Establishment of Miscanthus × Giganteus in North Carolina in Response to Phosphorus and Nitrogen Fertilization.

Giant Miscanthus (Miscanthus x giganteus) is a large perennial grass with potential use as an energy crop.  Research efforts have recently been increasing in the United States to evaluate the use of Giant Miscanthus as a bioenergy feedstock and to prepare growers with the most efficient management practices.  The overall goal of our study is to evaluate the growth of Giant Miscanthus in North Carolina soils, specifically with relation to phosphorus and nitrogen fertilization.  Specific objectives are to i) measure yield response to varying rates of P and N fertilizer, ii) identify interactions between P and N uptake, and iii) measure P and N removal rates from the soil over multiple years of growth and harvest.  Test sites were established at 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, 673, and 1009 kg P2O5 ha-1 applied and incorporated pre-plant and subplots of 0, 45, 90, and 135 kg N ha-1 broadcast annually. Soil samples are collected each year to a depth of 90 cm and analyzed for P and inorganic N.  Tissue samples are collected at harvest to determine yield and nutrient concentration.  Initial results have shown a significant response to phosphorus fertilization with no response to nitrogen and no interaction between P and N uptake.