Main content area

A nutrient-based sustainability assessment of purpose-grown poplar and switchgrass biomass production systems established on marginal lands in Canada

Ashiq, Muhammad Waseem, Bazrgar, Amir Behzad, Fei, Houman, Coleman, Brent, Vessey, Kevin, Gordon, Andrew, Sidders, Derek, Keddy, Tim, Thevathasan, Naresh
Canadian journal of plant science 2018 v.98 no.2 pp. 255-266
Panicum virgatum, Populus, biomass production, clones, cultivars, hybrids, nitrogen, production technology, Canada
The sustainability of purpose-grown biomass production on marginal lands in Canada is uncertain. In this study, an assessment of biomass yield and sustainability was performed for two poplar clones (Poplus deltoides × P. nigra, DN-34—PDN, and P. nigra × P. maximowiczii, NM-6—PNM) and two switchgrass cultivars (Panicum virgatum ‘Cave-in-Rock’—SGC, and P. virgatum ‘Nebraska’—SGN) on three marginal lands in Guelph (ON), Kemptville (ON), and Nappan (NS) in Canada. The differences in stem biomass across sites were not significant; however, differences in stem biomass among plants were statistically significant between poplar and switchgrass (p < 0.0001) and between poplar clones (p < 0.0001). The 2-yr stem biomass yield in PNM (15.27 ± 1.28 t ha⁻¹) was significantly higher than those in PDN (7.02 ± 0.54 t ha⁻¹), SGC (2.57 ± 0.28 t ha⁻¹), and SGN (1.45 ± 0.22 t ha⁻¹). Two sustainability indices based on macronutrients (MBSI) and nitrogen (NBSI), were developed to assess sustainability. Both indices show that the biomass production system of high-yielding poplar clone PNM depicts nutrient loss and may require external nutrient inputs via fertilization during the establishment phase. Higher index values for switchgrass SGC (1.47 ± 0.22, 1.11 ± 0.15) and SGN (1.37 ± 0.16, 1.17 ± 0.12) for MBSI and NBSI, respectively, indicate that despite low stem biomass yields, switchgrass biomass production is sustainable. These findings suggest that, from a nutrient perspective, sustainable biomass production systems can be established on marginal lands in Canada; however, there is a trade-off between high yield and long-term sustainability in purpose-grown biomass production systems.