Site-Effects Dominate the Plant Availability of Nutrients under Salix Species during the First Cutting Cycle

Fast-growing willows (Salix spp.) provide alternative sources of renewable energy generation, but need an adequate nutrient availability in the soil for high biomass production. In general, species mixtures can be more nutrient-efficient than pure cultures, this is scarcely known Salix spp. Therefore, study evaluates and P mobilization under two willow species, Salixdasyclados var. ‘Loden’ S. schwerinii × viminalis ‘Tora’, grown as mixed cultures at non-fertilized former arable sites Germany (Stagnic Cambisol) Sweden (Vertic Cambisol). The plant potassium (K), magnesium (Mg) phosphorus (P) phosphatase activities topsoil were measured spring year planting (initial) 4 years-old stocks (one after first 3-year cutting cycle). initial nutrients significantly differed between sampling dates both sites. K Mg was optimal to dates, rather low (after years ≤5 mg 100 g−1 soil). plant-available content decreased within growth acid alkaline activity German site (Rostock) lower growth, not Swedish (Uppsala). Higher compared recorded soils test based on site-specific pH (<7). slight decrease culture different species. Mixed did period, although no significant difference production observed. This valid sites, therefore, seems independent differences climate conditions. general validity assumptions should tested also other conditions future before site-adapted designs recommended Salix.