Dirt is just dirt, right? You’d be surprised! All that ground that you walk on and grow plants in isn’t just dirt, it’s ~Soil~.  Remember folks, dirt is what you get on your hands and clothes, soil is made up of elements that have been decomposing for millennia!

Soil Percolation

What you’ll need:

• 1 cup of water
• Outside ground to pour water on

What you’ll do:

• Label a new page in your nature journal “Soil Experiments”. Then, start a new paragraph with the label: “Soil Percolation”.
• Make a note of what the ground looks like before (what color is it? Does it seem dry or moist? Does it feel loose or very compact)
• Pour the water over the ground and observe what happens
• Take a note in your nature journal: How quickly did the water absorb? Did it soak right in, pool on the surface, or trickle off?

Why does it matter?

Healthy soil has worms and other invertebrates that make channels throughout to allow water to reach the roots of plants. Compacted areas, like where people walk on or where machines drive on, lose these channels. It can also indicate whether plants need water, like shown in the picture. If water was poured on saturated soil, it might pool or run off, telling you the plant has enough water.

Kitchen pH Experiment

pH tells scientists, cooks, gardeners, and the rest of us whether something is acidic or basic. It’s based on the concentration of hydrogen atoms and some math, but what you need to know is that pH affects nutrient absorption in plants. Take a look at the pH scale we have here, acidic things like lemons, tomatoes, and vinegar all taste sour. Basic things, like tofu and lentils, often have a slippery taste or texture, but tasting things is not a safe way to measure pH. So how can we test the  pH of our soil? Check this out:

What you'll need:

• 2 tablespoons vinegar or lemon juice
• 2 tablespoons baking soda
• 2 containers with water, about a half cup of water in each
• A sample of your soil (roughly 4 tablespoons)
• (This experiment might require materials you don’t have access to, luckily it is very basic and doesn’t always give us information we can use. If you don’t have the materials, you can still answer the questions on step 4)

What you'll do

1. Mix the vinegar or lemon juice into one of the containers of water, mix the baking soda into the other
2. Add roughly two tablespoons (or a large spoonful) of soil to each container.
3. On your Soil Experiment page in your nature journal, start a new paragraph section and label it : “Kitchen pH Experiment”. Make a note in your nature journal about any observations. If you saw bubbles and a reaction in the vinegar mixture, you have fairly basic soil. If you saw bubbles or other signs of a reaction in the baking soda mixture, you have fairly acidic soil.
4. What are some limitations of this experiment? (What can we learn from this test and what can’t it tell you?) Answer in your nature journal 

What does Soil pH mean to the gardener?

Identify your soil type with the jar test

What you’ll need:

• The measuring cup, or a clear jar or bottle.
• Water
• A cup or so of a sample of soil from your yard or an outdoor space

What you'll do:

1. Fill a clear glass jar halfway with your soil sample.
2. Fill the remaining half with water leaving 1" of air.
3. Attach lid, then shake the jar vigorously until you have broken up any clumps of soil.
4. Set the jar aside to rest, undisturbed overnight.

After 24 hours your jar's contents will have settled into distinct layers:

Sand, Silt, Clay 

By examining the proportions of these layers, you can gain a sense of what type of soil you have, and what you need to add to improve your soil. The middle jar below is the ideal soil (30% clay, 40% silt, and 30% sand)

Soil: what is it (good for)?

Sand

Particle Size: Large

Texture: Gritty, does not form a ball when squeezed 

Nutrient Content: Doesn't hold nutrients well

Drainage: Air and water move freely, good drainage

Silt

Particle Size: Medium

Texture: Powdery when dry, slippery when wet.

Nutrient Content: Doesn't hold nutrients well

Drainage: Lightweight, washes away if not mixed with other things.

Clay

Particle Size: Smallest

Texture: Sticky when wet, hard and smooth when dry

Nutrient Content: Holds nutrients very well

Drainage: Air and water barely pass through because it is densely packed so drainage is poor.

This Venn diagram shows how the three soil components contribute to loam. W can draw a triangle, where clay, sand, and silt sit at the vertices (corners).

Based on your sediment jar, what is your best estimate of your soil type? 

Sing the song Home on the Loam Song to the Tune of Home on the Range

Chorus:
Home, home on the loam
 That’s made of sand, silt, and clay 
where we can’t recall a dry day at all, 
and the worms rejoice every day.

Oh, give me a home on rich, fertile loam, 
that grows our forests today, 
Where we can’t recall a dry day at all, 
and the fungi rejoice ev’ry day.

Oh in my home, with that clay loam
That holds the water so well
Where it rains a lot, and the kids are all taught
To love the puddles and smell

Chorus

Oh, give me a home with plentiful loam 
that’s made of sand, silt, and clay. 
No one can debate that its texture is great, 
and the forests grow more ev’ry day.

Chorus x2

Now that you’ve learned about three major qualities of soil: Percolation (how fast water moves through it), pH (nutrient quality and acidity), and content of your soil (of sand, silt, and clay), check out the OSU  Willamette Valley Soil Quality Card. Pick one quality from the guide and tell us about it here:

Soil Quality Card Guide (google form)

Soil Horizons

Soil horizons or soil profiles are a way we can classify and characterize soil as we go deeper and deeper. There are a few distinct layers: Humus (the organic materials like leaves, pine needles, sticks, etc. being decomposed), Topsoil (the nutrient rich layer), Subsoil (usually the deepest water from the surface goes and mineral rich), and bedrock (where the soil horizons stop).

The Story of How oil Stacks Up (from bottom to top):

1. Bedrock: the the lowest level of soil, its solid rock
2. Parent Material: mostly rock that has been weathered, not a lot lives down here
3. Subsoil: made up of sand, silt, and clay that has not been broken up all the way
4. Topsoil: a thin rich layer where most nutrients for plants are found
5. Organic Material ""humus"

MO DIRT – Missourians Doing Impact Research Together

Get Eroded!

Explore the force of water erosion and create your own landforms

Soil Horizons

Match the soil horizon to the description