Soil Chemical Properties Associated with Stand-Establishment of Bioenergy Grass Freedom Giant Miscanthus.

Cultivating dedicated energygrasses is vital in achieving annual biomass production of billion tons required by 2030 for fulfilling the U.S. bioenergy vision for energy independence. Energygrasses Giant Miscanthus and switchgrass are perennial C4 grasses and their long-term and large-scale cultivation necessitates investigation of their associated soil properties. Freedom Giant Miscanthus (FGM) is a commercial variety with drought and heat tolerance, low or no nitrogen fertilization, with stand life up to 20 years and bred for highest biomass yield especially in southeastern U.S. The first four years of grass cultivation is considered as the stand establishment period. The overall objective of this study was to compare the seasonal and temporal variations of soil chemical and physical properties associated with FGM stand establishment at three geographical locations in Mississippi. At all three locations, FGM was cultivated without any nitrogen amendment or weed control, and biomass was harvested once each year after the frost. Soil samples were collected in spring, summer and fall from two plots in Lorman, and one plot each in Mound Bayou and Preston from 2014 to 2016. Statistical analyses indicated that the soil properties varied in locations, with significant changes over seasons and years. Changes in soil organic carbon and C:N ratio will be discussed. Since future large-scale feedstock production will see the adoption of commercial, high biomass yielding, region-specific energygrass cultivars, data from this study will provide practical and valuable insights into soil characteristics of a commercial energygrass variety.