How many times have you heard this comment at a field day? “My soybeans look pretty good, but I can hardly find a four-bean pod. I am after top yields, and I want to see more pods with four beans.”
If you have made that comment yourself, are you sure about it? Do you really want more beans per pod if it comes at the expense of smaller beans?
“It’s a catch-22,” says Steve Gauck, a regional agronomy manager for Beck’s, sponsor of Soybean Watch ’24. Gauck is based near Greensburg, Ind. “We always think we want to find as many pods with four beans per pod as we can. It just seems like common sense. In reality, it’s probably a point worth discussing to get a handle on what is really happening here.”
Bean number vs. bean size
Gauck pulled a few three-bean and four-bean pods and made comparisons during his final visit to the Soybean Watch ’24 field this fall, shortly before harvest. One of his comparisons is featured in the accompanying pictures. He wasn’t trying to be scientific or come up with a definitive answer. Instead, he was simply making comparisons to spark discussion.
“We know that one component of high yield is number of beans per acre,” he says. “That is why we want as many nodes per plant and pods per node as possible. Management practices such as planting as early as possible when conditions are right tends to deliver more nodes and pods. The dry spell in June that many experienced this year slowed vegetative growth, but it also tended to produce a shorter distance between nodes, which could lead to more nodes per plant.”
More beans per pod is the next logical goal for top yields, Gauck acknowledges. Good growing conditions throughout the season provide the opportunity for more pods to add an extra bean. In the Soybean Watch field this year, irrigation during dry weather later in the season appeared to promote good pod development near the top of plants, including several four-bean pods.
BIGGER BEANS BETTER? Size differences of soybeans were more obvious when agronomist Steve Gauck combined the beans from the two pods shown in the first picture. Bigger beans tended to come from the three-bean pod.
Here is the flip side of the discussion: “We know that individual soybean seed size also plays a big role in final yield,” Gauck says. “When it turned dry in late August and September in fields without irrigation, seed size suffered in many cases. That’s why yields in very dry areas were disappointing.”
So, in the final analysis, do you want four-bean pods or three-bean pods with bigger beans? “What you really want are four-bean pods with bigger beans,” Gauck quips. “The question is whether there are enough inputs, including water, coming into the plant to make that happen. By experience, we know we can have very good yields even if most pods have three beans. That’s only possible, though, if they are big beans.”
From the field:
‘Variability’ still the name of the game
This week’s soybean season summary comes from Chad Kalaher, a Beck’s field agronomist who has reported on the growing season in eastern Illinois throughout 2024. Like most reports from other states summarizing the season, this one also emphasizes variability in planting, growth and yields, most likely linked to variable weather patterns throughout the region.
In Illinois. “The 2024 soybean growing season across east-central and northeast Illinois can be characterized as highly variable, with most yields better than expected. Most of the soybean crop was planted between mid-April and mid-May, which is typical for the area.
“Many fields experienced heavy rainfall during May. These conditions promoted infection with sudden death syndrome, also known as SDS. Symptoms from SDS started showing up in August.
“June was dry, which allowed for timely postemergence herbicide applications. However, dry conditions limited vegetative growth. Rainfall in early July was welcomed, but this rainfall promoted some white mold infection. This disease became noticeable during harvest in infected fields.
“Many operations completed timely fungicide applications in July. More farmers adopted the practice of adjusting spray water pH for longer fungicide droplet survival and efficacy. In addition, foliar-applied potassium acetate and boron applied with the R3 fungicide and insecticide application seemed to be more popular this year.
“August was hot and very dry, with a little moisture coming near the end of the month. These conditions promoted some development of charcoal rot and brown stem rot. Lack of adequate rainfall during August and September promoted higher yields with early-planted and early-maturity varieties, (compared to later-planter and later-maturing varieties).
“Yields reported so far range from 66 to 103 bushels per acre. Soybean yields in the 75-to-85-bushel-per-acre range are most common this year.”
About the Author
You May Also Like