Certified Crop Advisor Practice Exam

Which method is most effective for decreasing odor and ammonia losses from biosolids?

1. Surface application

2. Injection

3. Composting

4. Drying

The correct answer is: Injection

The injection method is considered the most effective for decreasing odor and ammonia losses from biosolids due to its ability to immediately place the material below the soil surface. This minimizes the exposure of the biosolids to the atmosphere, thereby reducing the volatilization of ammonia and the release of odors. When biosolids are injected, they are incorporated directly into the soil where they can also enhance nutrient cycling and microbial activity without the associated odor issues linked to surface application. In contrast, surface application can lead to significant ammonia emissions and odors, as the biosolids remain exposed to air, promoting volatilization. Composting involves biological processing that can reduce odors over time but does not provide immediate application benefits. Drying can lessen the water content, potentially reducing some odor but does not inherently address ammonia losses as effectively as injection does. By understanding these dynamics, it becomes clear why injection is favored for managing odor and nutrient loss more efficiently.