Crop stress associated with nitrogen deficiency is showing up in some fields in the Midwest.

Tracy Blackmer, an Iowa farmer who is director of research for the Iowa Soybean Association, recently talked with Neil Trobak of KCIM in Carroll, IA about the situation.

“We do a lot of field research projects around the state focusing on nitrogen in corn,” said Blackmer. “Last year we had over 250 replicated nitrogen trials that we collected yield data on and over 1000 fields that we evaluated with aerial imagery and stock nitrate.”

It has been a wet spring in Iowa and Blackmer says one of the biggest issues with nitrogen management is the amount of spring rainfall. “When you have enough rain to move the soil profile, the nitrate will leach out with that water.”

With rainfall this spring in western Iowa well above normal, Blackmer says they have seen a lot more nitrogen stress in corn fields than normal, which means growers should be doing late spring soil tests and monitoring their crop carefully.

“Aerial imagery is one of the better tools that will let people evaluate the entire field at one shot,” he says. “Nitrogen stress doesn’t show up uniformly across the field and an aerial image will let you look at the entire field and see any small part of it at any point in time.”

Blackmer says John Deere’s OptiGro system is one tool that provides aerial imagery and processes it so a grower can see the amount of N-stress in the field and exactly where it is located. “So a grower can go in and actually go in and correct the N-stress with equipment at any point in the field.”

“With the high price of corn right now, this is something people really want to watch closely for the bottom line.”

More information about OptiGro can be found on-line from www.johndeereagriservices.com.

KCIM interview with Blackmer (4:30 min mp3)