What is Soil Health and Soil Quality?

Finding the right words to describe your soil can seem like a daunting task. Folks might use terms like “heavy”, “light”, “mellow”, “gumbo’, “good”, “bad”, etc., but the exact definition can change from person to person, depending on their perspective and experience.  The challenge for soil professionals is to relate observations from the field to more precise definitions that allow for measurement, research, and of course, further testing.   For example, terms like “kandic horizon” and “Argids” may sound funny, but the words convey very specific ideas about what is occurring belowground. However, some terms still seem a little fuzzy, despite how often they appear in the popular ag press.  Two terms that continue to puzzle our industry are ‘soil health” and “soil quality”.

For a myriad of reasons, these two terms are often used synonymously and sometimes interchangeably, despite different usage histories and origin.  Below I clarify the exact definition of both terms to help clear the air (Brady and Weil 2017) on two interrelated concepts.

Soil health – this term refers to the interaction between organisms and their environment in a soil ecosystem concept and the properties provided by such interactions (e.g., ecosystem stability). When you think of soil health, think of the biological integrity of your field (e.g., microbial population and diversity) and a focus on supporting plant growth.

Soil quality – this term is a bit older in usage than soil health and has broader application. Soil quality refers to how well a soil functions physically, chemically, and biologically and does its “job”.  For example, a forest soil has a different job than a farm soil and soil properties can be measured on how well the soil is performing.

As you can see, there are slight differences in the working definitions of soil health and soil quality. However, it is worth noting that the two concepts complement each other and are both important for meeting both crop productivity goals and farm ecosystem goals (Image from Andrews et al. 2004; Brady and Weil 2017).  With this in mind, I think using the terms interchangeably is OK and I will refer to both concepts as soil quality from here on out. Growers are becoming increasingly concerned on how they might implement programs for building the quality of their soil system and are looking for solutions and would rather not debate the semantics of the terminology.

Crop Productivity, (Image from Andrews et al. 2004; Brady and Weil 2017)

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The goal of crop production is supported by several interrelated soil health and soil quality concepts, which probably explains why they are used interchangeably by those concerned for their soil!

Modified from: Brady and Weil 2017 https://www.pearson.com/us/higher-education/program/Weil-Nature-and-Properties-of-Soils-The-15th-Edition/PGM219427.html

Andrews et al. 2004 https://naldc.nal.usda.gov/download/9094/PDF