“What do you know about biologicals?” is one of the most frequent questions I have received from farmers over the last several years. With a rapidly growing market estimated to be worth $30 billion by 2035, agronomists across the country will likely continue to answer that question for many years.
Biologicals are microbial products made of bacteria and/or fungi that are promoted to improve crop or soil health. They may be applied as seed inoculants, sprayed on growing crops or applied to soil.
Most farmers are already familiar with Rhizobium soybean seed inoculants, which have been used for decades. Building upon this, many companies have also added new species to seed treatments with claims that they will boost yield.
Recently, a large study evaluated nine new soybean biological seed inoculant products. This study was replicated 53 times spanning 21 states and was conducted by university researchers. Preliminary results have been mixed, with three locations showing a significant yield response compared to the untreated control. Notably, the four Ohio locations included in this study showed no yield increase with the use of these products. With this data, it is clear that there are conditions and locations where biological seed treatments boost yield, but in most scenarios they did not.
Unpredictability has been a hallmark of many biological products tested in independent research trials for corn and soybeans. The organisms in these products should be alive so they can grow and thrive once applied, and match the species on the product label. Improper storage and handling conditions can negatively affect the viability of the products, as heat or cold may result in the death of these living organisms. Additionally, some products have been found to contain the incorrect species of biological organism, which indicates a lack of quality control during manufacturing.
Adding to the unpredictability of these products is the competition from biological communities that already exist in your soil. Diverse communities of bacteria and fungi will exist in even the most mismanaged soils. Existing microorganisms in your soil may be more competitive, resulting in the applied products struggling to survive. These existing microbes may also be providing the same crop benefits as many biologicals, making an application redundant and not beneficial.
These products are being marketed to all regions of the U.S., despite the variety of different production practices used. While crop rotation is the normal practice here in Ohio, it is not the case as you move further west where continuous corn is common. Some products claiming an increase in corn yields of 10 bushels per acre, but if you dig into the research you’ll find that it was with the addition of AMS fertilizer in continuous corn under irrigation. This is a very different production system than we see locally, so these benefits may not be realized.
So, what is my answer when asked about biologicals? Biologicals are a growing market and each farmer should talk with their neighbors, do some reading and most importantly, conduct their own on-farm research. While most studies have found that biologicals do not boost yield and are not cost effective, under certain circumstances they can provide a benefit for your crops.
The only way to know for sure is to try it yourself in your soils, under your management practices and with your equipment. In crop years with tight margins, biologicals may be an attractive option, but with those tight margins you want to make sure they work before heavily investing.
