Living Soil Breathes – Measuring Respiration for Soil Health

Living microbes are hardworking and benefit plants in many ways. Among other things, soil microbes

Soil microbes interacting with plant roots and each other need to breath
  • Increase water holding capacity of soil
  • Release nutrients to plants (a.k.a. mineralization) – when the microbes die or through symbiotic relationships with plants
  • Keep disease in check
  • Enhance plant growth
  • Store nutrients in their bodies to prevent leaching or volatilization from the soil (a.k.a immobilization)
  • Excrete “glue” that binds soil together in a way that prevents erosion, decreases compaction, and increases water infiltration to benefit plant roots.

These benefits from soil microbes, in turn, benefit farmers by saving time and money through decreased fertilizer, pesticide and water use.  One way to measure the potential microbial activity of a soil is through a soil respiration test.

What is respiration and how is it measured?

As the members of the soil microbe biome go about these activities, they’re processing whatever food source they use for energy and releasing the leftovers.  In the case of aerobic soil organisms – microbes that use oxygen as part of the food processing – carbon dioxide (CO2) is released.  You might say they “exhale” CO2, just like humans.  And just like humans, these microbes exhale more CO2 the harder they’re working or the more of them there are.  So researchers developed an approach to measure how much potential a particular soil has for respiration.  You might see it called various names like CO2 Burst, Solvita, or Respiration test.  This test can be done as a “stand alone” but has been incorporated into more comprehensive soil health assessments as well, such as the Haney Test and the Cornell Assessment of Soil Health.  The basic idea is that a dry soil sample is rewetted, and the amount of CO2 released over a given time period is measured in one of several possible ways.

Interpreting soil respiration results

https://solvita.com/co2-burst/Respiration of CO2 varies with the soil microbe biome

The respiration test has been used to estimate the soil microbial community’s general ability to carry out its many functions. It’s important to remember that the test measurement depends on both the activity level AND the number of soil microbes, so it’s a composite number, reflecting both aspects. Microbes have a natural seasonal variation in activity, so sampling should take place at similar times of the year to minimize this variable.  This type of soil test could be part of a larger testing suite to compare and contrast management practices on a given piece of land, or to evaluate the relative quality of two or more pieces of land being considered for purchase or rent.

SymSoil offers a variety of soil amendments to improve soil health using the principles of the Soil Food Web.  In-depth consultation is available for customers wanting to develop a soil management plan.

About SymSoil® Inc.

SymSoil is a leader in development of biological soil amendments for agriculture that restores the microbes that provide the right food to the plant roots, improving plant health, and making food more nutrient dense and flavorful, the way nature intended. SymSoil has products and services for growers using regenerative agriculture methodologies which improve profitability. Its flagship product, SymSoil® RC (Robust Compost) is a complex community of soil microbes, which includes in excess of 1,000 species, covering broad biodiversity of bacteria, fungi, amoebae, and other protozoa, beneficial nematodes and microarthropods. SymSoil was named one of 2019’s AgTech Companies to Watch. Accredited Investors can learn more about SymSoil as an impact investment here.

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