Yield results of up to 50% more than originally forecast have been produced during trials of switchgrass as an energy crop by Ceres. The results, released today (20th May), follow a nation-wide network of field trials  and show that average biomass yields among switchgrass seed varieties tested last season were as much as 50% more than the government’s projected yields for 2022.

Commenting on the results Dr Cory Christensen, Ceres switchgrass product manager, said; "This result demonstrates the genetic potential of switchgrass grown under favorable conditions." He went on to predict that; "through trait development, better genetics and improved crop management practices, we can continue to increase average yields for many years to come."

Based on the results, says the company, policymakers will likely need to re-think their assumptions regarding energy crop production. A number of studies assume yields as low as two to four tons per acre for switchgrass, and rather than incorporating yield increases from breeding, many of these studies hold yields virtually flat into the future. More recently, a highly regarded biofuel study co-authored by Sandia National Labs used a conservative six tons of biomass per acre for energy grasses — similar to estimates by the U.S. Environmental Protection Agency (EPA).

Ceres chief executive Richard Hamilton says that Ceres needs additional data before formally proposing new benchmarks, but said the "writing was on the wall." Adding, "these results are not surprising when you look at the impact that utilizing modern biology has had on food crop yields, like corn, which has seen a five-fold increase since the first hybrids were introduced."

Even using the government’s conservative projections, switchgrass sequesters more carbon than any other raw material evaluated by EPA, which released its official analysis on advanced biofuels earlier this month."

According to Ceres, the switchgrass data were collected from small-plot, replicated trials at locations across the mid and southern latitudes of the United States on both dry and irrigated land in 2008. Like other crops, biomass yields can vary among specific locations and year-to-year.