• Managed grazing images [electronic copies to project or one complete printed set per pair of students]
• Radish seeds [20 or 40 seeds per group]
• Soil (loam or clay-loam; do not use potting soil)*
• Plastic bottle bottoms, milk carton bottoms, small yogurt containers, small clay pots, etc. (2- to 3-inch diameter; at least 1.5 inches deep) [2 or 4 containers per group]
• watering can or plastic cups with evenly spaced holes in bottom
• Plastic knife [one per group]
• Water

*Use soil that packs well; seeds placed on top of packed surface should lie on the surface and be able to be easily washed and/or blown away.

Create a space to store the planted containers. This may be indoors or outdoors, depending on the school setting and time of year. It is okay if the containers have to be distributed to multiple classrooms as long as individual groups' containers are placed together.

Tell students you have a puzzling phenomenon to share with them! Show students the photographs of the same location in the Republic of Zimbabwe taken nine years apart. (If your students are unfamiliar with the countries of South Africa, point out the location of Zimbabwe on a map.) Give students time in the alone zone (independent thinking time) to compare the two pictures and record any changes they observe. As you move around the room, encourage students to describe the changes they observe in as much detail as they can. For example, if students record more plants, you might ask them, "How many different kinds of plants do you see in the Year 0 picture? Which kinds of plants increased the most between Year 0 and Year 9?" and "Are there any kinds of plants in the Year 9 picture that are not in the Year 0 picture?"

Ask students to share their observations with a partner; make sure to tell students they may add changes their partner noticed to their own list.

Bring students back together. Invite students to share a change they noticed (or their partner noticed) with the class. Record students' observations in a public space.

Tell students, "Between the time these pictures were taken, a Zimbabwean scientist, Allan Savory, and his team brought cattle to this location twice each year and allowed them to graze for three days. No cattle or other large animals were allowed on the land during the rest of the year."

Pause, then ask students, "How many times did cattle visit this land in nine years?" Ask students to turn and talk with a partner before inviting them to share their answer with the class. (18 visits) You might next ask, "How many total days did cattle graze on this land in nine years?" Again, ask students to share their answer with their partner before asking for a volunteer to share  their answer with the whole class. (54 days)

Share two more photographs (above) with students. Make sure to give them the following information about these photographs:

• The photographs were taken on the same day.
• Locations B and C are next to each other.
• Allan Savory and his team brought (herded) cattle to location C two times each year for nine years. No cattle or other large animals were allowed on the land during the rest of the year.
• No cattle were brought (herded) to location B.

Allow students time, working in pairs, to compare the location B and C photographs and record differences between the two locations. Next, assign student pairs to small groups and ask them to create a group list of differences between locations B and C. Ask students, "What patterns do you notice in your observations of locations A, B, and C?" Give students time to work with their group members to identify patterns in their observations (data).

Bring students back together and ask them to share patterns they identified in their observations. Students will likely identify the following patterns:

• Land without cattle doesn't have very many plants/tall grasses.
• Land without cattle has big patches of dirt.
• Land with cattle has a lot of plants/tall grasses.
• Land with cattle has more kinds of plants than land without cattle.

Tell students, "Allen Savory, the Zimbabwean scientist, noticed the same patterns you did and made this claim: The hooves of the cattle are what cause the grass and other plants to grow."

You might choose to share a short clip, 30:30–32:40, from Kiss the Ground: For Schools (password: school) to introduce students to Allan Savory and his research on holistic management.

Guidance. Sharing the video clip from Kiss the Ground: For Schools with upper-elementary students.

• Keep the focus on the differences between land managed for grazing and land not managed for grazing. For example, Allan Savory and Ian Somerhalder (interviewer) use the terms desertification and regeneration in this clip. You might pause the video and connect desertification to the Location A- Year 0 and Location B photographs and regeneration to the photographs of Location A-Year 9 and Location C. It is not necessary to address all of the information presented.
• At 31:55, Ian Somerhalder uses a word you may deem inappropriate for students. Consider stopping the video at 31:55 and drawing students' attention to the phrase, "using hooved, herding herbivores, you've literally transformed that [area like location B], what we've been seeing, to this [area like location C]." Then skip ahead to 32:00 and play the video to share Allan Savory's claim with students.
• Allan Savory's full claim is this: "...the urine and the hooves of the animals are what cause this grass to grow." If students call this out, acknowledge them, but tell students that we will only be collecting data about the hooves.
• Consider playing a longer segment of the movie, 30:30–33:42, if you plan to discuss the role of holistic management in reversing climate change.

Show students photographs of cattle hooves and ask, "How do you think the hooves of cattle cause grass and other plants to grow on land managed for grazing?" Give students alone zone time to record their thinking using words, pictures, and symbols. As you move around the room, consider asking students some of the following questions to move their thinking deeper:

• What does the ground look like before the cattle walk on it? (Refer students to the photograph of location B if they are unsure.) What do you think the ground looks like after a herd of cattle walks over it? Why do you say so?
• What do you think the ground would look like if a large group of animals without hooves walked over it? Why do you say so?
• What would you need to grow grass on this spot right here? (Point to a bare spot of ground on the location B photograph.) If students do not include seeds, sunlight, and water, ask follow-up questions to guide their thinking.
• What are some reasons grass might not grow here (point to bare spot) even if seeds, sunlight, and water are present? How might you show your thinking using pictures and/or symbols?

Ask students to use their models to predict how hooved, herding herbivores (cattle) cause the grass to grow on land managed for grazing. Then instruct students to return to their small groups and share their predictions. Do not invite students to share with the whole class at this time.

Provide each small group the following materials*:

• 2 near-identical containers
• enough soil to completely fill containers (tightly packed)
• 20 radish seeds (minimum)
• 1 plastic knife
• watering container
• water

*If you have more materials readily available, provide each small group twice this amount of materials so that each student is responsible for preparing one container of seeds.

Share the following instructions with students:

1. Tightly pack each container with soil. When packed, the soil should be very slightly mounded above the edge of the container.
2. Count the seeds and divide them into two equal piles.

Bring the students back together. Say to students, "Each group will have one container representing land managed for grazing and one container representing land that is not managed for grazing. Right now, we have tightly packed soil in both containers. Which type of land do our containers represent?" Students likely will all agree that both containers are like land that is not managed for grazing.

Next, ask students, "How should we change one of our containers to represent land managed for grazing? That is, land that a hooved herd of cattle has walked over?" Ask students to quickly turn and share ideas with their group members, then bring the class back together. Invite groups to share their ideas. Students will likely suggest using the plastic knife to cut into the soil like the hooves of cattle do. You might as a class decide how many cuts to make, how deep to make the cuts, and whether or not the cuts should all be in the same direction. Give students time to make the cuts after the class has reached a consensus.

Ask students, "What do we need to keep the same between our two cups? That is, how can we make sure our test to see which container grows the most radish seeds is fair?" Again, ask students to discuss this question with their group members. Bring the students back together and ask groups to volunteer their ideas. Students will likely say they should put the same number of seeds in each cup, place the seeds in the same locations in both cups, give each cup the same amount of water, and place the cups in the same location in the room (or outside depending on the school setting and the season).

Allow students to place their seeds in the containers. Before students add water, ask them to draw each container, describing in words, pictures, and symbols the shape of the ground surface and the placement of each seed. Then instruct students to gently water the seeds (according to package directions). Some of the seeds may be washed off one or both surfaces; this is acceptable. These seeds should not be replaced. Ask students to record their observations.

Ask students, "What types of data should we collect, and how should we measure each type?" Give students time in the alone zone to record their ideas, then ask them to share their ideas with their group. As you walk around the room, listen for students to share ideas about recording how many seeds are sprouted (count them), the color of the sprouts (light green, dark green, brown); how tall the sprouts are (use a ruler); and the location of the sprouted seeds (show on a drawing). If cameras are available, students may suggest taking pictures of the containers as well.

Bring students back together and ask for volunteers to share their ideas. Make sure to call on the groups who shared the ideas you were listening for first. You might collaboratively work to create a table to record data. You might also decide how often you will collect data.

Allow the investigation to continue at least a few days after the last class radish seed has sprouted.

Instruct student groups to represent their data on a group poster. You might choose to provide students a template for a data table and/or graph or allow students to choose how to represent their group data. Ask students to include on their poster any patterns they identify in their data.

Display group posters around the room. Consider using a "three stray, one stays" gallery walk strategy; that is, one student remains with the group poster as the other group members move from group poster to group poster. Tell the students who "stray" to remain at each poster until you give them a signal to move. As students move from poster to poster, they should record at least one similarity and one difference between their own data and the data represented on the group poster they are observing. Make sure students note the group number or name when recording similarities and differences.

Give each group of students the opportunity to visit at least three posters before returning to their own group's poster. Ask students, "What patterns do you observe in the class data? Share your ideas with your group." Allow students time to first share with the student who "stayed" with their own poster the similarities and differences they observed between their group data and other groups' data. Then move the groups to identifying patterns in the class data.

Students may notice no patterns exist in the class data or that the containers representing land not managed for grazing grew more and/or higher and/or greener radishes than the containers representing land that hooved, herding herbivores walked across. Although students may become anxious because these are not the expected results, it creates an opportunity to discuss experimental design, number of trials, and the nature of science (they may find they get the same unexpected results after revising the investigation).

Provide students time in the alone zone to compare the results of the class investigation with their predicted results. You might ask them to complete a self-reflection using the following sentence stem:

I used to think ____, but now I think ____ because....

You might choose to collect students' reflections or give them time to share their thinking with their group.

Remind students of the claim made by Allan Savory: The hooves of the cattle are what causes the grass and other plants to grow. Then guide students in a brief building understanding discussion using one or more of the following prompts:

• Does any group have evidence to support Allan Savory's claim?
• What's your evidence?
• What data do we have that challenges Allan Savory's claim?
• What can we conclude?

To conclude this lesson, you might share some current headlines about hooved, herding herbivores being used to regenerate soil, like the one published in the Star Tribune on September 8, 2020: "Are Bison theKey to Bringing Back Minnesota Prairies?"

 KISS THE GROUND: FOR SCHOOLS—available now for free to all schools, students, teachers, and community educators—is a 45-minute-long educational version of the critically praised exo-documentary, KISS THE GROUND, produced and directed by Sundance award-winning documentarians Josh and Rebecca Tickell. KISS THE GROUND: FOR SCHOOLS has new scenes not in the feature film, including a series of person-on-the-street interviews with Rosario Dawson and a scene in which Tony Tenfingers, a Lakota Elder, describes the importance of the once-prevalent buffalo for Native American peoples. KISS THE GROUND: FOR SCHOOLS is also available with subtitles in 18 languages including English Closed Captions, Spanish, Mandarin, and Hindi.