Record Texas heat likely missed rice flowering but could affect dry-down

texas rice

Record Texas heat could cause drained rice fields to dry down faster than anticipated — photo courtesy Texas Farm Bureau

Most areas of Texas have set or tied high temperature records this summer, including a string of 100-plus days last week, according to the state climatologist.

Although much of the state’s rice acres were planted early enough they are past the heat-sensitive flowering stage, growers who have already drained fields could be surprised by the hot, dry conditions.

Dr. John Nielsen-Gammon, who is based in College Station, says San Angelo is experiencing its hottest summer to date, and much of the state is experiencing above-average temperatures. Records were tied or set in Brownsville, Amarillo, San Angelo, Waco and Fort Stockton over the past seven days, with the highest recorded temperature at 114 in Waco and 108 in San Angelo.

That puts Texas on pace to experience its second-hottest summer on record.

Extreme high temperatures have stressed plants and vegetation around the state, according to Texas A&M AgriLife Extension Service reports.

Dr. Lee Tarpley, Texas A&M AgriLife Research plant physiologist, Beaumont, says all plants and vegetation experience heat stress when daytime and nighttime temperatures hit extreme highs.

The heat and dry conditions have put the progress of some crops in doubt.

“A plant’s most sensitive period is flowering,” he says. “Most crops like corn and sorghum are well beyond that point, so they should be fine if there weren’t problems already.”

Most rice fields were planted early enough to get past flowering stage before extreme temperatures arrived, Tarpley says. But growers who have drained their fields already should watch them closely because the hot, dry weather could speed crop dry-down.

Some later-planted rice fields may show damage and experience reduced yields, but most fields were expected to produce good yields, he says.

The combination of high daytime and nighttime temperatures can negatively affect both flowering and processes in vegetation, such as photosynthesis and respiration. This can hurt cell membranes and metabolic efficiency.

“Anytime a plant gets out of the optimal range of temperature, it can be tough and there will be incremental damage from heat stress,” Tarpley says. “The combination of heat and drought stress can be worse than either of the two individually.”

Heat stress can damage cell membranes, he says, and drought stress can cause leaves to shut down transpiration, which further increases leaf temperature. These stresses affect the plant’s ability to photosynthesize.

When leaves start to wilt during drought stress, the crops are likely already experiencing economic damage, Tarpley says.

“It’s hard to completely recover from that,” Tarpley says. “If you catch the drought stress early, the plants can recover, but it’s downhill from there when it hits a certain degree of stress.”

One thing that can help protect plants from high temperatures is enough water to allow their metabolic processes, such as transpiration, to work efficiently, Tarpley says.

Some later-planted commodity crops, especially cotton, could be susceptible to the recent high temperatures, especially if they are coupled with a lack of moisture, he says.

Read the complete state weather roundup at Texas A&M AgriLife.

Texas A&M AgriLife contributed this article.