Growth rates of giant miscanthus (Miscanthus × giganteus) and giant reed (Arundo donax) in a low-input system in Arkansas, USA.
The US Department of Energy is currently building strategies for the expansion of clean and renewable energy sources, and tall, rapidly-growing grasses such as giant miscanthus (Miscanthus × giganteus) and giant reed (Arundo donax) are two of the many of species that could fill this renewable energy niche. The objective was to compare stalk growth components of giant miscanthus and giant reed, in a low-input system (no irrigation and no fertilizer use) in Arkansas, USA. Due to the potential invasiveness of giant reed, our study was conducted on an upland site to minimize escape. Plant height and dry weight per stalk were measured every week for two consecutive growing seasons in 2012 and 2013. Leaf area index (LAI) was measured every two weeks from May to September in 2012. A significant species × day interaction occurred for plant height and dry weight per stalk, due to the relatively greater height and weight of giant reed compared to giant miscanthus after May. Stalk elongation rate was greater for giant reed than giant miscanthus (1.85 and 1.11 cm day-1, respectively). Leaf area index differed between species, giant reed (10.4 m2 m-2) > giant miscanthus (4.4 m2 m-2). We showed that giant reed produced taller, heavier stalks, and had a greater stalk elongation rate, compared to giant miscanthus. For sustainable bioenergy production from giant reed in Arkansas, further studies should be performed to determine ideal number of harvests per year and associated production cost.