USA, ID: Wheat, barley expectations tempered by quality concerns

Recent reports of low test weights and widespread sprout damage are tempering once lofty expectations for this season’s wheat and barley crops in southern and eastern Idaho, the Post Register reported on August 26.

Juliet Marshall, a University of Idaho plant pathologist and head of the Department of Plant Sciences, conducts wheat and barley variety trials in Kimberly, Rupert, Aberdeen, Soda Springs, Idaho Falls, Ririe and Tetonia. At each location, she’s confirmed crop quality problems associated with kernels accumulating starch amid excessive heat, compounded by untimely rains and hail late in the season.

Test weight measures the pounds of grain in a bushel. A test weight above 60 pounds is considered optimal. After recently finishing her fall grain harvest, Marshall reported the average test weight was low overall, and in hard white fall wheat varieties in her trials at Rupert was just 53 pounds. Some hard white test weights came in below 48 pounds – evidence that thunderstorms just before fall grain harvest contributed to sprouting, thereby depleting kernels of their starch.

Sprout damage has ranged from 5% to 20% throughout some production areas. In malt barley, which requires kernels to sprout uniformly during the malting process, sprout damage is especially concerning and can be cause for rejection at such high levels. Furthermore, when starch content falls due to high heat during grain-fill, the amount of protein as a percentage of the kernel increases. High protein levels can be cause for rejection of soft white wheat varieties.

Fall grains are typically ready to harvest prior to the arrival of August monsoons. This season, however, a cool and damp spring considerably delayed crop progress, pushing back harvest and elevating the risk of thunderstorms contributing to sprout damage.

“Our beautiful winter crop held quite a lot of promise and still does if a grower was able to get the harvest in before any rains, but the changing weather and impacts associated with these August monsoons really emphasizes how our odd spring has resulted in additional problems,” Marshall said.

Optimism abounded among grain farmers in the state’s southern and eastern growing areas earlier in the season. The unusually cool and damp provided ideal conditions for plants to produce more seed-bearing stalks, called tillers, potentially setting the stage for big yields. Foliar diseases such as stripe rust and scald were also very low despite the favorable weather. But the spring conditions also stymied fall grain growth and delayed emergence of spring grain crops by more than two weeks, and the weather abruptly turned from below normal to excessively hot at a time while plants were filling or at flowering, shocking them at crucial points in their development.

During May, average temperatures were well below normal for 21 days at the National Weather Service’s Burley location in southern Idaho. On May 30, for example, Burley’s average temperature was a whopping 20.1 degrees below normal. The heat, however, arrived with a vengeance. In southeast Idaho, at Pocatello Regional Airport, temperatures were above average for 28 days of July. In eastern Idaho, Idaho Falls set record high temperatures of 97 degrees on July 17 and 96 degrees on July 29.

“The heat hit it late in the growing season and that contributed to a shorter window for grain-fill,” Marshall said. “We still had excellent yields in winter wheat, but the final couple of weeks of grain-fill and carbohydrate accumulation happened in the heat, which hurried the crop toward maturing but resulted in lower test weight.”

Marshall warns the outlook could be worse for spring crops. Delayed from emerging by the cool spring, spring crops were exposed to even more hot days during the critical starch-accumulation period, and there’s still more opportunity for them to sustain sprout damage.

“Spring wheat and barley yields were not as high as we were hoping, and we also have sprout damage later on top of it,” Marshall said.

In northern Idaho, UI Extension cropping systems agronomist Kurtis Schroeder said fall grain has avoided sprout damage. Crop quality has generally been acceptable, aside from some fields in the Camas Prairie that aren’t salvageable from recent heavy rains and hail.

“I’ve heard of some issues with test weights that are a little lower, but they’re not bad,” Schroeder said, adding test weights throughout his region were extremely low last season due to water stress amid a drought.

Spring wheat in northern Idaho was planted two to three weeks late due to spring rains, and Schroeder anticipates the delayed planting could hurt test weights. However, he said yields are significantly better than last year.

Casey Chumrau, executive director of the Idaho Wheat Commission, takes solace in knowing despite the variable test weights, yields will, nonetheless, be much higher than last season overall.

“We had really high hopes and now we’re seeing the reality a little bit more,” Chumrau said. “The winter wheat I think is still an overall positive story. With spring wheat, still time will tell.”

Chumrau said the farmers from throughout the state who serve on her commission have reported fall wheat test weights from the mid-50s to north of 60 pounds.

“Overall, I think this crop is still going to be acceptable for end users,” Chumrau said.

26 August, 2022