The site navigation utilizes arrow, enter, escape, and space bar key commands. Left and right arrows move across top level links and expand / close menus in sub levels. Up and Down arrows will open main level menus and toggle through sub tier links. Enter and space open menus and escape closes them as well. Tab will move on to the next part of the site rather than go through menu items.

The Buzz

Nature Curiosity: Where Does Dirt Come From?




(Photo via Shutterstock)

Dirt is ever present in the environment, which begs the question — where did it come from?

When we talk about dirt, what we are really talking about is soil. We use the words interchangeably, but they aren't one and the same. When we talk about the dirt that plants grow in, it would be more accurate to call it soil. Soil is what plants grow in, while dirt is what you get on your clothes, track into your house and car or find under your fingernails, according to the Kansas State University Research and Extension. Essentially, soil can make us dirty, but dirt can come from other sources too. 

The soil beneath our feet consists of four components: minerals, organic materials, air and water, according to the Soil Science Society of America. Soil is teeming with life. The organic material in soil includes both dead organic matter as well as a multitude of tiny living organisms. When we think of living things in the soil beneath our feet, earthworms, ants and other insects come to mind, but there's also bacteria, fungi, algae and protozoa. 

Soil is one of the most essential materials for life, too, because the foods we eat depend on nutrients in the soil to grow, and the animals we use for food also rely on those plants to help sustain them. 

New dirt is always forming, but it is a long, slow process, and the amount of time it takes to form varies depending on the climate, according to the soil society. It forms fastest in hot, wet regions, but even in those areas it takes hundreds of years for 1 inch of topsoil to form. In cold, dry climates, it can take more than 1,000 years for 1 inch of topsoil to form.

Five factors influence how soil forms: climate, organisms, relief (landscape of the Earth's surface), parent material and time. In the soil world, these factors are known as CLORPT. 

Soil is not the same everywhere and it changes as it ages, and this is because of CLORPT, according to the soil society. As soil ages, its composition changes because the components in it — minerals, organic materials, air and water — are constantly changing. New components may be added, while others may be lost.

Particles in soil are categorized into three groups: clay, sand and silt. Soils can consist of entirely one type of particular, although that is rare, the soil society reports. Instead, most soils are a combination of clay, sand and silt particles, and the percentages of each type of particle determine the texture of the soil. 

Maybe you've been somewhere in the world where the soil looks a lot different than it does in your own yard. That could be because of the texture or color. Some soils have a lot of clay, while others have a lot of sand or silt, and this alters how it looks and feels. The color of a soil is an indication of its mineral content. Soil with high iron concentrations are orangish-brown or yellowish-brown, while soils containing a lot of organic matter are a very dark brown or black. 

Soil is different all across the United States and the world. The soil in your own yard can even be different than that of your next-door neighbor. Many states, including Illinois, even have a state soil, like they have a state flower, tree, bird and more. In Illinois, the state soil is Drummer soil, according to the Soil Science Society of America.

Drummer soil is named for Drummer Creek in Drummer Township, which is in Ford County in central Illinois. Drummer soil is one of many soil types in Illinois, but it is the most prevalent, present on more than 1.5 million acres of land, the soil society reports. Drummer soil is a black dirt because it has a high concentration of organic matter from decomposing prairie vegetation. 

_______________

Stay up-to-date on the happenings in Will County's forest preserves by subscribing to The Citizen, our weekly digital newsletter that provides subscribers with updates on Forest Preserve news, upcoming events, and other fun and useful information for the whole family. If you're only interested in programs, subscribe to The Weekly Five, which outlines the five must-do programs each week. Signing up for either newsletter is easy and free of charge.

In Spring, Vernal Pools Are Teeming With Life

4/21/2021

Vernal pools are temporary waterways that are teeming with life in spring, but our way of life threatens their existence. 

Read More


It's A Wild World Out There, And The City Nature Challenge Hopes To Document It

4/19/2021

You can help paint a picture of Earth's biodiversity by participating in the 2021 City Nature Challenge.

Read More


Warblers Adding to the Sights and Sounds of the Spring Forest

4/19/2021

Spring is migration time for many songbirds, including warblers. These small birds add to the sights and sounds of the forest this time of year.

Read More


Sign up for a Newsletter