May 9, 2014 Pat Beaujot
Vertical Tillage in Wet Years?
I made a post last year around this time about vertical tillage, and made it clear that I didn’t think it was necessary after a bumper crop like we saw in 2013. Since that time I have gotten out and talked to a few growers about why they are surface or vertical tilling, to try to understand why this practice is re-appearing after all of the years of success we have had no-tilling.
Trying to dry things out and get rid of ruts in these extremely wet years does make sense. There is no doubt tilling in the fall will result in drier land in the spring. In these wet years that may be what you want. I still don’t understand spring tillage. I still think if it is dry enough to drive on with a tillage unit, then it is dry enough to drive on with a Seed Hawk and I would rather be seeding, especially when spring was late already.
I have heard spring and/or fall tillage will warm the soil up which is really important for soybeans. This crop is becoming increasingly attractive on the Prairies, so we may start to see more of this happening as guys begin to try this crop. I also know the research that was done by David Rourke in 1995 showed one pass seeding with knife openers warmed the soil up in the black strip area where the seed is just as much as working the whole field, so I see that method as the better choice.
I have also heard some say they found a 5-7bu yield bump from a tillage operation. I think that is likely from mineralized nitrogen and other nutrients from the organic matter that was broken down from the tillage operation. This organic matter was built up from no-tilling. There is a good article on that on page 69 of the Aug. 28 Western Producer http://issuu.com/westernproducer/docs/140827213617-e2d5cc273bb34dee9ee93679bd31fde0#signin. North Dakota University is saying after 6 yr no-till fields require 40-50lbs less N/ac. When you till that up you are basically taking nutrients from your own “soil bank account”, and destroying all of the work done to build that bank account. That mineralized nitrogen will diminish quickly if you till every year.
Another reason I hear people are using vertical tillage for is to break up hardpan. This reason has been proven to be false. I saw a research presentation at the ManDak show where there was no effect on the soil hardness except where the heavy vertical till machine was lifted and the tires were compacting the soil. Often sellers of this equipment claim the soil is fractured several inches below the disc point but the researchers saw none of that. I was curious this spring so I bought a tool for measuring soil hardness. All of the long term zero till fields I tested had no hard pan layer.
I guess all farming practices need to have some flexibility, as long as we don’t get so caught up in a certain practice that we do it even if the weather is telling us not to. Those dry dust blowing decades of the 70s-90s are hard for me to forget. Many years we would have given anything for a wet spring. If we see a hint of that coming back I am sure the tillage units will be parked again (at least I’m hoping!).
Scott Day dropped in for a visit two weeks ago. His farm was in the worst part of the flooding in South West MB in the spring. Many acres were still under water at the end of June. Then it didn’t rain again during the summer. He said they actually needed a rain in mid-August. Things sure can change in a hurry. It may be hard to resist the temptation to till, but I urge you to let the land be your guide.
I have spoken to some customers who believe this practice has helped their operation. Most are in the black soil zone and eastern prairies where we are in the middle of an extreme wet cycle. So, in summary, the legitimate reasons I see for surface/vertical tillage are:
-To get rid of ruts
-Residue management:it’s better than burning
-To warm and dry the soil-I would like to see some research on this
The costs involved will be:
-Capital cost of tillage unit
-Yield loss from moisture stress if moisture becomes a factor at any point in the summer
-Depletion of organic matter/soil health-research on the long term effects of this would be interesting also
-Potential erosion during spring runoff
The main cautions I have heard from farmers practicing this are to not mix the straw too deep into the soil or the knives will pull it back out again when you are seeding, making a bigger mess. You will result in an inferior seed bed. Also, make sure the machine is set level or you will create variations in your field.
I can see that in some of these areas, when vertical tillage is done properly, seeding can be made easier.
I’m interested to hear comments from anyone on this topic, if you have tried vertical tillage in long term no-till land, or not. Why did you decide to do it/are you thinking of trying it, and what is your experience? Tweet me @PatrickBeaujot or @NOTILLville .