Crop scouts love high-tech tools like drones. Without a doubt, aerial images can tell you a lot about a soybean field that you may not be able to detect from the ground. However, that small trowel or shovel you carry when you walk fields, while old technology, can help uncover answers you may miss if you’re relying solely on high-tech imagery.

“A little digging can often answer several questions,” explains Steve Gauck, a Beck’s regional agronomy manager and a farmer himself near Greensburg, Ind. Beck’s sponsors Soybean Watch ’24.

When Gauck goes to the field, he makes sure he has a trowel in his hand, a copy of the Purdue Corn and Soybean Field Guide in his pocket and a drone in his truck. “Then we start walking and look for anything that might seem unusual. We dig up an example plant and a normal plant and compare the two,” he says.

Soybean plant example

Gauck dug up the plant in the photo above on a recent visit to the Soybean Watch ’24 field. Here is what he discovered:

Nodule number and size. “They are about normal on this root system,” Gauck says. “Rhizobium bacteria living inside the nodules fix nitrogen from the air so plants can utilize it.”

If nitrogen fertilizer is added as starter at planting, or if manure is applied on the field, you likely won’t find as many nodules, he notes. Nitrate-nitrogen in the soil is antagonistic to bacteria setting up shop in nodules on roots.

Related:Watch for potassium deficiency in soybeans

“If it’s cool and wet, they may be slow to take off, too,” Gauck says. “This year, conditions were right for them to establish early, for the most part. By the time soybeans reach V2 or so, nodules should be active.”

Nodule activity. Finding nodules isn’t enough, Gauck says. You need to know if they are working and producing nitrogen for the plant. When Gauck pressed nodules between his fingers, he determined that they were pink inside. “Pink nodules are fixing nitrogen from the soil, and it will be available to plants,” he explains.

Nodules don’t produce all the nitrogen plants need. It’s still important for roots to take up some nitrogen from the soil. And they don’t fix N until the end of the season. Nodules tend to trail off in activity at some point during the R5 stage.

Compacted roots. Take a good look at the plant roots in the picture. “Roots are normal on one side, but there are only limited roots on the other side,” Gauck observes. “The most likely explanation is sidewall compaction during planting. Perhaps the soil was a bit tacky. Roots found it difficult to get through the planting trench wall on that side.”

Planting depth. Gauck always looks for the soil line on the plant to determine original seeding depth. “I prefer soybeans planted a bit deeper than most,” he says. “If they are around 1.5 inches deep, it tends to favor nodule development. That’s especially true if it is warmer and drier. Soil at 1.5 inches deep will be just enough cooler versus at 1 or 1.25 inches to give nodulation a boost.”

From the field:
Soybean reports from across Midwest

In Illinois. Chad Kalaher says things are stable for soybeans in eastern Illinois. If you’re spraying fungicide for soybeans, the Beck’s agronomist notes that data from Beck’s Practical Farm Research program in past years indicates there can be a synergistic effect from adding an insecticide with the fungicide. That means spraying both can produce a bigger yield increase and larger return on investment than spraying fungicide alone.

In Nebraska. “All early-planted soybeans have progressed well through R2 and should be approaching R3 this week. Replanted or later-planted soybeans are moving along through late vegetative stages. There have been some mild cases of septoria brown spot, but not many other diseases have been found. Japanese beetles, dectes stem borer and soybean gall midge have been the three pests we have been seeing in fields across the geography. Yield potential is high in early-planted soybeans, as we have had adequate moisture up to this point.” — Trey Stephens, Beck’s agronomist

In Missouri. “Majority of soybeans have progressed into R2 to R3 and beyond. There is a fair amount of fungicide and insecticide being applied. With timely rains, we’re setting up for a good-looking soybean crop. Double-crop soybeans have had great growing conditions and are progressing well. It is relatively clean as far as pest pressure so far. The next big threat could be stinkbugs in reproductive stages. With the moisture, it hasn’t been surprising to see a little septoria show up in the bottom canopy and a little phytophthora, as well. Hopefully, the area can continue to get timely rainfall events to help fill pods!” — Celena Kipping, Beck’s agronomist