Why use Vertical Tillage - 2013

I am going back to a topic I have talked about a number of times. A discussion some time ago on twitter leads me to want to clarify the purpose of vertical tillage.  The idea of vertical tillage probably dates back at least to the invention of the Paraplow.  A friend posted this video on Youtube explaining what he is doing with the paraplow.  The idea of vertical tillage is to disturb the soil in order to aerate, release nutrients, or reduce compaction while leaving high residue cover on the surface.  Why high residue?  Crop residue is the most effective tool we have to reduce soil erosion.
Tools like the paraplow and this DMI No-Till Ripper are used where the soil can benefit from deep tillage.  In-line rippers are much better for vertical tillage than V-rippers because they do not create lumps and roughness. 

There are also shallow vertical tillage tools that smooth and fluff the surface in order to prepare a seedbed without losing a lot of residue.  Shallow vertical tillage tools have become very popular in the past few years.  They can be used either as a primary tillage pass or to smooth out fields that have been tilled by a deep vertical tillage tool such as a Paraplow or No-Till Ripper.  In order to maximize residue cover and minimize compaction, the disks on your vertical tillage should be flat and should be run at a 5 degree angle or less.  One of the things the shallow vertical tillage tool does is it throws some soil dust onto the residue and cuts it up or sizes it.  This is important because it helps decompose some of that sturdy residue that is common in our modern corn hybrids.  Accelerating decomposition will help expose some soil and help the planter to get thru the trash in the spring.  It seems there might be merit in breaking up the residue mat in soybean stubble as well.

This leads me to the twitter discussion.  Some of the people I was chatting with thought that the primary purpose of the shallow vertical tillage tool was to size the residue so that they could get through it easier with the chisel plow.  I fail to see the merit in that use.  First the vertical tillage tool is an expensive answer to that problem.  Second I question the need to size residue to chisel plow or rip.  Most of those tools have disks on them already.  I have never seen a ripper or chisel plow that did not bury more than enough residue.  A few of those stray stalks sticking up will not cause any problems in spring.  Running the shallow tool at the same angle as your disk (about 23 degrees) is another issue.  The problem is that you will create the same scraping compaction with the vertical tillage tool that you will create with the disk.  You will also bury a lot of residue.

Vertical tillage is a wonderful conservation tool, but just because you use a vertical tillage implement does not mean you are doing vertical tillage.