If you've driven by soybean stubble fields chisel-plowed so deeply and well that they look like they're moldboard-plowed, all you can do is shake your head. Hopefully for those farmers, the winds won't blow across frozen soil or water cut ditches this spring. Soybean stubble is fragile anyway, let alone after it is buried and nearly all the soil exposed.
That wouldn't be considered light tillage. However, in other areas, even in heavier soils where some still opt to plot or chisel, especially after corn stalks, not everyone is ready to turn the landscape black. Todd Roush, Van Buren, and his family are trying out tools this fall, looking for one that leaves most residue on top.
"All we want to do is level out where the combine tire tracks and do enough tillage to get some dirt on residue to start breakdown," Todd says. "I'm not interesting in going deep enough to throw out rootballs and/.or chunk the soil. That's when you get soil compaction, and that's not what we're after."
While some believes freezing and thawing could take care of soil chunked out wet, fact isn't on their side. Gary Steinhardt, Purdue university Extension soils specialist, clearly demonstrated in the '80s that freezing and thawing doesn't always bail you out of working soils wet in the fall. In fact, it may take several winters to correct a serious soil compaction problem, if it can by itself. And the deeper you till, the deeper you tend to push soil compaction layers.
Instead, Roush, ran a Case 330 Turbo tillage tool 1 inch deep, mainly leveling the soil. Residue counts behind where he ran showed that he was leaving about 75% or more of the soil covered with corn residue. After the combine, before anything was done to the soil, the residue cover was only about 80%.
Roush's idea is to work just enough that soil may warm up slightly faster next spring, compared to not tilling. If the soil is level enough, he will no-till drill soybeans into it without making another pass next spring. If necessary, he will come back next spring with another very light tillage pass, then drill the field.
Roush is happy about having the residue left on top. His goal isn't to bury it, he assures, just to level things up and get enough intermixing to start some bacterial breakdown.
Tillage or not tillage is obviously in the eye of the beholder.