Wet spring, fall prompts wheat planting issues in some areas of Texas

Writer: Kay Ledbetter, 806-677-5608, skledbetter@ag.tamu.edu
Contact: Dr. Clark Neely, 979-862-1412, cbneely@tamu.edu

COLLEGE STATION – Mother Nature planted a wheat crop, and now producers want to know if it has value. The short answer is “yes,” according to a Texas A&M AgriLife Extension Service specialist.

“Torrential spring rains destroyed or otherwise prevented wheat harvest in some areas last spring, primarily in the Blacklands region,” said Dr. Clark Neely, AgriLife Extension statewide small grains specialist in College Station. “This left a unique situation that is unfolding for many wheat producers across the state of Texas this fall.”

The unharvested wheat last spring left a large seedbank in the soil, Neely said. Fields were abandoned or insured out, and drought set in for much of the summer months, allowing seed to sit dormant in the soil. Another round of intense and widespread rain at the end of October set the stage for a timely and uniform stand of volunteer wheat.

“With wet conditions continuing through November, the excessive rain this fall has prevented a number of acres from being planted and leaving many producers wondering, ‘Will my volunteer wheat make a grain crop?’”

Neely said the short answer is “yes it can” under the right conditions. But if not, replanting or spot seeding might need to be considered.

Due to the timing of the rains in October, many volunteer wheat fields emerged close to the optimum planting window for wheat in the Blacklands and Central Texas, he said.

Producers need to estimate their wheat stands and uniformity to determine if they have the potential to make a good crop, Neely said.

The general recommendations for wheat stand establishment are 10-25 plants per square foot, though irrigated or high-rainfall environments favor the higher end of this range, he said. Yield will generally begin to decline below 10 plants per square foot, unless favorable weather conditions – a warm winter and/or cool spring – allow for additional tillering.

Stand counts above this range can lead to lodging. High rainfall and high fertility can exacerbate lodging problems, especially with thick stands in wheat. Straw strength also varies considerably among varieties.

Neely said Fannin and Duster are two common varieties in Texas that are known to lodge more easily than other varieties, while varieties such as TAM 304 and WB Cedar are rated as very good or excellent for straw strength.

“Some producers may consider a growth regulator in the spring to shorten internode length and overall crop height in hopes of reducing lodging potential,” he said. “While there is research showing that these products can shorten plant height under certain scenarios, results have been inconsistent on reduced lodging.”

Another major consideration for growers should be disease observed in their wheat crop from the previous year, Neely said. Head smuts and bunts can survive in infected seed and infect the following year’s crop.

“These diseases can multiply rapidly from one year to the next,” he said. “They are easily treated with seed treatments, but that is not possible with volunteer wheat.”

Also, any viruses such as barley yellow dwarf and wheat streak mosaic virus present in the previous crop will be transmitted to the following crop via the seed, Neely said. These diseases can be devastating, and symptoms are typically worse the earlier a field is infected.

“And finally, producers need to remember that volunteer wheat is uninsurable, which does provide additional risk for their farm,” he said.

For planted wheat with unevenly emerged stands due to the weather or other factors, spot planting might be considered. Neely said while this decision is often not clear-cut, the best tool a producer has is to take stand counts and determine if stands are less than ideal. Generally, replanting is considered once stands are below 50 percent of the desired level in a given area.

When planting on top of a thin stand, it is best to seed at a 45 degree angle to the original row direction, he said. Double disk openers are preferred over hoe drills as they do not destroy what remains of the original stand.

When over-seeding on a previous stand with a double-disc opener, a 40 to 60 pound-per-acre rate may be desirable, but rates should increase slightly with hoe drills, Neely said. This rate will need adjusting depending on the remaining stand and timing of the replanting.

When spot seeding or overseeding poor stands, an earlier maturing variety may be considered to compensate for planting later; however, it is difficult to align harvest timing of the two plantings and only works if the original variety was medium or later maturity, he said.

In the case of delayed planting due to wet fields, Neely said producers may want to consider increased seeding rates or selecting an earlier maturing variety, although seed availability this late in the season may be limited.

The general consensus is seeding rates should increase by 30-60 percent for late planting wheat, so a 60 pounds-per-acre rate under an ideal planting date would now be 78 to 96 pounds per acre for delayed planting, he said. Increased seeding rates are thought to compensate for reduced tillering in plants due to a shortened growing season.

Neely said the majority of winter wheat planted for grain in the Rolling Plains and Blacklands is planted between mid-October and mid-November. Producers may want to consider increasing seeding rates after Dec. 1. The final planting date for individual coverage plans for insurance is Dec. 15 for the Rolling Plains and Blacklands.

Some examples of early maturing varieties include WB Cedar, Billings, TAM 401 and Fannin for hard red winter wheat, and AGS 2035, USG 3120, SY Cypress and LA 754 for soft red winter wheat, he said.

“If planting is delayed into January, producers will need to seriously consider whether it is worth planting wheat,” Neely said. “Generally, winter wheat receives enough chilling hours to vernalize if planted on or before early January in the Blacklands or Rolling Plains.”

However, he said, wheat planted in late January or later may not have enough cold to switch the plant over from vegetative to reproductive growth and prevent the formation of a seed head. In this case, spring wheat would be advised since it does not require vernalization.

“In either case, yield potential is greatly reduced by planting that late into the season,” Neely said.

For additional information on planting/replanting decisions, refer to the AgriLife Extension publications: Wheat Replanting Considerations, http://bit.ly/1Tahbt5; or Stand Establishment of Small Grains and Annual Grasses for Grain and Winter Pastures, http://bit.ly/1ObJIhL

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