Seasonal Dynamics of Aboveground and Belowground Biomass and Nutrient Accumulation and Remobilization in Giant Reed (Arundo donax L.): A Three-Year Study on Marginal Land

Giant reed (Arundo donax L.) is a perennial rhizomatous grass that shows promise as a bioenergy crop in the Mediterranean environment. The species has spread throughout the world, catalyzed by human activity, though also as a result of its intrinsic robustness, adaptability, and versatility. Giant reed is able to thrive across a wide range of soil types and is tolerant to drought, salinity, and flooding. This tolerance to environmental stresses is significant and could mean that growing energy crops on marginal land is one possible strategy for reducing competition for land with food production and for improving soil quality. We devised an experiment in which we cultivated giant reed in a sandy loam soil with low nutrient availability. Our goal was to evaluate the dynamics of aboveground and belowground biomass and assess the nutrient dynamics of this grass species, focusing particularly on nutrient accumulation and remobilization. The species demonstrated good productivity potential: In the third year, aboveground dry biomass yield reached around 20 tha−1, with a corresponding rhizome dry biomass yield of 16 tha−1. Results for this species were characterized by low nutrient contents in the aboveground biomass at the end of the growing season, and its rhizome proved able to support growth over the spring period and to store nutrients in the autumn. Nevertheless, the adaptability of giant reed to marginal land and the role of its belowground biomass should be investigated over the long-term, and any further research should focus on its potential to reduce greenhouse gas emissions and maintain soil fertility.