It’s been a long irrigation season thus far, but we are so thankful for irrigation in this part of the Country during this drought of 2012!  Questions continue to roll in regarding last irrigation for corn and soybeans.  Corn at 1/2 starch only needs 2.25″ to finish up so it’s important to know what your soil moisture status is.  For most irrigated producers, at 1/2 starch, you should be finished irrigating.  

For soybeans at R5 or beginning seed fill, you still need about 6.5″ to finish out the crop.  At R6 when the seeds are filling, that drops to 3.5″.  At R7 when you begin to see leaves yellowing, that is beginning maturity and you are finished irrigating.  They key is we don’t want to fill the profile going into the fall as we’d like to replenish the profile with fall and spring rains and winter snow.  However, with soybeans, it’s also critical not to stop irrigating too soon during seed fill.

Gary Zoubek, Extension Educator in York County sheds more light in the following video produced by UNL’s Market Journal.