By Kay Ledbetter
Bioenergy or high biomass sorghum can be grown in water-stressed situations and still produce good yields, according to a Texas A&M AgriLife Research study being conducted at Bushland and in Kansas.
Dr. Qingwu Xue, AgriLife Research plant physiologist in Amarillo, said this year’s environmental conditions at Bushland provided an excellent opportunity to evaluate drought tolerance and the water-use efficiency, or WUE, of the crop.
This is the first of a two-year study funded by the U.S. Department of Agriculture South Central Sun Grant Program.
Dr. Qingwu Xue, Texas A&M AgriLife Research plant physiologist, stands among the dryland high biomass sorghums on Sept. 27, about two weeks before harvest.
Co-investigators include Dr. Jourdan Bell, Texas A&M AgriLife Extension Service agronomist, Amarillo; Dr. Bill Rooney, AgriLife Research sorghum breeder, College Station; Dr. Sushil Thapa, AgriLife Research assistant research scientist, Amarillo; and Dr. Robert Aiken, Kansas State University crop physiologist, Colby, Kansas.
Dr. Sushil Thapa, Texas A&M AgriLife Research assistant research scientist, stands among one of the 100 percent evapotranspiration irrigated biomass sorghum plots at Bushland.
“We are tasked with determining biomass yield performance, water use, drought tolerance and WUE under water-stressed conditions,” Xue said.
Bioenergy sorghum has been identified by the U.S. Department of Energy as the primary bioenergy crop to meet the potential biomass demands for cellulosic ethanol production and other types of renewable energy.
Alternatively, the bioenergy sorghum can be used as a forage crop for cattle and dairy feeding, Xue said.
“In this study, we are investigating six photoperiod-sensitive bioenergy or high biomass sorghum genotypes provided by the AgriLife Research sorghum breeding program in College Station,” he said.
The study is being replicated in Colby, Kansas. At both locations, these genotypes were grown at three water levels: dryland and under irrigation to meet 50 percent and 100 percent evapotranspiration, or ET, demand.
“From the middle of May to Oct. 5, this crop only received 5 inches of rain, which was extremely dry for dryland plots during the growing season at Bushland,” Xue said. “As such, there are huge differences in crop yield and performance among the three water levels.”
With irrigation levels at 50 percent of the evapotranspiration rate, the varietal differences can be seen above and below when some reached about 10 feet and some only 6-7 feet.
Plants under dryland conditions grew about 3-5 feet tall but plants under irrigation at 100 percent ET level were up to 15 feet tall, Thapa said.
In this study, though, Xue and Thapa said they are more interested in the crop performance under water-stressed conditions such as irrigation at 50 percent ET demand and dryland.
Click here to see more...