The effects of nitrogen and accumulation interval on stockpiled cool-season forage in the Coastal Plain

Perennial cool-season forage grasses comprise a majority of pastures and hayfields for livestock production east of the Mississippi River. In areas outside of the traditional tall fescue (Festuca arundinacea Schreb.) zone of adaptation, there exists an opportunity to evaluate other sources of germplasm that can help extend the grazing season. The objective of this research was to quantify the response of tall fescue ('Kentucky-31' [KY31] and 'Texoma MaxQ II' [MAXQ]) and southeastern wildrye (SEWR) [Elymus glabriflorus (Vasey ex L.H. Dewey) Scribn. & C.R. Ball] to synthetic N application and stockpiling accumulation intervals during 2017-2018 (Year 1) and 2018-2019 (Year 2) growing seasons in eastern-central Mississippi. Year was significant for all main effects. Forage mass (FM) analysis displayed a species x interval interaction in which both tall fescue cultivars had greater mean FM than SEWR across all N rates and accumulation intervals. Leaf area index (LAI) was also greater for fescue cultivars than SEWR. Normalized differential vegetation index (NDVI) was affected by species and accumulation interval, with all cultivars and species experiencing decline as the season progressed. Nutritive value analysis observed differences between accumulation interval and species. Southeastern wildrye had greater crude protein (CP) and total digestible nutrients (TDN) and lower fiber fractions in Year 1 than tall fescue cultivars. Nutritive analysis suggests SEWR has potential as a perennial, cool-season forage crop outside the tall fescue zone of adaptation.