Research has been conducted on foliar fertilization of corn over the years, but not overly extensive in Iowa. One reason has been the lack of positive results when studies were conducted. Looking at data from the early 1970s to recent years I don’t find cases where foliar fertilization produced positive yield responses. An example is a study we conducted in 1999 with foliar application of low-biuret urea and mono-potassium phosphate at four growth stages from V6 to VT. There was no yield response with urea application, but a statistically significant yield decrease of 5 to 6 bu/acre with mono-potassium phosphate application. Results of recent university trials that I’ve seen with foliar fertilization have not indicated positive response. I have also on occasion received input from producers about corn growth problems related to foliar fertilizer applications.
Available at: http://works.bepress.com/john-sawyer/91/