Boosting Soil Biology: How Organic Matter Makes A Difference

DR. LEANDRO O. VIEIRA

BATON ROUGE, LOUISIANA

Organic matter is essential for the improvement of soil biological properties, which is crucial to maintain nutrient balance and support healthy crop growth. The metabolization of organic matter in the soil, which will result in the release of nutrients through mineralization and the emission of carbon dioxide are all dependent on microbial activity. Additionally, microbial metabolism generates stable organic compounds that can remain in the soil for decades, and in some cases, centuries, before they are oxidized and released as carbon dioxide. This resistance to decomposition enables the accumulation of organic matter in the soil, which in turn contributes to the long-term health of the soil.

The increase in microbial diversity is another significant effect that is likely to have a greater impact than the increase in microbial activity alone. The proliferation of a variety of microorganisms is facilitated by the abundance of fresh organic matter, which serves as their primary food source. This diversity improves the availability of nutrients for plants by enabling various microorganisms to fix atmospheric nitrogen, break down minerals and increase the availability of phosphorus.

Furthermore, organic matter increases the population of macro- and mesofauna, including earthworms and other soil organisms (Figure 1). There are numerous chemical and physical properties of soil that are enhanced by an increased population of these organisms, such as aeration, water infiltration, and retention. This improved soil structure promotes the growth and resilience of healthier plants.

Finally, an increase in organic matter in the soil can foster the suppression of plant pathogens by improving the diversity and activity of microorganisms. The proliferation of antagonistic microorganisms can effectively suppress detrimental plant pathogens, resulting in healthier crops and a decrease in the incidence of certain diseases.

There are several conservational practices that can promote organic matter accumulation in the soil, such as adopting cover crops, implementing no-till or reduced tillage, and applying organic amendments. Increasing the organic matter content in the soil is expected to positively impact not only soil biological properties but also its chemical and physical properties.   ∆

DR. LEANDRO O. VIEIRA: LSU AgCenter