Plan to Optimize Sidedress This Season

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3 Key Takeaways from This Article:

- Sidedress applications for nitrogen are a great way to ensure proper nutrition for corn.
- Test your customer’s soil when the corn is about 6 to 12 inches high.
- Apply sidedress prior to V9.

We know the world has changed rapidly over the last few months and that your way of doing business has likely changed as a result. Our hope is that Inputs & Insights can continue to serve as a guide for you to help your customers as everyone navigates the challenges ahead.

Depending on what this spring has been like in your area, you may have decided sidedress fertilizer applications will be needed for your customers. Sidedress applications are often necessary if the weather is not cooperative for a preplant spring fertilizer application.

For example: If there is too much rain, or if the soil is too wet, nitrogen will be vulnerable to leaching if applied. In addition, your growers may simply prefer a split application: applying some of their nitrogen preplant and then again during sidedress, which is typically around the late May to early June time frame.

When done correctly, sidedress can help ensure proper nutrition for corn precisely when the plants need it most.

The process is also recommended as part of The Fertilizer Institute’s 4R Nutrient Stewardship program.

First: Test the Soil

A pre-sidedress soil test is essential to make sure you apply only the necessary nitrogen to the corn crop.

Here are some good rules of thumb to follow:

  • Test when corn is 6 to 12 inches tall (typically late May to early June). 
  • Sample areas that are similar in texture and 10 to 20 acres in size. 
  • Avoid sampling from previous fertilizer application bands. 
  • Tests should consist of 15 to 20 cores per sample. 


Second: Apply at the Right Time, the Right Way

UAN, urea and anhydrous ammonia are all great options for sidedress fertilizer. That’s because they’re easily accessible to the plant after application. You’ll want to perform applications prior to V9 to ensure the best uptake for corn. Applying from V4 to V6 is ideal.

Anhydrous ammonia can be easily lost if soil conditions aren’t right or the application isn’t precise. So, when knifing anhydrous into the soil, make sure to fully close the openings to keep it from escaping. Make sure soil is not damp or clumpy when applying anhydrous.

Last: Protect Sidedress Nitrogen

Last, but certainly not least: It’s advisable to protect sidedress fertilizer applications with a nitrogen stabilizer. Urea, UAN and anhydrous ammonia are all immediately vulnerable to loss through leaching and denitrification. Instinct® nitrogen stabilizer will protect urea and UAN. N‑Serve® nitrogen stabilizer will protect anhydrous ammonia.

Visit to learn how Instinct and N-Serve work to keep nitrogen in the root zone. Good luck to you and your customers this season.


™®Instinct is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Do not fall-apply anhydrous ammonia south of Highway 16 in the state of Illinois. Always read and follow label directions.