The great soil biology experiment

© 2017-Sublette Examiner

This string of undies demonstrates the variations in soils around Sublette County

If you came by the SCCD fair booth this year, you probably saw our interesting display of soil-covered underwear hanging behind our table. This display not only grabbed the attention of fair attendees but also proved to be a great way to show soil biology of rangelands in Sublette County and how soil organisms attribute to the health of these rangelands.

Microorganisms are very small forms of life that can usually only be seen through a microscope. There are many different kinds of soil microorganisms. These include bacteria, fungi, algae and protozoa. Each of these organisms has a very different and important job! These organisms are primary decomposers of organic matter; they produce products that help stimulate plant growth, fix nitrogen, detoxify harmful chemicals (toxins) and suppress disease organisms. According to the Sustainable Agriculture Research and Education organization, soil microorganisms are also very beneficial to humans for another reason. They happen to be the source of many of the antibiotic medicines we use to fight diseases.

The next type of creatures found beneath our feet include things like nematodes, earthworms and a broad variety of insects – including termites, ants, beetles, millipedes, centipedes, slugs, snails and spiders. Some of these creatures maintain a balance in the soil by feeding on other soil organisms and help break down organic and plant material on the surface of the soil.

Earthworms are extremely hard workers! According to the NRCS, earthworms help to stimulate microbial activity, mix and aggregate soil, increase infiltration, improve water-holding capacity and provide channels for root growth. Earthworms are not essential to all healthy soil systems, like areas with lower precipitation, but their presence can be an indicator of a healthy system.

The last level of soil animals includes larger fossorial mammals and reptiles like moles, pigmy rabbits, snakes, white-tailed prairie dogs, badgers, uinta ground squirrels (chiselers), etc. These animals burrow into the soil profile to make their homes, find food and hibernate. Each of these animals generally spends some part of its life cycle underground. Some of these animals feed on organisms that live in the soil, including insects and earthworms; others persist on mostly plant and root material.

In some areas, the presence of these ground-dwelling animals is considered a nuisance. However, their burrows and activity underground can have positive effects on the soil as well. Burrowing can be beneficial to the soil because it mixes and aerates the soil, decreases compaction and incorporates organic matter. Burrows can also help conduct water away from the surface during downpours and decrease erosion. Lastly, many of these burrows serve as habitat for other secondary wildlife species.

Ok, now that we have met all of the hardworking soil critters, let’s get back to the britches! On May 16, pairs of underwear were buried at four locations throughout Sublette County, one pair in each precipitation zone (7-9 inches, 9-12 inches, 15-19 inches, 20+ inches). The underwear was buried 6 inches below the surface of the soil in the area with the most active plant roots and the greatest amount of soil organisms. We left the underwear to fend for itself for a 60-day period before excavating them on June 24.

The results were fascinating and showed differences in microbe activity throughout the different sites. Microbial activity levels were shown by comparing the “thinness” and holes present on the excavated underwear in comparison to the original pair.

Our native rangelands have varying results of microbial activity in different parts of the county. This is highly impacted by soil moisture, soil type, plant diversity and the availability of water. As we increased in precipitation and plant diversity, we saw an increase in soil activity, causing our underwear to become very thin with many holes present.

Here in Sublette County, we see that not only do plants depend on water for survivability and vigor, but soil organisms are equally dependent on soil moisture for their health and activity as well!

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