Seed & Chemical
Optimizing oat production
By Carolyn King
Oat is a competitive crop that is suited to central and northern Alberta growing conditions, but oat agronomic research has been lacking in Alberta in recent years.
“When I found out about the high yield potential of oat, I was fascinated by its potential to be a high-value crop for growers,” says Linda Hall, a weed scientist and agronomist at the University of Alberta.
Her excitement about oat’s potential inspired Hall to initiate a three-year project on optimizing production of food-grade (milling) oats in Alberta. She is working with Sheri Strydhorst, an agronomy research scientist at Alberta Agriculture and Forestry; Bill May, a crop management agronomist with Agriculture in Agri-Food Canada in Indian Head, Sask.; and Joseph Aidoo, a graduate student at the University of Alberta.
Based on Statistics Canada data, the average oat yield for Alberta for the past five years was 82.7 bushels per acre (3120 kilograms per hectare). This low average yield may be due in part because oat is often grown for hay and forage, rather than for grain, but also because oat is sometimes planted as a default grain crop when it’s too late to seed crops like wheat or canola. Results from variety trials and other sources show oat grain yields on the Prairies can be around 120 to 155 bushels. According to Hall, oat’s yield potential could be over 200 bushels under the cool, moist growing conditions preferred by the crop and using agronomic practices aimed at high yields.
“Although oat can be high yielding, the common variety grown in Alberta is not the best for high-value milling oats,” Hall notes. “So one objective of our project is to compare the yield of some newer high beta-glucan oat varieties. This may provide a new marketing opportunity for Alberta growers.” Food processors are interested in beta-glucan because this dietary fibre has important health benefits, such as lowering cholesterol.
“The most reasonable way to increase oat yield is to plant early and increase nitrogen fertilizer. Unfortunately, higher nitrogen tends to result in thinner seeds, which is not as good for the milling market, which prefers plump seeds with a high test weight,” she says. “So we need to find a balance – how do we maximize yield and yet still retain quality?”
Another effect of high nitrogen rates is a greater risk of lodging. Hall says, “Particularly in northern Alberta where moisture levels are usually good, when growers use higher rates of nitrogen, the crop tends to lodge, which causes harvesting problems and reduces yields. So our second objective is to determine if new plant growth regulators can improve the harvestability and standability of oat varieties.”
Plant growth regulators are synthetic compounds that modify plant growth; their effects on cereals may include shorter, stronger stems, reduced lodging and/or higher yields. Little research has been done on the use of growth regulators on oat in Canada, so Hall’s project could provide valuable insights.
The project, which started in 2014, involves two field experiments. Experiment 1 aims to evaluate the effects of nitrogen rate and oat variety on yield, lodging and beta-glucan content. In this experiment, nitrogen in the form of urea is banded at seeding. The treatments are 5, 50, 100 and 150 kg N/ha, with the amounts of the urea applications adjusted for the soil type and the amount of soil nitrogen. The experiment compares five oat varieties: AC Morgan (four to five per cent beta-glucan); OT3066 (four to five per cent beta-glucan); Stride (5.5 to six per cent beta-glucan); CDC Seabiscuit (5.5 to six per cent beta-glucan); and CDC Morrison (six to 6.5 per cent beta-glucan). In 2014, Experiment 1 was conducted at Edmonton and Barrhead, which are both in Alberta’s prime oat growing region.
Experiment 2’s objective is to assess the effects of four rates of a plant growth regulator on Stride, under the same four nitrogen treatments as in Experiment 1. The growth regulator is under
development and not yet registered for use on oat in Western Canada. The researchers chose Stride for this experiment because it showed lodging tendencies at higher nitrogen rates. In 2014, this experiment was carried out at Edmonton, Indian Head and Barrhead.
First year results
In Experiment 1 in 2014, oat yield increased as the nitrogen level increased, as expected. Hall says, “Our best yielding variety was AC Morgan, the variety used by most Alberta growers. But unfortunately Morgan had the lowest beta-glucan content of the varieties in our trial. CDC Morrison, the highest beta-glucan variety, was the lowest yielding.”
The optimal nitrogen rate for maximum oat yields varied depending on the oat variety and the location. For example, CDC Morrison’s yields were highest at the 150-kilogram rate at both locations, while AC Morgan’s yields were greatest at 50 kilograms at Edmonton and 100 kilograms at Barrhead. Higher nitrogen levels tended to decrease 1000-kernel weights and increase the percentage of thins. Also, plant height and lodging tended to increase as nitrogen increased, although there was minimal lodging at the sites in 2014. Height and lodging were variety dependent, with Stride lodging more than the other varieties.
In Experiment 2, at two of the three sites, the plant growth regulator reduced plant height and lodging. “As we increased the nitrogen, the height of Stride increased, and as we applied more plant growth regulator, we saw a reduction in height. So, by using a plant growth regulator, we were successful in counteracting the increase in height from the nitrogen,” Hall explains.
In 2014, the plant growth regulator did not affect oat yield. Hall notes, “Accurate timing is very critical for a plant growth regulator to be effective. In auxiliary experiments, we found that the growth regulator had to be applied at early stem elongation, after the herbicide application window and before fungicides are applied. To be effective, the plant growth regulator would have to be applied as a separate treatment.”
Once the project is completed, the researchers will be able to share up-to-date information on food-grade oat production with central and northern Alberta growers.