Panel will discuss falling number test

Matthew Weaver

Capital Press

A panel discussion will give wheat farmers information about falling number, which can impact the price they receive at grain elevators, during the Spokane Ag Expo and Pacific Northwest Farm Forum. USDA researcher Camille Steber says falling number is all about rainy weather and susceptibility to sprout damage. Washington Grain Commission CEO Glen Squires says the industry is still in a discovery phase to learn more about the issue.

In recent years, more farmers have seen the price they receive for their grain reduced by the falling number test.

A panel of industry experts will talk about the test during the 9 a.m. session Feb. 4 in Salon IV at the DoubleTree Hotel as part of the Spokane Ag Expo and Pacific Northwest Farm Forum.

The falling number test is used to measure wheat quality, particularly in the event of sprout damage.

The test involves grinding a small sample of grain and mixing it with water to create a paste. When placed in boiling water, the slurry thickens. If the enzyme alpha amylase, which is associated with sprout damage, is present, it begins to consume the starch, reducing the slurry’s thickness.

A small, weighted plunger then passes through the paste. The test measures the time it takes for the plunger to fall, plus 60 seconds for stirring.

The industry standard for soft white wheat is 300, meaning it takes 300 seconds for the plunger to fall. Numbers below that generally indicate lower quality wheat that could run into processing problems.

Farmers receive a reduced price for wheat that is below that standard.

“It’s an opportunity for growers to become more educated about the failing numbers, what it is, how is the test conducted, what are the causes, are there certain varieties,” said Glen Squires, CEO of the Washington Grain Commission, of the panel discussion. “A lot of producers were affected negatively by falling numbers. I think a lot of growers have questions about it.”

Growers can be docked for falling number results on the price they receive for their grain at elevators. Discounts vary according to elevator.

“It’s hard to know whether it’s just a cyclical thing or whether there’s some varieties that are more prone to that,” Squires said. The commission is funding research to consider variety susceptibility to sprouting and low falling numbers.

Camille Steber, USDA Agricultural Research Service wheat geneticist, believes the increased prevalence of dockage as a result of the falling number test in recent years is “entirely about weather” and genetic susceptibility in the wheat.

“Even rainfall that isn’t enough to wet the soil is enough to wet the spike,” Steber said. “The very start of germination is going to give you the expression of alpha amylase, even if you don’t have physical sprout.”

Steber advises farmers:

• Harvest wheat quickly after it reaches maturity to reduce the risk of rain. “The longer it sits in the field, the bigger your risk,” she said.

• Avoid cultivars known to be susceptible. “If you have to grow a susceptible variety, my suggestion would be to grow two cultivars separately, not intermingled, that have different maturity dates, so if you do have an isolated cold shock or rain event, you won’t lose the whole crop. Chances are it will hit one and not the other.”

• If you do have low falling number, it couldn’t hurt to store it for a while to see if it goes up a bit.

Steber encourages farmers to ask questions during the discussion panel.

“We have a tendency to forget what people do and do not know,” she said. “We have a tendency to want to tell people about our latest and greatest results, but it’s from people’s questions that I learn what I need to present.”

Squires said there are many questions right now as to whether there are steps growers can take, or if something needs to be done during the breeding process to avoid a low falling number, or even if something could be improved in current testing to create more uniformity in test results.

“I think we’re all in a discovery phase,” Squires said.


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