By Joel DeJong

I love basketball season. Like many tall northwest Iowa natives, tournament time still brings me a sense of excitement. Recently, I was asked to talk to a group of farmers about managing corn production in a year when margins are very narrow. While preparing for that presentation, I started thinking about how to profit when you don’t have all the great resources that others might have available, and I started looking at it from the perspective of a college basketball coach.

Which coach? Pete Carril, who spent many years coaching at Princeton. He developed the Princeton offense. Carril coached there for 29 years and compiled a 514-261 (.663) record. He was the only coach to win 500 games without the benefit of athletic scholarships for his players, so you know he wasn’t able to recruit the best pure athletes. All his players could dribble, pass, shoot from outside, screen and post up inside — very solid fundamentally. The Princeton offense was based on continual movement and adjustments to the situation.

I believe Carril was successful because his players did the basics, and did them well. The players worked hard and were very smart about how they played. (Princeton is an Ivy League school.) They were continual learners, and the offense demanded they continuously adapt to the situation occurring in each game, relying on their teammates to work together.

So, what does that have to do with corn planting recommendations in 2017? I believe for successful corn production, doing the basics very well at planting time is most critical. That means preparing well — equipment finely-tuned, high-yielding hybrids selected with defensive traits added to match individual fields, and alternative game plans prepared for those times when the weather isn’t doing what you hoped. Then you have to adjust when the calendar says it’s about time to plant, but the soil conditions do not. Also, keep communicating with your trusted advisers as new situations arise!

3 key considerations
There are three important variables to consider. First is corn planting population. Data from USDA’s National Ag Statistics Service show that our average corn planting population has gone up, on average, about 400 plants per acre per year in recent years. In 2015, Iowa’s average was 31,415 plants per acre as a final stand.

• What population should you plant? Several on-farm corn population trials we’ve conducted in northwest Iowa over time show that yields remain quite flat over a large population range. Often that range is from the lower 30s to the mid- or upper 30s, and some sites actually have similar yields when still in the upper 20s. Farmers choose their own hybrids for these on-farm studies. 

Economics tell us we want a population that is at the low end of that range, if possible. Buying more seed without getting additional yield is costly, and the NASS data shows that, on average, producers are doing that quite well. Like many of you, I also have looked at company data on yield x hybrid x population results. Some hybrids obviously perform better at higher populations, so answering the question “What population should I plant?” is very hard.

I suggest you talk with your trusted seed adviser and consider a couple of questions for him or her. First, can you see the data the adviser has about how this hybrid performs over a range of populations? Is the optimum recommendation he or she is suggesting based on top yield or top economic return? Is the population being discussed the planted population or the final stand information? With more information, together you can make better decisions.

• What about row spacing? NASS data shows the average row width in Iowa is now just a little bit below 30 inches. We all think about increasing populations and ask when the plant-to-plant spacing within the row is too close for optimum yield. Is it time to narrow the rows so the within-row plant spacing can increase? At Iowa State University’s Northwest Research and Demonstration Farm, we now have equipment so we can evaluate this question, but we only have data from two years so far. Our project in 2016 did show about a 9-bushel yield increase by using 20-inch rows instead of 30-inch rows. However, little difference was found in the two studies completed in 2015.

Likewise, two on-farm projects we’ve conducted have shown the same mixed results. Interestingly, the optimum population for the 30-inch rows has been the same as in the 20-inch rows — their response curves look the same. Nevertheless, I believe we will get to a time where it becomes quite obvious that higher plant populations will give more consistent returns in a narrower row spacing. But I’m not sure we are there yet. Again, keep learning.

• What’s the best planting date? The last item I’ll touch briefly on is date of planting. My father was happy when corn planting was completed by May 20. ISU research continues to look at this question annually. Each year is slightly different, but on average, the ideal window for Iowa still appears to be between about April 15 and May 8. Data in different parts of Iowa might be a little earlier for the “ideal” window. However, just because the calendar says it is the right window, if soil conditions aren’t fit, you probably should wait.

Granted, if you are at the end of the window, it becomes very hard to be patient. I also encourage you, during the first part of that window, to review what the short-term weather forecast is for the next few days after planting. If the forecast is cold and wet, imbibitional chilling might reduce your stand, and time gained early might ultimately cost you. That, however, is a topic for a different article.

In summary, think about how you can do the basics very well, what alternative plans you might need for a changing situation, and who you can trust to help you understand the things you do not understand — just like the Princeton basketball team used to do!

DeJong is an ISU Extension field agronomist covering northwest Iowa. Contact him at [email protected].