Grace Murphy

3. Horizon Layer of soil that differs in color and texture
4. The crumbly, topmost layer of soil, mixture of humus, clay, and other minerals
7. Chemical change when when a substance combines with oxygen
9. A soil organism that breaks down the remains of organisms and digests them
11. Darker contour line on a topographic map that rounds elevation units
13. plowing fields along curves of slopes to prevent soil loss
15. Grinding away of rock by other rock particles carried in ice, water,or wind
16. measure of how well soil supports plant growth
18. Rocks that break down on Earths Suface physically and chemically
19. rocks broken down physically
20. Line that connects points with the same elevation on a topographic map
22. rocks broken down chemically
24. Layer of soil beneath the topsoil, contains clay and other minerals
25. A map that shows Suface area
27. Solid layer of rock beneath the soil

1. Planting of different crops in fields each year to maintain soils fertility
2. area of the Great Plains where wind erosion caused soil loss in the 1930s
3. management of soil to prevent destruction
5. Loose layer and dead plant leaves and stems on the Suface of the soil
6. Method which dead stalks from the previous years crops are left in the ground to hold soil in place
8. Dark colored organic material in soil
10. thick mass of grass roots and soil
12. Principle that states that earth surface changed the same way forever
14. When water, ice, wind, or gravity moves weathered rock or soil
17. Anything in the environment that humans use
21. type of soil that is made up of about equal parts of clay, sand, and silt
22. The distance in elevation from Contour line to Contour line
23. The process when water seeps into cracks, freezes and expands
26. A material that is full of tiny connected air spaces that water can seep through