Red Seal Landscape Horticulturist Practice Exam

How does compost benefit garden soils?

1. Reduces biodiversity

2. Provides essential nutrients and improves soil structure

3. Increases soil acidity

4. Causes waterlogging

The correct answer is: Provides essential nutrients and improves soil structure

Compost plays a vital role in enhancing garden soils by providing essential nutrients and improving soil structure. When added to the soil, compost breaks down into a rich organic matter that contributes to the nutrient supply for plants. This organic matter is a source of macronutrients, such as nitrogen, phosphorus, and potassium, along with trace elements that plants require for healthy growth. Furthermore, compost improves soil structure by increasing its porosity, which facilitates better air circulation and enhances water retention. This improved structure helps prevent soil compaction, allowing roots to penetrate more easily and access water and nutrients. The increased microbial activity from the addition of compost also aids in breaking down organic materials, further enriching the soil and promoting a healthy ecosystem. In contrast, the other options do not accurately represent the benefits of compost. For instance, compost does not reduce biodiversity; instead, it fosters a more diverse microbial community. It usually tends to neutralize or balance soil pH rather than increase acidity and does not cause waterlogging; rather, it enhances drainage in heavy soils.