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A hydralic soil probe is mounted on the back deck of a work pickup. Two men are taking soil samples from the stubble field.
Photo Credit:
Jeff Gale
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Showcasing the long-term effects of cropping systems on soil

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When we started producing Center Points, we planned to feature occasional guest authors from counties surrounding the CREC. While we've co-authored blogs with the occasional Extension agent or Extension Specialist, this week's submission is written entirely by Jeff Gale, NDSU Extension agent for Foster County. We express our deep appreciation for his contributions to Foster County and NDSU Extension, and to Center Points. Let us know if you'd like to hear from other Extension agents!

As an Extension educator, I’m always on the lookout for effective visual aids to enhance my presentations. For years, I’ve dreamed of having a soil monolith to help illustrate soil concepts when speaking to adults and young people.

A soil monolith is a vertical slice of soil that’s carefully collected and stabilized to showcase the structure, color, and texture of each layer, from the topsoil down to the subsoil.

Creating a soil monolith is a big task, and I knew I’d need help. Three years ago, I contacted Wade Bott, the state soil scientist with NRCS in North Dakota, to see if he could assist. 

As we visited, I realized that the Carrington REC had a long-term (37 year) study which would be ideal for collecting monoliths contrasting the effects of different management practices on soil.

I asked Bott to create monoliths contrasting the effects of three treatments: (1) conventional tillage plus 100 lbs nitrogen annually; (2) no-till plus 100 lbs nitrogen annually; and (3) no-till plus composted manure (equivalent to 200 lbs N) applied once every four years.

Bott and his team used their probe truck to collect 4-inch-diameter soil cores from the surface to a depth of over three feet. 

A hydralic soil probe is mounted on the back deck of a work pickup. Two men are taking soil samples from the stubble field.
Photo Credit:
Jeff Gale
A probe truck was used to collect soil cores over three feet deep from three treatment sites within a 100-yard range.

It was exciting to push each core out of the probe and see the differences among treatments. For example, the dark layer in the conventional tillage treatment extended to about six inches below the surface before stopping abruptly. In contrast, the dark layer in the no-till plus manure treatment went nearly twice as deep and then gradually transitioned to a lighter color.

Two fingers point to the change in soil texture.
Photo Credit:
Jeff Gale
As the soil cores were carefully pushed out of the probe, the distinct soil layers became clearly visible.
Two people are outside, grading comparing soils to guides from the back of their pickup.
Photo Credit:
Jeff Gale
NRCS soil scientists Perry Sullivan and Wade Bott recorded soil characteristics such as texture, color, structure, depth, and drainage.

The NRCS team took the cores back to their lab in Bismarck, where they dried, stabilized, and mounted the samples onto wooden frames. 

Three four-foot-long wood cases hold soil profiles.
Photo Credit:
Jeff Gale
The completed soil monoliths are on display at the Carrington REC—be sure to check them out on your next visit!

The completed monoliths have now returned to Carrington and are on display at the REC. I’ll take the monoliths out to use in educational programs as I have opportunity.

The long-term cropping systems study at the Carrington REC is a unique and invaluable resource, offering researchers insights into how different management practices impact soil over time. To my knowledge, there is no other trial like it in the Northern Great Plains. 

I applaud the researchers and administrators whose foresight has established and sustained this remarkable study for over 37 years.

Jeff Gale
Jeff.Gale@ndsu.edu
NDSU Extension agent, Agriculture and Natural Resources, Foster County