Areas that experience heavy growing season rains may experience nitrogen loss through leaching. Heavy rainfall and rapid drainage can move nitrates below the root zone. This can significantly impact plant performance, according to LG Seeds Agronomist Justin Schneider.

Rainfalls of 5-plus inches in a few-week period, such as those experienced in the Upper Midwest, are a common cause for leaching. Schneider recommends that farmers watch for a dull green color that signals nitrogen stress. Don’t assume that yellowing corn is caused by nitrogen depletion. That is not typically the case. Soil nitrate testing and leaf tissue testing are other tools available.

Corn uses half of its nitrogen after it tassels. This gives farmers options to add supplemental nitrogen. One method is to use Y-drops or drop nozzles on self-propelled sprayers. Nitrogen can also be added to fungicide applications.

Read more on scouting for nitrogen deficiency here.