Chapter 2g

3. the difference in elevation from one contour line to the next
4. the magenament of soil to prevent its destruction
5. a heavier line that is labeled with the elevation of that contour line in round units
8. characteristic of a material that is full of tiny, connected air spaces that water can seep through
9. mixture of humus,clay,and other minerals that forms the crumbly, topmost layer of soil
10. process that splits rock when water seeps into cracks, then freezes and expands
11. the loose layer of dead plant leaves and stems on the surface of the soil
14. a line on a topographic map that connects points of equal Evevation
16. soil conversation method in which dead stalks from the previous years crop are left in the ground to hold the soil in place
21. the process that breaks down rocks through chemical changes
22. the grinding away of rock by other rock particles carried in water,ice, or wind
23. a thick mass of grass roots and soil
26. a map that shows surface features of an area
27. a chemical change in which a substance combines with oxygen, as well iron oxidates, forming rust
28. plowing fields along the curves of a slope to prevent soil loss
29. the chemical and physical processes that break down rock at earths surface

1. the layer of soil beneath the topsoil that contains mostly clay and other minerals
2. operated in the past to change the Earths surface
3. the planting of different crops in a field each year to maintain the soils fertitly
6. a loose weathered material on earths surface in which plants can grow
7. the area of the Great Plains where wind erosion cause soil loss during the 1930's
12. the layer of soil that differs in color and texture from the layers above it and below it
13. the type of weathering in which rock is physically broken into smaller pieces
15. a measure of how much soil supports plant growth
17. rich,fertile soil that is made up of about equal parts of clay, sand and silt
18. dark colored organic material that's in the soil
19. soil organisms that break down the remains of organisms and digest them
20. anything in the environment that humans use
24. the solid layer beneath the soil
25. the process by which water,Ice,wind, or gravity moves weathered rock and soil