Texas FFA Nursery Landscape Practice Exam

Which of the following is an indication of fertile soil?

1. Small brown pebbles

2. A grey or yellow subsoil

3. Grubs

4. Earthworms

The correct answer is: Earthworms

The presence of earthworms is a strong indication of fertile soil. Earthworms play a crucial role in soil health as they help aerate the soil, facilitating the movement of water and nutrients. They also break down organic matter, which enhances soil fertility by adding nutrients back into the soil, making them more available for plant uptake. Their activity results in the creation of humus, a rich organic component that improves soil structure and nutrient-holding capacity. In contrast, small brown pebbles may suggest a high sand content, which typically does not retain moisture or nutrients effectively, indicating less fertility. A grey or yellow subsoil can be a sign of poor drainage or the presence of certain mineral deposits, often associated with less fertile conditions. Grubs, being larvae of various insects, may not directly indicate soil fertility; their presence could signify potential pest issues that can harm plants, rather than a beneficial, fertile environment.