Soil

2. the process of wearing something down by friction
8. weathering breakdown or decomposition of rock that takes place when minerals change through chemical processes
11. the expansion of desert conditions in an area where the natural plant cover has been destroyed
13. the top layer of soil that contains humus
14. the size, shape, and position of the particles of soil
15. the process by which natural forces break down rocks and soil
17. the amount of open space between an object
18. horizon a soil layer with physical and chemical properties that differ from those of the soil layers above or below it

1. the decaying organic matter in soil
3. a chemical reaction in which an element combines with oxygen to form an oxide; iron oxide = rust
4. the makeup of rock or soil describing the minerals or elements present in it
5. weathering the breakdown of rock into smaller pieces of the same material without any change to its composition
6. the process by which rainwater dissolves and carries away minerals and nutrients in topsoil
7. the ability to let water pass through
9. the process in which layers or sheets of rock gradually break off
10. the process in which transported sediment is laid down
12. layer of rock beneath the soil
16. the process in which sediment is picked up and moved from one place to another