Lesson 4: Farmers Till With Care

SUBJECT: Social Studies, Current Events

OBJECTIVE: Students will learn that soil can be lost through wind or water erosion, and that plants or plant residue on the surface protect the soil. They will also learn that a majority of farmers are protecting the soil by using conservation tillage methods.

EVALUATION: Students can explain wind and water erosion in simple terms. They understand that new kinds of tillage and new methods of farming have greatly reduced the problem on farmland, but that farmland is not the only place erosion occurs.

BACKGROUND FOR TEACHERS:

In the early 1930s, disaster struck the Great Plains in a period known as the Dust Bowl. In parts of Texas, Oklahoma, New Mexico, Colorado and Kansas, drought and prairie winds blew away billions of tons of topsoil, increasing awareness in this country of the value of the soil, and the necessity for caring for it.

In 1935 the U.S. Congress created the Soil Conservation Service (SCS). The SCS, now known as the National Resource Conservation Service (NRCS), immediately started programs to restore the land. Realizing what erosion could do, Americans began to work to keep good topsoil on the land. Soil-conserving farming techniques, never before taken seriously, gained widespread acceptance.

Conservation tillage is now defined as "leaving more than 30 percent residue on the surface of the soil." It includes no-till, strip-till and mulch-till. Reduced tillage leaves between 15 and 30 percent residue. Intensive or conventional tillage (plowing) leaves less than 15 percent residue on the soil's surface.

Today, many builders, homeowners, farmers and public land managers wisely use soil conservation practices. Good soil conservation practices benefit everyone. When we care for our soil, we make sure that we have productive farmlands, healthy ecosystems, and abundant wildlife for years to come.

STUDENT ACTIVITIES:

1. Ask students to read the story Ann Learns to Plow, then ask, "Can you tell how Ann feels about the land, the soil?"

2. Ask if they have ever seen wind or water erosion. Remember that erosion is not only a problem in rural areas. Some of the highest rates of erosion occur on construction sites (buildings, highways.) where the land has been stripped of its vegetative cover.

3. Use a hair dryer blowing across a pan of bare soil to give a visual impression of wind erosion.

Use a spray bottle or sprinkling can poured over a pan of bare soil to give a visual impression of water erosion. Elevate the pan slightly. (You'll need a bucket to catch the soil that washes out). Demonstrate that, as the slope is increased (the pan tipped higher) the problem of water erosion increases. Water erosion is not as serious on flat fields.

If you have time, it's very effective to compare the erosion that occurs on bare soil with soil that is protected by plant material. To do this, sprinkle rye grass seed on the surface of another pan of soil, pat it in, and water until the soil is moist (not saturated). Cover the pan with plastic until the seed begins to germinate, then uncover and put it in the sun. A pan of grass grows well in a school window, and the students will enjoy "mowing" it when it's too long!

Repeat the wind and water demonstrations when the surface of the soil is covered with growing grass. Now, water running off the pan will not carry soil with it. And wind blowing across it will not carry soil either.

4. Younger students can add plants (corn, grass, trees, flowers) to this picture to show how the soil can be protected by plants and their roots. (Worksheet 1) (See Unit 2, Lesson 2 to learn about corn roots.)

5. Invite someone from your community to speak to the classroom about protecting the soil. Possible visitors are:

• Employees of the NRCS (National Resource Conservation Service). Ask them to discuss erosion control measures being implemented in both the city and rural areas.

• Farm equipment dealers (John Deere, Case IH, New Holland, etc.). Ask them to bring pictures or videos of the equipment they sell to farmers that protect the soil.

  (These make great field trips too!)

6. Invite a farmer to your classroom to talk about the tillage methods they use, or read about farmers who conserve the soil at http://farm.fic.niu.edu/earth/harmonyfarms.html.

Last reviewed May 7, 2004