After conducting two seasons of NUE assessments, UW Discovery Farms has an informative dataset, representative of Wisconsin’s farm systems. As you know, 2015 and 2016 were high yielding seasons. Our data showed yields ranging from 216-246 bu/ac for corn grain and 25-29 ton/ac for corn silage.
Did you witness high yields in 2015 and 2016 and how will this influence your N decisions for 2017?
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As you can see in the graphs above, yields were highly variable and did not correlate with an increase in nitrogen supplied. Since the additional nitrogen in higher rates was not realized as additional gains in yield or N removed in the harvest, these fields tended to have relatively lower NUE values. The graph below represents different categories of N rates, and their corresponding yield (blue dots) and percentage of N removed in the harvest (green bars). As nitrogen supplied increased, average yields remained relatively constant and the percentage of nitrogen removed in the harvest (or NUE) decreased.
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Do you think that there is a limit to the amount of N supplied that would result in a yield increase? Or, do you think that these results are specific to high-yielding weather conditions, like those we had in 2015-16?
To read more about our 2015-2016 findings, please find our March 2017 update: “Fine-Tuning Nitrogen Management” (click here!) and visit back on the WaterWay Network!