World Report: September 19, 2008 Vol. #14 Iss. #3
- This Issue:
- Table of Contents
- Cover Story
- Cover Story - Spanish Version
- Mini-Lesson
- Comprehension Quiz
- Teacher's Guide and Worksheets
Soil Stacks Up
Scientists identify soil layers by their content. Here are four of the layers.
OrganicDead plants and animals settle on the surface to break down.
TopsoilThis layer is rich in minerals. It is the most fertile.
In this layer of soil, water from rain and snow strips out minerals and color.
SubsoilMinerals wash down into this deeper layer to form clay.
Next: The Scoop on Soil
