Biomass yield comparisons of giant miscanthus, giant reed, and miscane grown under irrigated and rainfed conditions

The U.S. Department of Energy has initiated efforts to decrease the nation's dependence on imported oil by developing domestic renewable sources. In this study, giant miscanthus (Miscanthus x giganteus), miscane (Saccharum hybrid x Miscanthus spp.), and giant reed (Arundo donax) were grown on an upland site (35.08 degrees N) to determine the potential of these perennial grasses as bioenergy feedstocks, with or without irrigation. Irrigated and rainfed plots with subplots of each species were planted on a silt loam, and biomass yields were assessed in plant-cane, first ratoon, and second ratoon seasons. In the establishment year, giant reed biomass yield was greater than that of giant miscanthus, but not significantly different from that of miscane. Biomass yields of giant reed continued to increase significantly with every season, while giant miscanthus yields only increased from plant-cane to first ratoon, and miscane yields did not change with season. The miscane clone did not have sufficient cold tolerance to ensure vigorous growth of ratoon crops at this latitude. Giant miscanthus had the smallest stalk diameter each season, and the largest leaf:stem ratio in the plant-cane and first ratoon seasons. Irrigation increased dry matter yield of giant reed in the plant-cane and first ratoon seasons, but not in the second ratoon season. In both ratoon seasons, giant reed produced the tallest stalks, largest stalk diameters, and the greatest stem, leaf, and total dry matter yields. Giant reed was the most productive of the three species despite growing on an upland site away from its usual lowland habitat. (C) 2015 Elsevier B.V. All rights reserved.