Value-added products from wastewater reduce irrigation needs of Arundo donax energy crop.

Irrigation restrictions due to drought periods related to climate change, would affect different crops, especially to non-food crops. In this regard the effect of irrigation reduction should be studied in energy crops in order to obtain a sustainable bioenergy cropping system. Arundo donax, has been considered a crop with high water requirements, it has nevertheless been proven to be drought tolerant. However, there is a lack of knowledge on the effect of reduced irrigation combined with the use of different fertilizers. This work studied the combined effect of value-added products (VAPs) from wastewater (treated sewage sludge) or traditional inorganic fertilizers, and irrigation reduction in Arundo donax crop in a 2-year pot experiment. Plant biometric characteristics, chemical properties and biomass yield were studied as well as the effect of treatment on soil properties. Results showed that under reduced irrigation conditions, biomass production was reduced, especially during the second year. Organic treatments from sewage sludge minimize the effect of irrigation reduction. In these treatments, biomass yield for reduced irrigation was similar to that of the control treatment with irrigation at field capacity. For this reason, it is recommended to use VAPs from wastewater as organic amendments enabling water restriction with lower effect on Arundo production.

Assessing Arundo donax L. in vitro-tolerance for phytoremediation purposes.

Phytoremediation using high production crops could be an alternative for the recovery of metals polluted soils. In this sense, the Arundo donax L. energy crop has shown tolerance to moderate concentrations of heavy metals. The objective of this work was to test the tolerance of micropropagated plants of Arundo donax to increasing concentrations of cadmium, chromium, cooper, nickel and lead, in an in vitro culture medium. Biomass production and concentration of heavy metal in shoots and roots were analyzed. Results showed that heavy metals were accumulated mostly in subterranean organs. The increase in heavy metal concentration was dose dependent and not always follows a linear relationship. Arundo donax showed a broad tolerance to cadmium (0.5 mM), chromium (0.2 mM), cooper (2 mM), nickel (0.5 mM) and lead (1 mM). In relation to cooper, Arundo donax showed a hyperaccumulative potential. These results suggest the potential use of Arundo donax in the phytomanagement of polluted soils although further studies should be carried out using polluted soils.