DEKALB® Brand Corn Product Response to Nitrogen in Iowa
February 2, 2021
TRIAL OBJECTIVE
Nitrogen fertilization plays an important role in maximizing the yield potential of corn products.
Nitrogen is responsible for many soil fertility and crop nutrition studies with emphasis on finding the right rate, timing, source, and placement.
The objective of this study was to characterize the harvest intactness and yield potential of fourteen DEKALB® brand corn products to nitrogen fertilization. Nitrogen rates were selected to induce both nitrogen stress and excess nitrogen.
Such information can assist growers in making management decisions to help maximize profitability.
RESEARCH SITE DETAILS
- The nitrogen rate treatments tested in this trial included:
- Low: 30 lbs/acre for corn-soybean rotation or 50 lbs/acre for corn-corn rotation.
- Medium: 200 lbs/acre for corn-corn rotation (Huxley only).
- High: 230 lbs/acre for corn-soybean rotation or 240 lbs/acre for corn-corn rotation.
All nitrogen applications were made before planting.
Fourteen DEKALB® Brand Blend corn products were tested in this trial. Products were broken into an early maturity set (North set planted at Storm Lake and Huxley, Iowa) and a late maturity set (South set planted at Huxley and Atlantic, Iowa).
The North Set included DKC47-54RIB Brand Blend, DKC49-44RIB Brand Blend, DKC52-18RIB Brand Blend, DKC54-64RIB Brand Blend, DKC56-65RIB Brand Blend, DKC58-64RIB Brand Blend, and DKC61-40RIB Brand Blend.
The South Set included DKC58-64RIB Brand Blend, DKC59-81RIB Brand Blend, DKC60-80RIB Brand Blend, DKC61-41RIB Brand Blend, DKC62-89RIB Brand Blend, DKC63-90RIB Brand Blend, DKC64-64RIB Brand Blend, and DKC66-18RIB Brand Blend.
The trial was planted using 30-inch row spacing, with four rows per treatment, and 45-foot long plots with two replications.
The Huxley, Iowa site was in the path of the August 2020 derecho; therefore, yield data are not presented for this site.
UNDERSTANDING THE RESULTS
Figures 1 through 14 show the pictorial characterization of the ears of each product at the Huxley trial which had nitrogen rates of 50, 200, and 240 lbs/acre. Images were taken of representative ears for each plot prior to deterioration of the plot due to the derecho storm event.
In this trial, average grain yields were substantially higher for the high rate except for DEKALB® DKC59-81 Brand Blend in which yields were nearly the same at both nitrogen rates at Storm Lake, Iowa (Figure 15).
KEY LEARNINGS
Nitrogen status in the soil is a dynamic and complex phenomenon that is greatly impacted by the weather during the growing season, the soil type, and the inherent fertility of the soil. Thus, a plant’s response to nitrogen can be complex as well.
Even at low nitrogen rates, there were average yields of 191 and 189 bu/acre at Storm Lake and Atlantic, Iowa, respectively. This indicates the fields were of high fertility and should be sustainably managed to avoid nitrogen loss to the water system.
At the current market trend of $0.34/lb of nitrogen and $4.00/bu for corn, a minimum of 17 bu/acre is required to pay for the difference between the low and high nitrogen rates. Therefore, all products were profitable at the Atlantic location. At Storm Lake however, high nitrogen rate was not profitable in DKC52-18RIB Brand Blend.
- Corn products respond differently to farm inputs and they should be assessed on a small scale before they are deployed for the whole farm.
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