Performance of Salix viminalis and Populus nigra × Populus maximowiczii in short rotation intensive culture under high irrigation

On a plantation established in 2004 from stem cuttings at a density of 20,000 trees per hectare, we investigated growth and nutritional plant response to a high hydraulic regime for two species (Salix viminalis and Populus nigra × Populus maximowiczii), using a comparative approach with measurements from irrigated and control plots. The plantation was irrigated from June to September 2005 with about 140 mm per day. The equivalent of 120 Kg NO3–N, 40 Kg P2O5–P and 85 Kg K2O–K per hectare per year was applied by means of irrigation with wastewater. No mortality occurred and stem biomass production of both poplar and willow species were not statistically different on irrigated and control areas. However, S. viminalis revealed to be more tolerant to flooded conditions since these corresponded more closely to its nutritional requirements (foliar concentration of 20 mgN g−1). The capacity of S. viminalis to withstand waterlogged conditions could play an important role in the sustainability of a plantation for the filtration of effluent at low pollutant concentration.