Salt Tolerance in Panicum Virgatum and Spartina Pectinata.

Lignocellulosic biomass grown as a biofuels feedstock shows great promise in meeting the federal mandate for cellulosic biofuels.  However, to avoid potential competition with food and feed crops, the biomass will need to be grown on marginal or degraded land not able to support row crop production.  Biomass crops able to tolerate saline conditions would be able to fill an important niche in the bioeconomy.  A factorial greenhouse experiment was conducted to determine the effect of two levels of salinity (5 dS/m and 10 dS/m) and sodicity (48% and 73% Na salt) on biomass production of “Cave-in-Rock” and “Kanlow” switchgrass (Panicum virgatum) and three different populations (“Red River” and two wild types “IL-109” and “IL-102”) of prairie cordgrass (Spartina pectinata).  Seedlings of each population were grown under the various salt regimes and harvested after most control plants (watered with pure water) had undergone anthesis.  Sodicity was not significant but dry weight, height and tiller number were all negatively impacted by salinity.  “Kanlow” had the highest yields at each salinity level.  Both switchgrass cultivars showed a linear response to increasing salinity with 54% and 77% yield reductions at EC 10 compared with the control for “Kanlow” and “Cave-in-Rock”, respectively.  Prairie cordgrass populations showed responses to salinity similar to “Kanlow” with 57% yield reduction on average for EC 10 treatments compared with the controls.  Tiller number in “Cave-in-Rock” was most affected with 73% fewer tillers in the EC 10 treatments than in the control compared with all other cultivars which had 42% fewer on average. These results show that various cultivars of both switchgrass and prairie cordgrass may produce acceptable biomass yields on soils with high to very high salt levels.