Uncertainty Exists With Biologicals

Helpful or Overhyped: Uncertainty Exists With Biologicals

You'll need to focus deep to consider all the claims of the efficacy of biologicals. (Getty Images, Adobe Stock, Photo illustration by Barry Falkner, Adobe Firefly)

Larkin Martin was puzzled.

The Courtland, Alabama, farmer applied an in-furrow biological product called StrongSoil at a 5-gallon-per-acre rate in a corn field with highly variable soils. She had an objective third-party analyst use a statistical method called spatial analysis to compare check areas adjacent to treated areas.

One field area using this side-by-side comparison shows the dilemma that exists in evaluating these products. In the analysis, the treated areas showed a positive per-acre return on investment (ROI) three times: $7.58, $65.34 and $76.19. However, the check had a better per-acre ROI three times: $37.25, $23.27 and $2.81.

"All findings used a statistically sound method," she said.

Martin is still positive on overall product performance. However, the analysis showed different conclusions existed among individual field areas. These differences rooted in her farm's variable soils makes Martin wary of claims made by companies selling biological-based products.

"Promotional claims can be valid or complete fiction," she said. "It is all about how you look at the data."


Biologicals certainly aren't new to agriculture. Farmers have used soybean inoculants featuring rhizobia bacteria, for example, for years. What's new is the flood of firms selling biological-based products to farmers. Corteva officials note the 2021 global biological market size of $9 billion will grow to $30 billion by 2035.

Several factors are driving this growth, explained Amy O'Shea, Certis Biologicals CEO.

-- They reflect consumer sentiment. "We're seeing increased consumer perceptions and awareness of how food is processed and brought to market, and it's reaching all the way back to the farm," she said. "There's also a changing regulatory landscape of major European health ministries and the U.S. EPA moving to reduce or remove registrations for synthetic chemistries."

-- They're popular. Thirty-seven percent of U.S. row crops have some type of biological product applied to them, O'Shea continues.

-- They're affordable. Prices range around $6 per acre for inoculants all the way up to $20 per acre for N-fixation products, she added. "This is within the reasonable range for adoption in row crops."

-- They make environmental sense. "The potential to use natural systems is a wonderful advance over chemistries that we need to combat pests but also have peripheral negative effects," Martin said.

You'll likely see biologicals teamed with future seed purchases. "Biological bundles may someday be part of seed packages," said Marcus Meadows-Smith, CEO of BioConsortia.

Climate change is also impacting biological product development. "Pest shift triggered by climate change calls for new modes of action in pest control and better resistance-management tools, which is a key driver for biocontrol growth," explained Corey Huck, global head at strategic partnership for biologicals at Syngenta.

"With climate change, plant resilience to abiotic factors such as drought and heat tolerance becomes more and more important, hence the need for biostimulants," he added.

Two main biological classes exist. Biostimulants include seed treatments, in-furrow products and foliar sprays that run the gamut from capturing atmospheric nitrogen (N) to easing plant stress to boosting yields. Biopesticides target disease and insects, just as synthetic chemistries do. Biologicals differ from synthetic chemicals in that they are made from living or naturally occurring materials.

Like synthetic chemistries, biologicals have a federal regulatory framework to help ensure safety and efficacy, O'Shea explained. However, it's not as uniform as is the process for synthetic chemistries, particularly when it comes to biostimulants. Biostimulants are regulated only at the state level, which translates into differences between states. Steps are being taken to harmonize this process, she added.


Yet, as Martin discovered, the reams of biological product data often spur confusion.

Remember that no agricultural product works all the time, said Mike Miille, a Fellow with Ginkgo Bioworks, a biotech firm that partners with Bayer and other companies.

"Even under the best kinds of circumstances, negative results can occur," he explained.

Soil temperature can certainly cause less-than-ideal results from biological products. Syngenta's Huck points out that microbial activity generally increases with temperature up to a maximum that's unique to each microbial strain.

"At high temperatures, some microbes will die," he said. "Even in seemingly dry soils, soil bacteria live on water films that coat soil particles. As soils dry, microbial activity slows, and many species go dormant or employ other strategies, including spore formation, to survive until conditions improve.

"But, the enzymes and metabolites that they release into the soil may continue to function and support plants as the soils dry," Huck pointed out. "Dry soils are stressful to plants and microbes alike, but building soil health can help improve its ability to adsorb and retain moisture, even in elevated temperatures."

Field and soil variability complicate accurate data generation. "In so many cases, experiments are set up without enough replication and not going across different types of soil and other variables," Miille said. "That lack of understanding can be used to a company's advantage or disadvantage to make its point."

One independent study that ran counter to the claims of companies was unveiled in April 2023 from scientists from 10 Midwestern states that evaluated four N-fixing products from four companies. They included:

-- Azotic Envita

-- Corteva Utrisha N

-- Pivot Bio ProveN and ProveN40

-- TerraMax MicroAZ-ST

Researchers applied products either as foliar-applied, in impregnated urea, in-furrow or as a seed treatment. Most trials occurred in corn, but products were also tested in spring wheat, sugar beets and canola. Scientists found a significant yield increase occurred only in two out of 61 sites.

"We all hoped these products would do something," said Dave Franzen, North Dakota State University (NDSU) Extension soil scientist. But, in the study, nearly all products did not deliver as advertised, he added.

The companies disagree with the findings. Pivot Bio officials say yield is just one way to measure effectiveness. Reducing N rates while maintaining yield parity is another, which the studies did show, they say.

The trials highlighted in this Extension paper do support what Pivot Bio has told growers -- they can replace some of their synthetic nitrogen with Pivot Bio PROVEN 40 and maintain yield.

Others say label instructions were not followed. "Our product was used in only one location and used off-label rates," said Doug Kremer, TerraMax CEO.

Azotic's Envita product works best when applied on a foliar basis rather than when used in-furrow as in the study, said Tom Tregunno, Azotic Technologies director of commercialization.

Product results can also hinge on how products are applied, Corteva officials agree. In Utrisha N's case, Corteva officials say its research trials support recommendations for applying it during early morning on healthy crops free of poor nutrition or other abiotic or biotic stressors, and within current N programs.

Franzen defends the study's methods. "In the university setting, we give it our best shot to follow the label and then report the results," he said.


The relative newness of the biological space also spurs inconsistent results when compared to long-used agronomic inputs, Ginkgo's Miille explained.

"We are still at the early stages of having biological and microbial solutions that match the performance and consistency that chemicals and traits deliver," he said. "This doesn't mean we won't get there, but we have to be honest about what the current state is."

Today's biologicals have come a long way in recent decades. One early knock against them is because they are a living and breathing organism, one mishandling misstep can kill them.

"Years ago, products were frozen and had to be defrosted and mixed in a slurry until they got into a [implement] tank," Certis' O'Shea said. "Now, they are reformulated and can be as ready to go as a synthetic chemistry product."

Some microbial packages also are gene-edited, giving them an edge over native ones, said Dan Poston, Pivot Bio vice president of field research and development. "Native N-fixing microbes can be repressed by nitrogen in the soil," he said. "Ours are edited to be actively fixing N in the presence of synthetic N."

Adding microbials to a sea of soil teeming with native microbes can also be akin to dropping a troop of Girl Scouts into the Amazon and expecting them to survive and thrive. Just one cup of soil contains 9 billion microbes, some of which can quickly gobble up any invaders.

However, firms like Azotic stress their product works its way inside plant leaf and cells, and not in the soil. Officials for BioConsortia, Pivot Bio and other firms add their products colonize roots with microbes where they're protected from hostile soil microbes.

"Root colonization is what helps these products from getting eaten up in the soil," BioConsortia's Meadows-Smith said.

Like any other agronomic input, correct placement is key. "We already have an active biological system with cover crops and no-till," said Brian Hora, an Ainsworth, Iowa, farmer. "We've had good luck with some [biological products] that aren't native to our soils, such as ones from seaweed. Maybe it's because we are introducing something different to our soils."


When using biologicals, here are some recommendations from farmers and industry and university experts.

-- Brace yourself for unpredictability. "Fertilizer responses are predictable," said Dan Kaiser, a University of Minnesota Extension soil specialist. "Biologicals are not."

-- Aim biologicals where they have the best chance of agronomic success. "We see responses on corn where it's N-starved," he said.

-- Biologicals are not an all-or-nothing approach. "We look at the role biologicals can play in a rotation with synthetic chemistries," O'Shea said. "Using them in rotation or in a combined product can help forestall resistance in all cases."

-- Ask salespeople how their products work. For example, Bt bioinsecticides kill lepidopteran insects by releasing a Cry protein into the insect's gut, Miille said. "We can actually enhance it and optimize the Cry protein, because we know that is how the bioinsecticide works." That's not possible if the mode of action is not known, he added.

-- Be skeptical of products tested only in the lab. "You can have a product work under lab conditions and then test the same product under field conditions and find there is no difference," Alabama farmer Martin said.

-- Don't expect biologicals to work agronomic miracles. "Biological products won't fix soil pH problems," said Trent Newell, a Pattern Ag agronomist.

-- Test products on your farm first before committing to larger acreages. "Farmers can do this with today's GPS and yield monitors," NDSU's Franzen said.

"It's a lot of work, but evaluating performance in your own soil can pay dividends," TerraMax's Kremer added.

Despite her concerns about product inconsistency in variable soils, Martin hopes biologicals will find a place on her family's farm. "We live in an older agricultural area, and our soils have been degraded by erosion and tillage for centuries," she said. "These products have potential to improve our soil health, along with no-till and cover crops."


Fred Below admitted that agricultural biological products give here-and-there, maybe once-in-a-while results. Still, the University of Illinois crop physiologist believes assessing products in the correct context provides a better summary of their merits.

For example, spring-applied nitrification inhibitors don't work as well compared to fall applications, since the time frame to protect against N losses is less. Rather than boosting yields or cutting commercial N applications, Below believes N-fixing biologicals should be judged on if they can pull atmospheric N inside plants.

In corn's case, a critical time to supply N is between the V8 and VT stages. Below's studies indicate N-fixing biologicals can draw 25 pounds of atmospheric N during this time frame.

Corn's N sources vary between years. In some years, corn gleans more N from soil mineralization than fertilizer. In others, corn obtains more from commercial fertilizers than from the soil. And, in some years, corn could benefit from an N boost outside of both sources, such as from N-fixing biologicals.

"It's an insurance policy," he said.

Martin agreed. "Your product may be valuable 50% of the time and then priced accordingly," said the Courtland, Alabama, farmer. "You will sell more that way to someone who has a crop at risk and needs a safety net rather than telling them every time they apply the product it will work."