Giant Reed

Abstract Giant reed (Arundo donax L.) is a C3 perennial rhizomatous grass belonging to the Gramineae family, originating in Asia and later spreading to different subtropical wetlands and warm-temperature regions of Europe, Africa, North America, and Oceania. A wide range of yields is reported in the literature depending on the site, climate, soil type and fertility, inputs, cultivation and harvest practices, and age of plantation. Although it produces flowers, seeds are not fertile. Consequently, its propagation is carried out mainly by rhizomes or stem cuttings. Giant reed has an uncommonly high photosynthetic capacity as compared to other C3 species, and is very similar to those of C4 species. It is able to achieve high photosynthetic rates, up to ∼38 μmol CO2 m−2 s−1 in well-watered treatments, but with substantial transpiration, leading to low or at least lower water use efficiency than many C4 crops (1.19–2.47 g kg−1), but is still more efficient than most C3 species. Radiation use efficiency increases proportionally as nitrogen and available water are increased, and can range from 1.26 to 2.02 g MJ−1, although higher values of 5.74 g MJ−1-intercepted photosynthetically active radiation are also reported. These are much lower than miscanthus, a typical C4 species. Nitrogen use efficiency (NUE) can range from 168.4 to 467 g g−1; single and late harvests, young plantations, and low nitrogen rates lead to increased NUE. Giant reed is also considered as a moderately saline-sensitive plant as it was able to maintain >50% of its relative growth when salinity was