Table 2. Dry matter yield of GiantReed under harvest frequency treatmentsduring 2006 and 2009(Mg ha-1)Exceptionally High Yields and Soil Carbon Sequestration Recordedfor Giant Reed in AlabamaPing Huang, David Bransby, and Susan Sladden;Giant Reed (Arundo donaxL.) has been extensivelyevaluated as a dedicated cellulosic energy crop insouthern Europe, with very favorable results. Efforts tocommercialize it are being stepped up in Italy, Greece,France, Spain and Portugal. However, the informationon its potential for soil carbon sequestration and yieldresponse to harvest frequency is lacking. Therefore, theaim of our research was to determine yield response ofGiant Reed to harvest frequency and its potential forsoil carbon sequestration.Above-ground biomass yield of Giant Reed showed nopositive responses to broiler litter treatments afterestablished (Table 1). However, there was significantdifference in above-ground biomass yield as well asrhizome yield among different harvest frequency treatments(Table 2). Carbon and N contents varied significantlyamong leaf, stem and rhizome components of Giant Reed(Figure 1). In addition, average above-ground dry matteryield of Giant Reed was higher than that of ‘Alamo’switchgrass over the same 8-year period (Figure 2).1)Annual above-ground dry matter yield for annual andbiennial harvest in winter did not differ, but biennialharvest will likely result in lower cost Mg-1.2)Giant Reed sequestrated 40.18 Mg C ha-1over an 11-year period, approximately 4X that of switchgrassmeasured in another study.3)Average above-ground biomass yield of Giant Reedover an 8-year period was 39% higher than that ofswitchgrass over the same period in this study.Data from a replicated small-plot experiment with GiantReed planted during the spring of 1999 in south centralAlabama were analyzed. Plots were fertilized withammonium nitrate at a rate of 112 kg N ha-1in 2000.broiler litter was applied during 2001 and 2003 at a rateof 112 kg N ha-1. Four harvest frequency treatments(summer every year, winter every second year, winterevery year, and summer & winter every year) wereapplied during 2006 and 2009. Plots were harvested toobtain dry biomass yield data for different treatments.Rhizome yield was collected in 2009. Above-groundbiomass yield data and rhizome data were analyzedusing the GLIMMIX procedure of SAS and the GLMprocedure of SAS, respectively.Table 1. Annual above-ground dry matter yield of Giant Reed under broilerlitter treatments during 2001 and 2003IntroductionHarvest frequency : summer every year (left) VS winter every second year (right)AlamoAcknowledgmentsWe express our appreciation to the employees of the PlantBreeding Unit at the Al. Ag. E. V. Smith Research andExtension Center for their assistance with the field work.ProcedureResultsConclusionsDepartment of Agronomy and Soils, Auburn UniversityOct. 16th, 2009Nov. 2nd, 2009Oct. 16th, 2009Oct. 16th, 2009Oct. 16th, 2009Broiler litter treatments(Kg N ha-1)Above-ground dry matter yield (Mg ha-1)Year200120022003029.08±5.35a32.03±9.56a32.82±5.30a11230.03±9.20a26.55±7.53a23.61±3.87babmeans within the same column with different superscripts differ significantly (P<0.05)Harvest frequencyAbove-ground biomass yieldRhizome yieldYearYear2006200720092009Summer every year20.30±5.70b29.13±7.85b11.97±1.63c43.68±22.59bWinter every second year-----------55.29±17.03a81.01±31.36a117.10±12.25aWinter every year36.52±8.42ab25.94±7.18b38.93±10.78b93.59±22.25aSummer & winter every year39.49±13.21a20.89±6.79b29.67±6.59b46.95±13.28babcmeans within the same column with different superscripts differ significantly (P<0.05)Harvest frequency : winter every second year (left) VS winter every year (right)Nov. 2nd, 2009Harvest frequency : winter every year (left) VS summer &winter every year (right)Plant height: ‘Alamo’ switchgrass VS Giant ReedRhizome distribution of Giant Reed in the 0-30 cm topsoilGiant Reed rhizomes sampled from one square yard under the harvest frequency ofwinter every yearbabbca00.511.522.533638404244464850Rhizome Leaf StemNitrogen ContentCarbon Content

Carbon content (%) Nitrogen content (%)Parts of Giant ReedFigure 1. Carbon and nitrogen contents in different partsof Giant Reed in November 20090510152025303540455055602001 2002 2003 2004 2005 2006 2007 2009SwitchgrassGiant Reed

Above-ground dry matter yield (Mg ha

-1 )Year24.5034.01Figure 2. Annual above-ground biomass yield of Giant Reedand ‘Alamo’ switchgrass during the same period