Data from: Global warming intensity of biofuel derived from switchgrass grown on marginal land in Michigan

Energy crops for biofuel production, especially switchgrass (Panicum
virgatum), are of interest from a climate change perspective. Here, we use
outputs from a crop growth model and life cycle assessment (LCA) to
examine the global warming intensity (GWI; g CO2 MJ-1) and greenhouse gas
(GHG) mitigation potential (Mg CO2 year-1) of biofuel systems based on a
spatially explicit analysis of switchgrass grown on marginal land
(abandoned former cropland) in Michigan, USA. We find that marginal lands
in Michigan can annually produce over 0.57 hm3 of liquid biofuel derived
from nitrogen-fertilized switchgrass, mitigating 1.2-1.5 Tg of CO2 per
year.  About 96% of these biofuels can meet the Renewable Fuel
Standard (60% reduction in lifecycle GHG emissions compared with
conventional gasoline; GWI ≤ 37.2 g CO2 MJ-1). Furthermore, 73-75% of
these biofuels are carbon-negative (GWI less than zero) due to enhanced
soil organic carbon (SOC) sequestration. However, simulations indicate
that SOC levels would fail to increase and even decrease on the 11% of
lands where SOC stocks >> 200 Mg C ha-1, leading to carbon
intensities greater than gasoline. Results highlight the strong climate
mitigation potential of switchgrass grown on marginal lands as well as the
needs to avoid carbon rich soils such as histosols and wetlands and to
ensure that productivity will be sufficient to provide net mitigation.