Effects of Nitrogen Rate on Corn Yield Potential - DEKALB - Iowa


Trial OverView

This trial was designed to help determine optimum nitrogen rates for new corn products and to demonstrate crop input interaction with specific corn products.

Research Objective

To provide customers with helpful information when considering crop nitrogen needs.

Location Soil Previous Crop Tillage Type Planting Date Harvest Date Potential Yield/Acre Planting Rate/Acre
Victor, IA Silty Clay Loam Soybean Conventional 4/21/17 10/5/17 220-260 bu 35,000



    Nitrogen (N) was applied at rates of 110, 140, and 170 total lbs N/acre as anhydrous ammonia (NH3) applied in the spring 9 days before planting. Corn products were planted into each NH3 zone consisting of six 30-inch rows, approximately 370 feet long with 2 replications.

Understanding the Results


Figure 1.


Figure 1.

Figure 1. Average yield response of 7 DEKALB® corn brand blends at 3 nitrogen rates.


    At this single site in corn-soybean rotation, 140 lbs total N per acre of spring-applied anhydrous ammonia (NH3) provided the most profitable economic response to nitrogen.



Figure 2.Yield response of 3 individual DEKALB® brand blends at 3 nitrogen rates.


Figure 3.Yield response of 4 individual DEKALB® brand blends at 3 nitrogen rates.

What does this mean for your farm?

    Crop response to nitrogen is dependent on several variables such as corn product, soil, and environment.
    Low nitrogen rates can limit yield potential, while excess rates are not beneficial for additional crop response.
    Economic return to each additional unit of nitrogen will depend on grain price and nitrogen price.