Timing of Nitrogen Sidedress Application in Corn

Trial Overview

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  • There is substantial interest among farmers in mid-season nitrogen (N) application.
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  • N uptake by corn plants is usually greatest from V8 (8 leaf collars) growth stage through pollination and is weather dependent.
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  • Adequate N from V5 (5 leaf collars) through V8 growth stages can be critical as the plant is determining the number of potential ears and ear girth at this time. 
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  • Sidedressing can help minimize N losses because N is applied closer to the time of plant uptake.
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  • N is a significant input cost. Determining when corn responds best to N sidedress application timing might contribute to maximizing net return.
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Research Objective

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  • The objective of the trial was to evaluate different timings for N sidedress applications.
     
     
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Location
Soil Type
Previous Crop
Tillage Type
Planting Date
Harvest Date
Potential Yield
Planting Rate
Monmouth, IL
Silt loam
corn
conventional
04/26/2016
09/20/2016
240 bu/acre
36,000 seeds
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Site Notes:

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A 114 relative maturity SmartStax® RIB Complete® corn blend product was planted in all treatments. 80 lbs/acre of 32% UAN (32-0-0) was applied before planting in the spring and incorporated for all treatments. 100 lbs/acre UAN with a urease inhibitor was sidedressed using a high-clearance sprayer with 360 Y-DROP® at three different corn growth stages. Treatment timings were:
        - V4 (4 leaf collars) on June 3, 2016
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        - V8 (8 leaf collars) on June 21, 2016
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        - V12 (12 leaf collars) on July 5, 2016
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Understanding the Results

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Figure 1. Average Yield by Timing of Sidedress Application.
2016 Monsanto Learning Center at Monmouth, IL.
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  • Sidedress application at the V8 growth stage had the largest yield response in this study.
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  • High clearance equipment with 360 Y-DROP® allows application timing flexibility and allows later application of N in taller corn.
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What Does This Mean for Your Farm

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  • Ideal later season N application timing could vary from year to year due to weather and environmental conditions. 
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  • Individual seed products may respond differently to timing of N application. Consult your local DSM or Technical Agronomist for timing recommendations.
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  • All costs should be considered when making N management decisions, as yield differences due to N sidedress applications may not be economically justified in all cases.
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