UNIT
2: 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.
