By Rachel Curry and Nicole Haverback et.al
In part one of this series, panelists University of Illinois soil fertility specialist John Jones, University of Illinois agricultural economist Gary Schnitkey, and Illinois Corn Growers Association water quality specialist Laura Gentry at the December Farm Assets Conference explained how the Corn Nitrogen Rate Calculator identifies the profitable nitrogen range.
In the second half of the conversation, the focus shifted to what happens when nitrogen rates exceed that range and what farm-level data reveals about those decisions.
The “insurance nitrogen” mindset
Drawing from data collected through Precision Conservation Management (PCM), Gentry explained that many farmers apply nitrogen above the MRTN rate. In some years, average nitrogen applications have exceeded MRTN by 25 to 40 pounds per acre.
While those additional pounds are often viewed as “insurance,” Gentry noted that the MRTN model has consistently predicted profitable nitrogen rates in the years she reviewed. In fact, she emphasized that it has not underestimated the nitrogen rate needed to maximize economic return. “It’s a conservative estimate,” she said, meaning it is unlikely to result in under-application. Schnitkey said that when farms spend more than necessary in one area, they often do so in others, too, such as making extra field passes or adding more inputs, which raises overall costs.
Source : illinois.edu