Ontario Grain Farmer September 2022

NO SHALLOW SEEDS The study also compared seeding depths of one, two, and three inches. While depth did not impact yield in either year, lodging increased in oats planted shallower than one inch. "To have a lodging resistant oat, you want crown roots that are deep and wide," Nasielski says, meaning lodging increases when crown roots are shallow. He recommends setting the drill slightly deeper than one inch so that even the seeds that are shallower than average are planted one inch deep. Nasielski knows some farmers are concerned about deeper seeding delaying emergence, but the research shows that the delay does not translate into a yield loss. There was no yield penalty to seeding as deep as 2.5 inches. MAINTAIN SEED RATES The standard seeding rate for the study was 300 seeds per square metre. The seeding rate experiment compared 150, 300, and 400 seeds per square metre. While Nasielski knows of agronomists in the United Kingdom who recommend higher seeding rates to reduce lodging, he found the opposite true. The half-rate reduced lodging in some cases but had variable yield results. Since the findings were inconsistent, he encourages growers to stick with the standard seeding rate or the rate they find works for their location. LIMITED N BENEFIT While the recommended nitrogen rate for oats in Ontario is 32 to 68 pounds per acre, researchers wanted to determine what happens when the rate is increased, and applications are split. The standard nitrogen rate in the study was 90 kilograms per hectare (80 pounds per acre), split between 60 kilograms pre-plant and 30 kilograms at growth stage (GS) 39 or once the flag leaf is fully unrolled. The experiment tested full application preplant, full application in-season, 60 kilograms pre-plant and 30 kilograms in-season, and 30 kilograms pre-plant and 60 kilograms inseason. The trials tested two in-season timings, GS 32 when the second node is detectable and GS 60 just after head emergence. Application at GS 60 is not recommended. No significant differences were observed in yield or lodging among the different trials. Although the ideal nitrogen rate depends on location, Nasielski saw no real benefit to higher rates. "The typical rates seem to be good enough, especially since yields are limited by temperature more than any other factor," he says. SOMETIMES A PGR PAYS The last experiment involved growing oats at five different nitrogen rates up to 160 pounds per acre, with and without Syngenta's plant growth regulator (PGR) Moddus applied at GS 30 to 32. Lodging increased with more nitrogen, but the increase in lodging was lower with Moddus. The PGR reduced plant height by an average of eight centimetres but had little effect on yield. "If you're going to push nitrogen rates on an oat crop, it pays to have a PGR," says Nasielski. While most growers will find this conclusion intuitive, he appreciates confirming the evidence. NEXT STEPS This year Nasielski has partnered with three farmers in northern Ontario to test key findings on a field scale. An eight-acre field is being used to compare yield and lodging when oats are planted at five and seven-inch row spacings and soybeans at 10 and 14-inch row spacings. Farmers are also testing the timing of PGR application and its impact on oat straw. "We want to know if you are better off targeting the early or late part of the recommended application window," Nasielski says. "We're also looking at the effect of temperature at application timing, and we want to understand the whole data set to find out how we can get a more consistent effect." This research is funded by Grain Farmers of Ontario, the Ontario Ministry of Agriculture, Food and Rural Affairs through the Ontario Agri-Food Innovation Alliance, PepsiCo (which owns Quaker Oats), and Syngenta. PepsiCo funding was not used for this project's plant growth regulator portion. l ONTARIO GRAIN FARMER 11 SEPTEMBER 2022 This article features research supported by Grain Farmers of Ontario.

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