Crops: The Lynch File - What can you do about Corn Row Syndrome?

Monday, August 9, 2010

One solution is to use a starter fertilizer with wheat. Another is to work the ground, so spreading out the root masses and making the soil structure more uniform

by PAT LYNCH

Corn Row Syndrome (CRS) is the terminology given to wheat rows that appear different when they are planted over the top of an old corn row. These wheat rows show up when wheat is no-tilled into soybeans that were no-tilled into corn stalks.

Some suggest that CRS results from residual fertilizer from a corn starter fertilizer. One solution to overcome CRS is to use a starter fertilizer with wheat.

In the spring of 2010, there were a lot of fields with CRS. These occurred on light and heavy soils, with some on fields planted with a liquid starter fertilizer. The field in the accompanying picture had about 40 pounds per acre of phosphorus as a dry starter fertilizer, the point being that adding a starter fertilizer does not get rid of CRS.   

As I thought about this problem, I remembered growing wheat at home when I was a kid. Corn was always planted with a dry starter fertilizer. Wheat sometimes had a starter fertilizer. It depended on how much cash my father had at wheat planting time as to whether a starter fertilizer was used on wheat. We grew wheat mainly for the straw. If CRS was real, we should have seen it then.

In the 1970s and early '80s, numerous acres of wheat were planted without a starter fertilizer. This was a time when fertilizer was broadcast and starter fertilizer was rusting out drills. Corn always had a starter fertilizer. White beans generally had a starter.

But we never saw CRS in the wheat.

The reason we did not have CRS was because the ground was worked. CRS started when we went to no-till. CRS occurs because the corn roots are breaking down and the soil is mellower where the corn roots were. If the ground is worked, these root masses are spread out and soil structure is more uniform. This allows for better early wheat root development. In turn, this better early root development gets the wheat crop off to a quicker start, which means the roots get going earlier to allow better nutrient uptake.

Using a starter fertilizer may overcome some of the CRS, but it is no guarantee.

The only way to get rid of CRS is to work the ground. I do not mean going back to working the ground like I did when I was a kid. Then, we would work it several times, partly to kill the quackgrass. In the 1970s, ground was overworked because fuel was cheap and there was no real cost calculated for working ground. Now, when time and costs are calculated, there is less tillage. And today's secondary tillage tools are designed to work a lot of ground quickly and shallowly.

Even the severest critics of tillage will agree that tillage improves wheat yields. You may not have to work every field, but you should consider it on land that has shown CRS.
Finally, in my experience I see more CRS on later planted wheat on heavier ground. Early planting on lighter soils may not have as big a benefit to some light tillage before planting wheat.

This year, soys were planted early, so they should be harvested early. This may mean you can do your own trial. See if some tillage makes a difference. This year's unevenness at heading might have been less if more fields had been worked before planting. BF

Consulting agronomist Pat Lynch, CCA (ON), formerly worked with the Ontario agriculture ministry and with Cargill.