AgBC's: S is for Sensational Soil

Soil is so important, yet we hardly think about it! Soil anchors plant roots, holds water for plants, and even provides air spaces for plant roots to grow.

Image from the Extreme Pumpkin Store

But for all that, did you know soil is basically made of of 3 sizes of particles? Sand is the larges, clay is the smaller, and silt falls in the middle size-wise. The proportion of each of these particles varies from soil to soil, giving each soil unique characteristics. Some solid drain more quickly (sand), while others hold water or become saturated with water (clay). Many plants, trees and shrubs prefer to grow in a balanced mixture of these particles called "loam." Loamy soils hold a moderate amount of water, air and nutrients while supporting the plant.

A vineyard in Lake County, Ohio

Because characteristics of the soil can affect plant growth, farmers and gardeners often test soil to determine if it's good for growing specific plants. Two such simple tests include the ribbon test and the "soil shake" test. The results are a good predictor of whether or not the soil is good for growing specific plants. More accurate assessments can be sent to soil testing labs, and today it is increasingly common for farmers to have their cropland grid sampled and have the results of their soil testing GPS mapped to improve the efficiency of their farming operations.


Here are some simple instructions for conducting the ribbon and "soil shake" tests with your students:

• Ask the students if they've ever heard of the ribbon test. The explain that is can help determine what kinds of particles are in their soil. 
• Demonstrate the text by moistening a handful of garden soil or silt in the palm of your hand until it has the consistency of putty. Work the soil into a ball about 1/2" in diameter. Press the ball between your forefinger and thumb to form a ribbon (see below).
• If the soil will not form a ribbon, it is sand. If it makes a ribbon 1-2 inches long, it is loam. Ribbons longer and 2 inches are clay. Here is a more detailed description.
• Explain that each of the three types of soil particles forms a different type of ribbon. Repeat the test with clay and sand.
• Ask the children to describe the difference between the three ribbons.
• Pass out different kinds of soil without telling the students what soil type they have; let them each conduct their own ribbon test and hypothesize about what type of soil they have.

Making a soil ribbon.

Students can also conduct a "soil shake" test:

• Fill a jar 1/3 full with soil.
• Fill the jar 1/3 full with water.
• Add a tablespoon of alum (alum speeds the settling process and can be found in the spice section of the grocery store.
• Ask the children to predict what will happen when the jar is shaken. 
• Divide the children into groups of 3-4. Ask them to collect soil from outdoors or give them some soil you have collected.
• Tighten the lid and shake for 3 minutes. Make sure all the lumps have broken apart. Tell the children to observe the jar after 30 seconds, 1 minute, 2 minutes and 3 minutes and write down what they observe.
• Have them report their findings to the class. Discuss how the soil separates by particle size and identify the particles int he layers they see. The larger sand particles will be on the bottom, with the silt in the middle and any clay particles on top.

For more fun, investigate what kinds of plants grow best in various kinds of soil.

AgBC's: R is for Roots

Last week we talked about ducks and their wetland habitats. But did you know one of the other important functions of wetlands is that they help to stabilize the soil and hold it in place? This  helps to prevent erosion and trap sediments, which helps to create a rich, fertile habitats for plants and animals. But how do they do this?

The roots of the plants in this interior wetlands in North Carolina help protect the soil.
Photo from the National Oceanic & Atmospheric Administration.

The roots of wetland plants play a critical role in protecting the soil from erosion and keeping it in place. Want to see hands-on for yourself if and how roots hold soil in place? Try this simple experiment. Here's what you'll need:

• 5 radish seeds
• 5 mustard seeds
• 2 glass or plastic contains, about 1-cup volume
• earth/soil free from lumps
• water

Fill both containers roughly 2/3 full of soil. Then plant the radish seeds in one container and the mustard seeds in the other. Cover the seeds very, very lightly with soil. Add 1/4 cup water to each container and place in a sunny area or near a bright light. Make sure the soil stays slightly damp.

After 2 weeks, empty the container with the radish seeds onto some newspaper. Do the same with the mustard seed container. What shape does the soil have? Why? Talk about the impact of this discovery. What would happen to the soil if a fire burned all the plant material from a hillside if there was a heavy rain?

Students will have fun with this simple experiment, and you will, too!

AgBCs: O is for Onion

Onions are such a fun and accessible food to experiment with and learn about! Plus they have a long history. In fact, people have used onions for so long (before recorded history!) that no one is really sure where onions actually originated.

What we do know is that by 3000 BC several types of onions were grown in gardens, and writing on one ancient Egyptian pyramid wall even complained about the expense of providing slaves with onions and garlic! Other sources suggest Egyptian priests looked at the onion as a symbol of the universe with its round shape and the layers of the onion symbolizing the layers of heaven, earth and hell. In fact, onions are pictured on more pyramid tombs than any other plant!

Onions were even used in the creation of mummies in ancient Egypt.

Of course, the first thing most people think of when they think of onions is the aroma, which originates from an ail within the plant and escapes into the air as an irritating vapor when the onion is peeled or cut.

The release of oil from inside the onion is what brings tears to your eyes!

Early people thought onions with stronger scents had more power. In fact, early Romans often ate breakfasts of raw onions on bread, and Roman gladiators were often rubbed with onion juice to make them strong. Even Greeks in training for the early Olympics were told to eat 2 onions a day to make them strong.

Gladiators like these ate onions and rubbed their bodies with the oil from onions to improve their strength.

In North America, wild (meadow) onions grew long before the arrival of settlers, and Native Americans ate them raw after dipping them in salted water and dried them for food use during the winter. The first large yellow onions came over on the Mayflower in 1620, and they were a staple in Colonial gardens. Our nation's first president George Washington even said they were his favorite food!

George's favorite food? Onions!

Besides learning about the history of onions, how can you turn them into a learning lesson? Simple! Here's what you'll need:

• 3 large onions (you may want to try 3 different varieties—some are easier to grow than others)
• 3 jars/drinking glasses large enough to hold each onion without it rolling over
• water

Simple put the onion in each had with the rounded side down and add enough water to wet the bottom of the onion. Don't use too much water or your onion may rot. Then just put your jar in a bright area with plenty of light.

Within a week or so, you should see white roots coming from the bottom of the onion. A week or two later and you should start to see long green leaves coming from the top of the onion. The food for the leaves is being supplied by the bulb of the onion. Just make sure to keep enough water in the jar to cover the bottom of the onion.

When the leaves get about 4 inches tall, have an adult cut open the onion to see how the leaves have grown from the center of the bulb.

For a special treat, cook your onion in a dish for everyone to enjoy!