Abstract

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

Keywords

short rotation coppice; phosphatase activity; nutrient content; growth stages; biomass; willow; Salix

Published in

Forests
2021, Volume: 12, number: 9, article number: 1226
Publisher: MDPI

SLU Authors

• Weih, Martin

  • Department of Crop Production Ecology, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Ensure access to affordable, reliable, sustainable and modern energy for all


UKÄ Subject classification

Forest Science


Publication identifier

DOI: https://doi.org/10.3390/f12091226

Permanent link to this page (URI)

https://res.slu.se/id/publ/113885