- Beneficial microorganisms can create symbiotic relationships with plant roots, promote nutrient mineralization, produce plant growth hormones and provide biocontrol of plant pests.
- Many beneficial microorganisms are naturally present in soils, but they can be advantageous when re-introduced.
- If considering use of biologicals on your farm, leave check strips in each field to understand their value prior to broad adoption.
Soil microorganisms are by far the principal form of life found in soil, but due to their microscopic size they are often overlooked. In fact, there are more microbes in a teaspoon of soil than there are people on earth. Soil microorganisms are made up of a combination of many types of bacteria and fungi that are commonly recognized for their role in breaking down organic matter. Beneficial soil microorganisms can also create symbiotic relationships with plant roots, promote nutrient mineralization and availability, produce plant growth hormones and serve as biocontrol agents of plant pests, parasites or disease.
In general, beneficial microorganisms are naturally present in soils, but there can be benefits to reintroducing them. Although the specific way soil microorganisms behave in the soil and interact with plants is well understood, predicting when and where a farmer may see an economic response is more challenging. Continued work is needed to better understand and place the correct biological in specific fields, or areas of fields, where enhanced value may be seen.
Biologicals for Nutrient Management
Many products containing beneficial microbes are currently available for use as seed treatments or in-furrow applications. Each is unique to the specific type of bacteria or fungi utilized, as well as the approach used to enhance plants. The listed benefits by various biological crop product providers often promote improved nutrient availability in soil and increased root volume, resulting in increased water and nutrient uptake by plant roots.
The following biologicals and fertilizers were evaluated by the Golden Harvest® agronomy team in the 2020 growing season to better understand plant response and consistency:
- BioRise™ seed treatment: Combination of Penicillium bilaiae, which releases bound soil phosphate, and lipochitooligosaccharide to enhance mycorrhizal fungi root colonization and promote nutrient availability and nutrient and water uptake.
- Biodyne® Environoc 401 (in-furrow): Bacteria and unicellular fungi with phosphate-solubilizing microbes and nitrogen-fixing microbes.
- Terrasym® 450 seed treatment: Beneficial microbes called methylobacterium (M-trophs) that form a symbiotic partnership with plants to improve plant development and nutrient uptake.
- Feed grade dextrose (in-furrow): Reported to feed microorganisms in the soil to enhance nutrient mineralization (4 lbs/A).
- 10-34-0 (in-furrow): Traditional check used to provide early season phosphorous uptake (5 gal/A).
2020 Biological Evaluations
The team established trials at 8 locations in 2020 to better understand the potential value of biologicals for improving yield. 2 of 8 locations were lost to the late season derecho wind events. Results focus on the 6 remaining sites (Figure 1). Soil fertility for each location was managed according to normal practices of the local grower. Soil sampling was done prior to planting to understand nutrient availability that may influence trial results (Table 1).
In general, phosphorous and potassium levels were at high to very high levels at most locations. The 2 unique locations were Clay Center, KS, which had lower organic matter, CEC (cation exchange capacity) and phosphorous levels, and Clinton, IL, which had lower phosphorous levels (< 20 ppm). Depending upon the specific treatment, biologicals were either applied on the seed as a seed treatment or via an in-furrow application. One treatment not receiving any biologicals was planted to serve as a comparison to the 4 biological treatments. A traditional in-furrow application of 10-34-0 at 5 gal/A served as the sixth treatment to better understand if phosphorous was a limiting factor at each location. All treatments were planted on the same day and replicated 4 times per location.
Summary and Discussion
Yield environments were significantly different across the six trials conducted in the 2020 season, ranging from 178 bu/A at Sac City, IA, to 276 bu/A at Seward, NE. Of the 6 trials, significant yield differences among treatment were only observed at the Clay Center and Clinton sites. These were also the 2 locations most limited in soil phosphorous levels. At Clay Center, the Terrasym 450 seed treatment had only a small numerical yield advantage over the comparison plot without biologicals, but it yielded statistically more than all other treatments (Graph 1). There was no response to 10-34-0 observed at this location. However, in the Clinton trial, the 10-34-0 treatment yielded 13.8 to 17.7 bu/A more than all other treatments except for BioRise (Graph 2). BioRise didn’t statistically yield more than other treatments, but it did have a small numerical advantage of 4 bu/A over the treatment without biologicals.
There were no consistent yield advantages observed at any of the other 4 locations (Graph 3). Although not statistically significant, the BioRise treatment did average 2 bu/A more than other treatments.
Conclusions
There was no consistent response observed across locations for any of the biologicals evaluated. Small advantages from single locations were observed for the Terrasym 450 and BioRise seed treatments, but the only significant response came from the 10-34-0 starter fertilizer treatment at only 1 location. This was potentially due to a lack of yield limiting factors, such as nutrient deficiency or unfavorable weather conditions. Testing in other environments could have resulted in a different outcome, however, test environments were indicative of a high percentage of Midwest corn growing acres. If considering using biologicals, it is best to leave numerous check strips in each field to compare against to help understand the value prior to broad adoption.
For more insight into corn nutrient uptake and biologicals, contact your local Golden Harvest Seed Advisor.
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