Calculating Tank Mix Math for Spring Chem Applications

FBN Network

Apr 12, 2024

It’s time to dust off those math skills as you plan for spring chemical applications. Start with a few simple calculations to ensure you have enough product in the shed to complete the job. 

If you do the math now, you’ll only purchase what you need and won’t have to worry about storing and handling any extra chemicals at the end of the season.

Once you’ve identified the number of acres you want to treat along with the active ingredients and products you intend to purchase, a few calculations will reveal the total amount of product required to cover your fields.

Determine How Much Product to Order

Farmer Smith and his agronomist have decided to treat 625 corn acres with:

Additives required by the label are:

He intends to apply with a 10-gallon-per-acre carrier using a ground sprayer. How much of each product should he order to cover his 625 acres?

  • 625 acres X 3 qt./ac Meto 1.7 + Meso 0.22 + Atrzn 1.66 Value Pick  = 1,875 quarts 

    • To complete the calculation, convert quarts to gallons (4 quarts = 1 gallon). 

    • 1,875 quarts / 4 = 468.75, rounded up to 469 gallons Meto 1.7 + Meso 0.22 + Atrzn 1.66 Value Pick required.

  • 625 acres X 1.5 pints/ac AgSaver Glyphosate 53.8% = 937.5 pints

    • To complete the calculation, convert pints to gallons (8 pints = 1 gallon). 

    • 937.5 pints / 8 = 117.2, rounded up to 118 gallons AgSaver Glyphosate 53.8% required.

Next, calculate the total number of gallons to be sprayed based on a carrier volume of 10 gallons per acre. Use that calculation to derive the amount of adjuvant required.

  • 625 acres x 10 gallons = 6,250 gallons to be sprayed 

  • 6,250 gallons / 100 gallons adjuvant carrier volume = 62.5 acres covered

  • 62.5 x 2 pints of IN-Zorb™ ADV  = 125 pints 

  • 125 pints / 8 = 15.625, rounded up to 16 gallons of IN-Zorb™ ADV required 

  • 62.5 x 17 lbs. AMS (dry) 51 Pound Value Pick = 1,062.5 lbs. AMS (dry) 51 Pound Value Pick required 

  • 1,062.5 lbs / 51-pound bag = 20.8, rounded up to 21 bags AMS (dry) 51 Pound Value Pick required 

    • If you prefer to use liquid AMS instead of dry, try Even 34L which contains 3.4 pounds of AMS per gallon. In that case:

      • 62.5 x 17 lbs AMS = 1062.5 pounds needed / 3.4 = 312.5, rounded up to 313 gallons Even 34L required. (Even 34L comes in 270 gallon totes or boxes of 2 x 2.5 gallon jugs.)

Adhere to Label-Use Instructions

When mixing pesticides, herbicides, and additives, you may need to do additional calculations to ensure you follow label-use instructions accurately.

If you apply more than the recommended label rates, you’ll be off-label, spend extra money, may injure crops, and could be subject to fines. If applied rates aren’t high enough, product efficacy will be reduced and you won’t get the pest control you expected. 

Both of these scenarios can negatively impact crop yield and profitability.

Determine How Much Product to Add to the Tank Mix

Farmer Smith has a ground sprayer with a 1,200-gallon tank capacity. How much product should he add to each tank fill?

First, figure the number of acres Farmer Smith can cover with one tank spraying a carrier volume of 10 GPA.

  • 1,200 gallons / 10 gallons sprayed per acre = 120 acres

Now, calculate how much product to add to each tank mix.

  • 120 acres x 3 qt. Meto 1.7 + Meso 0.22 + Atrzn 1.66 Value Pick = 360 quarts 

  • 360 quarts / 4 quarts = 90 gallon Meto 1.7 + Meso 0.22 + Atrzn 1.66 Value Pick per fill

  • 120 acres x 1.5 pints of AgSaver Glyphosate 53.8% = 180 pints

  • 180 pints AgSaver Glyphosate 53.8% / 8 = 22.5 gallons AgSaver Glyphosate 53.8% per fill

Next, figure the number of acres Farmer Smith’s adjuvants will cover at a carrier volume of 100 GPA. 

  • 1,200-gallon tank / 100-gallon carrier = 12 acres

  • 12 acres x IN-Zorb™ ADV 2 pints = 24 pints IN-Zorb™ ADV

  • 24 pints IN-Zorb™ ADV / 8 pints per gallon = 3 gallons IN-Zorb™ ADV per fill

  • 12 acres x 17 lbs. AMS (dry) 51 Pound Value Pick = 204 lbs. AMS (dry) 51 Pound Value Pick

  • 204 lbs. AMS (dry) 51 Pound Value Pick / 51 lb. bag = 4 bags AMS (dry) 51 Pound Value Pick per fill

    • If using liquid AMS, like Even 34L, instead of dry AMS, use a similar calculation:

12 acres x 17 lbs AMS = 204 lbs needed per tank / 3.4 lbs per gallon = 60 gallons Even 34L per fill

Finally, determine how many tank fills will be required to cover the field.

  • 625 acres / 120 acres per fill = 5.2 fills

That means Farmer Smith will fill his tank five times, and his final fill will be only 20% of the tank volume or 240 gallons. 

Next, calculate the amount of each product to add to the partial tank fill. 20% or 240-gallon tank mix needs as follows:

  • 90 gallons Meto 1.7 + Meso 0.22 + Atrzn 1.66 Value Pick x 0.2 = 18 gallons Meto 1.7 + Meso 0.22 + Atrzn 1.66 Value Pick

  • 22.5 gallons AgSaver Glyphosate 53.8% x 0.2 = 4.5 gallons AgSaver Glyphosate 53.8% 

  • 3 gallon IN-Zorb™ ADV x 0.2 = 0.6 gallons or 2.4 quarts IN-Zorb™ ADV

  • 204 lbs. AMS (dry) 51 Pound Value Pick x 0.2 = 40.8 lbs. AMS (dry) 51 Pound Value Pick

  • 40.8 lbs AMS (dry) 51 Pound Value Pick / 51 pounds per bag = 0.8 pounds, rounded up to 1 bag AMS (dry) 51 Pound Value Pick

    • With liquid AMS, 40.8 lbs / 3.4 lbs per gallon = 12 gallons Even 34L

These calculations are basic math that you can do on a calculator. You can use the same math for fungicide and insecticide applications.

Doing the math ahead of time will help to ensure that your pesticide order is efficient and addresses complete control of your targeted pests. Consult with an agronomist to ensure you read and follow label use instructions correctly. 

[For more information to help plan your spring chemical applications, check out these blog posts about branded vs. generic products and premixes vs. tank mixes.]

Plan for Spring Applications with Chem from FBN®

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  • Know exactly what you’re paying for with transparent pricing and exclusive sale offers

  • Can schedule a delivery time that works with your schedule

  • Get your order delivered directly to your farm, without having to travel to pick up products

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FBN Network

Apr 12, 2024