Healthy Soil, Healthy Land
Use this lesson as an introduction to Challenge 1: Land in the Lexus Environmental Challenge
Goals: Students will conduct an investigation to better understand the cause-and-effect cycle of soil health, including the local and global effects of pesticides, toxins, and other soil pollutants.
Time Required: 40 minutes, plus research time
Materials: "Healthy Soil, Healthy Land" student reproducible, research materials, pen/pencil, supplemental information about soil (below)
Before Class Begins
Before students arrive, review the supplemental information about soil (below), including the environmental facts, conservation ideas, and real-world example showing the importance of soil health.
1. Ask: Do you think you have a personal responsibility to help keep our local environment healthy? If not, whose responsibility is it? Engage students in a lively discussion about the importance of caring for the environment. Discuss whether a healthy environment is the responsibility of individuals, governments, private businesses, nonprofit organizations, or everyone on earth. Ask if students consider themselves to be "polluters," and remind them that cars, home heating/cooling systems, waste, and even hairspray puts foreign particles (pollutants) into the air.
2. Ask: Do you think our local environment is healthy? What parts of our environment do you think we could study to try to find the answer? (Clues to the health of an environment can be found in its air, water, plant and animal ecosystems, and soil. Highlight the fact that although all of these factors are very important to a healthy planet, soil pollution heavily influences the health of every other part of the environment.)
3. Explain that when soil is polluted, the entire ecosystem suffers. Make a list on the board of ways that contaminated land and soil affect plants, animals, and humans, including:
• food shortages: Soil pollution reduces the amount of nutrients in the soil, making it difficult for farmers to grow enough food to meet demand. Americans and people around the world rely on "America's Breadbasket" for grains, produce, and other products to survive. Contaminated soil could lead to massive food shortages.
• toxic atmosphere: Polluted soil cannot produce the nutrients that plants and trees need to survive. Plants and trees remove carbon dioxide from the air, leaving behind the clean, oxygenated air we need to breathe. If contaminated soil reduces the number of plants and trees, carbon dioxide in the air could rise to toxic levels.
• mass extinctions: Contaminated soil cannot produce the nutrients that plants need to survive, so the animals that depend on the plants for food will starve.
• water contamination: Rainwater that drains across contaminated soil before arriving in lakes and streams could contaminate drinking water.
4. Discuss how waste management and recycling are two of many ways to help reduce soil contamination. Use the supplemental information (below) to answer any remaining student questions about the importance of keeping the soil clean.
Using the Student Reproducible
1. Separate students into groups of 5 to 8. Explain that each group is going to present a persuasive argument about the cause-and-effect cycle of soil health. Students will develop a hypothesis, conduct an investigation to discover the facts, and then inspire others to act.
2. Instruct each group to choose a specific human action that could lead to soil contamination. Each group should then decide what it thinks the primary effect of that action will be (e.g., human actions like poor waste management, deforestation, and the use of pesticides can lead to effects such as soil erosion, animal and plant extinction, and food shortages).
3. Distribute a copy of the "Healthy Soil, Healthy Land" student reproducible. Student teams should use this reproducible to help guide their research.
4. Provide class time for students to research and present their findings.
5. Take a class poll to find out which group had the most compelling argument for action! Discuss what was most persuasive about each presentation.
Special Project (optional)
Challenge students to make a difference in the health of their local land! Help student teams create and implement a "Protecting the Land" Action Plan for a chance to win more than one million dollars in scholarships and grants!
Here's how it works:
• Choose a topic: Help each student team choose one of the following areas of soil health to focus on:a. Waste management and recycling• Research: Provide class time for each team to research its topic.
c. Endangered animals
• Develop a plan: Instruct each team to create an original plan describing what it wants to do to help keep the land healthy. Each team should go to www.scholastic.com/lexus and complete the online Action Plan to describe its incredible idea!
• Take action: Guide each team as it implements its Action Plan. Remind students to keep track of any successes and challenges throughout the process.
• Submit your entry: Enter online at www.scholastic.com/lexus for a chance to win! Visit www.scholastic.com/lexus for complete entry details and the official rules.
Special Project Example
Review this sample idea with students to help them get started on creating their own amazing Action Plan!
Topic: Endangered animals
Research: Student teams research four endangered animals in four different areas of the United States. They discover how each animal has become endangered and why the potential loss of these animals will affect the entire U.S. and the world at large.
Action Plan: Student teams host an eco-awareness event at their school to share information about what everyday people can do to help endangered animals.
SUPPLEMENTAL MATERIALS: SOIL HEALTH
FACTS ABOUT SOIL
Reinforce students' understanding of soil and how it affects environmental health by sharing the following questions and answers:
• Why is healthy soil important?
o The products that drive our economy rely on healthy soil to succeed (e.g., produce, textiles for clothing, grazing land for livestock).
o Healthy soil also influences the health of other natural resources, including water, air, wildlife ecosystems, and plant habitats.
• What is "healthy" soil?
o Healthy soil is filled with microorganisms that filter and replenish the nutrients in the soil in a continuous cycle. This cycle also filters harmful pollutants out of the soil by processing the waste.
o Healthy soil is pesticide-free, so when rain or snow falls and flows into rivers and lakes, water supplies remain clean.
• What causes soil to be "unhealthy"?
o Soil contamination comes from pesticides, factory pollution, unwise farming practices, and waste.
o Waste: The United States produces 230 million tons of personal, commercial, and agricultural waste each year. Landfills are unable to keep up with the demand, leading to contamination of soil and water supplies.
o Deforestation: Trees are nature's filter. They remove air pollutants and drive the air-recycling process that produces clean oxygen. Deforestation also leads to soil erosion and landslides, and disrupts the composting cycle that nourishes the soil for other organisms.
o Tropical rain forests are home to 50 to 90 percent of all organisms on earth, including 90 percent of all primates.
o 50 million organisms can survive only in the rain-forest ecosystem.
o Rain forests are the source of 25 percent of all medicines.
• What does unhealthy soil influence?
o Animal and plant life
o Ecosystem health
o Water quality
o Air quality
Share some great ideas with your students about how they can help to keep the land healthy! Reinforce the importance of thinking both locally and globally. Local plans are often easier to implement, but global plans can reach a much wider audience.
• Wise waste management:
a. Composting: In nature, fallen plants and animals decompose naturally. Composted waste is gradually processed and cleaned by soil, providing fresh nutrients for plants and animals.
b. Preventing waste: When people make a commitment to using durable, reusable items and purchasing products with less packaging, they are reducing the amount of waste they produce.
c. Incineration or burning waste: Used wisely, incineration can produce steam, which is processed as electricity.
d. Recycling: Using recycled materials reduces the amount of greenhouse gases and pollutants that are put into the environment by traditional manufacturing plants. Recycling also conserves fossil fuels, saves energy, and reduces waste.
• Pesticide-free farming: Encourage farmers to "go organic" and use pesticide-free fertilizers to keep contaminants out of the soil.
• Prevent erosion: Plant a windbreak of trees or bushes around fields to reduce the chance that wind will blow the topsoil away into your water supply. Planting trees at water lines (like rivers and lakes) helps prevent erosion of the banks into the water bodies.
THE DUST BOWL: REAL-WORLD EXAMPLE
Illustrate the importance of healthy soil by discussing the Dust Bowl (1931–39) and how it led to the Soil Conservation Act of 1935.
Explain that during the Dust Bowl, dry topsoil began blowing off farmland all across the United States. Without topsoil, farmers were unable to grow enough food and the agricultural economy collapsed. It affected not only the human population dependent on the crops but also the plants and animals that relied on the nutrient-rich soil to survive.
Review the following sequence of events with students:
a. In 1931, the United States entered into a drought that lasted until 1939. Crops across the country died in the fields.RETURN HOME
b. As farmers tried to farm dry land, they realized that excessive grazing and plowing had disturbed the natural soil-replenishment cycle. Dust clouds began to blow across the Midwest in 1932.
c. By 1934, dust storms covered 74 percent of the United States.
d. The government tried to correct the damage to the overused soil but wasn't able to. According to the 1934 Yearbook of Agriculture, "Approximately 35 million acres of formerly cultivated land have essentially been destroyed for crop production. . . . 100 million acres now in crops have lost all or most of the topsoil; 125 million acres of land now in crops are rapidly losing topsoil."
e. In 1935, soil erosion was declared a "national menace" and farmers were paid to use soil-conservation farming methods such as strip cropping, terracing, crop rotation, contour plowing, and cover crops as part of the Soil Conservation Act.
f. By the end of 1935, 850 million tons of topsoil had blown off the southern American plains.
g. By the time it began to rain again in 1939, food riots and economic hardship had taken a harsh toll on the United States and the world.