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  • Writer's pictureRachel

In Pursuit of High Yield Corn

High Yielding Corn

If I had to guess, pursuing higher yielding corn is a goal for most of you. Who doesn’t want to see those numbers on the yield monitor? While many of your may include some economic threshold in that goal, I doubt any of you would turn down 400 bushel corn. So, what does it take to get there? What are the National Corn contest winners doing to push them over that 500 bushel threshold? What can we learn from their management practices to apply to our operations? This blog will cover some of the most impactful factors in pursuit of high yield corn, and then focus on some of the factors that we have the most control over. Read along to see what areas you are doing well in, and what areas you could start focusing on more.

Change in Corn Yield

We’ve seen a dramatic increase in grain yields since the 1960’s. In fact, the national average has increased over 100 bushels per acre since then, so what has changed? While a host of things have contributed to this shift, some of the major factors include increasing plant population, higher yielding hybrids, and more intensive management. As the nationwide average continues to increase, what factors are going to play in to that growth?

7 Wonders of the Corn Yield World

A researcher from the University of Illinois, Fred Below, outlines what he calls the 7 Wonders of the Corn Yield World. These are the 7 factors that he thinks have the most impact on our pursuit of high yields. Additionally, he has grouped these factors in order of importance and impact on total yield. I’ve listed his order of the 7 wonders below with his projected impact.

We’ve spent quite a bit of time addressing those same topics over the years. A lot of the in-field research we do is spent comparing treatment differences in some of those very categories. Of course, not all of them are in our control. We saw that the last two years with dramatic impacts by weather on our yield. Even intensive management can’t make up for the effect weather had on our yields. That is an important point that Below makes. The items higher up on the list have lasting impacts on the ones below them on the list. Weather dramatically impacts our nitrogen supply and availability. And even when we have good weather conditions, the best hybrid in the world will not be able to perform well with a lack of nitrogen. So, you can see how the order of these 7 wonders is important to their overall impact.

I want to spend a few minutes discussing some of the factors (that we can control) that we have spent time researching and focusing on the last few years. Let’s get started.


We all know the importance of Nitrogen to crop growth and development. And recently we’ve spent more time thinking about split nitrogen applications. Not only is this an economic benefit—we aren’t losing costly N applied in the fall during the winter and spring months—but it’s also more optimum for plant health. Corn doesn’t need its main supply of nitrogen until its latter vegetative stages and early reproductive stages. During that time, for a 230 bushel yield goal, the plant takes up nearly 7 lbs of nitrogen every day—for 3 weeks straight! It’s a dramatic advantage to have the nitrogen readily available to the plant during that time period. One of the best way’s do to that is to provide a split application of nitrogen. A base amount of N will go on in the fall or early spring, with the remaining applied as side dress in the middle vegetative stages, or later stages with a high clearance applicator or aerial application. Not only do we have a more economically optimum nitrogen rate, we also lose much less total N by splitting applications for when the plant needs it the most. Have you taken any steps to split your N applications? What do you feel is your biggest barrier to split applications?

Plant Population

This is probably one of the topics we spend the most time researching and planning for. We spend time each year preparing variable rate seeding maps with the goal of tailoring the right seeding rate for the soil in each part of your field. But we want to make sure these rates are correct. That is why you may notice that we include some check blocks to test the rates for accuracy in select fields each year.

An increase in plant populations played a major role in the increase in corn yields from 1960’s onward. In fact, populations increased from around 16,000 seeds per acre to nearly 32,000 seeds per acre. Many of the national yield winners are pushing populations of nearly 50,000 seeds per acre. Now, we understand that those are fairly unique situations and not the answer to increasing yields across all your fields. However, if we could find portions in each of your fields where it was feasible to increase populations and consequently increase yields, wouldn’t that be of benefit? That is a major advantage of variable rate seeding: the ability to increase populations where possible and the ability to back off populations to a more economic rate in portions of the field that can’t handle the stress or load of higher populations. We can make site specific decisions.

Curious what our results have shown? Our 2018 population studies are posted on the website. Remember that results are specific to year. In 2018, our optimum population as 30-34k. However, this may not be the case in other years. Look for future studies covering this topic and possibly adding in groupings by soil type and weather conditions.


This is another topic that we have studied for several years now. Fungicides have the obvious benefit of protecting against fungal diseases like gray leaf streak, northern corn leaf blight, or common and southern rust. In fact, we’ve seen results ranging from 2-22 bushel per acre increase over the last three years for fields treated with fungicide. The average across those years was 9.6 bushels, with disease levels described as moderate in two of the years, and low in one of the years. The potential for a dramatic return on investment is there in years with moderate to heavy disease levels. What about in the years with lower disease levels? Do we see as good results then? The results are mixed. Some locations we still get a dramatic yield increase. Others, the results are negligible. So, what is going on in low disease pressure years? It seems as if the fungicides do a good job of preserving leaf greenness. This in turn helps keep photosynthetic rates up and improves overall yield. This is largely anecdotal evidence. We hope to conduct some more research with fungicides in locations with lower disease rate. Based on what we’ve seen so far, fungicides are a critical part in reaching toward that high yield goal.

Fertility Recommendations

Fred Below makes the point that as we increase plant population, our root size decreases, and suggests that current recommendations are not tailored to the current genetics we have and the decreased root absorption size. This is a good point to consider. Have you changed your fertility practices as you’ve changed your population and hybrid management strategies? If not, it might be time to consider the rates you are applying as you are pursuing higher yields, as well as the placement location. With smaller root systems, applications closer to the rooting zone will be of benefit.

It’s something that we have seen with our Potassium rates throughout the years. Typical threshold levels suggest we often have sufficient levels. However, our research has shown that applying additional K has been of benefit and resulted in increased yields. While we can’t pinpoint why, it does serve as an example of how our fertility levels need to become more adaptive as we pursue the next big goal.


Without going too much in to it, we believe we are selling seed with the highest level of technology and best genetics on the market. We can stand behind it, because we believe in the meticulous process that has been taken to get the best quality seed to you. But besides that point, no matter what type of seed you are planting, our genetics have drastically improved over the years. Each seed has yield potential higher than ever before. Be sure to be discussing with your seed dealer the optimum hybrids for your acres—some will be more tailored for your high yielding acres and some for more defensive positions. Be sure to plan with them where each hybrid is best suited to ensure you are picking the best option for shooting for that high yield scenario!

Planting Date

We all know that planting date matters. And that sometimes we just have to play the hand we are dealt. But if possible, pushing planting date into the target windows identified by Pioneer as April 16 for the Central Corn Belt, and April 30th for the Northern Corn Belt preserved maximum yield potential. Past those windows, yield began to drop off, with as much as a 7% yield reduction four weeks after the optimum window in the Central Corn Belt and 15% yield reduction in the Northern Corn Belt. Timeliness matters!

Management Practices with the Greatest Response

While its hard to say what practices will bring about the largest response in yield, we can generally prioritize these topics mentioned higher on our “to-do” list. Take some time to test out which of these management practices are providing you the biggest change and then start incorporating them into your operation. Interested in testing some of these practices out on your farm? Contact one of the team to help you set up a study! Here’s to your next big yield goal, whether that is 200, 300, or 400 bushels.


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