Data from: Nitrous oxide emissions during establishment of eight alternative cellulosic bioenergy cropping systems in the North Central United States

Greenhouse gas (GHG) emissions from soils are a key sustainability metric
of cropping systems. During crop establishment, disruptive land-use change
is known to be a critical, but under reported period, for determining GHG
emissions. We measured soil N2O emissions and potential environmental
drivers of these fluxes from a three-year establishment-phase bioenergy
cropping systems experiment replicated in southcentral Wisconsin (ARL) and
southwestern Michigan (KBS). Cropping systems treatments were annual
monocultures (continuous corn, corn–soybean–canola rotation), perennial
monocultures (switchgrass, miscanthus, and poplar), and perennial
polycultures (native grass mixture, early successional community, and
restored prairie) all grown using best management practices specific to
the system. Cumulative three-year N2O emissions from annuals were 142%
higher than from perennials, with fertilized perennials 190% higher than
unfertilized perennials. Emissions ranged from 3.1 to 19.1 kg N2O-N ha−1
yr−1 for the annuals with continuous corn > corn–soybean–canola
rotation and 1.1 to 6.3 kg N2O-N ha−1 yr−1 for perennials. Nitrous oxide
peak fluxes typically were associated with precipitation events that
closely followed fertilization. Bayesian modeling of N2O fluxes based on
measured environmental factors explained 33% of variability across all
systems. Models trained on single systems performed well in most
monocultures (e.g., R2 = 0.52 for poplar) but notably worse in
polycultures (e.g., R2 = 0.17 for early successional, R2 = 0.06 for
restored prairie), indicating that simulation models that include N2O
emissions should be parameterized specific to particular plant
communities. Our results indicate that perennial bioenergy crops in their
establishment phase emit less N2O than annual crops, especially when not
fertilized. These findings should be considered further alongside yield
and other metrics contributing to important ecosystem services.