LSU AgCenter Researchers Get Grant to Study Cover Crops in Energy Cane

By Richard Bogren, LSU AgCenter

LSU AgCenter researcher Sonny Viator and research assistant Greg Williams plant sweet sorghum at the LSU AgCenter Sugar Research Station in St. Gabriel in April 2017. Photo by Brenda Tubaña/LSU AgCenter

BATON ROUGE, La. — A team of LSU AgCenter researchers has received a four-year, $387,000 grant to evaluate the feedstock potential of energy cane and sweet sorghum with winter cover crops.

Closely related to sugarcane, energy cane is grown for the production of feedstocks for biofuels and biobased products, said lead scientist Brenda Tubaña.

Energy cane produces three crops in four years from one planting. The growing cycle is similar to the pattern farmers use for growing sugarcane.

Unlike sugarcane, however, energy cane is harvested for biomass, which is generally done by removing the entire plant, leaving no leaves or other plant materials behind, she said.

Growers and scientists are concerned about soil health when the entire biomass of a crop such as energy cane is removed without leaving behind any organic matter to compost and return to the soil the nutrients and chemical compounds to maintain soil health and fertility.

To address this concern, AgCenter researchers are planting winter cover crops to protect the bare soil and maintain soil health, Tubaña said.

The typical crop cycle begins in August or September when the cane is planted. It will begin to grow in the fall, then go dormant during winter and resume growth in spring. Harvest is the following fall.

The cycle continues for two additional crop years, and the field is plowed following the third harvest. It then remains fallow until a new crop is planted late in the following summer.

During the fallow period, the soil is vulnerable to loss from wind or erosion, Tubaña said. This is a period for planting a sweet sorghum crop to take advantage of producing an additional crop on the open field.

The cover crops are planted following harvest and then chemically “burned down” to eliminate competition with the newly growing cane plants.

In addition to winter cover crops between harvests, the research program is also evaluating sweet sorghum as a fallow crop between the final harvest and subsequent replanting the following summer.

“The fallow year is a vulnerable time for soil loss, as are the periods during the crop cycle between cane harvest in fall and regrowth the following spring,” Tubana said.

The research program is evaluating the economic feasibility of different cover crop strategies, she said.

“We expect to deliver an established, well-synchronized cover crop, double-cropping system that can be adopted in the south central region where energy cane and sweet sorghum are the main energy crops to maximize production of biomass,” Tubaña said.

The results of the research will be available for sugarcane farmers who want to use cover crops to augment the soil health of their fields, she said.