The field studies concluded with at or above expected grain yields for the three locations utilized in 2024. There were clear response differences to biologicals dependent upon the environment in which supplied and the management by variety system in which implemented. The leading result from the yield data indicates that response to biologicals (positive or negative) was of greatest magnitude at the southern site, which had lower inherent organic matter and soil fertility than the other two sites. Conversely, under the highest yield potential at the central site, management with biologicals induced more positive responses as compared to the lower input system. These preliminary results indicate that biologicals may enhance low fertility systems and/or push high yield scenarios into higher yielding conditions. However, at sites of higher quality soil but with some other factor is limiting yield (such as drought during grain fill), biologicals were inconsistent in their response. This is three sites in a single year, and continued field testing will be necessary to further understand biological performance in soybean. A review of the literature and a survey of biological products identified as labeled for corn, soybean, or wheat crops 155 products, representing 113 unique company x microbial composition combinations, and in total 103 unique microbial blends (ten products were similar across companies). Review of these products found that 82% of products were labeled for enhancing crop nutrition, 9% for residue degradation, 5% as plant growth enhancements, 3% for soil inoculation, and 1% for drought tolerance. The nutritional category was then subdivided into more specific descriptions based on phrasing from the labels: 49% as nutrition only, 20% as nutrition and growth, 6% as nutrition and soil inoculation, 5% as nutrition and water uptake, and 2% as nutrition and drought tolerance. There is a clear trend that biologicals are largely targeted to improve crop nutrition, thus the marketing as replacements to some percentage of fertilizer inputs. The second highest category of residue degradation indicates this space to be growing, as this would not be directly associated with some of the traditional descriptions of biologicals to enhance nutrient availability, improve tolerance to stress, or improve yield or quality. Of the 113 unique company x microbial blend combinations, 8 microbes were found to be present in more than 10% of products, and 4 microbes were present in more than 20% of all products. This identifies a clear cast of characters most commonly utilized in these products, 5 of which were Bacillus species. Overall, the biological market is expanding rapidly and there is a growing need to educate industry agronomists, farmers, academic extension organizations, and the general public on what exactly are the microbes being utilized, how they work, and what questions to have ready for the sales rep when they come knocking at your door. The literature review and developing extension guide as a part of this project are the first steps towards this end.

The field studies can help inform on which practices and environments may be best suited for a yield success when utilizing a biological product. However, these environments are not all inclusive nor do they implement every possible management scenario one can conduct on an acre. It is important that farmers continue to test new products on their farm and always include check strips in the fields to be able to ground truth a benefit or decrease in yield as a result of using a new input. The key findings to the review of biological products are the identification as to what modes of action these products are targeted for, largely crop nutrition and then residue degradation. It was clear through label review, and some personal communications, that there are multiple biological manufacturers selling the same inoculants that are then being privately labeled by independent organizations. Some companies may have a unique formulation or carrier, while others may be utilizing the same mix in the jug behind a different name. This means a farmer may be looking at multiple product options for an intended use, but some of those may be much more similar than initially presumed. This provides growers with company options, but ensure one is equipped with the right questions as to which microbes are being sold, how do they work, and what data does company have to support those claims. This also makes assessment of the labels extremely important, and how to read a biological label. The proper way to list a microbial species and understand what the typical cfu counts should be can be a way to tell a good product from a bad one. If the species is incorrectly listed, or the cfu counts seem excessively low or high compared to the majority of products, there is either a solid scientific reasoning for this that the company can explain, or the product may not be as ground in hard data as one may being led to believe. Our guidebook will help train on what are the common labeling methods, cfu ranges, and proper way to list a microbial species. Beyond this, we have developed a list of common microbes utilized in certain products. If a product has one of the more common microbes, then it "fits the status quo", but if a product lists a microbe that is uncommon it may warrant some additional research as to its functions and impacts it may have for row crops. With this information in mind, we encourage farmers to consider new technologies in agriculture, biological or other. However, with any new investment it is important to have the preliminary research and background knowledge to best be prepared to use that new input. With biologicals, this is especially important given the challenges of working with a living input, and the rapidly expanding market making it difficult to stay up to date with what technologies are being offered and how they work. The major investments and rapidly expanding market indicate these products are going to be around awhile, and we are cautiously optimistic for their future role in row crop production systems.