Response of Miscanthus x Giganteus to Phosphorus and Nitrogen Fertilizer On Low Phosphorus Soils in North Carolina.

The perennial grass Giant Miscanthus (Miscanthus x giganteus) has been evaluated and grown in Europe as an alternative energy source.  Previous research has shown that established Giant Msicanthus can achieve relatively high yields with rather limited fertilizer inputs.  However, research to date on production of this potential bioenergy crop in the US has been limited, particularly in the humid Southeast.  The climate and topography of NC are such that successful production of a perennial bioenergy may be possible on lands with limited productivity and, particularly, sloping lands where erodibility may limit commercial row crop production.  The objective of this study is to evaluate the production capacity of Giant Miscanthus in NC, specifically to i. determine the effects of N and P rate on growth and yield, ii. evaluate interactions between N and P uptake by miscanthus, and iii. determine soil P and N removal rates following multiple years of miscanthus growth and harvest.  Initial research plots were established in Mills River, NC in 2008 and at Oxford, NC in 2009.  Treatments were arranged in a split-plot randomized complete block design with main plots of 0, 336, 672, and 1008 kg P₂O₅ ha^-1 applied and incorporated pre-plant and subplots of 0, 45, 90, and 135 kg N ha^-1 broadcast annually.  Preplant soil samples were collected to a depth of 90 cm and analyzed for P and inorganic N.  Tissues samples were collected for total nutrient analysis at harvest and yield determined.