What are common units used to express application rates?

The correct choice highlights commonly recognized units utilized in agriculture and horticulture to quantify the application rates of liquids, such as fertilizers or pesticides. Gallons per acre (GPA) is a classic metric for measuring how much liquid is applied over an area as large as an acre, making it intuitive for larger farming practices. On the other hand, gallons per 1,000 square feet serves as a more localized measurement, which is particularly useful for gardens, lawns, or smaller plots of land where precise quantities need to be applied.

Using these specific units helps ensure that applicators can measure and apply the correct amounts to achieve desired efficacy while minimizing waste and environmental impact. The familiarity of these units in standard agricultural practices further solidifies their importance in conveying information regarding application rates effectively.