Research Highlights

Research Highlights
Research Tackles Top Challenges to Texas Soybean Production

Planting date trials along the mid-Texas Gulf Coast show that soybeans planted as early as mid-February grow and yield better than soybeans planted in mid-March to April, under favorable conditions. Photo: Josh McGinty

By Laura Temple

Soybeans tend to serve as a minor rotational crop in Texas. However, Josh McGinty, an associate professor and extension specialist for Texas A&M AgriLife Extension Service based in Corpus Christi, believes local farmers could raise more soybeans and reap benefits from rotating to a nitrogen-fixing legume crop. They just need data and solutions to address key issues.

McGinty serves farmers managing the unique conditions of the Texas Gulf Coast. With soy checkoff support from the Texas Soybean Board, he conducts soybean research designed to help farmers see how the crop could fit in their rotation.

“In this region, farmers primarily plant cotton, grain sorghum and some corn,” he says. “My soybean research shows farmers this crop can be a viable option.”

Screening for Tolerance to Iron Deficiency Chlorosis 

McGinty believes soil chemistry presents the biggest issue to soybean production in his area.

“We are on a river flood plain with an abundance of calcium carbonate being carried downstream,” he explains. “As a result, the soil pH is very high, averaging 8.4 to 8.6 or even higher. At this pH, soybeans can’t take up iron from the soil, even though it is present.”

Variety trials screen for soybeans that can handle the alkaline soils of this region. For example, the variety on the left is tolerating soil conditions much better than the one on the right, where the yellowing is a classic symptom of iron deficiency chlorosis. Photo: Josh McGinty

He says many soybean varieties emerge well and look good for a few weeks, but soon yellow and fail. Every season, he screens commercial and public soybean varieties to learn which ones can grow in these soils. 

These trials have identified some commercial varieties that work well in the area. He also notes the value of a partnership with the University of Missouri soybean breeding program. 

“Breeders at the University of Missouri have improved on an existing line with germplasm from the USDA with strong iron deficiency chlorosis tolerance,” McGinty says. “They have developed a couple good varieties with Roundup Ready 1 genetics that provide good yield potential for this region.”

Revising Recommended Planting Date

The second challenge McGinty studies is the limited availability of moisture. The Texas Gulf Coast receives precipitation in late spring. Then fields usually endure very dry conditions until fall storms in the Gulf of Mexico bring rain starting in September.

“The existing extension recommendations for the mid to upper Texas Gulf Coast direct farmers to plant soybeans in March or April,” he says. “But this far south, they run out of water before the plants can fill the pods, resulting in very low or even non-existent yields.” 

He is investigating how early soybeans can be planted so that moisture from late spring rains allows the crop to fill pods. Freezing temperatures are very rare in the region, so he compares soybeans planted as early as mid-February to those planted as late as mid-April.

“Area farmers have learned to plant corn around Valentine’s Day, and my trials show that the timing for soybeans should be similar,” McGinty reports. “My early-planted soybeans often make a respectable yield, while I have yet to have anything worth harvesting from trials planted according to our current recommendations.”

He plans to gather a few more years of data before changing the official extension planting recommendations for soybeans, but in the meantime, he encourages farmers to plant proven varieties from his screening trials as early as possible.

“My research has shown that soybeans can yield between 30 and 50 bushels per acre in this area in favorable years, which makes them a viable option for our crop rotations,” he says. “With the cost of nitrogen fertilizer, adding a legume to the rotation may improve the cost efficiency of the main crops.”

Published: Aug 28, 2023

The materials on SRIN were funded with checkoff dollars from United Soybean Board and the North Central Soybean Research Program. To find checkoff funded research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.