1 Citation
Growing lignocellulosic crops on marginal lands is a promising solution
for sustainable biofuel production. We evaluated the productivity of
bioenergy cropping systems (switchgrass [Panicum virgatum L., var.
Cave‐In‐Rock], miscanthus [Miscanthus × giganteus, ‘Illinois clone’],
hybrid poplar [Populus nigra × P. maximowiczii A. Henry ‘NM6’], native
grasses [five species], early successional vegetation, and restored
prairie vs. historical vegetation [as reference control]) with and without
nitrogen fertilization on low‐fertility former cropland at five sites in
the Great Lakes Region, United States. We reported biomass yields for the
first 7 years after establishment. Switchgrass was most consistently
productive across all sites, but miscanthus was more productive at three
of the five sites. When averaged across sites, years, and nitrogen (N)
treatments, biomass yields followed the order miscanthus >
switchgrass > hybrid poplar ≈ native grasses > restored
prairie > early successional vegetation ≈ historical vegetation,
but varied substantially by crop and site, with a significant crop by site
interaction. Yields of miscanthus and switchgrass peaked after four to
five growing seasons and declined thereafter, while yields of both native
grasses and restored prairie increased throughout 6 years with no sign of
follow‐on decline, suggesting that polycultures may outperform
monocultures over the long term. Yields of early successional
vegetation—similar in composition to historical vegetation at each
site—did not improve with time. Nitrogen fertilization increased the
yields of all cropping systems at all sites. Our results demonstrate the
viability of low‐productivity former cropland for long‐term bioenergy
production and suggest there is no single crop best suited for all
low-fertility soils.