Basic Soil Facts

by | Feb 11, 2021 | Gardening Tips

Looking ahead to the 2021 gardening season at Sea Call Farm, it’s good to check the basics on topics such as soil health.

Here’s a very informative website: The Soil Association at soilassociation.org. Lots of good reading material and useful information.

Some interesting takeaways from a quick look at The Soil Association:

  • Healthy soil has six layers known as “horizons” ranging from uppermost levels of topsoil and organic matter down to the lower level of bedrock
  • Soils are home to 25% of the Earth’s species. Amazing!
  • A quarter of a tablespoon of soil can harbor up to 10 million organisms.
  • Soils store more carbon than the atmosphere and all of the world’s plants and forests combined.

Check out more fun facts here.

The six layers of soil, from top down, consist of the organic horizon made up primarily of leaf letter and humus (decomposed organic matter), then topsoil made up of humus and mineral particles, then a leaching layer of sand and silt, then subsoil made up of clay and mineral deposits, then the regolith layer made up of fragmented bedrock, and finally the bedrock layer.

What is soil, exactly? According to the USDA, soil is:

  1. “The unconsolidated mineral or organic material on the immediate surface of the Earth that serves as a natural medium for the growth of land plants.” AND/OR:
  2. “The unconsolidated mineral or organic matter on the surface of the Earth that has been subjected to and shows effects of genetic and environmental factors of: climate (including water and temperature effects), and macro- and microorganisms, conditioned by relief, acting on parent material over a period of time.”

Another definition also noted on the USDA website from “Soil Taxonomy, Second Edition”: “Soil is a natural body comprised of solids (minerals and organic matter), liquid, and gases that occurs on the land surface, occupies space, and is characterized by one or both of the following: horizons, or layers, that are distinguishable from the initial material as a result of additions, losses, transfers, and transformations of energy and matter or the ability to support rooted plants in a natural environment.”

So much to know about soil and soil health! Learn more here!