Dry matter yields of cool-season grass monocultures and grass-alfalfa binary mixtures

Cultivars used in grass-alfalfa (Medicago sativa L.) mixtures for hay produ ction in the semiarid Northern Great Plains have often lacked long-term pro ductivity. This study was conducted to compare dry matter (DM) yields of gr ass monocultures and grass-alfalfa binary mixtures receiving annual applica tions of 0 and 50 kg N ha(-1) over a 5-yr period. 'Reliant' and 'Manska' in termediate wheatgrass [Thinopyrum intermedium (Host) Barkw. and Dewey],'Lin coln' smooth bromegrass (Bromus inermis Leyss.),'Nordan' crested wheatgrass [Agropyron desertorum (Fisch.) Schult.],'Lodorm' green needlegrass (Stipa viridula Trin.), and 'Dacotah' switchgrass (Panicum virgatum L.) were seede d in monoculture and in binary mixtures with 'Range-lander' alfalfa [Medica go sativa subsp. x varia (Martyn) Arcang.] on a Parshall fine sandy loam (c oarse-loamy, mixed, superactive, frigid, Pachic Haplustolls) near Mandan, N D. Plant stands of green needlegrass and switchgrass were inadequate, and y ields were not measured. Total seasonal DM yields from two cuttings average d 8.74 and 2.71 Mg ha(-1), respectively, for grass-alfalfa mixtures and gra ss monocultures at 0 kg N ha(-1). At 50 kg N ha(-1) grass-alfalfa mixtures and grass monocultures averaged 8.72 and 5.04 Mg ha(-1) DM yield, respectiv ely. Yields of the grass component of first cut grass-alfalfa mixtures aver aged 35% of total yield for intermediate wheatgrass, 33% of total yield for smooth bromegrass, and 30% of total yield for crested wheatgrass in the fi fth production year. Cultivars included in this study, except those of gree n needlegrass and switchgrass, would be suited for use in binary grass-alfa lfa mixtures for dryland hay production in the Northern Great Plains.