James Adkins, Irrigation Engineer, adkins@udel.edu
In 2023, the University of Delaware evaluated the corn yield response to 14 biological products at 3 nitrogen fertility levels (optimum, 80%, and 50% rates). While some of the products claimed to provide nitrogen fixation, others were designed to improve plant health and root structure. Thirteen of the products were applied during planting through Keeton seed firmers, using five gallons per acre of water as a carrier. One product (Source) was sprayer applied at V4.
Irrigated yield results showed no statistical significance between any of the materials and the untreated check at a full 270 lbs./a of total applied nitrogen with a plot average of 265 bu./a. At the 80% nitrogen fertility level (218 lbs./a), the plots averaged 260 bu./a with 4 products being significantly worse than the untreated control and no products providing a statical yield benefit over doing nothing. The 50% nitrogen plots (135 lbs./a) averaged 234 bu./a with 4 products being significantly lower yield than the untreated check. While a few products, (ProveN40, Utrisha P, BioGrowth & Source) tended 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.
The same 14 products were tested in a non-irrigated field at 130, 102 and 65 lbs./a 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./acre of nitrogen.
Similar results were documented by Nicole Fiorellino in her trials at the University of Maryland. 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.
A detailed summary of the 2023 in-furrow biological application can be found here: https://sites.udel.edu/agronomy/2024/02/15/udbiologicals23/