String of high overnight temps likely to affect rice grain quality

By Ryan McGeeney
The Cooperative Extension Service
U of A System Division of Agriculture

Fast Facts:

High summer overnight temps in southern half of state likely to affect rice grain
“Chalky” appearance doesn’t affect nutrient quality
Rice harvest now in very early stages

(387 words)

STUTTGART — High nighttime temperatures during recent summer months will likely affect the quality of harvested rice in the southern portion of the state, according to University of Arkansas System Division of Agriculture experts.

Jarrod Hardke, extension rice agronomist with the Division of Agriculture, said this week that a stretch of about 20 days this past July, during which nighttime low temperatures never dropped below 75 degrees in the southern portion of the state, will likely result in rice grains with a “chalky” or opaque appearance at harvest.

“It’s of specific concern to rice during heading, between flowering and the final grain filling,” Hardke said. “Especially if the nighttime temperatures never fall below 75 degrees for a stretch of five to seven days or more.”

Although many consumers may think of rice as being typically white in appearance, healthy rice grains are actually translucent when harvested and polished, Hardke said. But when a rice crop goes long stretches without adequate “cooling down” periods at night in the months before harvest, it can affect the consistency of both the appearance and texture of the harvested product, he said.

“When you’re bagging that grain to sell, that’s something you can visually see in the bag,” Hardke said. “You’ll see the off-color appearance of the kernels. When you cook it, it can cause inconsistencies in grain texture and how they cook.”

“As with most industries, the rice industry’s looking for a uniform product, in terms of appearance, taste, and how it cooks,” he said.

The discoloration does not affect the nutrient quality of the grain, however.

Arkansas rice is predominantly grown in the eastern half of the state, and about one-third of the state’s total rice acreage is planted south of U.S. Interstate 40 between Little Rock and Memphis. Arkansas rice growers are only now beginning to harvest the earliest-planted rice fields, and growers in the southern portion of the state are ahead of those growers to the north of I-40, where the majority of the state’s rice is planted.

Hardke said that weather data recorded in Jonesboro reflected very few nights in which nighttime temperatures remained above 75 degrees over the summer in the northern portion of the state.

“In theory, the northern half of the state is positioned to have a better crop than the southern half,” he said.

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Media Contact: Mary Hightower
Dir. of Communication Services
U of A Division of Agriculture
Cooperative Extension Service
(501) 671-2126
mhightower@uada.edu

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