Soil Microbiome Health: Understanding the Difference Between Prebiotic, Probiotic, and Postbiotic

In recent years, attention to the soil microbiome and the rhizosphere has grown significantly, recognizing their key role in plant health and productivity. Within this field, three interrelated concepts have gained prominence: prebiotics, probiotics, and postbiotics. Although these terms originally come from human health, their application in agriculture is proving to be equally relevant and transformative.

Understanding the differences and synergies among these components allows for optimized plant nutrition, enhanced stress resilience, and the promotion of more sustainable farming.

Prebiotics: Food for Beneficial Microorganisms

In the agricultural context, prebiotics are compounds that selectively stimulate the growth and activity of beneficial microorganisms in the soil or rhizosphere. Unlike traditional fertilizers, prebiotics do not feed the plant directly but rather nourish the microbiome that surrounds it.

A clear example of a prebiotic in this context is L-α amino acids, which serve as a carbon and energy source for beneficial microorganisms, enhancing their activity and proliferation. By promoting a healthy microbial environment, prebiotics indirectly strengthen plant nutrition and defense.

Probiotics: Living Microorganisms That Benefit Crops

Probiotics in agriculture are live microorganisms that, when applied to the rhizosphere or directly on plants, provide direct or indirect benefits to crops. These benefits may include promoting plant growth, solubilizing locked nutrients, producing natural phytohormones, and competing with pathogens.

A notable example of a probiotic is Bacillus velezensis PH023, a strain that not only effectively colonizes the root environment, but also acts as a natural biofertilizer and bioprotector, enhancing the plant’s ability to cope with adverse conditions.

Postbiotics: Bioactive Metabolites from the Microbiome

Postbiotics are metabolites or bioactive compounds produced by microorganisms during their growth or fermentation. In other words, they are the result of microbial metabolism, and although they do not contain living organisms, they still provide beneficial effects to plants.

These compounds include organic acids, phytohormone precursors, enzymes, bioactive peptides, and other secondary metabolites that can:

• Improve nutrient availability.
• Stimulate the plant's natural defenses.
• Modulate microbial balance in the rhizosphere.
• Reduce oxidative stress.

Postbiotics represent a new frontier in plant biostimulation, combining safety, stability, and efficacy.

An Example of Synergy: Terra-Sorb radicular SymBiotic®

An innovative way to integrate these three concepts into a single product is through Terra-Sorb radicular SymBiotic®. This advanced biostimulant has been designed to act synergistically, combining all three types of “biotics” into one solution:

• Prebiotic: The L-α amino acids in its formulation provide highly bioavailable food for beneficial microorganisms.
• Probiotic: The inclusion of the Bacillus velezensis PH023 strain introduces a live microorganism with biofertilizing and plant growth-promoting activity.
• Postbiotic: Metabolites derived from microbial fermentation offer bioactive effects on the plant even in the absence of live organisms, delivering stability and immediate functionality.

This holistic approach helps improve crop vitality, enhance root development, increase nutrient absorption efficiency, and prepare the plant to face stress conditions.

Conclusion

In modern agriculture—progressively focused on sustainability and optimizing the plant microbiome—the concepts of prebiotic, probiotic, and postbiotic are solidifying as key tools. Understanding their differences and combined action is essential for designing more efficient, environmentally friendly management strategies that yield tangible improvements in crop health and productivity.

Products like Terra-Sorb radicular SymBiotic® pave the way toward regenerative agriculture, where nourishing soil microorganisms is just as important as nourishing the plant itself.