A good canola crop requires managing a lot of moving parts and hitting a lot of small windows of opportunity with necessary applications. But the rewards may be worth the effort for growers looking for a good rotation crop for wheat — and possibly a better market in some years.
“Canola is a good substitute for wheat,” says Josh Lofton, Oklahoma State University Extension cropping systems specialist. He offered some perspectives on opportunities and management demands for the crop at the Red River Crops Conference at Childress, Texas.
“Canola is becoming more profitable as producers learn how to grow it,” he says. ‘It also breaks up the monocrop cycle and reduces the weed pressure that builds up in continuous wheat.”
However, he cautions growers that canola may be a bit harder to grow than wheat. “It is sensitive to stress, including waterlogging issues in the fall. Soil pH is also a factor. Wheat does well with a pH of 5.5, and in some areas of Oklahoma as low as 4.5. Canola likes a pH of 5.8. We see a significant yield decline below 5.5. Most fields will lose yield at 5.0.”
Canola’s challenges begin at planting time, Lofton says. Dealing with small seed creates complications. “Planting is critical — you need to get the crop up and growing as fast as possible. You need to get adequate plant growth before the first freeze, so planting date is important.”
Optimum planting would fall between Sept. 10 and Oct. 10. “In early September, conditions may be too hot, so late in the month is recommended. Ten days around Sept, 20 would be ideal across the Southwest canola growing region.”
Row spacing matters, too, and narrow spacing works best. “With wide rows, we see yield declines. From 20 inches down to 7.5 inches is ideal. Anything over 20 inches results in yield loss.”
Planting depth should range from one-half to 1 inch. Lofton recommends a seeding rate of 1 pound to 5 pounds per acre. “Most fields do best at 3 pounds to 4 pounds per acre, but a lot depends on the planter, row spacing, and cultivation. We want to see 6 to 8 finished plants per foot of row. Planter calibration is critical with the small seed (50,000 to 120,000 seeds per pound, depending on varieties).”
As canola reaches cotyledon stage, pest management becomes a critical factor. “Weed and insect control are imperative,” he says. “Clean fields early are important because you have to get the crop off to a good start. Worms are the biggest insect concern, and protecting plants during the cotyledon stage is a priority. Worms can do a lot of damage at that point.”
NARROW APPLICATION WINDOWS
Grassy weeds are easy to control in canola, Lofton says; that’s an advantage over wheat and why canola is a good rotation. But even with Roundup Ready canola varieties, he recommends a residual herbicide to prevent resistance and to improve control. “Treflan works well as a pre-emergence material. Unfortunately, we don’t have a lot of options in season.”
Successful canola producers have to get the crop through the winter, and that means adequate early growth. “Going into winter, we want to see 4 to 6 true leaves. We want a good crown and a good taproot, and there is a narrow window of opportunity to get that done. There is also a narrow line between adequate growth and too much. Excess plant growth going into winter may mean more winter kill, and it uses up too much moisture to make vegetation.”
Lofton recommends frequent field checks to make certain the crop is prepared for cold weather. “Hardening off and adequate moisture are necessary. Steep drops in temperature can hurt the crop.”
Spring greenup is a sign that winter is over. “We can still suffer a freeze in late April, but canola can overcome some cold injury.”
There is a short window for fertilization, too. Applying too late may result in plant damage from equipment. ‘It’s best to apply nutrients early,” Lofton says. “The herbicide application window is narrow, too. When the crop starts to bolt, it’s off label to apply herbicide. Late herbicide applications will hurt the crop. Producers want to target weeds that are 4 inches to 6 inches tall.
Late season insect management concentrates on aphids. “Aphid management is vital — they can take out a canola crop, so be prepared.”
Harvest timing comes with another small window. Producers have two options, direct harvest or swathing and harvesting. Either comes with opportunities to lose a lot of seed.
“Beginning direct harvest too early means combining immature seed, but waiting too late results in pre-harvest shatter loss,” Lofton says. “It is important to set up the combine each year before harvest — and slow down.”
Swathing, cutting the plants, allowing them to dry down, and then combining, also requires proper timing. ‘Once the crop is swathed, the crop is less subject to loss. But swathing too early will mean green seed and dockage. Swathing too late will mean pre-harvest shatter losses.”
Canola doesn’t do particularly well in no-till situations. The seed is small and may require at least minimum tillage to insure proper soil contact. Canola also does not follow wheat well. “About 30 percent of wheat varieties will affect canola production,” Lofton says. Root growth may be affected. “We see an allelopathic effect, but all plants are allelopathic to some degree.”
Canola offers producers a potentially profitable crop to replace wheat when wheat markets are off, and can help them to make headway on weed management issues that show up in continuous wheat. But managing canola takes some effort. “Canola management comes with a lot of moving parts and a lot of small windows.”