Soil and Earth Materials Flashcards

Grade 3 · Science · Flashcards

Study key vocabulary about soil types, formation, and Earth's surface materials.

Flashcards

soil: A complex mixture of rock particles, humus, water, air, and living organisms
humus: Dark organic matter formed from decayed plants and animals; makes soil fertile
weathering: The breaking down of rocks into smaller pieces by natural processes
erosion: The process of soil being carried away by wind or water
topsoil: The dark, upper soil layer richest in nutrients and organic matter
subsoil: The soil layer beneath topsoil with less organic matter and more rock fragments
sandy soil: Soil with large particles that drains quickly but holds fewer nutrients
clay soil: Soil with very fine particles that holds water tightly and drains slowly
loam: A blend of sand, clay, and humus; the best all-purpose garden soil
decomposition: The breakdown of dead organic matter by bacteria, fungi, and other organisms
earthworm: A burrowing organism that loosens soil and adds nutrients through its castings
soil horizon: A distinct layer of soil visible in a cross-section
bedrock: Solid, unweathered rock that lies beneath all soil layers