Adaptability, Biomass Yield, and Phytoremediation of Arundo donax L. on marginal lands: salt, dry and lead-contaminated soils

Water shortage, especially during spring and summer seasons, is the main limiting factor the crop production (Araus et al, 2002; Passioura, 1977), moreover, in the Mediterranean area, inadequate irrigation practices may also exacerbate the problem of the soil salinity. The pollution of soils due to accumulation of heavy metals is a global problem that may involve the loss of agricultural areas: contaminated land is no longer suited to farming, and may be especially harmful to the entire ecosystem (Alloway, 1995). Plants tolerant to heavy metals, may be used to enhance sites unsuitable for biomass production, restoring the ecosystem services and providing valuable feedstocks to biorefineries, in a phytoremediation process. Among the perennial species for energy purpose, Arundo donax L. could be a suitable species for marginal lands including dry areas, salt and lead contaminated soil in the Mediterranean environment. On the basis of these premises the following research lines were carried out with the aim of assess the possibility of cultivate Arundo donax L. on dry, salt and lead contaminated marginal lands: - Line 1: Giant reed screening to salinity levels - Line 2: Response of Arundo donax L. clones at increasing levels of salinity and at different soil water content - Line 3: Phytoremediation of Arundo donax L. in lead-contaminated soils with different water levels of the soil - Line 4: Phytoremediation of different Arundo donax L. clones in lead-contaminated soils The effect of NaCl concentration in the soil induced by irrigation, influenced the morphology and physiology of the studied clones. The results showed that under conditions of salt and water stress all the physiological parameters were affected and plants growth, aboveground dry biomass yield were reduced. Giant reed was able to grow with irrigation water up to 12 dS m-1. However, if this parameter would be considered to classify a soil as marginal, it is clear that marginal land would be obtained marginal yields. Although the Arundo plants are not hyperaccumulators, high phytoextraction yields can be achieved in contaminated soils, due to a conjugation of phytotolerance and high yields. This allows us to consider that Arundo can be more efficient than certain hyperaccumulator plants but with very low yields. On the other hand, the viable growth of Arundo in contaminated soil and subsequent soil revegetation, ensures the long term stability of the surface, reducing the leachates, the amount of potentially toxic elements released into watercourses and groundwater and the development of a vegetative landscape or ecosystem in harmony with the surrounding environment.