4/22/2024 - By Dr. Paul Giordano

Ever wonder why most microbial products don’t work very well, even when the microorganism has proven effective in laboratory or controlled environments?

Often, the answer is a simple numbers game. Most beneficial bacterial or fungal organisms require very high concentrations (think billions per droplet of water) to effectively get into and onto our plants to deliver the desired result (i.e. root growth, stress mitigation, disease, weed, insect control etc.).

Some products may start with fresh, high concentrations of active microbes, but die or decline quickly when subjected to the challenges of our traditional supply chains. This has always been the “Achilles heel” for success with microbial products. It is also the major contributing factor to poor or inconsistent performance with beneficial microorganisms. Because of this, most growers and turf managers are skeptical when it comes to buying “bugs in a jug,” and rightfully so… But that’s all about to change. 

A Brief History of Azospirillum brasilense 

Azospirillum brasilense (Azo) is a gram-negative soil-dwelling bacteria that has been widely studied. The root growth and other plant health-promoting benefits of Azo have been documented for decades on numerous different plant species and crops of importance.

Azo works by first associating with plant roots and subsequently producing numerous beneficial compounds, most notably the root growth-promoting hormone indole acetic acid (IAA). Azo is also capable of fixing atmospheric nitrogen - allowing for small but beneficial amounts to be converted into plant-available forms. The primary documented benefits of Azo-associated plant interactions are: 

·         Enhanced root development 

·         Faster establishment and recovery 

·         Abiotic stress mitigation 

·         Better nutritional efficiency 

Over the years, commercial Azo products have been developed for broad use on agricultural crops, turfgrasses, and ornamental plants. While some of these products have had a degree of success, many have not performed consistently enough to warrant grower investment. Some products have tried to optimize the viability of the Azo bacterium only to be met with significant challenges in application techniques and constraints with expensive and tedious storage, shipping, and handling logistics. The two major obstacles with Azo-based microbial products are: 

1.       Ensuring high concentrations of viable (living) bacteria to produce positive results. 

2.       Poor survival rates in packaging and supply chain leading to product being dead on arrival. 

Overcoming the Challenges with Live-Microbe™ Packaging Innovation

The above challenges are not unique to Azospirillum and are the primary reason many living, microbial products underperform or “fail.”

3Bar Biologics is a company dedicated to solving the issue of growth and delivery of beneficial microorganisms in agriculture. Their patented Live-Microbe Technology allows for just-in-time, activation of microbes in the package to ensure fresh, pure, maximum concentrations of the beneficial organism prior to application. Here’s how it works in the new groundbreaking product Azo Root: 

The freeze-dried concentration of Azospirillum brasilense can remain viable for 10+ months in the Azo Root package, solving the major shelf-life issue other products face. Once activated, the bacteria grow in a closed, sterile environment to peak concentrations after just 72 hours. This avoids contamination and ensures optimal concentrations upon application for better, more consistent results.

Putting Azo Root to the Test - Trial Results 

Harrell’s is always in search of new, innovative products that can fit into a wide range of agronomic programs and deliver real, tangible benefits to plant health and function. Before any product is brought into the Harrell’s portfolio, we first put it to the test with targeted trials in cooperation with university experts to ensure the products do what they claim.

Azo Root was no different. We initially tested the product with turfgrass physiologist Dr. Zhang at Virginia Tech to better understand the effects of Azo Root on turfgrass root growth and other plant health indicators under moderate amounts of abiotic stress (heat). The results were both significant and remarkable:

Whether applied on a 14-day schedule or monthly, Azo Root at 25 oz/A significantly improved all creeping bentgrass root health metrics measured in the study (length, surface area, biomass, viability, volume) compared to the control. When Azo Root was combined with the molasses-based microbe food source BioMAX soil enhancer at 5 oz/1000 sq ft, the results were even more pronounced - as much as a 75% increase in root length and volume compared to the control.

Results from a controlled environment study with Dr. X Zhang, Virginia Tech. Treatments were applied on a bi-weekly (4x) or monthly (2x) basis for two months. Creeping bentgrass was subjected to moderate heat stress for 72 days. Pictures and data represent results at day 72.

Azo Root in the “Real World” 

The Virginia Tech trial results were undeniable. Plus, the packaging innovation of Azo Root offered the flexibility and reliability that could not only make it a commercially viable product but a truly unique solution in the Harrell’s lineup. But before moving forward, we needed to test Azo Root out in the real world. Below are a few results from our work on golf courses and horticultural nursery environments.

Results showed better uniformity, consistency, and overall health on a bentgrass fairway treated with Azo Root vs the standard program as well as significant root enhancement and development on coco plum transplants treated with Azo Root vs a grower standard program:

Azo Root: A New Staple in Root Health Programs – Exclusively from Harrell’s

The packaging innovation from 3Bar is a game-changer that solves the major hurdles that historically hindered the success of Azospirillum and other microbial products. Harrell’s is proud to bring this exciting technology to the turfgrass and horticultural markets to help golf courses, lawn care operations, athletic fields, and horticultural grow operations everywhere maximize their root growth, improve plant health, and mitigate plant stress. 

The TurPh.Dudes recently sat down with our friends at 3Bar Biologics to discuss all things Azo Root and to dive deeper into the fascinating world of microorganisms. The podcast explored how their innovative approach to packaging and delivery is changing the way farmers and growers take advantage of “beneficial bugs”.

Azo Root is available now and has a fit in most agronomic programs. Whether you’re trying to push better root growth after a difficult winter, recovering from an aerification event this spring, dealing with high traffic and water damaged areas, or have a big renovation/establishment project this summer – Azo Root can help. It can also be easily incorporated into regularly scheduled soil-targeted spray applications given its extensive tank-mix compatibility.

Contact Your Harrell’s Rep for More on Azo Root

But no product can do it alone. Harrell’s continues to develop programmatic strategies that leverage the strengths of different modes of action and mechanisms of functionality to maximize plant health, root growth, and stress tolerance beyond traditional nutritional inputs. Below is one example of how two living microbial products - Azo Root and Mycorrhizae Pro, serve as the backbone of a Harrell’s root health program that is truly second to none.

For more information on Azo Root and the ever-expanding portfolio of Harrell’s offerings, reach out to your Harrell's Territory Manager today!