Herbicide Application Rate Calculator
Application Results
Total Herbicide Needed: fl oz ( Gallons)
Total Carrier (Water) Needed: Gallons
Herbicide per Full Tank: fl oz
Area Covered per Full Tank: Acres
Total Tanks Required:
How to Calculate Herbicide Rates for Effective Weed Control
Calculating the correct herbicide rate is critical for successful agricultural management. Over-application can lead to crop injury, environmental runoff, and unnecessary expenses. Under-application, on the other hand, results in poor weed control and contributes to herbicide resistance.
Understanding the Variables
- Label Rate: This is the specific amount of product recommended by the manufacturer, usually expressed in fluid ounces or pints per acre. Always consult the product label before application.
- Spray Volume (GPA): Also known as the carrier rate, this is the total amount of water and chemical mixture applied to one acre. Most ground applications range from 10 to 20 gallons per acre (GPA).
- Tank Capacity: The maximum volume your sprayer tank can hold. Knowing this helps you determine how many "loads" or refills are required for the job.
The Step-by-Step Calculation Formula
To calculate herbicide rates manually, you can follow these primary formulas:
1. Total Herbicide Required: Total Area (Acres) × Label Rate (oz/Acre)
2. Herbicide per Tank: (Tank Size / Spray Volume) × Label Rate
Practical Example
Imagine you have a 20-acre field. The herbicide label calls for 32 fl oz per acre. Your sprayer is calibrated to deliver 15 gallons of water per acre, and you have a 300-gallon tank.
- Total Product: 20 acres × 32 oz = 640 oz (5 gallons).
- Coverage per Tank: 300 gal tank / 15 GPA = 20 acres per tank.
- Mixing: In this case, your 300-gallon tank exactly covers your 20-acre field. You would add 5 gallons of herbicide to the tank and fill the rest with water.
Key Safety and Accuracy Tips
- Calibration: Calibrate your sprayer nozzles regularly. Worn nozzles can increase output by 10% or more, leading to massive over-application.
- Mixing Order: Generally, you should follow the W-A-L-E-S method (Wettable powders, Agitate, Liquids, Emulsifiable concentrates, Surfactants).
- Weather Conditions: Avoid spraying when wind speeds exceed 10 mph to prevent drift, or during extreme heat where evaporation can reduce efficacy.