LESSON #5: Soil

Focus Question:
What is erosion and how can it be controlled?

Vermont Standards addressed:

2.2	Problem Solving: Students use reasoning strategies, knowledge, and common sense to solve complex problems related to alI fields of knowledge.
3.10	Students perform effectively on teams that set and achieve goals, conduct investigations, solve problems, and create solutions
7.15	Students demonstrate understanding of the earth and its environment in terms of the systems that characterize them and the forces that affect and shape them over time.
7.15e	Analyze and explain natural resource management.

Length of time needed to complete:
60 minutes for initial demonstration, walk around school yard and brainstorming within groups, 15 minutes to communicate plan, 45-60 minutes to conduct experiment and write in journal, 60 minutes for speaker or trip to park

Resources/Materials:
Project Seasons (Soil on the Run), 9x13 baking trays, soil, watering can or jars to pour water, collecting basins, items to control erosion (hay, grass sod, sticks)

Procedure:

1.	Gather students together for a demonstration. Explain that you are a hill farmer and you just finished harvesting and tilling your fields. Show the students a tray full of soil which is propped up on one side, creating a slope. Place beneath the tray a collecting basin which runs the width of the tray. Tell the students it has been a rainy fall and another storm is brewing. Ask them what will happen to the soil in this field after a rainstorm. In your journal, sketch this tray as it looks now and another sketch of what it will look like after the storm. Label your drawing.
2.	Let it rain for 1-2 minutes by pouring two cups of water onto the tray.
3.	Observe and discuss. What happened to the soil in the tray? What do you notice about the run-off? (Put the water into a clear jar to examine.) What happened to the top-soil? How does this affect the farmer's ability to grow crops? Record amount of water in run-off and clarity.
4.	Explain that this process of soil washing away is called erosion. "Soil erosion is a serious problem that is affecting farmers throughout the world. Every year 3 billion tons of topsoil is lost and it is the topsoil that is responsible for soil fertility. Remember, it takes 100 years to make an inch of new topsoil."
5.	Walk around school and to the woods to see signs of erosion. Discuss why erosion is occurring in some areas and not others.
6.	Tell students: Your challenge is to reduce the amount of erosion in your own sloping hill farm. In your group, discuss ways to reduce the amount of water that leaves your tray as well as reduce the amount of soil in the runoff.
7.	Groups meet and decide how they wish to control erosion. (It may be necessary to have a class discussion, reviewing what we observed, to facilitate finding options to explore.) Possible options include terracing, contour plowing, adding organic material to absorb water, cover cropping, adding mulch. Have available items such as hay, grass seed, sticks, compost, and sod to help them brainstorm ideas. Allow students time to research options by discussing it at home, looking in books, etc. Set deadline, such as next day, to meet again and choose a plan.
8.	Draw a sketch of plan in book for reducing erosion, titling page, "Erosion Control."
9.	On the day of the experiment set up trays and have the students present methods for erosion control. Have all the groups pour the same amount from a set height onto a sloping field. Examine the runoff of each field, noting clarity, color and amount collected. Which methods were the most effective at controlling erosion? On "Erosion Control" page in journal, write the results of your experiment. Draw a conclusion by comparing your field and the results to the first demonstration.
10.	In your journal answer these questions: What is erosion? Why is erosion a problem? What did you learn from doing this experiment?
11.	Have a soil conservation specialist visit the classroom and discuss soil and issues about erosion. Or, take a field trip to Marsh-Billings-Rockefeller National Historical Park to learn about George Perkins Marsh and his observations about the effects of the loss of trees on Mount Tom to the river.

Assessment:

	Students will:
		Observe the effects of water on bare soil
		Use knowledge and reasoning to create a way to reduce erosion
		Develop understanding of soil as a precious, essential resource that needs to be protected.
		Work cooperatively to solve the problem of erosion.
	Teacher will:
		Check for clarity of understanding of erosion and how to control it in their writing
		Write anecdotal notes and give feedback to students about their efforts as a group to find a solution and participate cooperatively
		Encourage, support, redirect, and facilitate groups in finding ways to reduce erosion

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