Seed Pre-Treatment Improves Field Establishment Of Switchgrass.

Switchgrass (Panicum virgatum L.) is a perennial grass often used in soil conservation, livestock forage systems, wildlife habitat programs, and more recently as a valuable feedstock for biofuel production. Despite its many positive attributes, switchgrass can be very difficult to establish. Low germination percentages and slow germination rates make young switchgrass stands vulnerable to competition, often leading to establishment failures. Pre-germination seed soaking has been used for many years in the commercial turfgrass industry to improve germination and establishment. We hypothesized this same pre-germination when imposed on switchgrass would yield similar establishment benefits. This work conducted at the Spindletop Farm in Lexington Kentucky, investigated the effects of pretreatment of switchgrass cvs. ‘Alamo’ and ‘Cave-in-Rock’ seed prior to planting in the field and laboratory. Seeds were soaked for varying day lengths (2, 4, or 6 d in water, 1 d in 50 µm or 100µM fluridone solution, or 5mM or 10mM ethephon solution), dried for 24 h, and then sown. Field data collected included days to germination, stand heights, and plant densities. There was an interaction between cultivar and seed pretreatment for plant density. The highest Alamo and Cave-in-Rock density was from seed soaked for 6 d in water. In 2012 Cave-in-Rock seeds soaked for 6 d in water emerged one day prior to all other Cave-in-Rock treatments. In 2013 Cave-in-Rock seeds soaked in 5mM, 10mM ethephon solution, as well as, 6 d and 4 d in water all germinated 2 days prior to other Cave-in-Rock treatments. In the future the efficacy of these seed pre-treatments could be tested to improve the germination and establishment rate of other slow to establish species. The results of these studies, if implemented in a production system, have the potential to make switchgrass easier to establish and a more economically viable forage or biofuel feedstock.