Soil, the substance that makes up the ground in which we walk, is often thought of and referred to as dirt. Actually, “dirt” is the substance that you sweep up off of the floor and then discard. Soil, however, can actually be regarded as a living organism. To begin with, soil consists of three basic components; the component being 45 percent mineral particles (sand, silt or clay), the second is 50 percent pore space (for water and/or air), and the last is 5 percent organic material (decomposed vegetable and animal matter). These three components will vary in percentages according to its mineral make up, its age, location, etc., of any given soil.
What is intriguing is that within these three components, a team of life exists in the forms of both micro- and macro-organisms. Micro-organisms found in soils for the most part consists of bacteria, but there is also fungi, algae, and protozoa to be found. Macro-organisms on the other hand may include earthworms, nematodes, slugs and snails, and various insects, like millipedes, pill bugs, spiders, mites, and the like. These organisms sustain life both below and above ground.
Fred Magdoff and Harold van Es in their book “Building Soils for Better Crops” described soil as a diverse community of over 100,000 living organisms. Bacteria, fungi, insects, and even small animals like moles all play an important role in the soil ecosystem and in plant health. Soil organisms, whether they be small or large, keep ecosystems in balance, move nutrients around, break down organic matter, make nutrients available and aerate the soil.
For examples, earthworms may not seem important to soil health, but they are one of the most important soil organisms. According to Magdoff and van Es, earthworms can create 800,000 underground channels per acre of soil that allow water to reach greater depths and provide more efficient infiltration rates during rain events. Earthworms are also remarkably good at moving soil particles. They state that in a 1 acre area, earthworms can move 1,000 tons of soil per year. That is a lot of soil for such a little critter.
Follow this link (https://bit.ly/1MiGJT5)to view a fun and informative short video called “Soils Are Living” from the Soil Science Society of America as part of their 2015 Year of Soils effort. If you want to read more about soil organisms, follow this link (https://bit.ly/2x31l2N) to the “The Living Soil” chapter in “Building Better Soil for Better Crops.”

Rip Winkel is the Horticulture agent in the Cottonwood District (Barton and Ellis Counties) for K-State Research and Extension. You can contact him by e-mail at rwinkel@ksu.edu or calling either 785-682-9430, or 620-793-1910.