The soil becomes too dry so plants wither quickly. The soil turns to dust so the top layer is swept away by wind, rain, or snow melt. The soil loses its fertility so more fertilizer is needed. The farmers need to make more money to pay for all of their equipment, so they plant every available clod of soil. More land is needed for planting, so marshes and ponds are drained.
More land is needed for planting, so stands of trees are cut down.
Use the world map and text on page 31 to explain and discuss the effects of clearing woodlands. Have the students fold a plain sheet paper into 4 sections. Direct them to use the information on pages 34 and 35 to identify and illustrate four steps for keeping soil healthy. Each illustration should include a caption. Create a graphic organizer such as a web to illustrate their conclusions.