Poisoning the Prairie

This lesson is reprinted with permission from the Habitat Ecology Learning Program, a multi-disciplinary life science program for grades 4-6 developed by the Wildlife Conservation Society with major support from the National Science Foundation. For more information about this curriculum and professional development opportunities call the Bronx Zoo at 1-800-937-5131. or check our website at www.wcs.org/education.

Lesson Introduction

There once was a huge diversity of plant life that could be found on the prairie. These are examples of native grasses found on a mixed prairie: Blue Bluestem, Buffalo Grass, Switch Grass, Little Bluestem, Prairie Cordgrass, Foxtail, Barley Game Grass, and Needle and Thread. This diversity of plant life helped to keep the prairies healthy and rich. If one grass died out due to disease or pests there were many left behind. Prairies in many cases have been converted to cropland. Generally there is only one type of plant growing in this area. Most of the living stuff in a prairie is underground. The huge root systems of prairie plants live for many years sending up new green shoots every year. The death of old roots adds humus to the soil.

Illinois State Goal	Standard	Learning Benchmarks
17	B	2b. Explain how physical and living components interact in a variety of ecosystems including desert, prairie, flood plain, forest, tundra.
17	C	2c. Explain how human activity affects the environment.

Lesson Objectives

• explain what pesticides are and why people use them.
• distinguish three main categories of pesticides.
• describe some of the negative impacts of pesticides.
• discuss the possibilities of alternatives to pesticide use.

Advance Preparation (Indoor Variation)

• Prepare one Special Role card to hand out to each group for the role-playing game. To prepare the cards, cut out the roles from the Special Role pages.
• Paste or staple each one onto a large index card.
• Divide the class into groups of four.

Time Allotment

45-60 minute class period

Materials (Outdoor Variation)

• Special Role cards
• empty bottles of pesticides (with warning labels intact)
• large index cards
• paste or stapler

PROCEDURE

Tap Prior Knowledge

1. Ask the students what sort of plants would they find on a prairie? What sort of animals live there? Since prairies have been converted to croplands what plants grow in this area? What kinds of animals might now grow there. Create a list on the board to show comparisons between original prairie and prairie turned cropland.

If a disease or pests finds a type of plant to be a suitable host, how does this effect the prairie verses the cropland? Does one area become more vulnerable to losing its plants and habitats for the animals that live there? How does the variety of plants affect the survival needs of animals and their habitats?

This discussion is intended to guide students to concludes that growing one species of a plant in an area leaves crops highly vulnerable to disease. It is easy for a pest to find a suitable host and wipe out an entire crop. Low plant diversity leads to impoverished habitats for animals.

Share with Neighbor

2. How do farmers prevent the demise of plant and habitat destruction? Discuss the use of pesticides with the class. Farmers use these to destroy forms of life that can reduce crop yields. They contain mixtures of certain chemicals. Brainstorm about positive and negative effects of pesticides. Make a list on the chalkboard.

3. Divide the class into four groups. Pass out one empty pesticide bottle to each group. Have students investigate the bottle and answer the following questions.

Why are all warnings necessary?
How are people affected by pesticides?
How are animals affected? Are all insects considered pests?

Discuss problems that may arise by using specific pesticides. Do pesticides only destroy intended target pests? What other groups of people might also use pesticides? For example, the natural populations of honeybees, which are important pollinators, are declining throughout the United States due to pesticides.

4. Introduce the following vocabulary words to the students:
Herbicide- a chemical that kills plants.
Fungicide- a chemical that kills fungi.
Insecticide- a chemical that kills insects.
All words have the same Latin root -"icide." Can students guess what possible meaning this root have? Can the groups come up with any other words with the same ending. Write these on the chalkboard. Possible answers might be homicide, suicide, fratricide. Raise the question to the class "Do all the words have a common meaning?" Yes, to destroy or kill.

Hands-on Activity

5. Provide each group with a role card. Ask each group to read and study their card. The students needs to evaluate the position their role card represents on the use of pesticides. Write the following questions on the board:

1. Does the person on your role card use pesticides?
2. Could this person be harming the environment by using pesticides? If so how?
3. What are other choices a farmer might have to help him make a good living other than using pesticides?
4. What other groups of people help to contribute to the farmers decision to use pesticides?
5. Has the person or farmer made the right decision? Why or why not?

6. Assign roles to each of the four group members. A spokesperson briefly summarizes and explains the position of their role card. A Material Manager is responsible for all the supplies necessary for this process. The Coach encourages group members and reports on how well the group used cooperative skills including working together, active listening, and ensuring that there is a respectfulness towards all group members. Finally, the Recorder writes down all information that the members use to research and formulate their position.

7. Randomly select a group to present their positions. After each group concludes its presentation give other groups a chance to formulate and debate questions or comments to be addressed by presenting group. For example the groups may want to disclaim the position taken by the presenters. Each group should write down on paper its questions or comments to be read by the spokesperson aloud to the presenting group.

Introduce Scientific Principle/Environmental Issue

8. Students will find that pesticide use is a complex issue. There are no simple answers; the solution is not to simply outlaw pesticides. Pesticides are used for a variety of reasons. They are a relatively inexpensive way to deal with pests. Producing large crop yields that feed multitudes of people and/or go to feed livestock mean months of hard work for underpaid farmers. To lose even a fraction of their crops may mean bankruptcy. Unfortunately in order to manage these huge farms they use potentially harmful pesticides. Pesticides can leech into ground water used for human consumption. Birds also eat the bugs, plants and worms that crawl along crops and in the soil. When they ingest pesticides they may produce weak offspring are result of which may eventually eliminate their species, thus valuable links in the food chain. Organic farming may be a solution to the pesticide problem, but one must have a small farm in order to manage the crops and this can increase the supermarket price of the fruits and vegetables grown.

Role Playing Cards

Traditional Farmer, Sam Brown
I've been farming all my life and I've always used pesticides. Farming is a tough business. You can try as hard as you possibly can and still a drought, flood, or an insect pest may come along and ruin the year's crops. I need to take advantage of everything I can, including pesticides, in order to grow enough food to sell to pay my bills and keep my farm. I also need to save some money and put it in the bank for our retirement. Soon I'll be to old to work and I can't afford to take chances with my future. I sleep better at night knowing that I have applied those chemicals and done all I can to avoid any problems with my crops.

I am concerned, however, for the future of my farm. Some farmers say I am poisoning the soil. I have noticed that it's a little harder each year to make my crops grow and turn a profit. I sure hope I'm not hurting my grandchildren's chances for making a living from this farm!

MegaFarm USA, Terry O' Neall, Owner
I was a small farmer and found myself struggling to compete in the marketplace. To improve my position I began to buy more and more farmland. I went one step further and formed my very own huge business, naming it MegaFarm USA. I had hoped this would allow me to sell my food at a lower rate. The government was happy to sell me cheap pesticides. But it has became very unpopular to use pesticides. People began to protest and refused to buy my products. No one in our family has ever become sick. I work a tremendous amount of land. I can't come up with a method to control so many of pests like insects and weeds. I am already using planes to drop the chemicals on the fields. This appears to be okay since the prices of chemicals are so low I still could keep my crop prices low.

People tell me there are other alternatives. They say if I had a smaller farm, I could begin using less chemicals. I could also integrate some organic farming methods. But that to has a costly drawback. I would have to hire more people to handle the change and this would be very expensive. After weighing all my options I have decided to stick with the least expensive way to run MegaFarm USA.

Organic Farmer, May Appleton
I am very committed to keeping the environment clean and green. I recently bought a farm. I have spent much time educating myself on alternative methods that are used to control the insect population. I release birds to eat some of the pests. I found that setting ladybugs and praying mantis' in my fields helps to control the pests. I also found a special way of planting my crops called 'companion planting', that helps to avoid problems.

I am very proud to have made this decision about my farming practices. Instead of spraying chemicals I do have to get out in the fields picking weeds one by one. There are times when my whole family is working side by side yet I still have to hire more people.

It is much harder to make ends meet using organic farming techniques. I have trouble buying some of the basic farm equipment that I need. The prices of organic crops are much more expensive because of all of the labor I need to put into growing them. People are not willing to pay higher prices. They also have a high expectation of how they view fruits to look. Creating a picture-perfect apple requires huge amounts of chemicals to make them look that way. Sometimes apples that have been grown naturally may have a few spots, but they taste just as good. But I always keep in mind that the main point is that natural farming practices allow people to not worry about the effect of pesticides on their bodies.

National Forest Service, Ranger Cory Miles
The National Forest Service is very involved in making important decisions as to how the Midewin National Tallgrass Prairie will be managed. One of the main goals of the "Prairie Plan" is to restore this huge area of land in a manner that will conserve and enhance the native populations and habitats of fish, wildlife, and plants. We also want to provide opportunities for scientific, environmental and land use education and research.. We want to provide a variety of recreation opportunities like hiking and bicycling.

This is not an area of land like the farms the others are telling you about. As a ranger I am not faced with the same problems. This area carries a different set of concerns to be dealt with. I am not trying to make money off this land by selling crops of any kind. I believe we must bring the native species and animal habitats back to their original state. Through people building homes, farming and using this land for industry we have lost much of our important native prairie plants and animals.

How will we remove species of plants and animals that have no business on the restored prairie? What can we do to destroy the deep root system of non-native species? We can try and kill them with pesticides. But, I believe we would be riding a very fine line. It is possible for the soil to become saturated with too many chemicals. If that is the case, the native species would have an extremely hard time making a go of it because not only would the non-native species get hit with the pesticides, but the native ones would too! I find that I am have both positive and negative feelings in regard to pesticide use.