Napiergrass, also called "elephant grass," is a native of Africa and is used as cattle forage in much of the Tropics. Napiergrass offers advantages for the Southeast: It is drought tolerant and grows well on marginal lands and in riparian areas. It can also improve water quality in riparian areas by filtering out nutrients in runoff from row crop fields.



Both energy cane and napiergrass are subtropical grasses and are prime candidates for biomass production because they don't flower in most areas of the Southeast and continue to grow until the first frost.



In Tifton, Ga., Anderson and colleagues compared napiergrass to energy cane, switchgrass, and giant reed (Arundo donax). They grew the crops for 4 years and compared biomass yields and soil nutrient requirements.

Joseph Knoll, a postdoctoral researcher in Anderson's laboratory in the ARS Crop Genetics and Breeding Research Unit in Tifton, led the research effort. The team also included Timothy Strickland and Robert Hubbard, ARS scientists with the Southeast Regional Watershed Research Unit in Tifton, and Ravindra Malik of Albany State University, Albany, Ga.

Results were published online in BioEnergy Research in 2012.



They found that energy cane and napiergrass are viable biofuel alternatives for growers in southern portions of Georgia and the rest of the region's southern tier, Anderson says. "Energy cane and napiergrass are not as cold tolerant as switchgrass, but they do offer advantages in areas where they can be produced, such as continued vegetative growth until killing frost," Anderson says.



Anderson and his colleagues are evaluating napiergrass with an eye toward improving yields, useable fiber content, and disease resistance. They are also testing different soil amendments, such as chicken litter, variable rates of inorganic fertilizer, and winter cover crops, and comparing those with no use of inputs.



"In one test, we're looking at six different rates of fertilizer use as well as different irrigation levels. We've also looked at the times of planting and harvest, comparing yields in areas where poultry litter was used and where synthetic fertilizer was used," Anderson says. Preliminary findings show that yields are sufficient without irrigation and that there is little difference in yield when poultry litter is used instead of inorganic fertilizer.