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Take care when applying spring NTake care when applying spring N

Seedlings can be injured if you are not careful.

February 24, 2017

2 Min Read
CORN SEEDLING INJURY: If you plan to make spring nitrogen applications, agronomists say there are several factors to keep in mind.Sportactive/iStock/Thinkstock

There is the potential for seedling injury when anhydrous is applied just ahead of planting, according to DuPont Pioneer agronomists.

When anhydrous ammonia leaves the knives of the toolbar, it expands from the point of injection in all directions 2½ 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 or seedling by either time or distance reduces this risk of injury. A good rule of thumb: Wait to plant at least three to five days after an ammonia application.

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 or 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 should 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.

Source: DuPont Pioneer


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