Farm and Ranch
Guar, wheat integration focus of new Texas A&M AgriLife study
By Kay Ledbetter, Texas A&M
Nov 1, 2018
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Environmental, economic benefits anticipated

Vernon -- A team of scientists from Texas A&M AgriLife and the University of Florida are working to increase and stabilize guar production in the U.S. by testing integration of guar into existing wheat production in the Southern Plains.

The team is funded for the next four years to conduct this work by the U.S. Department of Agriculture’s “Sustainable Agroecosystems: Functions, Processes and Management” grant program.

Guar produces a seed containing galactomannan gum, which is used in many food and industrial applications as a lubricant, binder, thickener and hardener, among other uses.

“Most people don’t know it, but guar affects our lives every day,” said Dr. Curtis Adams, Texas A&M AgriLife Research crop physiologist in Vernon. “Guar gum is in many of the foods we eat, it’s in products we use in our homes, it’s used to extract oil and gas from the ground.”

In recent years, Adams said, demand for guar gum has increased substantially, and the U.S. is the world’s largest consumer. In 2011, the U.S. Department of Agriculture reported the U.S. imported $1.1 billion in guar.

Guar is being studied in rotation with wheat in the Vernon and Lubbock areas as part of a new Texas A&M AgriLife research project. (Texas A&M AgriLife photo by Dr. Curtis Adams)

Guar is a legume, which means its roots can associate with Rhizobium bacteria in the soil to convert atmospheric nitrogen into fertilizer for the plant and soil, he said. It’s adapted to the semi-arid conditions of Texas and is among the most drought-tolerant crop plants, with relatively low water use.

“Introducing legumes, especially well-adapted legumes like guar, into our cropping systems provides a potential opportunity to improve soil nitrogen fertility and reduce input costs,” said Dr. Calvin Trostle, Texas A&M AgriLife Extension Service agronomist in Lubbock.

“Despite high guar consumption and benefits the plant can provide in cropping systems, U.S. guar production is unstable and only amounts to a small fraction of the world’s guar supply,” Adams said. “We believe this represents missed economic and environmental opportunities.”

U.S. guar production is centered in the Southern Great Plains region of Texas, though acreage has remained low relative to major crops in the region due to a variety of factors.

“One reason U.S. guar production is low is that guar has typically not had the income potential of cotton, the dominant summer crop in this area,” Adams said. “A lack of crop insurance for guar is another reason, which may be attributed to the lack of development in the industry.”

When guar is grown here, it is usually in cotton systems, and then only when cotton prices are particularly low or as an emergency crop following failed cotton, he said.

“We expect competition with cotton to be an ongoing barrier to guar production for producers,” Adams said. “But, wheat cropping systems, which are left fallow in the summer, may provide another venue for guar.

“Integration of guar into wheat cropping systems has not been rigorously tested. But data gathered by our team showed that wheat planted immediately following guar had far higher productivity than wheat following three other summer crops, including cotton, sesame and sorghum.”

Trostle said the results of published studies on guar and wheat planting dates, water use and other relevant factors also suggest that the crops would complement each other in a combined cropping system.

“We hope this new USDA project will provide useful information on how and why guar should be integrated into wheat cropping systems, helping to boost and stabilize U.S. production of the crop,” Adams said.

Joining Adams and Trostle on the research team are Dr. Srini Ale, geospatial hydrologist, Dr. Seong Park, economist, and Dr. Paul DeLaune, environmental soil scientist, all with AgriLife Research in Vernon, as well as Drs. Gerrit Hoogenboom and Ken Boote, plant modelers from the University of Florida.

In the new project they will test various system management scenarios for integration of guar into wheat systems in Vernon and Lubbock, measuring and simulating impacts of the integration on crop, soil, water and economic factors.

The researchers will identify optimal cropping intensities to enhance productivity and soil nitrogen fertility. In doing so, they said they expect soil organic carbon and rates of microbial activity will increase in wheat-guar systems, an indication of potential improvements in soil health. DeLaune will work on this aspect of the project.

Another core aspect of the project is development of an original Decision Support System for Agrotechnology Transfer, or DSSAT, model for guar to aid in data extrapolation and decision support. Hoogenboom and Boote will be working on development of the DSSAT model, while Ale will be making simulations with the new model.

“Our model will be the first of its kind for guar and will help improve our understanding of guar and how best to utilize the crop,” Ale said. “We expect the model to be used by researchers and policy makers in guar production areas around the world.”

Park will be assessing economic outcomes of the project. The team expects that integrated wheat-guar systems will bring higher proceeds than continuous wheat.

“Ultimately, we want to make producers aware of potential benefits and challenges associated with integrating guar into wheat production systems, benefitting producers and increasing domestic guar production,” Adams said.