Nitrogen-fixing organisms for sale?
One of the latest categories of biological products claim to enable corn and other non-nitrogen fixing crops to fix nitrogen from the air and transform it so crops can use it to decrease their fertilizer nitrogen rates. If the claims are true, these products would save money on nitrogen fertilizer and would also decrease nitrogen losses from the soil through ammonia volatilization, denitrification NOx loss and nitrate leaching. Not only have many crop producers enthusiastically purchased these products but there is also political interest because of the potential environmental impact of their use. Farmers are bombarded with product marketing telling them that using these products is both financially practical and the responsible thing to do. However, given that these products have only recently been released to the market, it is very important to generate unbiased performance data.
In the summer of 2022, NDSU soil scientist Dave Franzen initiated corn trials, funded by the North Dakota Corn Utilization Council, for products to be evaluated near Carrington, Oakes, Absaraka, and Prosper in cooperation with five NDSU researchers near the plot locations. The products tested were Envita™ (Azotic North America, Raleigh, NC) and Utrisha™ (Corteva Agriscience, Indianapolis, IN ). Marketing materials for both products claim that they reduce the nitrogen required to produce crops. The active ingredient in Envita is Gluconacetobacter diazotrophicus, a well-known bacterium of tropical origin that can fix up to 150 lbs N/a in sugarcane. The bacterium in Utrisha is Methylobacterium symbioticum. This N-fixing bacterium was only recently discovered, but it is naturally occurring.
Envita was applied in-furrow to corn at planting in treatments that either received no nitrogen or received 80 lbs N per acre. Utrisha was sprayed onto the corn canopy at five or six leaves, depending on the location, with treatments receiving 0 or 80 lbs N per acre. Applications were made according to the instructions on the product labels. To compare, nitrogen was applied to plots not receiving biologicals. The rates were 0, 40, 80, 120, 160 lbs N per acre at all sites except Oakes. At Oakes, a computational error at the time of treatment weighing resulted in treatments of 0, 8.5, 17, 25.5, 34 and 41 lbs N per acre. The two biologicals were applied at Oakes at the 0 and 17 lbs N per acre rate.
Corn yield increased with nitrogen rate at all four locations, but there was no significant yield response to Envita or Utrisha (see Figure).
The results of this study are not conclusive about the efficacy of biological products but show the need for further testing by independent organizations. Farmers should also test these products using replicated treated/untreated strips to determine their value before buying large quantities.
Thank you to the North Dakota Corn Utilization Council for sponsoring this research.
Use of trade names does not imply endorsement of nor discrimination against any product.
Soils Research Specialist