Three experienced scientists say soil pits are another tool no-tillers can use to examine soil structure, root development, compaction, soil quality and other important agronomical issues.
These pits might even reveal information that wouldn’t be obvious through soil tests, making it easier for no-tillers to solve yield-robbing problems.
“They can see if there were many shallow roots if the soils were wet,” says Mike Petersen, Orthman Mfg. Co.’s agronomist. “How deep did the corn roots go? Did the corn roots go down deeper when it was dry in August and September? How did the corn finish?
“A soil pit can also tell you about seed placement, and whether the corn extracted moisture late in the season so the crop could finish well,” he adds. “The difference between extracting the moisture from deep in the soil can be 150 bushels per acre vs. 200 bushels per acre.”
Jodi DeJong-Hughes, University of Minnesota Extension crops and soils educator,
says soil pits allow growers to assess the impact of management practices in a way that might not be possible with soil tests.
“These impacts — particularly compaction — will show up in root-resistance areas,” DeJong-Hughes says. “With a knife, dig across the top layer of soil in the pit. If there is good soil structure, the soil should fall off in your hand. Wheel traffic will show up as a U-shaped impression about 8 inches below the surface.”
Petersen recommends digging a soil pit at least 150 to 200 feet into a field…