The Sustainability of Miscanthus x Giganteus Cropping Systems.

Miscanthus x giganteus is now being adopted in the US after years of research and use in Europe. Widely touted as one of the more environmentally-friendly biomass candidates, what is this crop’s record on environmental sustainability?

Carbon: Carbon emissions are low, even compared to other biomass crops, primarily because of a low nitrogen fertilization requirement.  M. x giganteus is a strong contender for carbon sequestration, producing 15-20 t ha^-1 of rhizome biomass and accumulating  soil organic carbon at 0.6 – 1.12 t C ha ^-1 y^-1.

Water: M. x giganteus uses water to produce harvestable biomass more efficiently than other Miscanthus species. That does not mean water requirements are low, however, as M. x giganteus   has a longer growing season than corn or soybean and can use more water over the course of the year.  Nitrogen leaching is reduced under M. x giganteus, making it suitable for water quality improvement in sensitive areas.

Soil erosion: Sediment removal has yet to be measured in the peer-reviewed literature, but is expected to be minimal or negative in a mature crop given the rhizome network, stubble and litter produced.  Conversely, newly planted M. x giganteus   fields are very susceptible to erosion with current establishment methods.

Habitat: bird and insect populations are increased in M. x giganteus   compared to annual crop fields, likely because of greater winter cover. It is not clear if this will remain the case as improved crop culture leads to more homogeneous fields.

Nutrient removal: M. x giganteus   has shown diverse responses to fertilization, from a strong yield response to no response at all, leading to the perception that the crop can be grown without fertilizer. This is likely true for a few years on nutrient rich soils, but will not be the case in perpetuity or on poorer fields.