Crop-input confusion clarified

Lauren Quinn University of Illinois

Every time Fred Below and Connor Sible meet with farmers, they hear the same question.

“What’s the story with those biologicals? Do they work?”

University of Illinois crop scientists and University of Illinois-Extension specialists are happy to share what they know about natural growth stimulants, informed by dozens of trials and published research. But with new products constantly being added to the market – and a muddled regulatory landscape – it’s not always clear what farmers are even asking.

Below is a professor in the University of Illinois-Department of Crop Sciences, part of the University of Illinois-College of Agricultural, Consumer and Environmental Sciences.

“We do a lot of Extension talks, and we started to notice a disconnect,” he said. “Farmers and companies call those products biologicals, but the scientific literature and regulatory bodies call them biostimulants. When we started looking into it, we realized the terminology is not only confusing those very different products are all regulated the same, if they’re regulated at all.”

The realization prompted Sible, Below and colleague Juliann Seebauer to embark on a deep dive into the world of biologicals and biostimulants, publishing their commentary in Agricultural and Environmental Letters.

First, just what are those products? In the most basic sense, they are live microbial inoculants, and non-living, naturally derived chemicals or extracts applied to soil, seeds and plants to improve growth in some way. That can be through enhancing fertilizer efficacy, reducing crop stress, improving soil health or other mechanisms.

Sible is a research assistant professor in crop sciences and an University of Illinois-Extension specialist.

“The original biological was soybean inoculum,” he said. “That’s been around for decades, if not a century. But then the humic and fulvic acids – from decomposing organic matter or mineral deposits, hydrolysates – from plant and animal byproducts, and alginates – from seaweeds – came along, and were mostly applied in specialty crops. In those systems, anything you can do to improve the quality of your crop – the difference between a good juicy tomato and a small, dry one, for example – goes a long way.”

Once those products gained a foothold in specialty crops, the industry started moving into row crops such as corn and soybean. That spurred an explosion in the marketplace, with hundreds of products containing different active ingredients and promising various benefits.

Below said, “Very often, marketing exceeds the actual research. Clearly that’s the case here. We think it’s made more difficult by a lack of consistent terminology, and in some cases not necessarily the right regulation for what the product is. A lot of these are living bacteria, and they’re currently regulated at the state level as fertilizers. Largely, there’s no regulatory process for them at all.”

As part of the university’s land-grant mission, Below and Sible are tasked with providing unbiased research-based solutions to the public and policymakers. By diving deep into those products, they’re attempting to clarify for farmers what’s out there – and make it simpler for policymakers to apply logical regulations.

Although it’s possible to categorize the products into more than a dozen buckets based on their active ingredients, the researchers are calling for more simplicity.

Sible said, “The reality is, the market has gotten so big you can’t put them in one bin anymore. Our ultimate customer is the farmer. We need to talk about these products in the same language that farmers are thinking about them. They would largely associate ‘biologicals’ with the microbials and ‘biostimulants’ with non-living products. So that’s our recommendation for clarifying the terminology.”

The distinction matters if the industry is to be properly regulated, the researchers said. Currently only live microbial inoculants are defined in the U.S. Federal Insecticide, Fungicide, and Rodenticide Act. By qualifying as plant inoculants, those products are exempt from FIFRA regulations. And there’s no established policy to confirm that the organisms listed on the label are alive and present in the listed concentrations.

“Labeling is processed at the state level,” Sible said. “While state-level registration requires a label guarantee and expiration dates, there are currently no established third-party testing programs to enforce company claims. Furthermore, as each state has a unique process, the same product may be listed as a soil amendment in one state and as a plant inoculant in another.”

The researchers argue that federal regulations, aimed separately at biologicals and biostimulants, could also alleviate safety concerns specific to both product categories. Sible said grouping both products under the same regulatory framework just doesn’t make sense in terms of risk.

“Although all products, living or non-living, have their associated safety risks, the ability of microorganisms to mutate as they adapt to various environments, or if they are closely related to known pathogenic strains, warrants additional regulatory considerations compared to the non-living inputs that they are currently grouped with,” he said.

Although they are calling for more-nuanced terminology and regulations, the researchers said they don’t want to make it more difficult for industry to operate or for farmers to benefit from those products. They know, from their own trials and from farmers they meet during field days, that biologicals and biostimulants can absolutely move the needle on yield and quality at the farm gate. That’s all the more reason, they said, to define a common language and regulatory landscape around them.

Below said, “For this market and how fast it’s growing, we need all of the perspectives – academics, industry, and farmers – to come together on those products.”

The commentary, “Biostimulant or biological? The complexity of defining, categorizing, and regulating microbial inoculants,” is published in Agricultural and Environmental Letters – DOI: 10.1002/ael2.70027. The work was supported in part by the United Soybean Board Grant Number 25-211-S-A-1-A, and the North Central Region Sustainable Agriculture Research and Education program, project award no. NC1200, from the U.S. Department of Agriculture’s National Institute of Food and Agriculture. Additional funding was provided by the U.S. Department of Agriculture’s Agriculture Research Service project award no. 802-990.