Fourth Grade
Worksheets
Soil Crusts
The sandwich in your lunch box has a crust, but did you know that the soil beneath your feet might have one too? It's true! Biological soil crusts are made from bacteria and tiny plants. When these things grow together on the soil's surface or just below it, a crust is formed. Soil crusts can be found on rangelands in the western United States and other dry, arid places around the world. Unlike the crust in your lunch box, these crusts can be colorful. When they're wet the crusts can be yellow, orange, or green. When they are dry, however, the crusts are dark. Soil crusts are .....
