James Adkins, Extension Engineer, adkins@udel.edu,  Jarrod Miller, Extension Agronomist

In 2023, the University of Delaware evaluated the corn yield response to 14 biological products at 3 nitrogen fertility levels (optimum, 80%, and 50% rate).  While some of the products claimed to provide nitrogen fixation others were designed to improve plant health and root structure.  Products tested include:        

Invigorate (AMVAC)   

Ion Strike (Planet Earth Agronomy)

Zypro (Helena)   

BioGrowth (Willard Ag)

UtrishaP (Corteva)     

Source (Sound Ag)

ProveN40 (Pivot Bio)   

Blaine (Farmer 2 Farmer)

Accomplish Max (Loveland)     

Blaine with humic (Farmer 2 Farmer)

RioZyme Supreme (Schaeffer’s)   

Nexia (Innvictis)

RioZyme Plus (Schaeffer’s)     

Launch (Ag Concepts)

Thirteen of the products were applied during planting through Keeton seed firmers using five gallons per acre of water as a carrier and one product (Source) was sprayer applied at V4, The following methods were performed at the UD Warrington Farm in Harbeson, DE: 

  • Conventional tillage, chisel, field cult.
  • JD 7200 with v-set meters, hyd downforce, 2×2 starter, in-furrow w/surefire & agitation.
  • Axis 63M73 Planted May 10-14 at 34 ksds/a
  • 15 gpa of 20-12-0-1.8S-0.15B applied 2 x 2
  • Pre-Emerge Bicep Mag & Simizine – May 17
  • Post HalexGT & Atrazine – June 6
  • VRT MAP (180 lbs/a avg.) – June 13
  • 150 lbs./a Potash – June 13
  • 40 – 80 gpa (rate by trt) 28-0-0-3S – June 15
  • Seasonal irrigation total 11.1”

Figure 1.  Planting 6 row by 45’ long randomized plots.

Irrigated yield results showed no statistical significance between any of the materials and the untreated check at the full 270 lbs N acre-1 with a plot average of 265 bu acre-1 (Figure 2, orange columns).  The products with a high humic acid content performed above average pointing toward the potential for humics to be of benefit at this location.

Figure 2 – Dry yield by product at full rate (270 lbs./a) total nitrogen in orange, 80% rate (218 lbs./a) in light blue, 50% rate (135 lbs./a) in dark blue.

At the 80% nitrogen fertility level (218 lbs N acre-1), the plots averaged 260 bu acre-1 with 4 products (Zypro, RioZyme Supreme, BioGrowth, Nexia) being yielding significantly lower than the untreated control.  No products providing a statistical yield benefit over the untreated control plots (Figure 2, light blue columns).  

The 50% nitrogen plots (135 lbs N acre-1) averaged 234 bu acre-1 with 4 products being significantly lower yield than the untreated check (Figure 2, dark blue columns).  While a few products, (ProveN40, Utrisha P, BioGrowth & Source) trended to yield more than the control at the 50% N rate, the differences were not statistically significant. This resulted in a net economic loss versus applying the full rate of nitrogen.  Zypro, Accomplish Max, RioZyme Supreme, and Nexia all yielded significantly less than the untreated control however these products do not claim to provide a nitrogen credit and would be extremely stressed in this low nitrogen plot (Figure 3).

Figure 3: September 1st, 2023 aerial imagery showing the yellowing and advanced maturity of the low nitrogen plots.

The same 14 products were tested in a non-irrigated field at 130, 102 and 65 lbs N acre-1 of applied nitrogen.  None of the products out yielded the untreated check at the lower nitrogen rates while four products (Invigorate, Accomplish Max, RioZyme Plus & RioZyme Supreme) provided a minor but statistically insignificant yield bump at the full 130 lbs N acre-1.

Farmers should keep in mind that crop response to a biological product will be dependent on enumerable factors such as soil type, OM, CEC, compaction, moisture, manure history, etc.  Growers need to conduct side-by-side evaluations of these products to determine the real-world economic benefits to their operation keeping in mind that results may vary by field within a farm.  The University of Delaware will be evaluating these products again in the 2024 season.


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