Effects of Utrisha^® P Microbial Biostimulant on Corn Yield

• Utrisha P is a microbial biostimulant that helps release soil-bound phosphorus (P) for plant uptake.
• The majority of P in the soil is not available for plant uptake – it is contained in organic compounds and P minerals, or it is adsorbed to clay particles.
• The active ingredient in Utrisha P, Bacillus amyloliquefaciens FZB45, is a phosphate solubilizing bacteria that colonizes plant roots and produces compounds that increase the availability of P for plant uptake:
  • Organic acids - (citric acid, acetic acid, lactic acid) lower the soil pH in the area around the roots, increasing the solubility of P bound to calcium
  • Phosphatase enzymes - solubilize organic P molecules into plant-available organic forms
  • Chelators - siderophores that degrade iron-phosphate compounds by chelating iron
• Utrisha P is applied in-furrow at planting at a rate of 3.5-7.0 fl oz/acre with either a starter fertilizer or water.
• Utrisha P is likely to provide the greatest value in soils where P availability is limited, such as high clay soils or soils outside the ideal pH range for P solubility.

• A study was conducted in 2023 to evaluate the impact of Utrisha P on corn yield.
• On-farm trials were conducted at 33 locations, primarily in the western portion of the U.S. Corn Belt where soil pH levels tend to be higher (Figure 1).
• Each field in the study included a treated area and untreated area to determine yield response to application of Utrisha P.

• Utrisha P treatment significantly increased corn yield, by an average of 2.3 bu/acre across all locations (Figure 2).

Impact of Soil pH

• The soil pH range of minimum P absorption and maximum P solubility is 6.0 to 6.5 (Havlin et al., 1999).
• At pH levels above this range, P solubility decreases as fixation by calcium increases (Figure 3).

• Utrisha P would be expected to have a greater yield impact in soils with a pH outside the range of highest P availability.
• Yield results generally conformed to expectations based on soil pH of trial locations (Figure 4); however, the vast majority of locations in this study fell within the upper pH range, with relatively few locations represented in the lower and middle range. Further research is needed to refine performance expectations for Utrisha P based on soil pH.

Soil Clay Content

• Utrisha P could potentially have greater value in soils with a high clay content.
• As the amount of clay in the soil increases, sorption capacity increases as well. Clay particles have a large amount of surface area where phosphate sorption can take place, which can reduce the amount of solution P available for plant uptake (Havlin et al., 1999).
• By increasing availability of P from organic matter and secondary minerals, Utrisha P could help offset lower solution P due to higher adsorption by clay.
• Comparing yield response to Utrisha P between trial locations with higher and lower soil clay content showed that higher clay locations did have a higher average yield response (Figure 5); however, the magnitude and consistency of difference that could be expected generally is not certain based on the limited number of locations in this study.

Havlin, J.L., J.D. Beaton, S.L. Tisdale, and W.L. Nelson. 1999. Soil Fertility and Fertilizers – An Introduction to Nutrient Management. 6th ed., Prentice Hall, Upper Saddle River, NJ.