Changes in Potential Soil Carbon and Nitrogen Mineralization: A Multistate Analysis of Miscanthus x Giganteus Under Nitrogen Fertilizer Treatments.

Miscanthus x giganteus is viewed as a promising perennial in the field of biofuels. Before M. x giganteus is cultivated on a large scale, it is important to understand the effects it has on the surrounding environment. Furthermore, it is essential to understand the roles of different N fertilizer treatments in any possible production system. The objective of our study was to determine the effects of M. x giganteus on soils under three different fertilization rates (0, 60, and 120 kg N/ha/yr), and across five different planting locations (Illinois, Nebraska, New Jersey, Virginia, and Kentucky). We evaluated potential soil mineralizable N rates, permanganate oxidizable carbon, soil moisture, biomass yields, and general soil characteristics after four years of growth by comparing soil samples collected in early 2012 to those sampled before planting in 2008. We found that during the first three years of M. x giganteus growth, N fertilization had no significant effect on plant height, tiller density, or dry biomass yield across the five sites, but increased harvested N in biomass. Effects M. x giganteus growth on soil mineralizable C and N varied among sites and with the amount of fertilizer applied. At the Illinois site, N₂O emissions increased with increasing fertilization rates, but no effect was found on CO₂ fluxes. Overall, these multi-site data give us a more complete understanding of the effects of N fertilizer on a wide range of plant and soil characteristics, important to the long-term sustainability of M. x giganteus production.