Development of Switchgrass for Biomass Production in Marginal Soils.

Sustainable production of biofuel grasses, such as switchgrass (Panicum virgatum L.), will require the use of marginal lands not suitable for agronomic crop production.  Currently, the development of high-yielding switchgrass cultivars is being conducted on prime land; however, it is not well known if performance in prime soil will be reflected when plants are grown in marginal soil.  Therefore, the objective of this research was to compare various agronomic traits of switchgrass grown in both prime and marginal soil.  A total of 75 switchgrass lines produced at Rutgers University were planted in 2013 at one location with prime soil (Freehold, NJ) and one reclaimed mine land with marginal soil (Philipsburg, PA).  An additional 75 lines produced by Cornell University were planted in 2013 at a prime location (Ithaca, NY) and the reclaimed mine land (Philipsburg, PA).  In 2014 and 2015, vigor was visually assessed, plant height was measured, and biomass yield was determined at the end of the growing season.  Overall, measurements varied significantly by location, year, and switchgrass line.  Average biomass yield was higher at the prime location in 2014 for the Rutgers lines (289 – 2,536 g DW plant^-1) compared to the marginal location (0 – 425 g DW plant^-1), but this trend was opposite in 2015.  For the Cornell lines, average yields were significantly lower at the marginal site (14 – 340 g DW plant^-1) compared to the prime site (160 – 1040 g DW plant^-1) for both 2014 and 2015.  Overall, several lines from the Rutgers and Cornell populations were identified as having higher vigor scores and better yields at both the prime and marginal sites compared to all other plants evaluated.  This suggests that for certain traits performance will be stable across a wide variety of environments and soil types.