Agricultural biologicals are plant support and protection products derived from microbes, beneficial insects, plant extracts and other naturally occurring materials. They comprise a growing sector of the agriculture industry — one that is expected to triple to a $33.7 billion market by 2035.
Connor Sible, a research associate at the University of Illinois, has spent the past 8 years studying biologicals and shares 8 categories of biological products to help inform decisions for your no-till or strip-till program.
1. Nitrogen-Fixing Bacteria. Nitrogen-fixing bacteria convert atmospheric nitrogen to ammonia and then to plant-soluble ammonium. Like humans, plants can’t use atmospheric nitrogen (N) directly. Instead, they scavenge nitrogen or trade it for sugars in a symbiotic relationship with bacteria. In soybeans, bacteria located in root nodules may supply up to 50% of the required N. Corn, which lacks nodules, traditionally relies on fertilizer and soil mineralization to fulfill its nitrogen requirements. Sible says a N-fixing biological provides a third source from which to pull N — the atmosphere — and increases the overall amount of plant-available N in the system.
2. Phosphorus-Solubilizing Microbes. Sible says many soils have the phosphorus (P) levels needed to supply what that crop will need, but the P isn’t always plant available. When mineral phosphate binds to aluminum, calcium and iron, the P is rendered unavailable for plant use. P-solubilizing bacteria (PSB) secrete organic acids that solubilize inorganic phosphorus, making it available for plant uptake and increasing the value of applied starter fertilizer. Increased P uptake occurs when there is adequate soil contact near the root, resulting in greater fertilizer efficiency and a potential ROI.
3. Mycorrhizal Fungi. Arbuscular mycorrhizal fungi (AMF) inoculation encourages root growth for increased surface area and nutrient acquisition. Although AMF are naturally occurring, Sible says seed inoculation shows a significant benefit as growth can begin immediately instead of waiting for root association with naturally occurring sources. Dekalb’s BioRise is an example of a product that includes AMF.
4. Residue Degradation. The naturally occurring Bacillus soil bacteria promote nutrient cycling by producing proteins and enzymes that naturally mineralize the soil, facilitate symbiotic plant interactions, stimulate nearby microbe populations and encourage root growth. Some also solubilize P.
5. Enzymes (Phosphatases). When cultured and released into residue, phosphatases break chemical bonds to release organic P, increasing its overall availability. Not all phosphatases are the same, and test site results reveal different enzymes target P in different ways in different locations. Sible says there’s a synergistic effect when P-solubilizing microbes and mineral P combine with phosphatases and organic phosphorus. The result is an increased availability of two different types of P, possibly allowing for a fertilizer reduction.
6. Humic & Fulvic Acids. Humic acid is comprised of large molecules that enhance the soil’s ability to retain nutrients and water. When paired with P solubilizers, they may allow for continual chelation of cations throughout the season. Both humic and fulvic acids contain carbon. Microbes feed on the carbon, eventually depleting it.
7. Marine Extracts. Marine extracts, also called alginates, provide environmental stress mitigation when foliar applied proactively and enhance the crop’s root zone when applied to the soil. The extracts comprise amino acids, sugars and hormones that stimulate the crop. When soil applied, it promotes root growth and microbial activity.
8. Sugars. Sugars provide an energy source for microbes, stimulate roots and provide stress mitigation when foliar applied. Commonly labeled as glucose, fructose and sucrose aka molasses products, Sible says they have the added benefit of being easy to store. Applied proactively to foliage with alginate, sugar acts as a stress mitigator. It also triggers a plant growth response.
