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Sorting out the stacks

New research in Alberta suggests big yield gains for wheat when combining some agronomic practices — especially dual fungicide applications

AC Foremost red spring wheat at Killam, Alta. The left side represents standard agronomic management while the right side includes standard agronomic management plus 30 pounds of nitrogen per acre applied prior to stem elongation. It also includes applications of plant growth regulator, flag fungicide and head fungicide. The plot was part of a three-year project in Alberta dedicated to identifying yield-maximizing practices in wheat and barley.

Farmers experiment with their agronomic practices all the time. It’s not uncommon to see them “stack” inputs, for instance by combining fertilizer, plant growth regulators (PGRs) and fungicides to see which combinations boost their yields.

But until recently, there has been little in the way of small-plot research into the yield potential of stacking agronomic practices on the Prairies. Researchers generally don’t like to test too many combinations because the size and scope of such experiments can get out of control. However, an Alberta Agriculture and Forestry (AF) research team — armed with funding from various industry groups — was up for the challenge.

Although the small-plot research project fell short of achieving its goals of 25 per cent yield increases in wheat and barley, the AF team was still able to identify practices which increase yield in both crops as well as in peas. The big news is the prominent role dual fungicide applications played on wheat yields: up to 17 per cent on one hard red wheat variety.

The team identified more success with wheat than with barley, says Sheri Strydhorst, lead researcher of the Advanced Agronomic Practices in Wheat, Barley and Pea to Maximize Yield and Harvestability project. The best input combination for wheat drove an 18 per cent yield increase averaged over three site-years while the best “stack” for barley saw an average seven per cent yield gain over the same period.

So why stack agronomic practices in the first place? Strydhorst says most agronomic research is based on testing one practice at a time, which may not reflect what many producers are doing on their farms.

“One of the unique things about this research is that it includes nitrogen fertilizer, PGRs and foliar fungicide in the same experiment. It was nice to mimic what growers are doing in the field so we can get results that are most applicable to what they’re doing.”

Amisk feed barley trial near Edmonton, Alta., where 64 treatment combinations were applied to test the impacts of stacking seeding rate, PGR, in-crop nitrogen fertilizer application and foliar fungicide. photo: Chelsea Jaeger

Craig Shand, an agronomist from south-central Alberta and a player in the Barley 180/Wheat 150 research trials of 2011 to 2014 (which were in many ways the field-scale precursors to Strydhorst’s research), says the study’s results will be a foundation for management practices for many years to come.

“These tactics that Sheri is working on are definitely taking us to a new level of management and a new level of yield potential,” Shand says.

Key takeaways

A total of 50 wheat and barley agronomic practices and 15 pea management practices were duplicated at five locations throughout the province over the three-year project, resulting in a total of 15 site-years of data. The research locations included irrigation and dryland plots near the southern Alberta city of Lethbridge. Other plots were located near the town of Killam in east-central Alberta, just north of Edmonton in central Alberta and close to the town of Falher in the northern Peace region.

“All of the agro-climatic zones in the province were represented,” says Strydhorst.

Following are the project’s key takeaways.

Dual fungicide on AC Foremost

Perhaps the most significant find of the study was the impact of a dual fungicide application on AC Foremost (photo at top of page), a red spring wheat variety. This accounted for most (17 per cent) of the yield increase in the project, followed by the PGR trinexapac-ethyl (2.3 per cent) and 30 pounds of actual nitrogen per acre of post-emergence nitrogen fertilizer (0.8 per cent). The combined use of trinexapac-ethyl and dual fungicide application increased AC Foremost yields by 18 per cent.

These results confirmed Strydhorst’s belief that not all varieties are created equal and not every one will respond the same way to a given set of agronomic practices. Depending on the cultivar, the combined use of post-emergence nitrogen, Manipulator (a chlormequat chloride PGR) and dual fungicide increased wheat yield by seven to 26 per cent.

“I think in the past everyone figured ‘wheat is wheat’ and we can manage it the same. But when you start seeing that you can put $100 worth of input into two different varieties and one gets you the payment back while the other one doesn’t, I think there are some really good opportunities for growers to fine-tune their management based on the cultivar to make the most efficient use of their inputs.”

The nitrogen, PGR and fungicide formula performed best under wet conditions, says Strydhorst. While that is hardly surprising, this knowledge can still help producers adjust their management accordingly.

“Growers know that if you get rain you are going to get yield, but also knowing they have the opportunity to input extra nitrogen fertilizer and foliar fungicide and get bigger yield responses when they get that rain can be beneficial.”

Little gain for feed barley

Overall, feed barley yields fared poorly despite the large number of agronomic practices applied. Individual agronomic practices showed small yield increases: five per cent from post-emergent nitrogen, two per cent from the Manipulator PGR and three per cent from a dual foliar fungicide application — all on the feed barley cultivar Amisk. Pushing the seeding rate to 355 plants per square metre only drove 0.4 per cent in increased yield but resulted in earlier maturity.

The combined use of a seeding rate of 355 plants per square metre, Manipulator and dual fungicide increased Amisk yields by just under seven per cent.

“We were not able to push Amisk feed barley as hard as the AC Foremost wheat,” says Strydhorst.

Middling results for PGRs

Lodging in field peas is a huge problem for producers, particularly at harvest time. The research team tested multiple unregistered PGRs on peas and inter-row seeding to see which practice improved field pea standability the most.

“We found the PGRs really did not improve standability and didn’t help yield,” says Strydhorst. “It’s disappointing but it is an important thing for growers to know. Don’t waste time as they are not registered and they shouldn’t be registered for field pea use.”

Inter-row seeding — in which stubble from the previous pea crop is left standing to support the new crop — was found to be far better than the PGRs in reducing lodging, says Strydhorst.

Barley is another consideration, she says. “With barley we used the PGR Manipulator. It is not registered for use on barley but we were testing to see if it works and it didn’t really help out.”

This doesn’t mean there is no place for PGRs in barley crops, says Strydhorst. “There are different active ingredients out there. Manipulator may not be a fit with barley but there is another active ingredient coming that works better on the crop and we are working with the company as they pursue registration.”

The study revealed some potential for PGRs on wheat depending on the cultivar. “The PGRs worked on the wheat to varying degrees. Something like an AAC Penhold (photo below) didn’t work with it but it often helped the standability of CDC Go. We are continuing to figure out which cultivars of wheat respond to PGRs better than others on a consistent basis.”

AAC Penhold Canadian Prairie Spring wheat at Killam, Alta. The left side represents standard agronomic management while the right side includes standard agronomic management plus 30 pounds of nitrogen per acre applied prior to stem elongation. It also includes applications of plant growth regulator, flag fungicide and head fungicide. photo: Sheri Strydhorst

New PGR registrations

Agronomist Craig Shand says it’s important for companies and industry to advocate for PGRs to help make sure the entire supply chain will accept wheat or barley grown with those products.

“With barley, farmers are patiently waiting for Syngenta to register Moddus, a new trinexapac-ethyl PGR. I see Syngenta working really hard on getting approval from the brewers and maltsters before it gets registered so we can go ahead and implement that product when the time comes. We are in a bit of a holding pattern on barley, especially malt barley, when it comes to PGRs at the moment.”

Wheat could get a boost from Manipulator now that the U.S. has established a maximum residue limit (MRL) for the PGR on spring wheat, winter wheat and durum. The product has been registered for those crops in Canada since 2015 but a lack of policy on the U.S. side created trade difficulties. However, the 2018 drought season in much of Alberta rendered Manipulator less effective regardless of resolution of the MRL issue, says Shand.

“Now that the MRL is out of the way we are hoping we can get back to some good growing conditions here and get some Manipulator sprayed on wheat this season,” Shand says.

The Advanced Agronomic Practices in Wheat, Barley and Pea to Maximize Yield and Harvestability project ran from 2014 to 2017 and was funded to the tune of just under $788,000 by the Western Grains Research Foundation, $788,000 from the Alberta Crop Industry Development Fund, $150,000 from Alberta Innovates Bio-Solutions, $300,000 from the Alberta Wheat Commission, $290,000 from the Alberta Pulse Growers Commission and $30,000 from the Alberta Barley Commission.

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