Across
- 2. water seeps through rock, freezes the expands
- 3. planting new crops each year to keep the soils fertitily
- 4. material of air spaces that water can go through
- 7. breaks down rock by chemical change
- 9. rock particles carried by wind, water, or ice
- 11. difference of elevation from a contour line to another
- 12. dead stalks from the last year to keep soil in place
- 13. map shows surface features of an area
- 16. thick grass roots and soil
- 19. dark-colored material in soil
- 20. process that operates today operated in the past
- 22. plants can grow with this weathered material
- 23. curves of a slope to prevent soil loss
- 27. soil that differs from color and texture
- 28. soil beneath the topsoil contains mostly clay and other minerals
- 29. measure of how soil supports plant growth
Down
- 1. to prevent soil destruction
- 5. layer of rock beneath the soil
- 6. rock is physically broken down to smaller pieces
- 8. dead plant leaves on the surface of the soil
- 10. contour line that is labeled with elevation
- 14. connects points of equal elevation on topographic maps
- 15. something that a human can use
- 17. Wind erosion in the 1930s that caused soil loss
- 18. breaks down remains of organisms and digest them
- 21. water, ice, wind, or gravity move weathered rock
- 24. chemical change by forming rust
- 25. top layer of soil with mixture of humus and clay
- 26. chemical and physical process that breaks down rock
- 30. rich, fertile soil made most up of clay, sand, and silt