16 | Advancing Seed in Alberta grower is going to be able to harvest earlier, and as we found last fall, can be an important asset.” Beres says his emphasis is shifting from the practice of thinking of seeding in terms of a volume or a bulk per unit area, to a spatial density per unit area. So, seeds per square metre or per square foot. “The problem is that the ‘bushels per acre’ rule of thumb resulted in a lot of plant stand variation from one class of wheat to another because kernel size, shape and weight varies considerably and more so now, even within classes, given that kernel visual distinguishability has been phased out as of 2008,” he says. “For example, we had many growers back in the old days who, even with winter wheat, went at about 200 seeds per sq. m., or 20 seeds per sq. ft. We were able to show that that needs to be up around 450 seeds per sq. m. We were able to show with those high- yielding classes such as durum or the high-yielding varieties within CWRS, they could withstand the higher density and not lodge. “As a starting point, the ‘sweet spot’ for winter wheat would be 450 seeds per sq. m.; and for springs across the board, 400 seeds per sq. m., but some high-yielding, strong-strawed spring varieties are definitely going to respond to rates higher than that as well.” No matter your variety of wheat, Beres stresses the importance of ensuring a good germination rate and good vigour. But equally important is calibration. “Growers need to think about planting spatially per unit area, such as 40 to 45 seeds per sq. ft., and that they know what their kernel weight is,” he says. “The kernel weight can alter what they think their planting is, it’s pretty significant.” Strydhorst agrees. “To achieve 40 seeds per sq. ft., a seed lot with a thousand kernel weight of 37 g/1000 seeds will require 142 lbs seed/ac compared to a seed lot with a thousand kernel weight of 41 g/1000 seeds which will require 157 lbs seed/acre.” Growers can use Alberta Agriculture and Forestry’s Cereal Seeding Rate Calculator (www.agric.gov.ab.ca/app19/ loadSeedRateCalc) to assist them with these calculations. Janet Kanters Sheri Strydhorst is an agronomy research scientist with Alberta Agriculture and Forestry. Brian Beres is a research scientist with Agriculture and Agri-Food Canada. Introducing the Alberta Seed Guide’s eNewsletter Alberta’s Only Seed Specific Newsletter Delivered to Your Inbox Subscribe for free online: seed.ab.ca Stay Ontop of Seed Technology, Emerging Best Practices and Practical Information that Impacts your Farm Business