Soil health focuses more on the biology of the soil and the conditions beneficial organisms need to thrive. It refers to the soil’s ability to maintain uniform conditions and provide ecosystem services especially in the context of agriculture. Metrics that quantify soil health include CO₂ burst, plant-available P, and aggregate stability.

Soil quality is a part of soil health, but focuses on the soil’s physical and chemical properties. Metrics that quantify soil quality include soil organic matter, nutrient quantities, soil structure, etc. Since these attributes can be influenced by management, they can dynamically improve or diminish soil health (Michigan State University Extension¹). We should simultaneously consider soil quality and health when thinking about soil sustainability. 

Here are some common soil health measurements in the Haney Soil Health Test:

●      Water soluble extractions provide a snapshot of nutrients immediately available to plants.

●     H3A extractions mimic organic acids produced by living plant root systems to more accurately measure nutrients available to crops.

●       CO₂ Burst is a measurement of soil respiration, a direct effect of microbial activity. This test is highly related to available carbon pools.

●      Organic carbon (C) is a component of soil organic matter. Organic matter includes all elements (mainly hydrogen, oxygen, nitrogen, etc.), not only carbon. In fact, 58% of the organic matter is made up of carbon. This measurement reflects the food/energy source that drives soil microbes. 

●      Organic nitrogen (N) pool is replenished by fresh plant residues, composts, manure, and decaying soil microbes.

●      Organic C/N ratio is a critical component of the nutrient cycle. For example, a soil C/N ratio above 20 generally indicates that N is tied up and not available to plants. The ideal range is to release nitrogen is between 8:1 and 15:1.

So, what does this mean for you?  Agronomists, farmers, and operators have been monitoring their soil quality and productivity since the first plow broke the sod. Their intuition was spot on; organic matter in a soil is a time-tested indicator of soil quality. Soil with high organic matter content provides a hospitable environment for plants and beneficial microbes, particularly by increasing the quantity of soil aggregates and aggregate stability (Penn State University Extension²).

To maintain our yields without degrading our most valuable natural resource, we should also periodically give our soil a check-up. Viewing soil health alongside soil quality by way of precise soil maps is the next step in integrated crop management (ICM) which can increase yield potential but more importantly, profitability. 

References

1) https://www.canr.msu.edu/news/soil_health_and_soil_quality

2) https://extension.psu.edu/introduction-to-soils-soil-quality