Picking Up Rocks

Every spring in Iowa many farmers either have to pick up rocks from their fields or pay for it to be done. This occurs because of the roll over in soil from plowing the field, and the wind and water erosion due to lack of erosion prevention efforts. This is a common occurrence in Iowa and a great way to look at how the topsoil changes because of cycles below the Earth as well as changes in the topsoil.

Why do farmers in parts of Iowa have to pick up rocks every spring?

How does the ground in Iowa change based on how it is used?

Students could:

• Discuss how even though rocks that could damage machinery in the fields were picked up one year, more rocks “grow” the next year. 
• Use this conversation to discuss soil conservation or soil loss. You can also discuss how those rocks got there or what changes the Earth’s crust has gone through.

• Iowa Geological Society (IGS) | Historic Alterations of Surface Hydrology: History of the Des Moines Lobe and how the soil was affected.
• Leopold Center for Sustainable Agriculture | Economic Impact of Soil Erosion in Iowa: Study by Iowa State University about the cost of soil loss.
• Natural Resources Conservation Services (NRCS) } From the Ground Down: An Introduction to Iowa Soil Surveys: Overview of the Iowa Soil Surveys.