G Chapter 2

1. area of the Great Plains where wind erosion caused soil loss in the 1930s
3. The crumbly, topmost layer of soil, mixture of humus, clay, and other minerals
5. A material that is full of tiny connected air spaces that water can seep through
7. plowing fields along curves of slopes to prevent soil loss
8. Dark colored organic material in soil
11. Anything in the environment that humans use
14. Chemical change when when a substance combines with oxygen
16. rocks broken down physically
18. Loose layer and dead plant leaves and stems on the Suface of the soil
19. measure of how well soil supports plant growth
20. Darker contour line on a topographic map that rounds elevation units
22. type of soil that is made up of about equal parts of clay, sand, and silt
25. Grinding away of rock by other rock particles carried in ice, water,or wind
27. When water, ice, wind, or gravity moves weathered rock or soil
28. Horizon Layer of soil that differs in color and texture

2. Rocks that break down on Earths Suface physically and chemically
3. A map that shows Suface area
4. Planting of different crops in fields each year to maintain soils fertility
6. management of soil to prevent destruction
9. Method which dead stalks from the previous years crops are left in the ground to hold soil in place
10. Principle that states that earth surface changed the same way forever
12. Line that connects points with the same elevation on a topographic map
13. rocks broken down chemically
15. The process when water seeps into cracks, freezes and expands
17. The distance in elevation from Contour line to Contour line
21. A soil organism that breaks down the remains of organisms and digests them
23. Solid layer of rock beneath the soil
24. Layer of soil beneath the topsoil, contains clay and other minerals
26. thick mass of grass roots and soil