Features Agronomy Cereals
Heeding the lessons of 2008

One lesson worth learning from 2008 is to maintain rotations.

Crop producers looking to get the most out of the 2009 growing season need look no further. Top Crop Manager consulted several experts on the practices they saw in 2008 that should, and should not, be used in 2009. “What I learned is more of a reinforcement of what we already know rather than anything new,” says Chad Anderson, a certified crop advisor based in Brigden, Ontario. “Rotation is very important. In terms of the spindle streak virus we saw in wheat in 2008, quite a bit was in fields where the rotation was wheat-soybean-wheat. I found myself being able to predict that this was the rotation in the field from the extent of disease I saw.”

Anderson says one grower he worked with saw a 10 percent yield improvement across his bean and corn yields when there was a three-crop rotation over a two crop, probably due to lower disease pressure.
In another situation, in fall 2007, a grower planted a field with half corn and half soybeans, where the year before the entire field had been wheat. In 2008, he planted the whole field with the same variety of soybeans. In comparing the two soybean harvests, Anderson says the first-year soybeans out-yielded the second year beans by 12 bu/ac. “It’s simply a huge response,” he says. “The lesson learned here is rotation pays. In a year like 2009, where everyone is scrambling to determine what to grow this spring, it goes to show that keeping it simple and staying to a solid rotation is a more dependable way to improve bottom lines versus trying to out-guess the market.”

Another factor to consider besides rotation in terms of keeping yields high in winter wheat is when to plant, says Peter Johnson, cereals specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs. “I saw some growers in Exeter planting winter wheat at the end of August in 2007. That is too early,” he cautions. “Fields planted the second week of September gave much better yields.”

Have faith
The one observation of 2008 that strikes Johnson over all others is the resilience he saw in winter wheat. “I’ve been astounded by wheat’s ability to recover from disease and environmental stress,” he says. “Growers should consider the fact that even if there’s been damage done, the yield may turn out to be much more than they might have imagined.”

For example, high temperatures in fall 2007 resulted in far more top growth in winter wheat than normal, and powdery mildew ran amok. However, Johnson says that farmers need not have worried. “Fall disease control most years is not going to make a difference,” he notes. “Just let it go. The crop will be okay.”

Similarly, in early 2008, the dearth of snow and top growth resulted in significant snow mould infestations. Again, not to worry, says Johnson. “Wheat can definitely recover from this, but if you’re going to plant early in the snow belt of Ontario where snow mould is expected, you should keep your seeding rate low. Reducing seeding rates by 25 per cent significantly reduces snow mould development.”

In the spring of 2008, Johnson also observed the use of herbi-cides such as bromoxynil during some low temperature periods resulted in a lot of leaf injury. “It looked really terrible, but it turned out to be no big deal. The plants bounced back,” he says. “Conversely, with the hormone herbicides, I saw a lot less visual symptoms, but a greater yield loss resulted. Don’t jump to conclusions.”

Likewise in 2008, it seemed that the spindle streak virus would impact yield significantly, but it did not. “In the case of the army worm outbreak, the worst I’ve ever seen, lots of spraying helped,” says Johnson, “Still, yield loss in unsprayed fields ended up being less than anticipated, from 5 to 15 bu/ac.”

“But growers have to do their spraying right away,” he says. “There’s no use in doing it after the damage is done. All you’re going to do is waste your time and money.”

More options, better control
Anderson also believes that more growers should act early, in this case with weed control. “Early season weed control and the value pre-emerge or early season herbicides give good advantages in protecting yield,” he says. “With the increased use in Roundup Ready corn last year, it was easy to see fields where growers had delayed applications due to the wet weather.”

In some cases, Anderson says the early season weed pressure caused the corn to exhibit nitrogen deficiency. “These fields never caught up and yield loss was the result,” he notes.

Jonathan Klapwyck, Pride Seeds product development and agronomy manager, agrees. “Many late applications of glyphosate were made to Roundup Ready corn in 2008. Ontario corn yields could single-handedly be increased if RR corn growers ensure weed control during the critical weed-free period, generally from two to eight leaf corn.”

Anderson adds, however, that even in situations where glyphosate spraying was late during 2008, “Where we used some pre-emerge chemistry, we had excellent weed control, especially since we had lots of moisture to activate. These fields had light weed pressure which we addressed with Roundup, but never enough to cause a yield threat.”

Anderson says using some residual herbicide in Roundup Ready soybeans is becoming popular in Michigan. “This is something that I am interested in trying in 2009 to see if we can protect some yield here as well because it certainly pays big dividends in corn,” he says.

In terms of other advice for corn, Klapwyck says, “Plant early, when conditions are fit. Some of the best corn planting conditions were the week of April 20 in 2008.”