Nitrogen-enhancing biological products provide a level of nitrogen to a corn crop.
Positive yield responses to microbials become more consistent as nitrogen rates fall below plant requirements or environmental nitrogen loss occurs.
Biologicals are a hot topic in agriculture production. The U.S. Farm Bill defines biologicals, or biostimulants, as substances or microorganisms that when applied to seeds, plants or the rhizosphere, stimulate processes to enhance or benefit nutrient uptake, nutrient efficiency, tolerance to abiotic stress or crop quality and yield. Biological products containing bacteria that can fix atmospheric nitrogen (N) and provide plants with plant-available N are a big focus in the agriculture industry.
Figure 1. Trial design with N blocks stripped by biological product and hybrid randomized within those strips at Clinton, IL Biologicals for Nitrogen Management
Many companies have introduced separate biological products that utilize bacteria to form a mutualistic relationship with the plant, resulting in biological nitrogen fixation. The Golden Harvest® Agronomy in Action research team evaluated 3 of these products that are currently on the market at 3 N rates: 100, 140 and 180 lbs. of N/acre. The products include:
- Envita™ – a naturally occurring, food grade bacteria (Gluconacetobacter diazotrophicus) from Azotic North America, applied in-furrow
- Pivot Bio PROVEN® – microbial (Klebsiella variicola) developed by Pivot Bio, applied in-furrow
- BlueN™ – endophytic bacterium (Methylobacterium symbioticum) developed by Symborg, foliar-applied at V4. Recently, Symborg reached a multi-year agreement providing an exclusive distribution license of the bacteria to Corteva Agriscience under the brand name Utrisha™ N.
Each N rate and product was implemented across 3 hybrids at 5 Agronomy in Action locations throughout the Midwest (Figure 1). There was no significant effect between the interaction of hybrid, N rate and product on grain yield, therefore, all results were averaged across hybrid.
Graph 1. Effect of N rate on grain yield averaged across 3 hybrids
* Effect of N rate on yield was significant at α = 0.10. Corn Yield Response to Nitrogen and Biologicals
Clay Center, KS, and Seward, NE, were the only 2 locations where N rate had a significant effect on grain yield and are considered N responsive sites (Graph 1). At Seward, NE, each additional 40 lbs. of N/acre applied resulted in an increase in yield. Statistically at Clay Center, KS, there was no yield advantage when increasing the nitrogen rate from 140 to 180 lbs. of N/acre. The addition of N enhancing biological products did not affect grain yield at the 140 or 180 lbs./acre N rate at any location. Except for Seward, NE, 140 lbs. of N/acre were sufficient to maximize yield, therefore yield responses to biological products that supply plant-available N would not be expected.
The 100 lbs./acre N rate simulates an environment where N loss (from leaching, denitrification, runoff, etc.) may have occurred, resulting in soil N levels below what is required by the plant. In the more N-stressed environment at Seward, NE, applying Pivot Bio PROVEN in-furrow significantly increased yield by 9 bu/A (Graph 2). At Keystone, IA, Envita applied in-furrow resulted in a 27 bu/A yield increase compared to when no biological was applied. There was a 12 bu/A yield response to the foliar application of BlueN at Clay Center, KS. The Clinton, IL, and Slater, IA, plots showed no biological product that significantly increased yield, although, numerically, plants responded positively to Envita at Slater, IA.
Graph 2. Yield response to N-enhancing biologicals at the 100 lbs./acre N rate averaged across 3 hybrids
* Significantly greater compared to no biological at α = 0.10. Basal Stalk Nitrate Test
1 to 3 weeks after black layer, lower stalk samples were collected and analyzed for nitrate levels. Foliar-applied BlueN treatments were excluded due to destructive sampling rows not receiving full application rates.
The basal stalk nitrate test is an end-of-season diagnostic tool that can indicate if N was overapplied. If corn plants have sufficient N available to attain maximum yield for the specific growing conditions, nitrate will accumulate in the lower stalk and increase stalk nitrate levels.
Graph 3. Basal stalk nitrate concentration response to N-enhancing biologicals averaged across 3 hybrids at the 100 lbs./acre N rate
* Significantly greater compared to no biological at α = 0.10. Iowa State University categorizes nitrate concentrations into 3 levels: < 250 ppm = N was likely deficient during the growing season; 250–2,000 ppm = yields were not likely limited by N; and > 2,000 ppm = N was likely overapplied.1
Only at Seward, NE, was the stalk nitrate concentration considered low at the 100 lbs./acre N rate (Graph 3). Neither biological product increased the stalk nitrate concentration to be considered sufficient. Envita and Pivot Bio PROVEN applied at Clay Center, KS, more than doubled the nitrate concentration in the lower stalk compared to when no biological was applied. The increase in concentration did not have a significant impact on yield, suggesting N was not the limiting factor in that environment. Stalk nitrate concentrations tended to slightly increase when Envita and Pivot Bio PROVEN were applied at Clinton, IL, and when Envita was applied Keystone, IL.
Stalk nitrate levels of the untreated check being 1,000 ppm or greater at 4 of 5 locations indicate that other sources of N such as organic matter mineralization contributed significant amounts of N in addition to the 100 lbs./acre N rates. Increases in nitrate levels at Clay Center were negated by sufficient levels in absence of biologicals, resulting in minimal yield increases for both products. However, the increase in nitrates levels does confirm that both products have the ability to influence N availability within the plant.
Biological Technology and Corn Crop Performance
Results from this study aligned with a similar study conducted by the Agronomy in Action team in 2019. Data from both years would suggest nitrogen-enhancing biological products are providing a level of N to the corn crop. However, positive yield responses are inconsistent. Biologicals applied with lower N rates at N responsive locations tend to increase yield potential more consistently. However, there is an inherent risk of yield loss when using microbials to lower synthetic N rates below plant requirements for the given environment.
Biological technology is continuing to advance rapidly. The role of microbials in N management is likely to increase.
References
1 Sawyer, J. and A. Mallarino. 2018. Use of end-of-season corn stalk nitrate test in Iowa corn production. Iowa State University Extension and Outreach. CROP 3154: 1-5.
All photos are either the property of Syngenta or used with permission.
Syngenta hereby disclaims any liability for Third Party websites referenced herein.
Performance assessments are based upon results or analysis of public information, field observations and/or internal Syngenta evaluations.
Product performance assumes disease presence.
© 2022 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties. Please check with your local extension service to ensure registration status. AAtrex 4L, AAtrex Nine-O, Acuron, Agri-Flex, Agri-Mek 0.15EC, Agri-Mek SC, Avicta 500FS, Avicta Complete Beans 500, Avicta Complete Corn 250, Avicta Duo Corn, Avicta Duo 250 Corn, Avicta Duo COT202, Avicta Duo Cotton, Besiege, Bicep II Magnum, Bicep II Magnum FC, Bicep Lite II Magnum, Callisto Xtra, Cyclone SL 2.0, Denim, Endigo ZC, Endigo ZCX, Epi-Mek 0.15EC, Expert, Force, Force 3G, Force CS, Force 6.5G, Force Evo, Gramoxone SL, Gramoxone SL 2.0, Gramoxone SL 3.0, Karate, Karate with Zeon Technology, Lamcap, Lamcap II, Lamdec, Lexar EZ, Lumax EZ, Medal II ATZ, Minecto Pro, Proclaim, Tavium Plus VaporGrip Technology, Voliam Xpress and Warrior II with Zeon Technology are Restricted Use Pesticides.
Some seed treatment offers are separately registered products applied to the seed as a combined slurry. Always read individual product labels and treater instructions before combining and applying component products.
Orondis Gold may be sold as a formulated premix or as a combination of separately registered products: Orondis Gold 200 and Orondis Gold.
Important: Always read and follow label and bag tag instructions; only those labeled as tolerant to glufosinate may be sprayed with glufosinate ammonium-based herbicides. LibertyLink®, Liberty® and the Water Droplet logo are registered trademarks of BASF. HERCULEX® and the HERCULEX Shield are trademarks of Corteva Agriscience LLC. HERCULEX Insect Protection technology by Corteva Agriscience LLC. Under federal and local laws, only dicamba-containing herbicides registered for use on dicamba-tolerant varieties may be applied. See product labels for details and tank mix partners. Golden Harvest® and NK® soybean varieties are protected under granted or pending U.S. variety patents and other intellectual property rights, regardless of the trait(s) within the seed. The Enlist E3® soybean, LibertyLink®, LibertyLink® GT27®, Roundup Ready 2 Xtend®, Roundup Ready 2 Yield® and XtendFlex® soybean traits may be protected under numerous United States patents. It is unlawful to save soybeans containing these traits for planting or transfer to others for use as a planting seed. Only dicamba formulations that employ VaporGrip® Technology are approved for use with Roundup Ready 2 Xtend® and XtendFlex® soybeans. Only 2,4-D choline formulations with Colex-D® Technology are approved for use with Enlist E3® soybeans. The trademarks or service marks displayed or otherwise used herein are the property of a Syngenta Group Company. ENLIST E3® soybean technology is jointly developed with Corteva Agriscience LLC and M.S. Technologies, L.L.C. The ENLIST trait and ENLIST Weed Control System are technologies owned and developed by Corteva Agriscience LLC. ENLIST® and ENLIST E3® are trademarks of Corteva Agriscience LLC. GT27® is a trademark of M.S. Technologies, L.L.C. and BASF. Roundup Ready 2 Xtend®, Roundup Ready 2 Yield®, XtendFlex®, VaporGrip® and YieldGard VT Pro® are registered trademarks used under license from the Bayer Group. All other trademarks are the property of their respective owners. More information about Agrisure Duracade® is available at http://www.biotradestatus.com/.