The Canada-Saskatchewan Irrigation Diversification Centre in Outlook updated producers on 2021 research projects during two recent virtual field days.
Even under irrigation, the drought affected some of the projects.
Gursahib Singh, co-research director at the Irrigation Crop Diversification Corp., was trying to study fungicide application timing to prevent fusarium head blight in winter wheat, durum, bread wheat and barley.
“It’s been an unusual year for all the plant pathologists,” he said during a presentation filmed in late July. “We don’t see much disease in any of our crops. We tried to irrigate our crops to keep the canopy down. We also inoculated our plots but didn’t see any disease.”
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Typical fungicide application charts recommend spraying when the heads are out of the sheath to about 50 percent anthesis, or flowering.
His project intended to examine four fungicide application times, including at the heading stage, the start of anthesis, 50 percent anthesis, and at the end of anthesis.
The three-year study also includes plots at research centres in Saskatoon and Melfort.
Singh said his earlier doctoral work was conducted on durum using the same four treatments and two others: spraying in late milk stage or about 20 days after flowering and a double fungicide application at the beginning of anthesis and again at early milk stage.
He found that all treatments using Caramba at anthesis offered good control over the disease.
“The harvested grain had lower mycotoxins and there was a yield increase,” he said.
But later stage applications indicated disease and mycotoxin levels similar to unsprayed check plots.
Results from comparing the double application to others found that a single treatment at 50 percent anthesis was as good as the double treatment, Singh said.
“So, whether you spray your plot once at 50 percent anthesis or you spray twice at the start of anthesis or milk stage, it has the same disease level, the same mycotoxin level and the same yield increase,” he said.
Singh recommended integrated disease management to combat fusarium head blight.
“We don’t have any magic bullet or a single magic pill to control the disease,” he said.
“Anything with the slightest benefit should be used together.”
The first strategy is to keep crop rotations in mind. Three or four-year crop rotations excluding cereals should control the disease.
The second thing to know is field history.
“Go out and scout your field in mid-August or when the crop is maturing. If you see the bleached heads in your plot for sure you have the disease,” he said.
Also, receipts from delivered grain will indicate the presence of the disease in that crop, which should inform the grower how to proceed the next year.
Singh added that the weather conditions around flowering will also play a role.
“If it’s overcast during anthesis, temperatures around 25 C and you have a damp canopy… for sure I recommend go for the fungicide application.”
Targeting the right stage of 50 percent anthesis to apply fungicide is also important.
A project looking at root rot in field peas was meant to look at possible ways to limit the damage from aphanomyces.
Garry Hnatowich, the ICDC co-research director, said the project was done at Outlook, Scott, Melfort and Swift Current.
“There’s nothing that we found that we can either bottle or bag that is going to eliminate Aphanomyces and prevent the pathogen from infecting the peas,” he said. “But there might be some agronomic practices or inputs that we can do that can mitigate the damage such that yield that we obtain from those inputs may be cost effective.”
The study was factorial, with multiple applications of combinations of different products, he said.
Pre-seed applications included glyphosate on half the plots and glyphosate with trifluralin on the other half.
Seed treatments included a control, Vibrance Maxx, and Vibrance Maxx and Intego.
Half the plots received the base rate of 20 pounds of phosphorus and a granular rhizobial inoculant while the others received a higher rate of 50 lb. of phosphorus, 20 lb. of potassium and 10 pounds of sulfur.
“On top of that on a couple of trials in here we’ve come in at herbicide timing, post-emergent timing, and applied a micronutrient blend that is purported to show some greater degree of yield response on aphanomyces,” Hnatowich said.
The field was historically planted to peas when a pulse was in the rotation, but the aphanomyces got so bad that researchers switched to soybeans about seven years ago.
Prior to this year’s planting a soil test indicated aphanomyces was still present and that’s why the trial was conducted on the site. Hnatowich said the other participating sites also chose fields where aphanomyces was present.
Researchers dug out roots at five weeks and eight weeks after emergence and assessed for root rot and nodulation.
“We found aphanomyces at both sampling times and by week eight we had severe aphanomyces in some of these plants,” he said.
Nodulation was occurring and the nodules were fixing nitrogen.
Hnatowich said none of the treatments mitigated the degree of aphanomyces that was found.
This was the second and final year of the trial. CSIDC plans to compile the information from all of the sites and issue a report next spring.
He added the micronutrient blend used in the trial was a chelated formulation containing zinc, manganese and boron.
He said disease studies are tricky.
“The amazing thing that I got out of it is we have not peas on that field now for I believe at least seven years at least,” he said, noting it’s suggested to keep peas out of rotations for six to eight years to keep disease at bay.
“We are under irrigation, so we are moist, so that would keep populations of pathogens potentially higher, but our treatments were decimated. Even after seven years we can still have the problem.”
The first of a three-year evaluation of seeding date and irrigation requirements for canola was conducted by Erin Karppinen, co-ordinating biologist at Agriculture Canada.
She said the trial is part of a larger project to address the uncertainty of agricultural water supply in a changing environment of more extreme droughts and floods. Water use efficiency will be key in drought-prone areas.
Karppinen said early May seeding is generally recommended for canola because that results in higher yields and better quality. There are risks of spring frost and delayed emergence, however.
Earlier work has found a significant yield effect depending on seeding dates.
“The data shows that the yield loss in canola is greater than any other crop and that canola seeded in early May generally yields about six percent higher than canola seeded in mid-May and about 12 percent higher than canola seeded in late May,” Karppinen said.
“Practically though, seeding is often delayed into late May or even into June depending on individual farm operations and our local environmental conditions that year.”
Data from Saskatchewan Crop Insurance shows that about 43 percent of irrigated canola is seeded after the third week of May.
In this trial, plots were seeded April 30, May 17 and May 31, all at 6.5 lb. per acre. They all received 140 lb. of nitrogen and 15 lb. of phosphorus.
Karppinen said plant emergence counts, height, staging and flowering were all measured and soil moisture was monitored in the top five centimetres and at 30 and 60 cm.
Moisture sensors were monitored frequently to determine when irrigation was to be used. The threshold was 50 percent of soil-available water capacity.
After harvest, yield and seed quality, as well as water use efficiency, are being calculated.
Early results showed there was a large difference initially between growth stages, and above-ground and below-ground biomass.
By June 24, the early-seeded treatment was flowering, the mid-May treatment was at the rosette stage to early bolting, while the late-seeded treatment was only at the four to six leaf stage.
But Karppinen said the differences soon disappeared. The early-seeded crop took 50 days to flower, while the others took 45 and 35 days, respectively.
“So, there’s really no longer that two-week difference,” she said.
For irrigation, the plots were randomized and had to be large to allow for individual treatments, she said. At harvest only a 1.5-metre strip was taken from the centre.
Total rain and irrigation applied came to 12.5 inches for the early-seeded crop, 10.3 for the mid-May and 8.2 inches for late May.
Karppinen said flea beetles were a problem across all treatments, but the early-seeded plots saw more damage.
Plant heights were not different.
Preliminary yield data found the mid-seeded treatment yielded higher than the other two, by about five bushels per acre. She added that even under irrigation the canola suffered from the extreme heat.
Videos of all the presentations are available on the Irrigation Saskatchewan YouTube channel.
