Data from: High temperatures and low soil moisture synergistically reduce switchgrass yields from marginal field sites and inhibit fermentation

'Marginal lands' are low productivity sites abandoned from
agriculture for reasons such as low or high soil water content,
challenging topography, or nutrient deficiency. To avoid competition with
crop production, cellulosic bioenergy crops have been proposed for
cultivation on marginal lands, however on these sites they may be more
strongly affected by environmental stresses such as low soil water
content. In this study we used rainout shelters to induce low soil
moisture on marginal lands and determine the effect of soil water stress
on switchgrass growth and the subsequent production of bioethanol. Five
marginal land sites that span a latitudinal gradient in Michigan and
Wisconsin were planted to switchgrass in 2013 and during the 2018-2021
growing seasons were exposed to reduced precipitation under rainout
shelters in comparison to ambient precipitation. The effect of reduced
precipitation was related to the environmental conditions at each site and
biofuel production metrics (switchgrass biomass yields and composition and
ethanol production). During the first year (2018), the rainout shelters
were designed with 60% rain exclusion, which did not affect biomass yields
compared to ambient conditions at any of the field sites, but decreased
switchgrass fermentability at the Wisconsin Central - Hancock site. In
subsequent years, the shelters were redesigned to fully exclude rainfall,
which led to reduced biomass yields and inhibited fermentation for three
sites. When switchgrass was grown in soils with large reductions in
moisture and increases in temperature, the potential for biofuel
production was significantly reduced, exposing some of the challenges
associated with producing biofuels from lignocellulosic biomass grown
under drought conditions.