Biomass Yield and Mineral Composition of Six Potential Perennial Grass Bioenergy Crops for the Southeast.

Finite petroleum reserves and climate concerns associated with fossil fuels have led to renewed interest in bioenergy in the U.S.A. Thus, we evaluated yield potential, dry matter, and mineral composition of six potential perennial tall grass bioenergy crops to identify favorable species for the region. Sugarcane (SC) and energycane (EC) (Saccharum spp.), elephantgrass (PP; Pennisetum purpureum), giant reed (AD; Arundo donax), Erianthus arundinaceum (EA), and Miscanthus x giganteus (MG) were grown at three sites in North, Central, and South Florida. Dry matter yields generally did not differ for SC, EC, PP, and EA (30-42 Mg ha^-1) across site or species. Dry matter yields were less for MG and AD (9-21 Mg ha^-1), except for AD in South Florida (35 Mg ha^-1). Dry matter concentration differed primarily by species, ranging from 280 g kg^-1 in SC to 590 g kg^-1 in MG. Tissue ash concentrations ranged from 25 g kg^-1 in SC to 35 g kg^-1 in AD, PP, and EA. Nitrogen concentrations were greatest in AD (6.5 g kg^-1) and lowest in MG (4.1 g kg^-1). Phosphorus concentrations were greatest for PP (1.4 g kg^-1) and lowest for AD (0.8 g kg^-1). Calcium concentrations were 1.5, 2.0, 3.4 and 3.6 g kg^-1 in SC, PP, EC, and MG, respectively. Chloride concentrations were greater for PP and EC (5.5 g kg^-1) compared to MG and SC (3.0 g kg^-1). Sulfur concentrations were greater in AD (2.8 g kg^-1) compared to MG (0.8 g kg^-1). Although MG generally had low tissue mineral composition and high dry matter concentration, its yield was relatively low. Relatively low yields of AD coupled with high tissue mineral concentrations made this species less attractive. Biomass yields of EC, PP, SC, and EA were comparable, but EC and especially SC generally had more favorable tissue mineral compositions.