Oswald No-Till Farm Cleghorn, IA | Greetings,
Here's the philosophy I use as I think about tension/compression on soil by tools pulled through it. Like others have said, when you carry the weight on the wheels, you are changing the distribution of the compression. How negative compression is to crop performance is a different issue (depends on conditions).
For a tillage tool to polish, it has to compress soil as that soil slides over the face of the tool. Even a single straight coulter blade running with zero angle to travel will polish as it cuts a slot.
Even the 1" wide tip of the mini-mole knives I ran for strip till will smear the soil at the bottom of the track. But, the fracture due to the lifting will leave the bottom the primary area of compaction.
So too with a disk blade. It will cause a smear where the downward force is balanced as the angled blade shears at depth. Between those zones, the soil is fractured and broken away from that from which it was attached. I believe one can make the argument that one "primary" disk tillage pass is less damaging than multiple passes with a disk in that multiple passes at the same depth completes the lattice of compacted/smeared zones. We found this out the hard way years ago when trying to deal with heavy residues with a finishing type disk.
This could support the argument that vertical tillage disks fracture more than damage if used only once. Not having run or dug behind a VT "disk" I can't support either side.
The key point is that you can argue many sides of how various tools "break" the soil in the tillage debate. It is a separate issue from should we do tillage at all. Should we "break" soil at all... is tillage damaging?? Your results may vary. |
disk compaction in the Spring
