What is soil? It is mixture of minerals, air and water, along with dead and living organisms. It is one of the four things we can’t live without: water, sunlight, air and soil. Soil is not dirt. Dirt is what is under your fingernails and what is found inside your vacuum cleaner. Soil is an amazing natural resource and according to the Soil Science Society of America, there are 22,000 different soils just in the United States!
Soil is formed in layers, what soil scientists refer to as horizons. The top layer is called the organic layer (O), also called humus by gardeners, and is comprised of decomposing plant and animal material. Underneath the O layer is the most productive layer, the A horizon or topsoil, where plants and other organisms live. Below the A layer is the B horizon, or subsoil. The next layer is the C horizon, which is the deposit at the Earth’s surface from which the soil developed, called parent material. In some areas there are additional layers defined by soil scientists, including the R horizon, the mass of rock that forms the parent material. In Delaware County we might see limestone, typically west of the Scioto River, or sandstone in the eastern part of the county.
So why is soil important? Soil is a nonrenewable resource. It can take more than 500 years to form one inch of topsoil. Five tons of topsoil spread over an acre is only the thickness of a dime. Here are some reasons to appreciate your soil:
• Soil is alive. Millions of species and billions of organisms make up life underneath our feet. This includes bacteria, algae, insects, earthworms, beetles, ants, mites, and fungi and they recycle nutrients, build the soil, and give it structure.
• Soil is the foundation on which homes, roads, waste water treatment plants, hiking trails, camp grounds, office buildings, and home sewage treatment systems are built.
• Soil holds water for our streams, rivers, lakes, and ponds, providing us with recreational activities such as fishing, boating, and swimming.
• Soil holds the water for wells (groundwater) and reservoirs which supply us with drinking water.
• Soil stores and filters rainwater and snowmelt, mitigating floods and drought.
• Soil grows the food to feed humans, domestic animals and wildlife. Globally, about 95% of our food comes from soils.
• Soil grows the trees we need for lumber, shade, oxygen, and much more.
The soil beneath you is essential to life and must be protected. Wind and water can erode our valuable topsoil. Erosion not only depletes the topsoil layer, it moves the soil into our rivers, lakes, and streams, degrading water quality. The B horizon cannot match the richness of the topsoil layer so the quality and quantity of plant growth is impacted. To learn more visit facebook.com/IheartSoil. Excellent resources for educators can be found at soils4teachers.org.
Visit us at the Delaware County Fair from Sept. 18-22. We are located next to the pig and lamb barn. A schedule of events will be posted to our website at soilandwater.co.delaware.oh.us.
Bonnie Dailey is deputy director of the Delaware Soil & Water Conservation District. For information, go to https://soilandwater.co.delaware.oh.us/.