February 19, 2020
TRIAL OBJECTIVE
The objective of this study was to characterize the yield response and harvest appearance of different corn products to nitrogen (N) stress.
RESEARCH SITE DETAILS
Sixteen DEKALB® corn brand blends were used in this study, an early relative maturity (RM) set (97-113 RM) and a late RM set (108-115 RM).
The trial was set up as a split-plot design at each location with N rate as the blocking factor with 2 replications.
Plot size was 4 rows at 30-inch row width, 35 feet long, and the center rows were harvested for data.
Planting dates were near normal in the southern part of the state while slightly delayed across Northern Iowa.
Nitrogen was applied before V3 stage. See the table above for N rates.
UNDERSTANDING THE RESULTS
Yield differences between products when grouped at the low N rate were not different statistically. The same was true of the high N rate.
Products displayed N deficiency symptoms at the low N rate during most of the season.
Yield differences within N rates can be attributed to germplasm by environmental interactions.
Physical plant integrity i.e. harvest appearance of products at the high N rate aligned with the product guide rating. However, harvest appearance was slightly worse for products at the low N rate.
KEY LEARNINGS
This study could not confirm that there are differences in product sensitivity to either a yield-limiting low N rate or a crop-sufficient high N rate.
This study suggests products have similar response to N rate; however, supplying adequate N and monitoring N losses is important for the best return on investment.
Understand that environmental conditions such as seasonal rainfall, soil type, and temperature that can affect crop-available nitrogen.
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