Stressful conditions have taken the top end off yield potential and caused a great deal of variability in Iowa corn fields this year, agronomists report as farmers gear up for harvest.

“This is not the same crop as the last two years, but we’re sitting in pretty good shape considering the environment we’ve had this year,” said Mark Licht, Iowa State University cropping systems specialist. “What we’re finding is there’s a fair amount of variability within a field and...