What type of soil is described as humus-rich and very fertile?

• A. Sandy soil
• B. Saline soil
• C. Pebble soil
• D. Humus-rich soil

Answer: (D)

Humus-rich soil is very fertile because the organic matter from decaying plants and animals (humus) adds nutrients and greatly improves soil structure. This rich organic content helps hold water and minerals, making nutrients more available to plant roots, and boosts the activity of soil organisms that recycle nutrients. The result is a soil that retains moisture well and supports steady plant growth. Other soils described—sandy soils drain quickly and hold few nutrients, saline soils have high salt that can harm plants, and pebble soils are coarse with little organic matter—do not provide the same level of nutrients or moisture retention, so they’re less fertile.