Crops - The Lynch File: Confessions of a closet strip tiller

Tuesday, April 1, 2008

Hitherto, our columnist had been reluctant to promote the system because of the cost and expertise required, and other reasons. But times have changed

by PAT LYNCH

It is time for me to come out of the closet and admit that I believe more producers should switch to strip till.

Some call it strip till, while others call it strip till planting. Whatever you call it, this system combines the benefits of no-till and conventional tillage systems. It combines the no-till benefits of reduced erosion and soil moisture conservation with the conventional tillage benefits of having a worked seedbed. Strip tillage has overcome the greatest challenge to no tilling, namely successfully planting corn across a wide range of environments.

A turning point in my coming out of the closet was research from Dr. Tony Vyn, formerly a researcher at the University of Guelph and currently a researcher at Purdue University. His long-term tillage trials show the yield advantage of strip till across numerous soil types compared to no-till and conventional tillage.

Strip tilling consists of working a strip about 10 inches wide and then planting into this strip. This leaves a strip 20 inches wide that has not been worked. The strip tilling occurs any time from the fall before planting to two to 24 hours in spring before planting.

I like to see wheat stubble strip tilled in the fall and then assessed in the spring to see whether it needs to be strip tilled again before planting. For bean stubble, I like to see the strips made in the spring two to 24 hours before planting. Corn stubble going back into corn can be handled in the same way as soy stubble.

Most strip-tilling machines are a combination of three coulters and a cultivator shank that goes deeper than the coulters. The system is designed to incorporate trash and make a seedbed. Some growers are applying fertilizer as they till the strip.

It is not uncommon to apply three years quantity of phosphorus and potash in this strip. That leaves only nitrogen to be applied to the corn and wheat crop. Soybeans feed off the residual P and K from the corn crop. Because the fertilizer is spread across the 10-inch strip, you can safely apply higher rates of starter fertilizer than in the conventional 2X2 band. This allows you to plant corn without the bother of fertilizer on the planter. You can get any benefit from a seed-placed fertilizer that may exist.

Hitherto, I had been reluctant to promote this system. First, there is the expense and expertise to set it up. Secondly, for years there was no good way to apply fertilizer as the strips were made. Thirdly, there was the extra cost of another planting system.

But times have changed. A lot of producers have not been able to afford to switch planting systems because of lower commodity prices. These planting systems now must be changed. And, because of the current shortage of planting equipment, many growers have stuck with their current system for this year. If you are thinking of switching your planting system, check out strip till.

Another thing that has changed is the advent of air carts. Today, there are more of them that are suited to Ontario conditions. Air carts allow you to apply starter fertilizer in a band. This is especially good for nutrients like zinc, which is needed in small amounts early in the corn's life. Also, there is the advent of ESN, a polymer-coated urea that is released over time. This reduces the burning affect of urea and allows higher rates at planting. We may even be able to apply ESN in the fall.

There are growers who use strip till and conventional fertilizer. Broadcasting fertilizer before strip tilling is better than broadcasting for no-till. The P and K in the strip will be worked in, and time and Mother Nature will move the P and K that was not worked in. The use of ESN or another additive, such as AgroTain, to prevent volatilization of nitrogen also works.

Another benefit of strip tilling is controlled traffic. If you combine a strip till system with a guidance system, you have the potential to increase yields by reducing the affects of tire compaction.

Strip tilling is not for every one. You will probably need to be planting 300 acres of corn a year to justify the system. You cannot use it for wheat, so you still need a no-till drill. But you can continue to use your conventional corn planter to plant corn in these tilled strips. BF

Pat Lynch CCA (ON) is head agronomist for Cargill in Ontario.