- Custom P Blend/Product
- Custom K Blend/Product
04 Soil Only - P & K Build
Group 04 formulas allow you to target ONLY your soil data. These formulas will allow you to set a build target in either ppm or for potassium you can also target your base saturation. The formulas will then provide you with the product needed to build your soil to your target level.
Supported Products:
- MAP 11-52-0
- DAP 18-46-0
- MESZ 10-40-0-10S-1Zn
- Potash 0-0-60
- Custom P Blend/Product
- Custom K Blend/Product
05 Manure
Our Manure prescription formulas are comparable to the Group 2 Crop Removal + formulas, but instead of a commercial product, the final output is in total units of manure needed. The formulas will work for either Liquid Manure or Dry Manure. You simply have to enter your manure analysis numbers in either Lb/ton N and P or Lbs/1000 gal N and P. Set your yield adjustment if you'd like and select your yield season.
06 Zinc & Sulfur
The Zinc and Sulfur formulas let you either build your Zinc and Sulfur soil levels, or balance your Zinc to Phosphorus ratios. These formulas reference your soil data only.
Supported Products:
- AMS
- Zinc Sulfate 35.5%
- Elemental Sulfur
07 Micronutrients
Once you've got your macro-nutrients taken care of, the next possible limiting factor is your micro-nutrients. Use the group 7 formulas to either balance your micros or build certain values. The Balance formulas don't require any user defined inputs, the micro-build formulas do require you to enter your build target.
Supported Products:
- Boron 15%
- Iron
- Copper Sulfate
- Manganese Sulfate
- Others by request
08 Nitrogen
Whether you split apply your nitrogen or if you put it all down up front, our Nitrogen formulas can help you build prescriptions that help your fields use nitrogen efficiently. Even if you blend products such as Urea and AMS, these formulas will provide you with the needed Nitrogen to grow a great crop. Customize the formulas by editing the Yield Adjustment, Split application percentage, Nitrogen use efficiency, and Organic Matter credits.
Supported Products:
- Dry Fertilizer
- Liquid Fertilizer
- Anhydrous Ammonia (NH3)
09 Seeding
Our Seeding prescription formulas will generate your prescriptions based on either a single previous year's yield or multiple years. The only thing you need to enter is your minimum population and maximum population. We do suggest running a manual prescription on this formula prescription before uploading to your monitor as the formula will have a different rate for every 60ft by 60ft grid, the manual rx tool smooths all of the similar rates to one single rate.
