Summary:
- Soil is a mixture of eroded rock, minerals, partly decomposed organic matter, and other materials.
- It is essential for plant growth, so it is the foundation of terrestrial ecosystems.
- For human purposes, soil is a nonrenewable resource.
- It can be depleted of nutrients through careless use, and eroded by wind and water.
- Soil must be used wisely to preserve it for the future.
- Conservation practices include contour plowing and terracing.
- The Dust Bowl occurred between 1933 and 1939 in Oklahoma and other southwestern U.S. states.