Weathering and Soil

2. the solid layer of rock beneath the soil
5. when water freezes inside cracks of rocks expanding the crack then melting
7. measure of how well the soil can support plant growth
10. plowing the previous year's crop into the ground to return the nutrients into the soil
14. management of soil to limit its destruction
15. the process that breaks down rock and other substances
17. anything in the environment that humans use
20. a crumbly dark brown soil that is a mixture of humus, clay, and other minerals
21. soil beneath the topsoil
23. the process of wearing down and carrying away rocks

1. wearing away of rock by rock particles carried by water, ice, wind, or gravity
3. the principle that states the geologic processes that operate today operated in the past
4. measures acidity
6. iron combining with oxygen in the presence of water creating rust
8. weathering that physically breaks rock
9. weathering that breaks down rock chemically
11. organisms that break down the remains of dead organisms into smaller pieces and digest them with chemicals
12. soil with equal parts of clay, sand, and silt
13. a material is full of tiny connected air spaces that allow water to seep through it
16. the loose weathered material on Earth's surface in which plants can grow
18. a layer of soil that differs in color, texture, and composition from the layers above or below it
19. planting different plants in the soil each year to keep nutrients in the soil
22. a dark-colored substance that forms as plant and animal remains decay