The Benefits of Rhizobacteria for Crop Production

Bacteria are ubiquitous. These single-celled organisms are found everywhere, from our digestive tracts to the soils that sustain us, they stitch together the biological fabric of all complex life on Earth. A single teaspoon of soil can hold up to one billion bacteria. This incredible density of microbial life is critical to nutrient cycles, plant decomposition, and the health of entire ecological systems. 

Certain species of bacteria can even dramatically improve the health and performance of cultivated plants. Called plant growth-promoting rhizobacteria (PGPR for short), these beneficial soil microbes have been used for decades to boost yields and the overall quality of key crops like soybean, corn, wheat, and rice.

Microbial inoculants containing PGPR have been proven to improve plant nutrient uptake, root development, and stress tolerance across dozens of plant species. 

Growers are increasingly utilizing PGPR as a plant biostimulant to improve crop yields, reduce their use of conventional fertilizer, and sustainably produce high-quality fruit, flowers, vegetables, pulses, and grains. To understand the benefits, let’s take a look at why rhizobacteria are important, and what the science says about the potential benefits of PGPR in any type of crop production.

 

What are Rhizobacteria?

Before getting into how plant growth-promoting rhizobacteria benefit plants, it is important to know what exactly rhizobacteria are, and what makes these microscopic wonders have such an outsized impact on plant growth.

Despite appearances, plants are not individuals. They are entwined in deep, complex relationships with the soil or substrate in which they grow. Plants and soil microbes interface  through the rhizosphere, the thin layer of soil that surrounds plant roots. The complexity of connection and activity in the rhizosphere blurs the boundaries between plant and non-plant. The rhizosphere has even been called an “information super highway”, given the incredible density of interactions and chemical signals exchanges between plant roots and soil microbes.

Bacteria that inhabit this world connecting worlds are classified as rhizobacteria. Most are useful, some can be parasitic, and many are beneficial to plant growth—the so-called plant growth-promoting rhizobacteria.

These PGPR enhance plant access to nutrients, produce growth-stimulating hormones, and enforce symbiotic relationships that protect plants from parasitic microbes, pests, and abiotic stresses like drought, salinity, and extreme heat.

Plant Growth-Promoting Rhizobacteria in Agriculture

PGPR have been used as plant biostimulants for over a century, beginning with rhizobacterial inoculations of legume crops. There is now extensive research documenting yield increases associated with certain rhizobacterial strains, particularly the Bacillus, Mucilaginibacter, and Pseudomonas genera of bacteria.

Microbial inoculants with one or multiple PGPR improve yields by encouraging plant growth through various mechanisms, including:

• Facilitating biological nitrogen fixation
• Increasing the bioavailability of key nutrients, like phosphorus and potassium
• Producing growth stimulating plant hormones

PGPR microbial inoculants can also boost yields by improving resilience in the face of pest pressures and plant abiotic stress tolerance. Many species, including some in the genera Bacillus, Paenibacillus, and Pseudomonas are effective biocontrol agents. Under certain circumstances they produce compounds that make it difficult for pathogens to take hold, along with pathogen-killing metabolites, and encourage plants to do the same. Some rhizobacteria species successfully control powdery mildew in strawberry, pea, and cucumber crops. Others, even the same species groups work by simply taking up the space and resources that pathogens would otherwise use to thrive. Microbes are adaptive, and what they do is often dependent on what they need to do; dependent on the environment. 

PGPR and Sustainable Production

Synthetic fertilizers are a major source of emissions and freshwater pollution and are routinely applied in excess on most crops. Likewise, use of chemical pesticides can decimate the very soil microbes that contribute to plant health and disease resistance, resulting in a vicious cycle that requires ever more pesticide use.

Demand for food is expanding rapidly, and how it is grown will have profound implications for our planet. Replacing some synthetic inputs with microbial inoculants is one way to work with nature to support plant growth, crop quality, and disease resistance, all while reducing emissions and building healthy soils and rhizospheres.

And as abiotic stresses like drought and extreme heat become more common with every passing year, prioritizing the health of the rhizosphere will become even more critical. PGPR can help plants weather uncertain and demanding conditions—building some much-needed resilience into both individual crops and our larger agricultural systems.

Applying PGPR for Outdoor and Controlled Environment Agriculture

Incorporating plant biostimulants like PGPR reduces reliance on synthetic inputs for outdoor and indoor agriculture, offering one potential solution for growers looking to prioritize both sustainability and exceptional quality.

Microbial inoculants like Impello’s Continuµm™ can work in any environment, any growing medium, and any irrigation system. With an inoculating blend of naturally occurring Bacillus & Paenibacillus species, Continuµm™ is a carefully crafted microbial consortia employing advanced fermentation techniques to ensure the rhizobacteria continue to thrive after application.

Continuµm™ can be applied at all stages of plant growth, as a root drench or foliar spray for plants in hydroponic, soilless, soil-based, and field cultivation systems. Regular applications of PGPR—as often as every watering—encourage rapid plant growth, root development, and stress resilience. Nutrient availability and water retention will improve, helping optimize yields and quality. It is OMRI certified for organic use and compatible with any fertilizer program. 

Learn more about PGPR dosing, application guidelines, and the power of Continuµm™ here, and drop us a line at tech@impellobio.com if you have more questions about how PGPR can benefit your crop production!

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