Crossword Puzzle

3. the area of the Great Plains where wind erosion caused soil loss during the 1930'S
4. the loose, weathered material on earths surface in which plants can grow
5. the solid layer of rock beneath the soil
8. a line on a topographic map that connects the points of equal elevation
10. the difference in elevation from one contour line to the next
12. a thick mass of grass roots and soil
14. a measure of how well soil supports plant growth
16. soil conversation method in which dead stalks from the previous year's crop are left in the ground to hold the soil in place
17. the process that breaks down rocks through chemical changes
19. plowing fields along the curves of a slope to prevent soil loss
20. rich fertile soil that is made up of about equal parts of clay, sand, and silt
23. the chemical and physical processes that break down rocks at earths surface
24. the plants of different crops in a field each year to maintain the soils fertility
25. mixture of humus,clay, and other minerals that forms the crumbly,topsoil layer of soil
28. operated in the past to change earths surface

1. anything in the environment that humans use
2. a map that shows features of an area
4. the management of soil to prevent its destruction
6. process that splits rock when water steeps into cracks, then freezes and expands
7. characteristic of a material that is full of tiny, connected air spaces that water can steep through
9. The loose layer of dead plant leaves and stems on the surface of the soil
11. the layer of soil that differs in color and texture from the layers above and below it
13. the type of weathering in which rock is physically broken into smaller pieces
15. soil organism that breaks the remains of organisms and digest them
18. a heavier contour line that is labeled with the elevation of that contour line in round units
21. the layer of soil beneath the topsoil that contains mostly clay, and other materials
22. a chemical change in which a substance combines with oxygen,as when iron oxidizes,forming rust
26. dark-colored organic material in soil
27. the process by which water, ice, wind or gravity moves weathered rock and soil
29. the grinding way of rock by other rock particles carried in water, ice,or wind