Time to Turn the Water on in Corn

Author: Angela McClure, Extension Corn and Soybean Specialist Comments Off on Time to Turn the Water on in Corn

If you haven’t watered corn yet this week, you may want to think about doing so.  We have been blessed with an abundance of rain that has helped support corn development, and little irrigation has been needed.  High temps mean water demand is higher too, and it is critical to not get behind on watering corn.  Earliest planted corn is close to tasseling or tasseling which is peak demand time.  Suggested irrigation amounts are listed below for corn for those using the ‘checkbook’ method of applying water. The ‘checkbook’ method of irrigating is not high tech, but can supply water needs of the crop pretty well as long as you check growth stage regularly (don’t guess– go look at the crop!), keep up with rainfall and subtract rain received from total water needed each week based on crop stage.  Obviously, if you have sensors and/or are using MOIST or another irrigation scheduling program, keep following the recommendations provided by the scheduler.

Growth stage Importance Est. crop water use
V9 – V12 Rapid vegetative growth 1.75”/wk
V12 – V17 (almost tasseling) Ear length determined 2.0”/wk
VT – R2 (blister) Ear size potential 2.3”/wk
R3 (milk) – R6 (black-layer) Grain filling period 1.75”/wk*

* If water needs have been kept up with during grain fill you can back off on water to about 1.5″ per week when kernel milk line reaches about 3/4 way down the kernel meaning crop is close to reaching physiological maturity or ‘black layer’.



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