Orchardgrass and Tall Fescue Utilization of Nitrogen from Dairy Manure and Commercial Fertilizer

Our objective was to compare multiyear N utilization by orchardgrass (Dactylis glomerata L. ‘Okay’) and tall fescue (Festuca arundinaceae Schreb. ‘Stargrazer’) from dairy manure or commercial fertilizer N. The study was conducted from 1994 through 2000 at the Cornell University Baker Farm, Willsboro, NY, on a poorly drained Kingsbury silty clay (very fine, illitic, mesic Aeric Epiaqualfs). The design was a split plot in a randomized complete block with two annual manure rates (33.6 and 67.2 Mg ha−1) and a recommended rate of inorganic fertilizer N as main‐plot treatments and grass species as subplot treatments, replicated six times. Dry matter (DM) yield of grass receiving the higher manure treatment was similar to that of N‐fertilized grass after 2 yr of manure applications, and residual effects of manure were large at least 3 yr following manure application. Orchardgrass had higher tissue N concentrations but lower total seasonal DM yields than tall fescue. Orchardgrass produced greater spring harvest yields but lower regrowth yields than tall fescue under two‐ or three‐harvest management regimes (1995–2000). No differences in N removal were observed between grass species under a three‐harvest management regime. Relative N recovery (including N supplied from the soil) was 59 to 86% from inorganic N fertilizer and 28 to 70% from manure (1995–1997). Manure at commonly used rates resulted in grass yield and N uptake comparable to commercial N fertilization at a recommended rate.