So you've gotten back the results of the cornstalk nitrate samples collected this fall. Now, what do the results mean? The stalk nitrate test is based on the concentration of nitrate-N in the lower cornstalk (8-inch segment from 6 to 14 inches above the ground) when the plant reaches maturity (ISU Extension publication PM 1584, Cornstalk testing to evaluate nitrogen management). In general, as the amount of plant-available N in the soil during the time period before plant maturity increases, nitrate in the lower stalk increases. However, the stalk nitrate-N concentration can be greatly influenced by other external and internal plant factors.
Iowa State University
Sawyer, John E., "Cornstalk nitrate interpretation" (2006). Integrated Crop Management News. 1353.
The Iowa State University Digital Repository provides access to Integrated Crop Management News for historical purposes only. Users are hereby notified that the content may be inaccurate, out of date, incomplete and/or may not meet the needs and requirements of the user. Users should make their own assessment of the information and whether it is suitable for their intended purpose. For current information on integrated crop management from Iowa State University Extension and Outreach, please visit https://crops.extension.iastate.edu/.