Biogeochemical Fluxes for Three Bioenergy Crops

Themes: Sustainability

Keywords: Field Data

Citation

Moore, C.E.von Haden, A.C.Burnham, M.B., Kantola, I.B., Gibson, C.D.Blakely, B.J., Dracup, E.C., Masters, M.D., Yang, W.H.DeLucia, E.H.Bernacchi, C.J., Dec. 22, 2020. “Ecosystem-Scale Biogeochemical Fluxes from Three Bioenergy Crop Candidates: How Energy Sorghum Compares to Maize and Miscanthus.” GCB Bioenergy. DOI: 10.1111/gcbb.12788.

Overview

Total cumulative ecosystem respiration (ER) fluxes and the soil heterotrophic respiration (RH) and autotrophic respiration (RA) components for energy Sorghum bicolor (sorghum), Zea mays (maize) and Miscanthus × giganteus (miscanthus) from June 30th to October 9th of 2018 at the University of Illinois Energy Farm, Urbana, Ill., USA. Total soil respiration (RS) represents the sum of RH and RA. Letters above bars represent significant differences between RH only.

Perennial crops have been the focus of bioenergy research and development for their sustainability benefits associated with high soil carbon (C) and reduced nitrogen (N) requirements. However, perennial crops mature over several years and their sustainability benefits can be negated through land reversion. A photoperiod‐sensitive energy sorghum (Sorghum bicolor) may provide an annual crop alternative more ecologically sustainable than maize (Zea mays) that can more easily integrate into crop rotations than perennials, such as miscanthus (Miscanthus × giganteus). This study presents an ecosystem‐scale comparison of C, N, water and energy fluxes from energy sorghum, maize and miscanthus during a typical growing season in the Midwest United States. Gross primary productivity (GPP) was highest for maize during the peak growing season at 21.83 g C m−2 day−1, followed by energy sorghum (17.04 g C m−2 day−1) and miscanthus (15.57 g C m−2 day−1). Maize also had the highest peak growing season evapotranspiration at 5.39 mm day−1, with energy sorghum and miscanthus at 3.81 and 3.61 mm day−1, respectively. Energy sorghum was the most efficient water user (WUE), while maize and miscanthus were comparatively similar (3.04, 1.75 and 1.89 g C mm−1 H2O, respectively). Maize albedo was lower than energy sorghum and miscanthus (0.19, 0.26 and 0.24, respectively), but energy sorghum had a Bowen ratio closer to maize than miscanthus (0.12, 0.13 and 0.21, respectively). Nitrous oxide (N2O) flux was higher from maize and energy sorghum (8.86 and 12.04 kg N ha−1, respectively) compared with miscanthus (0.51 kg N ha−1), indicative of their different agronomic management. These results are an important first look at how energy sorghum compares to maize and miscanthus grown in the Midwest United States. This quantitative assessment is a critical component for calibrating biogeochemical and ecological models used to forecast bioenergy crop growth, productivity and sustainability.

Data

Download (67 KB) includes:

  • Soil Respiration Data
  • N2O Daily Fluxes
  • Agronomic measurement and yield metrics
  • Flux and meteorological variables