Monday, April 19, 2010
LL Conference Facility (Hilton Clearwater Beach)
Warm-season perennial grasses have the greatest potential for biomass production in the Southeast. The larger root systems of perennial crops should be able to adapt to lower inputs of water and fertilizer, and should also contribute to soil carbon sequestration. This study was initiated in fall 2005 at Tifton, GA, to assess the performance of perennial grasses under rainfed conditions with no fertilizer inputs. The test consisted of four replications in a randomized complete block design, and included the following entries: two energycanes (Saccharum sp.) US 01-012 and L 79-1002; two Napiergrasses (Pennisetum purpureum Schum.) ‘Merkeron’ and N51; two switchgrasses (Panicum virgatum L.) GA-001 and GA-993; three giant reeds (Arundo donax L.) ADS, ADE, and ADF; and Erianthus arundinaceum. Total shoot biomass was harvested and weighed each year (2006 – 2008) in December, and was analyzed for total carbon and nitrogen content. Soil samples were collected in spring 2007 and 2008 to assess possible changes in soil carbon and nitrogen. For most entries, dry matter (DM) yield was highest in the second year, although energycane L 79-1002 maintained exceptional yields throughout the first three years, averaging 23,115 lb DM/acre. Averaged over three years, DM yields of energycanes, Napiergrasses, and Erianthus were significantly higher than switchgrasses and giant reeds. Switchgrasses and giant reeds were not significantly different in DM yield, but switchgrasses had higher nitrogen use efficiency, based on the nitrogen content of the harvested plants. From 2007 to 2008, no significant changes in soil carbon or nitrogen were observed.