Commodity Fumigation License Practice Exam

At what depth do most commercial soil fumigation applicators typically inject the fumigant?

1. 2-4 inches

2. 4-6 inches

3. 6-8 inches

4. 8-10 inches

The correct answer is: 6-8 inches

Most commercial soil fumigation applicators typically inject fumigants at a depth of 6-8 inches. This depth is effective for treating a variety of soil-borne pests and diseases, as it allows the fumigant to adequately reach the root zone of plants, where many pathogens and pests reside. Injecting at this depth ensures that the fumigant can effectively disperse through the soil, allowing for better penetration and distribution needed to achieve optimal efficacy. Moreover, penetration at this depth helps minimize loss of the fumigant to the atmosphere while maximizing its contact with targeted organisms, which enhances its overall effect. While shallower depths, such as 2-4 inches or 4-6 inches, may not provide sufficient control, especially for deep-rooted crops, depths greater than 8 inches may also hinder the effective action of the fumigant due to increased soil density and potential volatilization issues. Therefore, the established practice of injecting between 6-8 inches balances efficiency and efficacy in soil fumigation.