Dry Matter Production of Orchardgrass and Perennial Ryegrass at Five Irrigation Levels

cultivar Paiute, which originated from a single plant introduction (PI-109072) (Alderson and Sharp, 1994), Within the Great Basin, availability of irrigation water throughout very little breeding has been done to develop improved the growing season is the limiting factor in the development of improved pastures. The choice of species and their water requirements cultivars of cool-season perennial grasses for irrigated are critical factors for providing a stable source of forage throughout pastures in the Intermountain West. Plant growth in the grazing season. A line-source irrigation system was used from this environment is frequently limited by lack of soil 1995 to 1998 to evaluate dry matter (DM) production and seasonal water during the later portions of the growing season. forage distribution of nine orchardgrass (Dactylis glomerata L.) and Ideally, improved cultivars must have adaptations that perennial ryegrass (Lolium perenne L.) hybrid cultivars along with allow them to maintain forage production under watercheck cultivars of meadow brome (Bromus riparius Rehm.) and limiting conditions. smooth brome (B. inermis Leyss.), tall fescue (Festuca arundinacea Plant selections under dryland conditions (Asay and Schreb.), and quackgrass [Elytrigia repens (L.) Nevski] 3 bluebunch Johnson, 1983) have resulted in improved forage prowheatgrass [Pseudoroegneria spicata (Pursh) A. Love] hybrids (RS) duction and quality within the crested wheatgrasses under five irrigation levels ranging from 41 to 91 cm per year. Mean (Agropyron spp.) (Asay et al., 1985a; Asay et al., 1995; DM production rankings across water levels combined over years Asay et al., 1997; and Asay et al., 1999) and Russian were tall fescue . orchardgrass . meadow brome . RS-hybrid . wildryes [Psathyrostachys juncea (Fisch.) Nevski (Asay smooth brome . perennial ryegrass-hybrids. The DM production response across water levels was largely linear with a minor but signifiet al., 1985b; Jensen et al., 1998] on marginally produccant quadratic component at lower water rates. Tall fescue was most tive semiarid rangelands. Johnson and Bassett (1991) responsive (i.e., produced more DM production) to increased irrigareported significant differences in water use efficiency tion rates. At lower water levels, meadow brome outyielded or(dry matter produced per unit of water consumed) bechardgrass. However, when water was not limited, orchardgrass outtween accessions of perennial ryegrass, orchardgrass, yielded meadow brome. The RS hybrid and smooth brome had and tall fescue when grown under dryland and irrigated relatively low DM production at both low and high water levels. All conditions. With the ever-increasing demands for water species produced significantly (P , 0.01) more DM than perennial in the Intermountain West, there is a critical need to ryegrass at lower water levels. Under limited irrigation, tall fescue develop improved cool-season forage pasture grasses and meadow brome will produce more DM. that maintain productivity under periods of limited irrigation. A early as the mid 1950s, Bateman and Keller Orchardgrass is a native of Europe but has been (1956) recognized that pastures played an imporgrown for over 200 yr in North America, where it occutant role in the agricultural economy within the Interpies an important place as a cultivated grass for hay mountain West. They concluded that as long as nearby and pasture. A breeding history of orchardgrass was valley bottoms or other public land not well suited for reviewed by Casler et al. (2000). It is one of the major cultivation were available, pressure for more productive grass species for pastures in areas of high rainfall in the pastures remained secondary to that for cash crops. Northeast, North Central, and Pacific Northwest regions Grazing on public lands in the West is becoming more of the USA (Hoveland, 1992). It has been used west restricted by environmental pressures and a limited waof the Rocky Mountains where adequate irrigation is ter supply, particularly in the later portions of the growavailable. Its major limitation in the Great Basin is its ing season. Interest in maximizing the potential of prineed for high soil water supply throughout the growvate irrigated grazing lands has escalated. Productivity ing season. of these lands can be increased through genetically imPerennial ryegrass is a temperate perennial grass that proved plant materials and better and more intensive is indigenous to southern Europe, North Africa, and management systems. southwest Asia. Because of its high forage quality, it is Breeding efforts in orchardgrass and forage-type peone of the most important pasture grasses throughout rennial ryegrass have historically been concentrated on western Europe, New Zealand, and the northwestern forage traits (yield and quality), disease resistance, and USA. It has become an important pasture species in adaptation to the more humid, temperate regions of the eastern Canada and southern British Columbia (Smolworld (Balasko et al., 1995; Casler et al., 1997; Christie iak, 1992; Balasko et al., 1995). Within the Great Basin, and McElroy, 1995; Jung et al., 1996; Stratton and Ohm, perennial ryegrass does not persist in highly productive 1989). With the exception of the dryland orchardgrass stands for more than a few years unless it is reseeded to thicken declining stands. However, despite its shortK.B. Jensen, K.H. Asay, and B.L. Waldron, USDA-ARS, Forage and lived nature, the reputation of perennial ryegrass generRange Research Laboratory, Utah State Univ., Logan, UT 843226300. Cooperative investigations of the USDA-ARS and the Utah ates interest for intensively managed pastures on dairy Agric. Exp. Stn., Logan Utah 84322. Approved Journal Paper No. operations (Jensen, 1995). 7227. Received 1 Dec. 1999. *Corresponding author (kevin@cc. usu.edu). Abbreviations: DM, dry matter; WL, water level(s); RS, Elytrigia repens (L.) Nevski 3 Pseudoroegneria spicata (Pursh) A. Love. Published in Crop Sci. 41:479–487 (2001).