Organic matter: The backbone of soil health

Authors: Young, Eric

Submitted to: Journal of Nutrient Management
Publication Type: Trade Journal
Publication Acceptance Date: 1/7/2022
Publication Date: 2/25/2022
Citation: Young, E.O. 2022. Organic matter: The backbone of soil health. Journal of Nutrient Management. February 2022. pg. 16-17.

Interpretive Summary:

Technical Abstract: Soil organic matter (SOM) underpins many aspects of soil health due to the many beneficial effects on soil properties and crop growth. While SOM is chemically heterogeneous, a large fraction is organic carbon. SOM serves as a storehouse for nutrients beyond carbon. In particular, nitrogen (N) and sulfur tend to be highly associated with SOM. Land grant university soil fertility guidelines typically adjust N recommendations based on SOM. In addition to nutrients residing in SOM itself, the ability to retain positively charged nutrients from the soil solution (e.g., calcium, iron, magnesium, manganese, copper, zinc) increases with greater SOM due its net negative charge. SOM also fuels biological activity by providing a labile carbon source for microbial respiration in addition to other nutrients. Developing a better understanding of SOM composition and its impacts on soil health is an active research area. Glomalin is an important constituent of SOM that acts as a cementing agent for soil aggregates. Research shows that glomalin can comprise up to 25% of SOM, with a relatively long residence time (>40 yrs). Several studies in different countries have reported significant correlations between total soil glomalin content, aggregate stability, and lower erosion potential. Practices that maintain or increase SOM are essential for realizing long-term agronomic and environmental benefits. A continued challenge going forward will be determining how best to synthesize the large amount of emerging soil health data to develop effective soil tests and tools for producers.