Effect of Initial Harvest Timing on Cultivar Yield in Cool‐Season Forage Grass Trials

Abstract

Cool‐season forage grasses have a range of inter‐ and intraspecies heading dates in the spring. Selecting a manageable harvest schedule that does not confound yield estimates through a harvest × maturity interaction is troublesome in forage variety trials. Our objective was to determine the extent of interaction between cool‐season forage grass maturity and initial spring harvest when estimating total season yield. Cultivars of orchardgrass (Dactylis glomerata L.), perennial ryegrass (Lolium perenne L.), smooth bromegrass (Bromus inermis Leyss.), tall fescue (Festuca arundinacea Schreb.), and timothy (Phleum pratense L.) differing in relative maturity were established in silt loam soils in 1997 and 1999 at Rock Springs, PA. Orchardgrass and perennial ryegrass were established at the same site in 2001. After the seeding year, three harvest schedules resulting in four harvests per year were applied: (A) each individual cultivar was harvested when it reached boot stage (R0 stage); (B) all cultivars within a species were harvested when the average cultivar maturity within that species was at boot stage; and (C) all cultivars of all species were harvested when the average maturity of all species/cultivars was at boot stage. Subsequent harvests were taken at 35‐d intervals. There was no cultivar × harvest schedule interaction for dry matter (DM) yields in this research. Tall fescue (12140 kg ha−1 yr−1) was the highest‐yielding and perennial ryegrass (5316 kg ha−1 yr−1) the lowest‐yielding species. Cultivars within each species differed in DM yield. Delaying orchardgrass or smooth bromegrass harvest beyond the boot stage (Harvest Schedule C) resulted in increased yields. The results of this research indicate that timing of initial harvest has no effect on relative cultivar total‐season yield within the species tested.