Zone Tillage?

You’ll often hear strip and deep zone tillage referred to as “zone tillage.” For something to be considered zone tillage in the traditional sense the tillage would be accomplished using a series of coulters. The coulters are positioned in front of a planter or can be attached to a toolbar and used as a separate implement. These coulters are usually arranged in a staggered fashion and ideally spaced about 2-3 inches apart.

In my experience three fluted coulters seem to provide the optimal amount of tillage. This arrangement creates a nice grinding action which breaks up soil clods. As a side note it’s really interesting to walk behind the tractor and watch the coulters work. Watching the coulters work while driving the tractor is fun too, except the rows don't allways turn out straight.

Click on the movie below to see an example how zone tillage works. It’s a little hard to see the grinding action due to the camera angle and that the soil was a bit wet.

Why then is zone tillage used as a synonym to strip and deep zone tillage? I’m not entirely sure why, but here are some of my thoughts on the matter. Part of the difference is probably regional. Another factor might be that zone tillage is sometimes coupled with deep ripping.

In my opinion the brand name of a certain piece of tillage equipment, the Unverferth Zone Builder, might have something to do with it. From what I’ve heard it seems that the definition of zone tillage is changing to mean: tillage with 2-3 coulters or tillage using an implement configured like the one seen below.

To eliminate potential confusion in writing and talking about experiments here is how I like to define these three types of tillage.

Zone Tillage: tillage with three coulters.
Strip Tillage: tillage with a shank to a depth of about 10-12 inches.
Deep Zone Tillage: tillage with a shank to a depth of greater than 12 inches.