Yield Response of Summer-Dormant and -Active Tall Fescue to Stockpiling.

Tall fescue [Lolium arundinaceum (Schreb.) Darbysh. = Schedonorus arundinaceus (Schreb.) Dumort.] that originated from Mediterranean regions has the potential to be more adapted to the southern Great Plains region because of a summer dormancy trait. Little information is available on the production characteristics of summer-dormant types of tall fescue compared to ‘continental’ or summer-active type tall fescue.  A study was established near Ardmore, OK. on a silt loam soil to compare the yield response of 'Flecha' summer-dormant tall fescue infected with a novel endophyte against the summer-active tall fescue types: 'Ky 31'+ infected with a toxic endophyte, 'Jesup' MaxQ and 'Texoma' MaxQ II both infected with a novel endophyte. Secondary objectives were to evaluate the response of tall fescue to nitrogen rates (0, 67, 134, 202 kg/ha) and the effect of harvest date (November to May from 2008-2010) on forage mass. Two harvests were conducted each year for the November to April harvest dates. The first harvest (Harvest 1) was made approximately the 15^th of each month. A second harvest of re-growth was taken on the November to April plots in May. This re-growth harvest mass was added to Harvest 1 mass for total yield (Total).  Year had a significant influence on Harvest 1 and Total forage mass. In both years forage mass declined during the winter months.  The tall fescue varieties responded similarly to nitrogen treatment.  The quadratic response to nitrogen treatment was significant.  Mean forage dry matter yield of Texoma MaxQ II was significantly greater across years at each nitrogen treatment than the other varieties. Tall fescue yield was influenced by variety, harvest month, and nitrogen for both Harvest 1 and Total yield in both years of the study.