Sidedressing nitrogen applications can be a great complement to preplant, and, is a recommended practice from The Fertilizer Institute’s 4R nutrient stewardship program. Specifically, sidedress applications allow for fine-tuning of preplant nitrogen rates and provide additional nitrogen when the crop needs it the most.
Sidedress, though beneficial, can be a fickle process if not done correctly. Soil type, previous nitrogen applications and weather conditions impact the how, what and when of sidedress. Despite that, here are some best practices to keep in mind as you and your customers consider sidedress application this year:
Conduct a pre-sidedress soil nitrate test
This test can confirm how much nitrogen was lost due to volatilization, leaching or denitrification after preplant and/or fall fertilizer applications so that more nitrogen can be applied at the right rate. It is recommended to sample the soil when corn is 6 to 12 inches tall, or in late-May to early-June. Sample areas that are similar in texture and 10 to 20 acres in size. This test works best if farmers avoid previous fertilizer application bands, including starter and anhydrous ammonia bands. Tests should also consist of 15 to 20 cores per sample.
Apply a readily available nitrogen source at the right time
Urea Ammonium Nitrate (UAN) and urea are two of the best options for sidedress fertilizer because they are readily available to the plant after application. UAN (28% or 32%) can be dribbled on the soil surface or injected into the soil between rows and dry urea can be applied broadcast. Iowa State University Extension research shows that maximum nitrogen uptake in corn occurs between V9 and V18. Nitrogen applied prior to V9, V4 through V6 preferably, has shown to be one of the most effective ways to ensure corn can take up the maximum nitrogen after V8.
Protect sidedress nitrogen from volatilization
Though urea and UAN are preferred sources for sidedress applications, they are immediately vulnerable to loss through volatilization. Specifically with dry urea, at least 0.5 inches of rain is needed within 10 days after application for proper incorporation. A nitrogen stabilizer that protects against volatilization, such as PinnitMax™, is recommended to ensure that the nitrogen gets to the root zone and doesn’t escape into the air. PinnitMax prevents volatilization of urea and UAN for up to 14 days, protecting nitrogen until incorporation, and the formulation is user-friendly and easy-to-blend. The ultra-low use rate and easier handling of PinnitMax also improves operational efficiency by cutting processing time, increasing treated acres and enhancing inventory management.
Find more information on how to keep nitrogen where it belongs and protect against volatilization during sidedress by visiting NitrogenMaximizers.com.
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