Field-tested findings

Planting started earlier than ever for MFA’s 2024 agronomy research trials, with the first variety plot going in the ground on March 29. Our test sites in Boonville and Columbia were not planted this early, but the variation of seeding dates across our trial territory gave us a great opportunity to test planting timing on soybeans. We achieved some record yields in both corn and soybeans last year, and this success was greatly impacted by timely planting that allowed the crops to take advantage of early-season rains.

At these locations, MFA tests both corn and soybean in many ways. In addition to variety plots containing MorCorn, MorSoy, Dekalb, Asgrow, Brevant and NK seed brands, other trials included fungicide timing, seed treatments, nutrient use efficiency products, biologicals, plant growth regulators, fertilizers—including sulfur products—and cultural practices such as planting timing. For this article, we will focus on results of our trials on soybean planting date, fungicide applied by drone, enhanced soybean management and basic corn management.

Site Management

Our research site at Boonville is 14 acres of a corn-soybean rotation. The corn was planted on May 20 at a rate of 32,500 seeds per acre. The corn was fertilized with SuperU at planting with 280 pounds of actual nitrogen per acre. Since this is a high-yielding test site, we push nitrogen fertilization in an attempt to eliminate the possibility of N being a limiting factor that affects yield. The soybeans were planted on May 30 at a rate of 140,000 seeds per acre.

The site east of Columbia is 27 acres of a corn- soybean rotation. The corn was planted on May 31 at a rate of 32,500 seeds per acre. The corn was fertilized with 180 pounds of actual N per acre with SuperU. The soybeans were planted on May 30 at a rate of 140,000 seeds per acre.

At both sites, all our corn plots were planted with MorCorn 4457, except for variety trials. This has been the standard corn hybrid for our research for some time now. This allows us to compare results from trials conducted over the years more effectively because we don’t have to count for varietal difference in the results. Likewise, we used a single variety, MorSoy 3965 XF, across all soybean trials, except for variety testing. The soybeans were treated with CrusierMaxx Vibrance.

All trials that include treatment of fertilizer are excluded from bulk field applications and are spread by hand. Both fields were worked prior to planting.

Soybean Planting Timing

For the 2024 planting timing trial, we tried to get soybeans in the ground as early as soil conditions allowed at the east Columbia site. We were able to start in March and plant every month all the way through July, targeting a three-day window before or after the 15th of every month and choosing the best planting conditions inside that window. We ended up planting on March 13, April 15, May 13, June 12 and July 15, using MorSoy 3965 XF and MorSoy 4623 XF, both treated with CruiserMaxx APX seed treatment. The seeding rate was the same across all planting timings and varieties at 140,000 seeds per acre. 

Figure 1A shows the yield from each variety at each planting timing. There was no statistically significant yield advantage from one variety over the other at either timing. However, numerically MS 3965XF did have the highest average yield, though comparisons in Figure 1A indicate MS 4623XF has more consistent yield from planting in March and April.

Since variety was not significant, the variety data was combined to focus on comparisons between planting timing. Figure 1B shows a peak in April, when we achieved the highest average yield of 73 bushels per acre followed by March and May with 66 and 63 bushels per acre, respectively. Yield falls off drastically after this at an average of 40 bushels per acre when planting in June and 15 bushels per acre in July.

While this study is a repeat of the 2023 study, the planting window was much wider. In 2023, field conditions only allowed us to plant April 13, May 4 and June 1 due to cold temperatures in March and lack of soil moisture in July. That year, our highest yield was 42 bushels per acre coming from planting on May 4. Rainfall totals also indicate that 2023 was much more difficult compared to 2024. This past year, we had almost 12 inches more rainfall from March 1 to Sept. 1. This explains most of the yield gap between years, but it does not explain why our earliest planting yielded less both years. In 2023 and 2024, we had eight days that were below 40 degrees, and of those eight days, two days were at or below freezing. These cold events led to stand thinning that impacted yield. Our average last day of frost, around 36 degrees, for Missouri can range from April 9 in the Bootheel to April 30 in northern Missouri. Taking advantage of earlier planting windows when weather is nice can pay off, as we saw this past year. That said, spreading the risk over several planting dates is more ideal than making one single planting early.

Fungicide Applied by Drone

For the first time, we had space, time, equipment and licensing to pull off some small-scale strip trials using our drone. While this is a proof of concept, and more work is needed, our first trial run has allowed us to see the same results as our previous data would suggest. This trial was set up differently than our traditional research plots and was only at the Columbia location due to its size. In the trial, we looked at Trivapro fungicide on corn compared to other tank-mix partners, including Powershot adjuvant and Gold Advantage Trend-B foliar fertilizer, as shown in Figure 2A.

The Trivapro application added 5 bushels per acre, as shown in Figure 2B. Adding Powershot, an adjuvant with both spray deposition aid and nonionic surfactant qualities, added another 3 bushels per acre. Combining Gold Advantage Trend-B, Trivapro, and Powershot added another 4 bushels per acre. While fungicide applications do not always get surfactant in the mix given extra cost, these trials indicate there is a yield and efficacy benefit. This does not mean to add any adjuvant to the tank mix at any growth stage. Read and follow labeled instructions when pairing an adjuvant to a fungicide as some may require another type than a nonionic surfactant. Additionally, growth stage during application is a consideration. Applying any fungicide after V8 and before VT can cause arrested ear syndrome.  

High-Yield Soybean Management

In previous research, we had several trials comparing single products and a few trials on soybeans combining fungicide, insecticide and Gold Advantage foliar fertilizer. While this paved the way to show producers the benefit of these products, I wanted to combine other practices to see the peak yield we could get at our two sites. Further, given the vast difference in growing environments, we wanted to evaluate whether the same products and practices would be comparable. The treatments we devised included an application of ammonium sulfate, fungicide, insecticide, Gold Advantage and some biologicals. The product rate and application timings are in Figure 3A.

With these products, we tried 13 combinations growers might use themselves. Those combinations are listed in Figure 3B. This list is not exhaustive but did allow us to see all treatments alone compared to several combinations to start to understand how these products interact, which ones may be driving yield the most, and whether a certain product combination had added benefits.

The yield results highlight the most advantageous combinations as well as the highest-yielding treatment in the plot as shown in Figure 3C, which includes both research sites combined. Neither research site had heavy fungal disease pressure, and insect infestation was moderate. The Miravis Top, Gold Advantage and Endigo ZCX were the highest-yielding single treatments in the plots, and the two multi treatments listed were the highest yielding of the combinations we tried. In the single treatments, we did not see a profound yield increase from either biological product, Smartfoil or Utrisha N, nor did our application of ammonium sulfate stick out. However, when pushing for top-end yield, we did find Utrisha N and ammonium sulfate helped add 1 more bushel. While this has only been a one-year study, I am interested to see how these combinations fare in subsequent growing seasons.

Corn Management Basics

One of our trials on corn this year was set up to compare management of two different hybrids with differing levels of fertility, along with differing levels of herbicide programs. What we found was that both fertility and herbicide program were significant factors. It’s no surprise that fertility matters, but herbicide selection is crucial as producers plan crops. The herbicide programs and yield in this trial are listed in Figure 4. Seeding rate as well as application date of pre-emergence and postemergence applications were all the same. While fertility and herbicide program were statistically significant, there were no interactions between them or the two hybrids included in this study. The first herbicide pre-emergence application was made the same day as planting. The postemergence was applied 28 days later on June 28. 

The herbicide programs include both single-pass and two-pass programs. The most aggressive program had five sites of action, while the least aggressive program only had two sites. There was a 32-bushels-per-acre increase from the least aggressive to most aggressive program. Not surprising, but while yield was not significantly different among the first three treatments, there is a numerical trend associated with a more aggressive herbicide program with a yield increase.

The concept of having higher yield when controlling weeds is not something new. What should be noted is that herbicide programs must be carefully considered to gain top-end yields and not rely on only a few sites of action. A successful program should be based on what weed species we have and how we can stack residuals to avoid rescue applications. While this data was collected on corn, this same concept applies to soybeans.    

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Click here to hear Garret Imhoff and the agronomy team discuss their research on the MADE FOR AGRICULTURE PODCAST.

CLICK HERE to read the original report as printed in the March 2025 Today's Farmer Magazine.

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