PGRs, nitrogen may be good barley pairing

A research project from Saskatchewan seems to have found a fix to the on-again, off-again issue of lodging involving nitrogen and plant growth regulators.

The issue of high-yielding genetics with low straw strength was a particular problem in 2010 2012, and 2014, when barley and wheat had high production that coincided with severe lodging.

“We had very high production years, lots of moisture and lots of conditions that promoted lodging,” Mitchell Japp, research and extension manager at SaskBarley, said at the recent Top Crop Summit in Saskatoon.

“So at the time, we had relatively poor genetics for lodging, and the straw strength wasn’t there, and so our fertility management was one of the few things that we had to be able to control lodging.”

Controls were promoted such as increased potassium to improve straw, reduced seeding rates and lowering nitrogen to ensure plants stayed standing and protein stayed low enough for malt barley.

In 2014, PGR Manipulator with the active ingredient chlormequat chloride was registered for wheat, and researchers at the Indian Head Agricultural Research Farm in Saskatchewan performed trials on barley with it for application timing and effect of the product. Their results were promising.

“They found that it decreased height, decreased lodging and even in the absence of those, sometimes led to a yield increase,” Japp said.

“And certainly if lodging was present, there would be a yield increase.”

However, in 2021, Manipulator was yellow labelled by Keep it Clean, and many contract companies didn’t want crops that used it.

However, the same year, a different PGR was released and then trialled. It was found to be most effective, although PGR’s influence on a crop varies depending on location, environmental conditions and variety.

“In 2020, ‘21, and ‘22, there was a lot of really low-producing sites,” Japp said.

“Very low yielding, high stress, which is not the conditions to use a plant growth regulator in. And so what they saw was a significant yield decrease from the control treatment.”

Other sites had higher yields but no significant improvement over the control methods of lower nitrogen, lowered seed rate and additions of potassium.

In 2023, they ran an enhanced growing project with six varieties and four management packages. The third package focused on plant height and included a PGR.

However, it was another dry year, which meant mid-range yield and no “real” lodging pressure , although the PGR did help reduce height despite these challenges.

To really trial the efficacy of the PGR, Japp wanted to induce lodging.

To do this, they applied nitrogen alongside the PGR at the Indian Head site in 2024 and were granted a cool wet spring, good heat in July and wind and rain in August. These results were some of the best, with clear differences to note benefits.

A full rate of Modus had a notable decrease in lodging compared to the untreated control. Both varieties, CDC Fraser and AAC Connect, responded the same.

In comparison, the other trial sites at Melfort and Prince Albert saw nearly no effect on yield or lodging because they were dealing with dry conditions.

Japp said the key is to start with good genetics and find a good balance between products, whether it’s the right amount of nitrogen for a good yield, alongside a PGR, or not using a PGR at all.

Seeding rate should also be considered because a higher rate is good for weed management. Staying economical with the rate is important for yield and lodging.

“I think we can say comfortably that a timely PGR application, in really good growing conditions, can improve both harvest operations and increase yield,” he said.

“If the conditions aren’t optimal, there’s may be no benefit. Maybe you get a slight lodging decrease but not likely yield (improvement). And in the poor conditions, it does remain a (yield) risk, so we’re trying to avoid those risky conditions.”

More information is yet to come because a project is currently underway to predict risk of lodging at an early stage for better indication of the potential benefit in using a PGR in a barley crop.