Higher canola yields achieved under irrigation

Saskatchewan researcher says growers should not be afraid to apply more water if they are doing everything else right

A survey of 15 irrigated canola fields in Saskatchewan found an average yield of 70 bushels per acre in 2020.

The provincial dryland average was 37 bu. per acre.

This is the second year of the survey, which is being done to assess production methods in order to make recommendations, said Joel Peru, an agriculture ministry irrigation agrologist in Outlook, Sask.

The three-year project is in the Lake Diefenbaker Development Area.

Peru told the provincial irrigation conference in December that he collects seeding dates, varieties, fertility data and production methods, along with how much water the irrigators apply.

“This year conditions were more ideal than last year in terms of timing of rain, and also producers’ ability to get their crop off in good time,” he said.

There was good spring rain, followed by a hot, dry mid-summer before harvest.

Peru said all the growers applied similar amounts of water, with an average 5.4 inches applied in July and August. In total, the crops received an average 12.3 inches.

Corn heat units were lower than the average 2,356 at 2,220, he said, and that might have impacted water use.

Canola can use up to 15 inches of water, which led to the question of whether the growers should have put even more on. However, Peru said yields weren’t affected, so perhaps the 15 inches should be a guideline, especially when heat units are lower.

One field, which produced the lowest yield at only 40 bu. per acre, was an outlier.

“There was a mechanical issue with the pivot during peak water use, (resulting in) a good chunk of time where no irrigation was applied,” Peru said.

Seven out of the 15 fields yielded more than 75 bu. per acre.

“I always ask every producer I work with what their target yields are and most of the time it’s between 70 and 80,” he said.

The top-yielding fields received “a lot of fertility,” Peru also said, including through incorporation, broadcast and spread out over three or four applications.

“The big thing is to have the correct amount of nutrients available,” he said, adding that the timing and method may be secondary.

The fields that yielded 75 bu. per acre had more than 200 pounds of nitrogen available to the crop, including the soil test amount, and 70 lb. or more of phosphate.

The better fields were also seeded no later than May 17.

Peru said the growers planted several varieties of canola; Liberty 233P was the most common and with the best yields.

He said there were a few take-home messages from the 2020 data.

One farmer grew both a specialty oil canola and a generic canola.

“From this year, that producer says he will no longer grow the specialty oil variety because of the difference in yield,” Peru said.

The premium for the specialty crop didn’t pay considering the other variety yielded 15 bu. per acre more.

Another grower suggested he might have not irrigated enough because he was trying to avoid disease. Peru said disease pressure was low, and it was extremely hot in late July and early August. The crop canopy would have been able to dry out quite quickly.

Growers shouldn’t be afraid to put more water on if they’re doing everything else right, he said.

Most did apply fungicide, which is recommended under irrigation.

In addition to low disease, insects weren’t much of a concern.

One other highlight from the 2020 survey was the information gleaned from a field seeded with a row planter. Peru said there has been quite a bit of talk about whether a planter is better than conventional seeding systems. In this case, it seemed to pay off.

The farmer seeded at 130,000 seeds per acre, or about 1.5 lb. per acre. That compares to conventional solid seeding at about five lb. per acre.

This producer also saw the 75 bu. per acre yield on that field, even with the lower seeding rate.

Peru said rough estimates suggest that seeding at the regular rate is about $70 per acre, while the planter rate is $20 per acre.

“So this producer, not only (did) he (have) one of the highest yielding crops, he also saved $50 an acre in seeding costs,” he said.

A full report on the survey is expected to be available later this winter.

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