Soil scientist Dena Anderson expertly positions the hydraulic soil probe. “So, this is where you want to pull this core?” she asks.

“That should do it,” Connor Williams answers. “The soil map indicates you should hit gravel at 3 feet.”

The hydraulic apparatus presses the metal tube into the soil. Inside the tube is a 2-inch clear plastic sleeve. Soil preserved inside the sleeve will represent the soil profile.

Soon, Anderson pulls up the probe and removes the sleeve. Sandy clay loam gives way to pure sand and gravel at about 30 inches, shallower than expected.

“It is marked as an Ockley soil on the NRCS Web Soil Survey, and depth to gravel can vary from 24 to about 40 inches,” she says. “Now you know why that irrigation rig is here.”

Special opportunity

No, you don’t see soil scientists with the Natural Resources Conservation Service in farm fields pulling cores every day. Besides her duties with NRCS, Anderson served as the official judge for numerous high school soils judging contests in 2024. Williams, a Franklin Community High School FFA member in Johnson County, Ind., convinced Anderson to bring her specialized truck to his area. An avid soils judger, Williams knew there was lots of soil variation and wanted a firsthand look for a school project.

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Williams and Anderson did their exploring in the Soybean Watch ’24 field, which was already divided into four areas to sample for soybean cyst nematodes and nutrient levels. They pulled four soil cores, one from each sampling area.

“It’s exciting to pull cores in south-central Indiana,” Anderson explains. “The Wisconsin glacier, the most recent glacier to cover this part of the Midwest, began ending here. As it melted and slid back and forth over thousands of years, it created interesting features you don’t find everywhere.

“Plus, this field lies less than a mile west of a major river and about a mile west of a major creek. So, you never know for sure what you might find in a single core.”

Why soil sampling matters

Who cares what lies 3 feet below the surface? “That information can help you with management decisions,” Anderson says. “For example, you decide to sample different soil types separately because soil type can influence how nutrients react in the soil.”

Specialists working with SCN note that sand content can influence how much damage to expect from the pest. Based on testing, nematodes were found in the Soybean Watch field, with the highest numbers on a hill, followed by the eastern section with Ockley soil.

Mandy Bish, plant pathologist at the University of Missouri, where the Soybean Watch field samples were analyzed for nematodes, explains that sand content is a factor for the SCN Profit Checker Tool. Developed by The SCN Coalition, the tool estimates percent yield losses at various nematode levels.

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Because the eastern sample with Ockley soil was higher in sand content, even though the surface was medium-textured, the SCN Profit Checker predicted the highest yield losses there, compared to the rest of the field. That sample only had the second-highest nematode egg count, but the highest sand content.