GrainsWest Spring 2021

Winter 2021 grainswest.com 23 Improved genetics can also play a role in the development of varieties that can be seeded earlier, he said. “We can plant the crop when the top couple inches of the soil reach 0 C, and through improved genetics it is easier for the plant to sync with the environment.” Combine genetic improvements with agronomic practices and it is possible to break through the invisible ceiling of yield constraints, he said. “I don’t think there is any one magic bullet, but through this yield gap process we can better understand why farmers aren’t achieving higher yields. And with that we can guide research in genetics and agronomic practices to push through that yield ceiling.” The lead researcher on the GYGA is Patricio Grassini, University of Nebraska–Lincoln associate professor in the Department of Agronomy Horticulture. He believes understanding the yield gap will help farmers improve production efficiency as well as increase world food supply. The Yield Gap project has determined yield potential for wheat across the central U.S. fromMexico north to the Canadian border. The potential wheat yield over that large geographic area is about 80 bu/ac. The actual average yield is about or 39 bu/ac, a gap of 41 bu/ac. “It is a large area and obviously there is wide variability in wheat yield over that region, but it is a starting point,” said Grassini. “And the other important aspect is that it shows there is room for improvement.” Like Beres, he hopes computer modelling to be completed this year will determine Canada’s wheat yield potential. The determination of yield potential is phase one, while phase two of the project involves the collection and analysis of farm data to determine what agronomic and management practices farmers employ. This will include information such as seeding dates and rates, crop fertility rates, weed and pest control practices and more. “Farmers have collected a huge amount of data. If we can begin to analyze that it will give us some idea what needs to be changed or improved,” said Grassini. “And it may also show us where more research is needed to improve plant genetics or agronomic practices.” The Yield Gap project began its work with soybeans, wheat and corn, but will potentially expand this selection to include canola, pulse crops and barley, said Grassini. Sheri Strydhorst is an Alberta Wheat Commission agronomic research specialist who is studying the wheat yield gap primarily from a fertility standpoint. She said the goal is first to determine the theoretical yield potential of wheat and compare those numbers with real production averages. “Using models and other techniques we need to define the theoretical yield potential, which isn’t easy,” said Styrdhorst. “The trick in optimizing yield is in managing the proper genetics for the environment you are in and applying proper agronomic practices.” One research project has determined fertilization of wheat well above usual soil test recommendations will produce a yield increase. The question this raises is, does it make economic sense to do so? “Often, if there is a yield shortfall, it is due to a nitrogen deficiency,” said Strydhorst. “My research has shown there is still a yield increase in wheat at a nitrogen rate of up to 200 pounds per acre. The yield is increasing but when does it stop being economical? When do we reach that point of diminishing return?” Even if and when the wheat yield gap is calculated, many agronomic, management and environmental factors in combination can affect yield, she said. For example, targeting higher yields with higher fertility may also result in lodging while greater use of plant growth regulators can reduce it. “And there are also socio-economic factors to consider,” she said. “Targeting higher yields means increased input costs and higher risk, so will farmers be able to get financing for operating loans? And again, with higher rates of fertility there could be increased environmental risks or concerns.” Strydhorst said there is probably potential for Canadian farmers to produce 150 bu/ac wheat yields, but questioned the value in this ambitious target. “In Canada we also have to consider the trade off between yield and protein,” she said. “The higher the yield, the lower the protein.” If Canada is to maintain its reputation as a producer of high-quality CWRS milling wheat, maximizing yield in this particular class may not be an option, said Strydhorst. In New Zealand, Western Canada and the U.S. Midwest, farmers and researchers alike have demonstrated wheat does have greater yield potential. Considerable effort is being put into the measurement of the wheat yield gap, which will also reveal its yield potential. This will determine where we are and where we can be, but how do we get there, and is it worth the effort? “The trick in optimizing yield is in managing the proper genetics for the environment you are in and applying proper agronomic practices.” —Sheri Strydhorst