Grade 6 soil layers quiz with answers and explanations

📚 Quick Study Guide

🌍 Soil is made up of distinct layers called horizons. 🍂 The main horizons are: O (Organic), A (Topsoil), B (Subsoil), C (Parent Rock), and R (Bedrock). 🌱 O Horizon (Organic Layer): The uppermost layer, composed of decaying organic matter like leaves and twigs. 🐛 A Horizon (Topsoil): Rich in humus (decomposed organic matter) and minerals; vital for plant growth. 🧱 B Horizon (Subsoil): Accumulation of minerals leached from above; less organic matter. ⛰️ C Horizon (Parent Rock): Partially weathered bedrock; little organic matter. 🪨 R Horizon (Bedrock): Solid, unweathered rock layer. 🌧️ Leaching is the process where water carries minerals from upper layers to lower layers. 💡 Soil composition affects water retention, drainage, and fertility.

Practice Quiz

1. Which soil horizon is known as the topsoil and is rich in humus?
   1. O Horizon
   2. A Horizon
   3. B Horizon
   4. C Horizon
2. Which horizon is primarily made up of organic matter such as decaying leaves and twigs?
   1. A Horizon
   2. B Horizon
   3. O Horizon
   4. C Horizon
3. The process by which water carries minerals from the upper layers of soil to the lower layers is called:
   1. Erosion
   2. Deposition
   3. Leaching
   4. Weathering
4. Which horizon consists of partially weathered bedrock?
   1. A Horizon
   2. B Horizon
   3. C Horizon
   4. R Horizon
5. Which horizon is also known as the subsoil?
   1. O Horizon
   2. A Horizon
   3. B Horizon
   4. R Horizon
6. What is the solid, unweathered rock layer beneath the soil called?
   1. C Horizon
   2. B Horizon
   3. R Horizon (Bedrock)
   4. A Horizon
7. Which horizon contains the least amount of organic matter?
   1. A Horizon
   2. O Horizon
   3. B Horizon
   4. R Horizon