What amount of formulated herbicide should be used per acre foot of water based on a desired ppm?

The correct choice involves determining the appropriate amount of formulated herbicide to achieve a specific concentration in parts per million (ppm) within an acre foot of water. An acre foot is a unit of volume that represents the amount of water required to cover one acre to a depth of one foot, which is equivalent to about 325,851 gallons.

The formula for calculating the amount of herbicide to achieve the desired ppm utilizes the relationship between weight (in pounds), volume (in acre feet), and concentration (in ppm). The factor of 2.7 pounds is derived from converting the desired concentration in ppm to a weight based on the volume of one acre foot of water. This units-based approach ensures that the final concentration is accurately set.

When you multiply the 2.7 pounds by the ppm desired and by the acre foot, you are effectively calculating the total pounds needed to reach that specified concentration in the total volume of water present. This calculation is fundamental in ensuring that pesticide applications are both effective and compliant with environmental regulations.

The other choices do not correctly incorporate the necessary components to accurately determine the appropriate application rate based on the desired ppm. They either lack the necessary variable for concentration or do not relate directly to the volume of water being treated. Thus