Nutrition of Hybrid Willows for Bio-fuel Production
Seven different clones of willow grown as a potential bio-fuel crop were evaluated in their response to irrigation and N, P, K and S fertilization. After three growing seasons, prior to harvesting the plots for biomass measurements, seven stems per plot were be sampled and analyzed for N, P, Ca, Mg, Al, Fe, Mn, Cu, Zn, B, and Na concentrations. As well residual nutrient concentrations in the soil down to 60 cm (24 in) were assessed.
IPNI-2010-CAN-SK42
07 Mar 2011
Justification
Growing willow as a renewable dedicated bioenergy and bioproduct feedstock is advantageous for a number of reasons, such as its naturally fast growth rate, along with possessing important environmental benefits like providing a much cleaner energy source relative to fossil fuels, effective vegetation filter for environmentally harmful compounds, and increasing biodiversity within the agricultural landscape (Sage and Robertson, 1994; Perttu, 1998, 1999; Reddersen, 2001; Labrecque and Teodorescu, 2003; Main et al., 2007). Nevertheless, in order to compete with fossil fuels and renewable residues from both the agricultural (i.e., straw) and forestry (i.e., woody residues) sectors, the economic return from growing willow biomass feedstock must be competitive. In order to increase its competitiveness and, therefore promote its adoption among farmers, it is necessary to increase its value in terms of energy production efficiency and/or suitability for bioproduct development. The majority of research to date has focused on the quality of willow biomass for bioenergy conversion and increasing plantation productivity through cultural practices (Mitchell et al., 1988; Kenney et al., 1990; Kopp et al., 2001; Weih and Nordh, 2002; Kauter et al., 2003; Tharakan et al., 2003); however, no one has investigated the effects of different agronomic practices on the wood quality of willow biomass for its different potential end uses.
Wood quality is a subjective term and consequently can change depending on the context of its end use (Jozsa and Middleton, 1994), such as a feedstock for different bioenergy conversion technologies (i.e., anaerobic fermentation, pyrolysis, gasification, or simple combustion) or in manufacturing varied bioproducts (i.e., plastics, adhesives, lubricants, pharmaceuticals, etc.). The principal chemical and physical biomass feedstock properties affecting end use efficiency include: the relative amount and composition of extractives, cellulose, hemicelluloses, and lignin; inorganic element content; specific gravity, calorific energy value; ratio of bark to wood, ash content; and moisture content. Substantial interspecific and interclonal variation in these biomass quality properties exist naturally and has been primarily attributed to genotype x environment (i.e., available soil moisture and nutrients) interactions (Sennerby-Forsse, 1985; Mitchell et al., 1988; Mosseler et al., 1988; Kenney et al., 1990; Tharakan et al., 2003). The potential exists, therefore, to not only increase plantation productivity through irrigation and fertilization, but also to accentuate favourable biomass quality characteristics through optimizing soil moisture and nutrient availability under an intensive management regime. The objective of this study is to determine the effect of different agronomic practices (i.e., irrigation and fertilization) on willow biomass feedstock quantity, as well as its quality, in order to meet specific bioenergy conversion industry requirements, which should help support the commercial development of SRIC willow plantations in Saskatchewan and abroad.