Growth, Yield and Physiological Responses of the Bioenergy Crop Miscanthus × Giganteus To Fertilizer, Biochar and Drought

This study was done to determine whether giant miscanthus (Miscanthus × giganteus) could produce acceptable yields in western North Carolina and whether fertilization and biochar improve growth. Fertilizer and biochar treatments were applied in a randomized block design (0 and 100 kg NPK ha-1 and 0 and 15 t ha-1) at two sites: Mills River (650 m) and Valle Crucis (830 m). Rhizomes were planted in 2012 and allowed to grow for two seasons. No treatment differences were found for gas exchange but rates were higher at Mills River. No biochar or fertilizer effects were found for yield in either site in both years. Second year yields averaged 15.57 and 16.95 Mg DW ha-1 at Mills River and Valle Crucis, respectively, showing that this perennial bioenergy crop can grow in western North Carolina and produce yields comparable to those in other geographic areas. A greenhouse drought study, with and without biochar (50 t ha-1), showed no biochar effects, but gas exchange and water potentials declined after 12 days of drought. Remarkably, plants recovered nearly pre-drought functioning within three days of rewatering. The ability of giant miscanthus to recover quickly may contribute to its ability to grow productively in marginal soils.