What the research measured
The cited North Central review and three Iowa organic trials reported no significant corn yield increase at the nitrogen rates tested. Kentucky reported responses at particular nitrogen-rate and soil combinations. The linked Australian wheat study and manufacturer trials cover different crops or conditions.
Independent replicated trials across five North Central states plus three Iowa on-farm strip trials, but the US independent record is small and ends in 2023, with no US peer-reviewed field study.4 independent sources · 1 manufacturer-authored, labelled.What it is. A foliar-applied biological containing the nitrogen-fixing bacterium Methylobacterium symbioticum, sprayed at 5 oz/ac at V4–V8 on top of a normal N program. OMRI-listed, and marketed as an average +5 bu/ac in corn and +2.5 bu/ac in soybean.
Study conditions and limitations
- Application is demanding: 10–25 gal/ac of water with under 2 ppm chlorine and pH 5–8, on a healthy canopy, rain-fast after one hour; Corteva’s soybean data show about four times the response from morning sprays.
- It often needs its own pass: Iowa cooperators found it incompatible with their post-emergence tank mixes, which is what pushed the cost to about $17/ac, and none planned to use it again.
- Where responses appeared (Kentucky 2022) they were tied to one N rate on one soil and did not repeat at other rates, limiting the applicability of the response to other conditions.
- Corteva’s own corn trials report the largest gains in low-yield environments (+7.2 bu/ac under 179 bu/ac; +3.3 bu/ac over 220 bu/ac); those are company trials.
- The organism’s measured N contribution in Portuguese field maize varied between 58.8 kg N/ha in one year and 14.5 kg N/ha the next.
- OMRI-listed, so it is one of the few N biologicals allowed on organic corn, but the three organic Iowa trials showed no yield gain.
Read the sources · 5
- Performance of Selected Commercially Available Asymbiotic N-fixing Products in the North Central Region ↗
Land-grant trials in ten states through 2022: 59 of 61 corn site-years showed no yield increase from any product over the N rate alone. The review reported a significant yield benefit for PROVEN 40 in 0 of 15 site-years and Utrisha N in 0 of 11.
- Utrisha N Biological Nitrogen Supplement for Organic Corn ↗
Three replicated strip trials on Iowa organic corn farms in 2023 found no significant yield difference between Utrisha N at V7–V8 and untreated strips; the largest numeric edge was about +3 bu/ac. Cooperators spent about $17/ac, often in a separate pass.
- The Application of a Foliar Spray Containing Methylobacterium symbioticum Had a Limited Effect on Crop Yield and Nitrogen Recovery in Field and Pot-Grown Maize ↗
Two years of field silage maize in Portugal with the same organism (sold there as Blue N): dry matter 24.2 vs 20.2 t/ha and 15.6 vs 14.1 t/ha with and without the spray, neither significant. Apparent N fixation was 58.8 and 14.5 kg N/ha, which the authors call modest and inconsistent.
- Australian Dryland Wheat Growth and Yield Are Positively Impacted by a Methylobacterium symbioticum Biostimulant Under Reduced Nitrogen Supply ↗
In large replicated dryland wheat plots in New South Wales, the foliar bacterium at 75% of standard N gave 14% higher grain yield and 25% higher N uptake than the reduced-N control. A wheat result in a low-input Australian system, not US corn.
- Utrisha N Nutrient Efficiency Biostimulant Effects on Soybean Yield ↗
Corteva’s own 233-location on-farm soybean comparisons averaged +1.1 bu/ac; morning sprays averaged +1.95 bu/ac against +0.5 for afternoon sprays. Manufacturer data, in soybean rather than corn.
Before you buy, ask
- Is the formulation and application method I would buy the one that was tested?
- Was the comparison a yield gain at the same nitrogen rate, or held yield with less fertilizer?
- What happens to my result if I cut nitrogen and the product does not fix enough?
Record
- Sources checked
- September 26, 2026. Every figure shown is printed on the linked page; unit conversions are noted on the chart.
- Company response
- None yet. Corteva Agriscience can send corrections, additional trials, or a statement; it is published here, labelled, and never edits the research summary. Send a correction →