Grainswest - Spring 2019

Spring 2019 grainswest.com 49 BYMELANIE EPP • PHOTOS COURTESY OF GRAHAM COLLIER Information Service tools available at weatherdata.ca. The resource allows farmers to examine weather variability in their areas. “They can go back to 1961 and see how the frost-free years varied year to year,” said Wright. “They can look for trends, and they can also notice that there can be abrupt changes year to year.” Frost-free days means the number of days between the last fall day it reaches -2°C to the first day it reaches -2°C again in spring. Wright pointed out that frost impact varies. “A -2°C frost this year may do nothing, whereas a -2°C frost in another time can be way worse, depending on how long the frost lasts, what the moisture content of the air is and what state the plants are in,” he said. Other factors important for growth is growing-degree days or heat units. “Plants are funny,” said Wright. “It’s very predictable how much heat it takes to grow a plant. We may have 120 frost- free days in a year, but the amount of heat that occurred [during] those will dictate how fast the crop grows to maturity. It’s not just a day thing. “The only thing that’s normal is variability and that it chang- es abruptly without any warning,” concluded Wright. “Mother Nature is always throwing curveballs.” SURPRISING RESEARCH RESULTS Under the supervision of Dean Spaner and Agriculture and Agri- Food Canada agronomy research scientist Brian Beres, PhD stu- dent Graham Collier conducted a series of five ultra-early seeding experiments funded by AWC. Typically, early seeding date studies have been based on date, but Collier’s experiments looked at soil temperature. In the first experiments, he planted three cold-tolerant varieties, as well as CWRS variety AC Stettler at soil temperatures between 0°C and 10°C in two-degree increments. AC Stettler performed just as well under early-season cold con- ditions as cold-tolerant varieties. The latter were spring wheats created by crossing winter and spring varieties that yielded cold-tolerant traits. Although they didn’t exhibit 100 per cent of the cold tolerance that they do when planted as winter wheat, these crosses did provide an increase in tolerance. “That’s actually really good news for us in terms of imple- menting an ultra-early seeding system because it means that we don’t need specialized varieties to do it,” said Collier. “We have the genetics available in varieties that we’re already using, so it just becomes a matter of choosing which varieties are best suited to that use.” The study found that optimal seeding temperature was as low as 2°C. From 2°C to 6°C, there was no yield penalty. Yield was re- duced in stands planted at 10°C. At 0°C, a significant decrease in yield was not seen, but the overall stability of the seeding system was compromised. Zero degrees worked surprisingly well, said Collier. “There was essentially no yield penalty. You’d expect that you’d lose a lot of plants to frost. But the most stable systems were those 2°C to 6°C seeding dates, whereas your variation started to increase quite a bit at 0°C and 10°C.” The second experiment looked at building an agronomic sys- tem around the idea of ultra-early seeding. Here, Collier looked at a seeding date, seeding rate and a couple of cold-tolerant varieties. “There were not any real big surprises coming out of that,” said Collier. “The higher seeding rate, as you can imagine, increased the stability of the system.” “The single most important factor across the experiment in terms of maintaining yield was seeding rate,” he added. That optimal seeding rate will differ depending on where it’s planted. The recommendation will be the maximum seeding rate for a given area. As well, the experiment evaluated seeding depths of one inch and two inches and found that depth had no effect. The results of the first two experiments show great promise. “We’re going to be able to use our conventional spring varieties in an ultra-early system,” said Collier, adding that it’s very impor- tant to use an optimized seeding rate, and to plant in the ideal soil temperature range of 2°C to 6°C.” Soil temperature can be measured using a soil thermometer at a depth of five centimetres at the same time each day. Collier measured at 10 a.m. in his experiments. “The first time you see that your soil is at 2°C at your selected time is when we went ahead and seeded. We started referring to the soil temperature target as a trigger temperature for seeding. There will be varia- tion up and down after that trigger temperature is hit.” The three additional experiments evaluated residual herbicide systems for ultra-early seeding, various nitrogen-application technologies and a wide variety of genetics for their suitability for ultra-early seeding. Results should be available early in 2020. With funding fromAWC, research scientists have conducted five ultra-early seeding experiments.