Forage Yield of Stockpiled Perennial Grasses in the Upper Midwest USA

Abstract

Stockpiling forage is an effective method to extend grazing beyond the growing season. This study was conducted to determine standing forage organic matter (SFOM) and vertical biomass distribution, with and without applied N fertilizer, of seven cool‐season grasses (early‐ and late‐maturing orchardgrass [Dactylis glomerata L.], quackgrass [Elytrigia repens (L.) Desv. ex Nevski], reed canarygrass [Phalaris arundinacea L.], smooth bromegrass [Bromus inermis Leyss.], tall fescue [Festuca arundinacea Schreb.], and timothy [Phleum pratense L.]) stockpiled over winter. Forage was sampled pre‐ and postgrazing at one site and clipped to both 8 and 2.5 cm as layers of vertical distribution at two other sites in October, December, and late March. Four N fertilizer treatments ranged from 0 to 168 kg N ha−1. Stockpiled SFOM ranged from 2.06 to 3.73 Mg ha−1 at the end of the growing season across three locations. Tall fescue and early‐maturing orchardgrass yielded the highest and quackgrass and smooth bromegrass the lowest at all harvest dates. Tall fescue, early‐maturing orchardgrass, and reed canarygrass were most suited for grazing beyond December, while the late‐maturing orchardgrass and timothy would be utilized most efficiently by grazing before heavy and prolonged snow cover. Quackgrass and smooth bromegrass are not suitable grasses for stockpiling. Nitrogen fertilizer applied in late summer increased yield of the stockpiled forage by nearly 75%. Application of N also increased the distribution of biomass above 8 cm by nearly 50%.