Spring Nitrogen Applications

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If you plan to make spring nitrogen (N) applications, there are several factors to keep in mind.

There is the potential for seedling injury when anhydrous is applied just ahead of planting.

When anhydrous ammonia leaves the knives of the toolbar, it expands from the point of injection in all directions 2 ½ to 3 inches, leaving a 5- to 6-inch cylinder of N (expansion can be greater in dry or coarse soils). Free ammonia in this band can damage or "burn" seeds and/or roots by removing water from the plant tissue. Separating the ammonia from the seed/seedling by either time or distance reduces this risk of injury. A good rule of thumb: wait to plant at least 3 to 5 days after an ammonia application.

Photo: Corn seedling injury

An additional waiting period may be beneficial if the following conditions occur:

  • If NH3 applications are made when the soil is wet because the knife creates sidewall compaction. This forms a channel for the NH3 to move up to the seed zone before getting absorbed by the soil.
  • In dry/sandy soils, ammonia (in search of water) can diffuse further into what will become the seed zone.
  • Shallow NH3 applications of 6 inches or less can increase injury because the placement is closer to the seed.
  • In any of the above circumstances, increasing the number of days from NH3 application to planting will help reduce injury.
  • Consider planting at a slight angle from the NH3 application direction when possible. Doing this can help reduce the number of plants that may be affected if ammonia burn would occur.

Consider Additional Steps

There are additional steps growers can take to help ensure that adequate levels of N will be available for maximum crop yield. These include:

  • Add an N stabilizer such as N-Serve® and Agrotain®.
    These can help keep anhydrous ammonia and urea in more stable forms by reducing microbial activity that converts these N sources into less stable forms.
  • Add an N stabilizer such as ESN®, Environmentally Smart Nitrogen.
    ESN is another type of N stabilizer which encloses N in a patented polymer membrane and releases the N as soil warms. This time release method is an alternative way to reduce N losses due to volatility.

N-Serve® is a registered trademark of Dow AgroSciences.

Agrotain® is a registered trademark of Phosphate Resource Partners Limited Partnership and is licensed exclusively to AGROTAIN Int'l. LLC.
ESN® is a registered trademark of Agrium Advanced Technologies.
Use this information as a guide and it should not be the only factor in making decisions.