How to Manage Nitrogen Applications Under Price Pressure

While this year’s input costs are hitting the bottom line harder than most years, several things can help maximize production and justify the money invested in nitrogen (N).

Use a nitrogen stabilizer

Understanding how N can leave a field is important. Leaching, denitrification, and volatilization can lead to significant losses (15 to 90%) depending on soil types and growing conditions.1 If we knew in advance about the upcoming year’s weather, it would help take much of the risk out of farming. Since we can’t predict the weather with the amount of certainty we would like and N stabilizers can’t be applied after the fact, it is important to do your research and talk to your local seedsman to help understand when using a stabilizer is worth investing the extra money.

Pay attention to TOTAL soil fertility including pH

Liebig’s Law of the Minimum (most often represented as a wooden barrel with staves of different lengths) shows that the nutrient that is most deficient is the nutrient which limits yield (Figure 1).2 Nitrogen might often be the focus, but other nutrients could be causing the leak in the yield barrel. The only way to know if you have a leaky barrel is to have your field soil sampled.

Wooden Barrel drawing Figure 1. Drawing of wooden barrel to depict Liebig’s Law of Minimum.

Nutrient interaction

Soil pH

Another interaction affecting nutrient availability (and yield potential) is soil pH. Most macro and micro soil nutrients are available when soil pH is between 6.5 to 7.5.6 Beyond this range, some nutrients are unavailable for plant uptake and yield is potentially limited. Furthermore, the bacteria responsible for the nitrification process are hindered at low pH, which decreases nitrate availability and forces plants to utilize ammonium, lowering N use efficiency.4 Table 1 shows the relative yield potential if your pH falls outside of this optimum range.

Table 1. Crop yield relative to pH.*,5,8
Crop Soil pH
  4.7 5.0 5.7 6.8 7.5
  Relative Yield (100 is best, 0 is worst)
Corn 34 73 83 100 85
Soybean 65 79 80 100 93
Wheat 68 78 89 100 85
Alfalfa 2 9 42 100 100

*Adapted from Smith, J.L. and Doran, J.W. 1996. Measurement and use of pH and electrical conductivity for soil quality analysis. Methods for Assessing Soil Quality. SSSA Special Publication Number 49. Soil Society of America.

Split application of nitrogen

Since N is mobile in the soil and subject to loss not only via leaching, but volatilization and denitrification as well, keeping N where it is needed can be difficult. Ideally, apply N as close to the period of rapid nutrient uptake. This provides a smaller window for loss to occur before it is used by the growing crop. Split N applications frequently lead to higher yield potential versus a single application. In irrigated operations, center pivots can apply N along with water. In rainfed environments, liquid coulter machines, 360 Y-Drop® nozzles, or even dry spinner spreaders work for applying N later in the season. 

Lastly, it is important to revisit fundamentals. Nitrogen is primarily taken up through the roots. Therefore, anything that maintains root health can help maximize N applied. Soil insecticides and corn products such as SmartStax® corn or SmartStax® PRO technology can help limit rootworm damage. A solid herbicide program to minimize weed competition for water, sunlight, and nutrients should also be used.

Given the nature of this year, with supply and price issues, it is even more critical to dial in your N management program.

An excellent resource to help determine N rates is the Corn Nitrogen Rate Calculator sponsored by Iowa State University and associated with the Universities of Iowa State, Illinois, Michigan State, Minnesota, Purdue, The Ohio State, and Wisconsin.

Sources:

1Bastos, L., Maharjan, B., Wortmann, C., and Ferguson, R. 2018. Nitrogen fertilizer stabilizers in corn. CROPWATCH. University of Nebraska-Lincoln. https://cropwatch.unl.edu/2018/nitrogen-fertilizer-stabilizers-corn.

2Greg Klinger, Shane Bugeja (Host). (Oct. 25, 2021). The Leaky Barrel (Episode 1) [Audio podcast episode]. In The Story of Nitrogen. University of Minnesota Extension. https://www.listennotes.com/podcasts/the-story-of/episode-1-the-leaky-barrel-Axp5azNXMPo/#transcript.

3Mullen, R. Liebig’s law of the minimum. Nutrient Science. eKonomics. Making Sense of Today’s Crop Nutrition Research. Nutrien®. https://nutrien-ekonomics.com/latest-fertilizer-research/liebigs-law-of-the-minimum/

4Hoiberg, A. 2020. Back to the basics of soil pH. Calcium Products. https://www.calciumproducts.com/back-to-the-basics-of-soil-ph/.

5Smith, J.L. and Doran, J.W. 1996. Measurement and use of pH and electrical conductivity for soil quality analysis. Methods for Assessing Soil Quality. SSSA Special Publication Number 49. Soil Society of America.

6Jensen, T.L. 2010. Soil pH and the availability of plant nutrients. Plant Nutrition TODAY. International Plant Nutrition Institute (IPNI).

8Soil pH. Soil quality indicators. 2011. USDA Natural Resources Conservation Service. https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/health/assessment/?cid=stelprdb1237387.

Andrew Swanson

Legal Statement

Bayer is a member of Excellence Through Stewardship® (ETS). Bayer products are commercialized in accordance with ETS Product Launch Stewardship Guidance, and in compliance with Bayer’s Policy for Commercialization of Biotechnology-Derived Plant Products in Commodity Crops. Commercialized products have been approved for import into key export markets with functioning regulatory systems. Any crop or material produced from this product can only be exported to, or used, processed or sold in countries where all necessary regulatory approvals have been granted. It is a violation of national and international law to move material containing biotech traits across boundaries into nations where import is not permitted. Growers should talk to their grain handler or product purchaser to confirm their buying position for this product. Excellence Through Stewardship® is a registered trademark of Excellence Through Stewardship.

SmartStax® PRO corn products will be commercially available for the 2022 growing season.

ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. B.t. products may not yet be registered in all states. Check with your seed brand representative for the registration status in your state.

IMPORTANT IRM INFORMATION: RIB Complete® corn blend products do not require the planting of a structured refuge except in the Cotton-Growing Area where corn earworm is a significant pest. See the IRM/Grower Guide for additional information. Always read and follow IRM requirements.

Performance may vary, from location to location and from year to year, as local growing, soil and weather conditions may vary. Growers should evaluate data from multiple locations and years whenever possible and should consider the impacts of these conditions on the grower’s fields.

Roundup Ready® 2 Technology contains genes that confer tolerance to glyphosate. Glyphosate will kill crops that are not tolerant to glyphosate. Channel® and the Arrow Design® and Seedsmanship At Work® are registered trademarks of Channel Bio, LLC. Herculex® is a registered trademark of Dow AgroSciences LLC. LibertyLink® and the Water Droplet Design® is a trademark of BASF Corporation. Respect the Refuge and Corn Design® and Respect the Refuge® are registered trademarks of National Corn Growers Association. Bayer, Bayer Cross, RIB Complete®, Roundup Ready 2 Technology and Design™, Roundup Ready® and SmartStax® are trademarks of Bayer Group. All other trademarks are the property of their respective owners. ©2022 Bayer Group. All rights reserved.

This browser is no longer supported. Please switch to a supported browser: Chrome, Edge, Firefox, Safari.