Iowa Soils“The soil is the great connector of lives, the source and destination of all. It is the healer and restorers

and resurrector, by which disease is passed into health, age into youth, death into life. Without proper care for it we can have no community,

because without proper care for it we can have no life”

-Wendell Berry, The Unsettling of America

Geosphere• Crust approx 25 miles deep• Interaction with climate

– Sedimentary rock• Deposits, compression, and cementing of small particles

of mineral, small animals, and plants

– Igneous rock• Molten magma cools and solidifies

– Metamorphic rock• Mineral changes in the rock without the rock itself

melting (heat and pressure)

Obsidian :Igneous rock Iron Ore: Sedimentary Rock

Andesite: Metamorphic Rock

Present is Key to Past

• Glaciation• Shallow Seas• Rift Valleys• Devonian Fossil Gorge: Johnson County, Iowa

City (405) » Iowa's Simple Pleasures with Dan Kaercher » Iowa Public Television

Soil

• “unconsolidated surface material of earth that supports plant life”– Parent material– Climate– Soil biota– Topography– Time (takes approx. 250 – 1000 yrs/1 inch of soil)

Foundation

• Mineral• Living and non – living organic matter

Classified

• Main parent material• Size of mineral particles

Clay Soil

• Microscopic, flattened mineral particles• Pack closely together when wet• Little space for air or water• Sticky feel

Sandy Soil

• Large round particles• Large spaces for air and water, does not hold

water well• Loses soil and nutrients quickly

Silty Soil

• Intermediate between clay and sand• Can hold some nutrients, good flow of water• Feels smooth

Loam

• Ratio of silt, sand, and clay• Sustains plants and resists erosion

Habitat and Construction

• Plants are affected by drainage• Suitable building sites

– Sewage and wastewater– Septic system or leachfield

• Percolation test

Soil Stories• “Recipe for soils” (part A)

– Divide into teams of two– Each team will analyze different soil samples

• Materials: Soil Investigation worksheet, Hand Shovel, Ziploc Bag, Toothpicks (4), Hand lens, Glass jar w/lid

– Collect sample, return back to the room.• Transfer soil onto white paper• Examine the soil by sorting out the soil particles into

different materials• Answer Questions #1 and #2 (Part A) in Journal

Soil Stories• “Soil Shake” (part A)

– Label a glass jar with member of your team– Place ½ cup of soil into a jar – Add to cups of water (What do you think is going

to happen?)– Put a lid on the jar and shake the jar hard for a

couple of minutes.– Allow the jar to settle overnight– Day (2) observe/sketch and answer #3 (in journal)

A Soil Mystery (part B)

• Read the Mystery as a class• Divide into teams• Complete “Soil Percolation Test”

– Record your findings in your journal (#4 a – g)

Soil Survey

1. Use a Soil Survey Map (Book) • Determine the soil types for our county

– List the texture and qualified uses

2. Use the http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm

– Determine the soil types for where you live– List the texture and qualified uses