More than 200 farmers coming from all corners of southeast Indiana heard Lloyd Murdock describe how to check for soil compaction. The tool he suggested, a penetrometer, wasn't what made his advice unique. It was insistence that it be done on wet soils, not dry soils.
The crowd was gathered for the 15th annual No-till Breakfast in southeast Indiana. Still sponsored by the Ripley County Soil and Water Conservation District, other agencies in and outside of Ripley County also participate in the event.
This meeting is special because farmers provide the program. Topics discussed are questions posed by farmers, sometimes in writing before the meeting, sometimes on the spot. Murdock, a long-time researcher from the University of Kentucky, moderated, but farmers also provided part of the answers. Murdock has worked most of his career in no-till research at the Princeton Research Station in western Kentucky.
Soils there range from well-drained to very poorly drained, somewhat like those in southeast Indiana, and other parts of the Hoosier state. It's the somewhat poorly drained soils where coil compaction typically becomes more of a concern, Murdock says.
"The best way to tell if you have a soil compaction problem is to probe with a penetrometer that measures the pressure it takes to push a slender rod into the soil," Murdock says. Many Extension offices and SWCD's in Indiana have made such devices available to farmers for years. They became popular when Gary Steinhardt, a Purdue University soils specialist, first began to raise concerns about soil compaction in the mid-80's.
"When the soil is wet, it's like the soil is lubricated," Murdock explains. "When it's dry, it tends to stick together. But on saturated soils, if there is compaction, you will feel a change in pressure. Then you should break through it. If you don't, it's probably a fragipan or area of high clay, a feature in the soil, not soil compaction."
The irony is that while spring when soils tend to be wetter is the best time to detect soil compaction, fall is the best time to work on it. "Soils must be dry enough that they will shatter when you rip the field," Murdock explains. "Otherwise, you might actually make conditions worse."
Through their years of research, Murdock says that they have discovered that if 30% or less of the field is compacted, it probably won't pay to rip it. The 30 to 50% zone is a gray area, although he would be inclined to rip, he notes. If more than 50% of the field has compaction reaching 300 pounds per square inch on the penetrometer dial, ripping will usually pay, he concludes.