Fertilizer and intercropped legumes as nitrogen source for Jerusalem artichoke (Helianthus tuberosus L.) tops for bioenergy

Authors

• Kenedy E. Epie Montana State University, Western Triangle Agricultural Research Center (WTARC)
• Arja Santanen Department of Agricultural Sciences, University of Helsinki
• Pirjo S.A. Mäkelä Department of Agricultural Sciences, University of Helsinki http://orcid.org/0000-0002-8757-6015
• Frederick Stoddard Department of Agricultural Sciences, University of Helsinki http://orcid.org/0000-0002-8097-5750

DOI: https://doi.org/10.23986/afsci.70110

Keywords:

Helianthus tuberosus, synthetic nitrogen fertilizer, intercropping, legumes, biomass, mineral element composition

Abstract

Jerusalem artichoke (Helianthus tuberosus L.) produces substantial shoots not used as food. To test its potential as a sustainable bioenergy crop, we studied the effects of synthetic fertilizer and intercropped legumes as nitrogen (N) sources on the growth, aboveground biomass dry matter yield and energy qualities of this crop. Plant height, leaf area index (LAI), SPAD-value, biomass yield, ash content and mineral element composition were determined. Mean aboveground biomass yields were not significantly affected by N source (legume intercrops and synthetic fertilizer) and ranged from 13 to 17 t ha^-1. Remarkably, plants given no fertilizer yielded equally to plants given 90 N kg ha^-1. These results confirm that Jerusalem artichoke, compared to other energy crops, have less need for N and can potentially be sustained by N fixing legumes in an intercropped system. This could reduce or eliminate production and environmental cost in cultivation of biomass feedstock for energy use.