I like to do a version of this activity with older students in the fall as we begin to plant cover crops and to spread compost on to our garden beds. The take away is that there is something really important that we can do which is to appreciate our soil for the precious resource that it is and not to treat it like “dirt”! I like to have a basket of finished sweet smelling rich compost to pass around after the lesson to show students that this is what we can create and that we can actually build the soils in our garden!
1. Hold the apple out so the class can see it.
“Think of this apple as a physically representation of the globe.”
2. Cut the apple into quarters. Hold out 3/4 in one hand.
Ask the class: “What do these 3/4 represent?” (Water.) 1/4 Land
3. Set the three “water” sections aside and hold out the remaining quarter.
Ask the class: “What fraction of the apple remains?” (1/4.) This 1/4 represents the total land surface.”
4. Slice the land (the remaining 1/4) in half, lengthwise. Hold out one of the pieces.
Ask the class: “What fraction of the apple is this?” (1/8.) “This 1/8 represents the half of the Earth’s surface that is inhabitable to people and to crops: the polar regions, deserts, swamps, and high or rocky mountains.”
5. Set that 1/8 aside and hold out the other.
“This 1/8 represents the other half of the Earth’s surface. These are the areas on which people can live, but cannot necessarily grow food.” Habitable but not all is arable land.
6. Slice this 1/8 crosswise into four equal pieces. Hold out 3/32 in one hand.
“These 3/32 represent land on which people can live, but cannot grow food. Some of it was never arable because it’s too rocky, wet, cold, steep or has soil too poor to produce food. Some of it used to be arable but isn’t any longer because it’s been developed by being turned into cities, suburbs, highways, etc., so it can no longer be farmed. Governments have earmarked other areas, such as parks, nature preserves and other public lands to remain undeveloped forever.”
7. Set 3/32 aside and hold out 1/32.
“So, only 1/32 of the Earth’s surface has the potential to grow the food needed to feed all of the people on Earth. ”
8. Carefully peel the 1/32 slice of Earth. Hold up the peel.
“This tiny bit of peel represents the topsoil, the dark, nutrient-rich soil that holds moisture and feeds us by feeding our crops.”
How can we preserve arable land?
- By not building on arable land: Land covered up by buildings, highways, and other forms of development can’t be used for growing crops.
- By supporting our local agriculture, shopping at farmer’s markets and buying local produce!!
- By caring for the soils in our gardens! How can we care for the soils? We can add compost and plant cover crops!!
Want to learn more about soils! Check out the educational resources on the Natural Resource Conservation Service website.
– Laurel Anderson, SGN Board Member and Mentor