Poultry Litter Effects On Switchgrass and Sorghum Biomass Yield and Nutrient Removal.

Switchgrass, biomass sorghum, and sweet sorghum were tested for yield and nutrient removal after receiving 0, 100, or 2000 kg/ha per year of total nitrogen (N) from poultry litter. Plots were established in 2007 in Fayetteville, AR, and Haskell, OK, with 'Alamo' and NSL 2001-1 switchgrass, 'Hybrid 1990' biomass sorghum, and 'M-81' sweet sorghum. The sorghum crops were replanted each year into tilled seedbeds at Fayetteville and no-till drilled into stubble at Haskell. Switchgrass biomass yield ranged from approximately 9 to 18 Mg/ha. Biomass yield showed little or no response to litter application at Fayetteville, but responded positively to litter at Haskell. NSL 2001-1 generally yielded 12% more than switchgrass. Switchgrass yields were stable across wet and dry years, whereas sorghum yields were severely reduced in dry years. Favorable growing conditions resulted in biomass sorghum removing more fertilizer nutrients from the field than switchgrass, whereas the opposite was true during dry years. Biomass sorghum has a greater potential for remove excess nutrients from litter-applied fields than switchgrass when harvested as a biomass crop; however, the perenniality and drought tolerance of switchgrass resulted in more consistent biomass yields and nutrient removal.