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Closing the yield gap in Alberta

“The people who run field trials are meticulous – they run them in a standardized way, they maintain them well, use a good fertilizer treatment, use appropriate management strategies,” says Good, a professor in the department of biological sciences at the University of Alberta, whose research focuses on nutrient uptake efficiency in field crops.

“But they are the standard. Then you ask what real farmers get? The good farmers are managing things well, and if you were to come along with a good management team and fancy academic researchers, you still couldn’t improve what they do. But there are some producers who don’t get those yields.”

Good believes those gaps can be overcome with a combination of the right genetics and improved management practices.

Last year, Good and his University of Guelph colleague Tejendra Chapagain co-authored a report entitled “Yield and production gaps in rainfed wheat, barley, and canola in Alberta,” which argues that closing those gaps could result in potential yield gains of 3.42 million tons of wheat, 1.92 million tones of barley and 1.65 million tons of canola in Alberta each year worth $769 million, $297 million, and $564 million (USD) respectively.

The report lays out management gaps between attainable and actual yields of these three crops, and offers suggestions for improved efficiency in crop production.

Yield gaps
Good and Chapagain collected data from co-operative trials for variety registration run in Western Canada, comparing it to publicly available crop production data by region.

The study looked at 18 wheat genotypes, 20 barley genotypes and 22 canola genotypes tested at 21 locations across north, south, and central Alberta between 2005 and 2014.

The researchers considered “optimal” crop and nutrient management practices including soil testing and targeted application of nutrients, as well as ideal planting density and control of abiotic stresses.

What they found? The average actual yields for rainfed wheat, barley and canola over the 10-year period were 3.20, 3.46, and 2.06 tonnes per hectare, where attainable yields were 3.96 (wheat), 4.32 (barley) and 2.68 (canola) tonnes per hectare.

“The management practices of the actual farm yield in the Alberta Prairies mainly constitutes large-scale production of a few genotypes with effective chemical weed control, higher soil disturbance due to removal of crop biomass after harvest, and reliance on synthetic nutrient formulations which can result in nutrient deficiencies in cropping systems,” the study concludes.

Key areas of improvement include the use of soil tests (according to public data, only 20 per cent of Alberta’s fields have been sampled using soil tests, and some of those only every three years). The result: “growers apply fertilizer based on reasons other than available soil N” – such as past experience, or attempting to hit yield goals.

But this approach can be counterproductive, when targeted nutrient applications result in better productivity over time.

The authors conclude soil testing, nutrient management planning, and minimum tillage/zero-till are considered top-performing best management practices in Alberta that could potentially increase expected net revenues by 19, 33, and 35 per cent, respectively.

Good says tools such as precision mapping can be helpful for increasing efficiency, but only if yield maps are consistent. Over the long-term, he says, producers should be able to discern whether, for example, low-lying areas are producing poorly due to lack of fertilizer or salinity.

Once producers have the data, they should go in search of its rationale.

“Agronomists say you have to go and walk the fields. That’s what precision management is about,” he says. “There’s no point having that much information unless it makes you a more cost-effective producer.”