2Activating Prior Knowledge Think of an area of land that has a wide are of dirt like a construction site or a vacant lot…
3What do you think happens to an area like this when it rains? What is the water like that runs off the area?Is there anything that could be done to prevent this erosion of soil?
4If you were in the 1800s…You would have seen lots of prairies on your settler’s journey. (Think Oregon Trail)Prairie soil is very fertile and is rich with humus.Sod –the thick mass of tough roots at the surface of the soil keeps it in place and holds onto moisture.
5The Value of SoilSoil is one of Earth’s most valuable resources because everything that lives on land depends directly or indirectly on soil.Plants depend on soil to live and grow.Animals depend on plants (or animals that eat plants) for food.Soil formation can take hundreds of years for just a few centimeters of soil to form.
6The Value of Soil (cont’d) Fertile soil is very valuable because less than one-eighth of the land on Earth has soil that is well suited for farming.What does it mean for soil to be fertile?What substance must be in soil for it to be fertile?
7Soil Damage and Loss Soil is so important, but can be damaged or lost. Soil can lose its fertility.This happened in the South in the late 1800s when cotton was the only crop grown on farms.In the early 1900s, George Washington Carver developed new crops and farming methods to make the soil fertile again.
13Soil ConservationAfter the Dust Bowl, people began to realize how important soil is and developed new farming techniques.Soil conservation is the management of soil to prevent its destruction.Two ways that soil can be conserved include contour plowing and conservation plowing.
14Contour PlowingContour plowing is the practice of plowing fields along the curves of a slope.This helps slow the runoff of excess rainfall and prevents it from washing the soil away.
15Conservation PlowingConservation plowing disturbs the soil and its plant cover as little as possible.Dead weeds and stalks of the previous year’s crop are left in the ground to help return soil nutrients, retain moisture, and hold soil in place.