Growth Rate of Herbage Initially Dominated by Reed Canarygrass or Tall Fescue

摘要

Herbage growth rates may fluctuate during the growing season. Yet decisions concerning herbage management, particularly in pastures, are based partially on expected production. No comprehensive study of herbage growth rates has been conducted in southern New England. Such information could be used to better predict seasonal availability of forage. The objective of this study was to determine herbage growth rates using swards initially dominated by reed canarygrass (Phalaris arundinacea L.) or tall fescue (Festuca arundinacea Schreb.). A 2 by 4 factorial experiment was conducted between 1988 and 1990 for reed canarygrass and in 1990 for tall fescue. Treatments were (i) N rates (125 and 250 Ib/acre per year) and (ii) date of initial harvest (four initial spring harvest dates, each taken at weekly intervals). Regrowth was harvested at monthly intervals from each plot. Yield estimates obtained throughout the growing season were used to calculate growth rates using a reiterative pooled estimate procedure. Growth rates of both species peaked in early-mid May, producing 60 to 105 Ib dry matter (DM)/acre per day. Patterns of growth rates following this peak varied with year. Growth rates in 1990 were similar for swards initially dominated by either species. Growth rates and dry matter yields were greater for herbage fertilized with 250 Ib N/acre than for the lower N rate. Seasonal herbage growth rate patterns were similar at the two N rates, however. The varying growth rates observed over years and within seasons suggest that hay and pasture management must be site-specific.