Last fall many producers around the province had the fall seeded canola bug. Ken Sapsford, SSCA's Regional Soil Conservationist in the West Central said there are a number of reasons for the high interest in fall seeded canola. "Reducing the spring work load is one of the reasons that makes seeding in the fall so appealing. Another is that the crop might be able to get ahead of the heat and insects that can sometimes wreak havoc on spring seeded crops. And based on early research, the fall seeded crops have fared pretty well in terms of both yield and grade."
The research Sapsford refers to is that which has been conducted by Dr. Ken Kirkland and Eric Johnson at the Scott Research Farm. They have been working on fall seeded canola since 1993 using a Roundup tolerant variety that allows a wide window for broad spectrum weed control.
Over the course of the study, fall seeded canola, especially that seeded into standing stubble, has shown a number of advantages when compared to mid May seeding.
Fall seeded canola emerges very early. However, with the early emergence, there is a risk of damage due to frost. Kirkland and Johnson found that early canola can survive up to 8 degrees Celsius of frost and has tolerated frost for up to 8 consecutive nights.
Earlier crop maturity is another advantage to the fall seeded canola. Kirkland and Johnson report that harvest of fall seeded canola can begin as many as 19 days sooner than canola seeded in the middle of May. With the earlier maturity, the fall seeded canola comes into flower earlier in the summer, thereby taking advantage of the normally cooler and moister conditions of mid June than those of mid to late July.
Based on three site years of data, the late fall seeded canola seeded into standing stubble yielded, on average, 44% higher than the canola seeded in mid May. The earlier flowering and seed set that occurs with the late fall seeded canola most likely plays a large role in the increased yield.
Heavier seed weight and higher oil percentages are often recorded in the late fall seeded canola as compared to those of the canola seeded in mid May.
And because the fall seeded canola crops are often shorter than the crops seeded in mid May, they are, therefore, less prone to lodging.
But what about the canola seeded in the late fall of 1997? "The first difficulty encountered with the 1997 seeding was the seeding date," Sapsford said. According to the work done previously by Kirkland and Johnson, the later the seeding date (meaning just before freeze up), the better. In previous years, the benchmark date was October 28. So many producers scrambled to seed their canola by that date. But the snow never arrived. "In fact", Sapsford said, "the first week of November, the soil temperature was still reaching +10*C".
Sapsford points out that initially, there was some concern over the warm temperature and the effect it would have on the dormancy of the canola seedlings. As it turned out, the temperature wasn't an issue. "Since the abnormally higher temperatures occurred for such a short period each day, the dormancy wasn't affected. And despite the lack of snow until late December and the warm winter temperatures, the canola appeared to survive quite well", he said.
And then a heavy frost occurred on April 30. Dr. Perry Miller from SPARC at Swift Current said that frost had a devastating effect on the fall seeded canola seedlings. "Based on a visual estimate, we lost 80% of our stand. Of the remaining 20%, 3/4 of those were severely injured although their growing points were alive. The other 1/4 were probably late stragglers." Miller said that although 20% of the seedlings survived, they have grown in to weak and spindly plants. "Our stand of fall seeded canola is pretty thin and patchy. In fact as of today (June 5), it isn't much ahead of our canola seeded on the 16th of April".
So, what went wrong? "Deacclimated" is the word Miller uses to describe what might have happened to the little seedlings. "In 1997, our fall seeded canola didn't emerge until April 29 & 30. This spring, the greatest wave of emergence occurred between April 9 and 12. After emergence we recorded 8 consecutive nights of frost from April 13-20, including two at - 7 *C, with no crop injury. Then 8 out of the next 10 days were unseasonably hot with maximum temperatures of 21 to 27 *C. During this period, the plants deacclimated and were not prepared for a sudden drop to -6*C."
Having said that, Miller points out the number of hurdles the fall seeded canola had overcome prior to the heavy frost. "The fall seeded canola had no snow cover, emerged very early under dry and abrasive conditions and was under attack by flea beetles almost as soon as it emerged. In addition, 2 frosts of minus 7 degrees C occurred on April 15 and April 19 but caused no injury at all!"
In contrast, the fall seeded canola at the Scott Research Station has fared pretty well. Eric Johnson, Soils & Crops Agrologist with Sask. Ag and Food says that the canola there is already flowering. "The late April frost wasn't as damaging to the canola at Scott as it was at Swift Current because the frost wasn't as severe and our seedlings weren't as advanced". Johnson says the canola didn't begin to emerge until the 18th of April at Scott. "Most of the emergence occurred between the 18th and 21st of April. In 1997, emergence didn't occur until the 29th and 30th".
In terms of maturity, the fall seeded canola began blooming at Scott on the 4th of June. In contrast, the canola seeded at the end of April is just beginning to bolt while that seeded May 19 is only in the 2 leaf stage.
Johnson says he's been hearing from producers that establishment has been very variable. "Some producers are reporting good establishment while others are reporting poor stands. It seems the common thread here is due to surface crusting. Even in stubble this spring, crusting has been a problem in some places".
Overall, Johnson is pleased with how the fall seeded canola emerged. "We were very concerned that the canola wouldn't overwinter as soil temperatures didn't drop to below freezing until the 8th of November. However, it is suffering from severe spring drought and it's yield potential may be severely reduced".
What conclusions can be drawn about fall seeded canola? The practise will always prove risky as the weather will continually change. Current research is focusing on reducing the risk of fall germination. Seeding the canola into standing stubble will ensure that snow is trapped (assuming any falls during the winter) for moisture in the spring. An early, hard frost can severely damage the seedlings, especially if there haven't been frequent minor frosts to harden off the little seedlings. And if the growing season should continue to be hot and dry as it is at the time of writing this article, how well the fall seeded canola will fare as compared to the canola seeded in mid May will be very interesting.
In summary, Sapsford says, "Canola producers should minimize their risks by seeding at different times of the year: late fall or early spring and mid May. Late fall seeded canola is only one management tool in canola production. Don't rely on a single tool and throw the rest of the tool box away."
Will producers have the fall seeded canola bug in 1998? We should know by October.