Tassel Time

Tassel Time from Central Valley Ag on Vimeo.


by Keith Byerly

As I look across Cornfields, I see tassels becoming more prominent every day. Pollination time is here, and it’s without a doubt one of the most critical times in our corn plants life. During this stage, our water use begins its peak for the season. It is also one of the most key times of the year when stress can significantly affect yield.

All season long I have been adamant about using your moisture probes to make decisions with your irrigation scheduling. You will never hear me say anything to the contrary. And there have been times when I have gotten up on a soapbox and challenged those that wanted to irrigate. I said “don’t do it, a little heat stress isn’t a huge yield-robbing factor.” “Don’t do it, you could affect your rooting action.” “Don’t do it, there is plenty of moisture in the profile right now.” And I will stand here and defend every statement that I have made thus far in the season. My guys out there that have done no more irrigating than what they needed for chemigation are no further behind than those that have been around 3+ times.

Al that being said, different times call for different actions. I am going to tell you something that I am not overly confident in saying. Over the next 10 days, its ok to let stress conditions override what your sensors are saying to do. While it seems like that is a bit of a no-brainer statement to make, believe me it doesn’t come lightly. Here are some reasons why I think I can say this now…

Root development is done.

Once we reach the end of our vegetative development and begin the reproductive stages, the corn is done adding roots as well. Irrigation will no longer affect our root zone development, just our active root zone. This means that a more frequent, low volume application that only affects the 4-8” root zone is fine. Our only real risk is that it limits our ability to hold a rain.

This is a short term strategy.

When I say that you can let stress be a determining factor in deciding when to irrigate, I mean you can use this strategy for a few days. Like a couple days before pollination begins to the end of silk emergence. If you have your planter working properly, this should be less than 2 weeks total. Not 10 weeks, 10 days. I don’t want to see this strategy used the rest of the season. I mean it. We can do better the rest of the year.


Of course, this all assumes we are going to have a hot, dry pollination period. If we have more mild temperatures, I want you to forget that you have even read this. In fact, if we get through pollination and the temp never goes above 85, I am going to deny ever putting this out there. But if we get into the 90’s, it is time to scout. Don’t just probe for moisture, pay attention to what your plants are saying. Look to your dryland corners and acres first for those signs of stress, and then put a plan together.

In the end, the goal of AquaSystems is unchanged. We still want to grow the most profitable corn crop we can with the appropriate irrigation to do so. If your local ACS Specialist is hosting an AquaSystems meeting, make sure you carve out time to go. The interactive nature with your neighbors and others who care about using water effectively brings a lot more opportunities for learning and growth than if we just talk to you on a one on one basis. Remember, managing stress is a short term strategy. Managing the water in our soil profile is what yields success.