G Chapter 2

1. Layer of soil beneath the topsoil, contains clay and other minerals
3. Darker contour line on a topographic map that rounds elevation units
6. measure of how well soil supports plant growth
8. A material that is full of tiny connected air spaces that water can seep through
11. Anything in the environment that humans use
12. Method which dead stalks from the previous years crops are left in the ground to hold soil in place
13. The process when water seeps into cracks, freezes and expands
14. Principle that states that earth surface changed the same way forever
15. management of soil to prevent destruction
16. plowing fields along curves of slopes to prevent soil loss
17. When water, ice, wind, or gravity moves weathered rock or soil
18. thick mass of grass roots and soil
19. Solid layer of rock beneath the soil
21. rocks broken down chemically
23. Grinding away of rock by other rock particles carried in ice, water,or wind
25. Horizon Layer of soil that differs in color and texture
26. A soil organism that breaks down the remains of organisms and digests them
27. type of soil that is made up of about equal parts of clay, sand, and silt

2. Chemical change when when a substance combines with oxygen
4. area of the Great Plains where wind erosion caused soil loss in the 1930s
5. A map that shows Suface area
7. The crumbly, topmost layer of soil, mixture of humus, clay, and other minerals
9. Dark colored organic material in soil
10. rocks broken down physically
16. Line that connects points with the same elevation on a topographic map
20. Planting of different crops in fields each year to maintain soils fertility
21. The distance in elevation from Contour line to Contour line
22. Rocks that break down on Earths Suface physically and chemically
24. Loose layer and dead plant leaves and stems on the Suface of the soil