Biomass yield assessment of five potential energy crops grown in southern Ontario, Canada

Abstract

Biomass yields of five commonly grown bioenergy crops, miscanthus, switchgrass, poplar (2293-19), willow (SX 67) and a mix of native grasses (polyculture) were assessed on a marginal land. When long-term yield responses were examined, miscanthus yield significantly increased from 5.96 ± 1.06 odt ha−1 y−1 in 2011 to 17.03 ± 8.1 odt ha−1 y−1 in 2014. Willow yield also increased from 3.21 ± 2.92 odt ha−1 y−1 in 2011 to 12.15 ± 4.94 odt ha−1 y−1 in 2014. However, for willow at this stage, we only compared the 1st year yields between 2011 and 2014, hence, three-year mature average yield in 2016 (mature stage) may not be much different from 12.15 odt ha−1 y−1, as willow yield increase over time is not linear. Among all other tested biomass species; polyculture, switchgrass and poplar, they recorded numerically higher yields during the mature growth stage (2013/2014) but, failed to reach statistical significance (p > 0.05). In this study, we separated the growth stages as; early (2010/2011) and mature (2013/2014) stages. At the early stage, poplar and polyculture recorded significant yield differences (p = 0.005) and poplar biomass yield was significantly higher (7.71 ± 2. odt ha−1 y−1) than polyculture (2.96 ± 0.43 odt ha−1 y−1). At the mature stage (2013/2014), miscanthus biomass yield was significantly higher than the two other tested herbaceous species (polyculture and switchgrass). Miscanthus yield was 17.03 ± 8.10 odt ha−1 y−1, which was almost three times higher than polyculture (5.64 ± 0.40 odt ha−1 y−1) and switchgrass (5.99 ± 0.46 odt ha−1 y−1) biomass yields. In relation to fertilization effect, miscanthus, polyculture and willow significantly and positively responded to fertilization. The significant yield increases between unfertilized and fertilized treatments were: 12.06, 10.61, and 8.8 odt ha−1 y−1 for willow, miscanthus and polyculture, respectively. Miscanthus, willow and polyculture yields as influenced by fertilizer treatment were 23.81 ± 3.55, 21.80 ± 5.99, 12.13 ± 0.66 odt ha−1 y−1, respectively.