RAGES Agronomy Facts 27 Smooth bromegrass is L )is a leafi sod. forming perennial grass that is best suited for hay or early ESTABLISHMENT spring pasture.It is deep-rooted and spreads by A moist.firm seedbed is required for smooth bromegrasso It mat res somewhat later in th g when weather conditions usually are more favorable. compares well with other cool-season grasses,being Seed may be either drilled or broadcast.Drilling is edpayyaemieywcdcoal m depth of seeds.however.often bridge in conventional Canada and the north-central United States Smooth ely in seed drills and make planting difficult.Alternate seeding bromegrass survives periods of drought and extremes in methods may help avoid this problem:(1)mixing sphate 1).It can be grow drill,or(2)mixing bromegrass with a small amount of oats tolerant of salinity and acidity but will perform best at a soil pH between 6.0 and 7.0. onlymet ofyou ADAPTED VARIETIES however,be sure to cover the seed.This can be done by ded fo s high- light disking or by following ith a drag or harrow sten variety adapted to well-drained soils Bayor,like ortaedbed Saratoga,is a high-yielding and persistent variety in Generally when seeding bromegrass aone,rates of 1-16 start growing earlier in the lb per acre are sufficient.When seeding in mixtures with a uncertain genetic makeup. Table 1.Characteristics of perennial coo-season grasses in Pennsylvania Tolerance to Grass Early H y-medium H Medium.lat M Medium-late weegngtkgerebtetmeofsegheadapeaanoenthespingTmswdependnaomyonthe species PENNSTATE College of Agricultural SciencesCooperative Extension
1 Agronomy Facts 27 Smooth bromegrass Smooth bromegrass (Bromus inermis L.) is a leafy, sodforming perennial grass that is best suited for hay or early spring pasture. It is deep-rooted and spreads by underground rhizomes. It matures somewhat later in the spring than orchardgrass and makes less summer growth than orchardgrass. Forage quality of smooth bromegrass compares well with other cool-season grasses, being affected primarily by stage of maturity. Smooth bromegrass is the most widely used coolseason grass in North America. It is grown extensively in Canada and the north-central United States. Smooth bromegrass survives periods of drought and extremes in temperature (Table 1). It can be grown on a variety of soil types, but grows best on well-drained silt-loam or clayloam soils. It is fairly tolerant of alkalinity and somewhat tolerant of salinity and acidity but will perform best at a soil pH between 6.0 and 7.0. ADAPTED VARIETIES Saratoga, a variety recommended for many years in Pennsylvania, is a vigorous, high-yielding, and persistent variety adapted to well-drained soils. Baylor, like Saratoga, is a high-yielding and persistent variety in Pennsylvania. These varieties start growing earlier in the spring and stay green longer than “common” bromegrass. Common bromegrass is not a variety but a bromegrass of uncertain genetic makeup. ESTABLISHMENT A moist, firm seedbed is required for smooth bromegrass or bromegrass-legume mixtures. Most often planted in spring, smooth bromegrass may also be planted in late summer, when weather conditions usually are more favorable. Seed may be either drilled or broadcast. Drilling is preferred because it provides a more uniform depth of planting. Plant seed 1/4-to 1/2-inch deep. Long, narrow bromegrass seeds, however, often bridge in conventional seed drills and make planting difficult. Alternate seeding methods may help avoid this problem: (1) mixing bromegrass seed with a small amount of super phosphate and sowing through the fertilizer attachment of the grain drill, or (2) mixing bromegrass with a small amount of oats and sowing through the small grain attachment of your grain drill (only for spring seeding). Most hopper-type fertilizer spreaders can be calibrated to broadcast smooth bromegrass seed. If seed is broadcast, however, be sure to cover the seed. This can be done by light disking or by following with a drag or harrow. Smooth bromegrass seeding rate varies with seedbed condition, method of seeding, and quality of seed. Generally, when seeding bromegrass alone, rates of 12-16 lb per acre are sufficient. When seeding in mixtures with a legume, seeding rates of 6-8 lb per acre of bromegrass are recommended (Table 2). Table 1. Characteristics of perennial cool-season grasses in Pennsylvania. Seedling Tolerance to soil limitations Tolerance to Relative Grass vigora Droughty Wet Low pHb Persistence frequent harvest maturityc Kentucky bluegrass M L M M H H Early Orchardgrass H M M M M H Early-medium Perennial ryegrass H L M M L H Early-medium Reed canarygrass L H H H H H Medium-late Smooth bromegrass H H M M H L Medium-late Tall fescue H M M H M H Medium-late Timothy M L L M H L Late a L = low, M = moderate, H = high b pH below 6.0 c Maturity characteristic refers to relative time of seed head appearance in the spring. This will depend not only on the species but also on the variety. College of Agricultural Sciences • Cooperative Extension
Table 2.Seeding rates for smooth bromegrass and a the growing point(4 inches)to assure a good third harvest single legume in mixture The quality of the aftermath harvests is only slightly affected by time of harvest. Species lb/A FEPTILITV Smooth bromegrass 6-8 With any one of these legumes 5t2omm needs at seeding should be det ined by soil tes oot trefoil 0 8 e absence o est,assuming a me 20-201b00 bromegrass is seeded with a legume,reduce or eliminate HARVEST MANAGEMENT nitrogen application at seeding. Growth stage is the most important factor in smooth a s very ponsireoNfenmiation production.If you plant smooth bromegrass with alfalfaor During this initial flush of growth.the growing point is another legume,restrict N applications to 40or 50 Ib per below the ground.Later,when shoots begin to elongate acre to limit th ointing the growing point may be r30601o0o20 of the legun acre in early spring when the grass becomes regrowth will be slow because new growth will have to green and 50 Ib per acre after each cutting come from basal buds not yet developed.When seed heads arvest the forag SUMMARY regrowth of the new erop Timely harvest of the spring cro resulted in a 33 percent increase in total season yield over above 6.0.It will not tolerate frequent cutting.Spring harvesting too early.Smooth bromegrass pe makes bromegr s unsuitable in mixture withafafa that in forage digestibility and protein content(Table 4). s that will ot be harvest ed before harvest If it is neces to harvest the regrowth durin the for Per jointing stage of development,adjust the cutter bar above
2 Table 2. Seeding rates for smooth bromegrass and a single legume in mixture. Species lb/A Smooth bromegrass 6-8 With any one of these legumes Alfalfa 8-10 Birdsfoot trefoil 6-8 Red clover 6-8 White clover 2-4 the growing point (4 inches) to assure a good third harvest. The quality of the aftermath harvests is only slightly affected by time of harvest. FERTILITY Fertility needs at seeding should be determined by soil test. Soil pH between 6.0 and 7.0 is best for smooth bromegrass, however it is adapted to slightly alkaline or acid soils (Table 1). In the absence of a soil test, assuming a mediumfertility soil, plow down 0-45-135 lb per acre and apply 20- 20-20 lb per acre at seeding (banded if possible). If bromegrass is seeded with a legume, reduce or eliminate nitrogen application at seeding. Smooth bromegrass is very responsive to N fertilization and requires a high level of fertility for maximum production. If you plant smooth bromegrass with alfalfa or another legume, restrict N applications to 40 or 50 lb per acre to limit the effect N has on reducing nitrogen fixation of the legume. If smooth bromegrass is grown without a legume, apply 100 to 200 lb N per acre in split applications of 50 lb per acre in early spring when the grass becomes green and 50 lb per acre after each cutting. SUMMARY Smooth bromegrass is a deep-rooted, sod-forming grass which grows best on fertile, well-drained soils with pH above 6.0. It will not tolerate frequent cutting. Spring harvest should be made before jointing or after the earlyflower stage of development to ensure maximum smooth bromegrass persistence. This restriction on harvesting makes bromegrass unsuitable in mixture with alfalfa that will be harvested at the bud stage. However, mixtures with legumes that will not be harvested before 1/10 bloom are excellent. Smooth bromegrass is a good cool-season grass for Pennsylvania conditions but proper management is essential to obtain adequate yield and persistence. HARVEST MANAGEMENT Growth stage is the most important factor in smooth bromegrass harvest management. Bromegrass is somewhat tolerant of light grazing during the tillering stage of growth. During this initial flush of growth, the growing point is below the ground. Later, when shoots begin to elongate (jointing stage of growth), the growing point may be destroyed by mowing or close grazing. If the growing point is destroyed at early jointing, regrowth will be slow because new growth will have to come from basal buds not yet developed. When seed heads emerge, it is time to clip pastures or to harvest the forage for hay or silage. This will assure quality forage and quick regrowth of the new crop. Timely harvest of the spring crop resulted in a 33 percent increase in total season yield over harvesting too early. Smooth bromegrass persistence and yield are adversely affected by early harvesting of the spring growth (Table 3). However, delaying the spring harvest beyond early bloom will result in large reductions in forage digestibility and protein content (Table 4). The aftermath crop similarly produces a growing point that is above ground approximately 5 weeks after the first harvest. If it is necessary to harvest the regrowth during the jointing stage of development, adjust the cutter bar above
est Timb ersistaRceaners地reoy9am %ground cover Pre-joini 3.2 20 Early-head 213519 030 Early-bloom 3 38 3 Late-bloom High 80 38 09 38 ay-Dicon 333. 9 Late-bloom Means of N rates 188 二 'Pennlate'orchardgrass,RC=common reed canarygrass.SB='Saratoga'smooth bromegrass,Tim='Climax Table 4.Nutritional value of perennial cool-season grasses at first harvest during spring and summer. Tim OG Tim % Pre-joint Late bloom 11.1 8.6 8.8 505557,and Management and Productility o Perennial ared by Marvin H.Hall,assistant professor. here trade names appear,nodiscrimination is endorsement by Penn State Cooperative Extension is implied. d in turther nia Sta nal cha nd eristi bility,perform ined by University r.disability R5M693
3 Table 4. Nutritional value of perennial cool-season grasses at first harvest during spring and summer. Stage at Crude protein Digestible dry matter first harvesta OGb RC SB Tim OG RC SB Tim % Pre-joint 28.3 24.5 31.9 32.3 82 79 84 76 Early head 16.8 17.0 18.0 16.1 66 72 72 62 Early bloom 14.7 15.4 14.1 11.3 63 71 67 59 Late bloom 12.5 11.1 8.6 8.8 57 60 54 55 a Grasses were fertilized with 200 to 250 lb N the previous year. b OG = orchardgrass, RC = reed canarygrass, SB = smooth bromegrass, Tim = timothy Adapted from Northeast Regional Publications 550, 554, 557, and 570. Management and Productivity of Perennial Grasses in the Northeast. West Virginia Agric. Exp. Stn. Table 3. Yield and persistence of perennial cool-season grasses when the first harvest was taken at different stages of grass development and fertilized at two rates of N, averaged over three production years. Stage at Dry matter yield Persistence after three years first harvest Na OGb RCb SBb Timb OG RC SB Tim tons/acre % ground cover Pre-joint High 3.2 3.3 3.0 3.3 54 100 22 32 Low 2.2 2.1 2.3 2.5 58 100 30 47 Early-head High 3.5 3.5 3.9 3.4 49 100 23 32 Low 2.0 1.9 2.9 2.4 57 100 30 32 Early-bloom High 3.6 3.7 4.9 3.9 51 100 25 14 Low 2.4 2.0 3.7 2.8 55 100 35 35 Late-bloom High 3.6 3.8 5.1 4.0 42 100 30 13 Low 2.5 2.0 4.0 3.6 53 100 38 40 Means of harvest schedules Pre-joint 2.7 2.6 2.7 2.9 56 100 26 39 Early-head 2.8 2.7 3.4 2.8 57 100 27 32 Early-bloom 3.0 2.9 4.3 3.3 52 100 30 24 Late-bloom 3.0 2.9 4.6 3.4 48 100 34 26 Means of N rates High 3.5 3.6 4.3 3.6 48 100 25 22 Low 2.3 2.0 3.2 2.7 56 100 33 38 a High N treatments received 200 to 250 lb N per acre per year, low N treatment received 100 to 125 lb N per acre per year. b OG = ‘Pennlate’ orchardgrass, RC = common reed canarygrass, SB = ‘Saratoga’ smooth bromegrass, Tim = ‘Climax’ timothy. Adapted from Northeast Regional Publications 550, 554, 557, and 570. Management and Productivity of Perennial Grasses in the Northeast. West Virginia Agric. Exp. Stn. Prepared by Marvin H. Hall, assistant professor of agronomy. Where trade names appear, no discrimination is intended, and no endorsement by Penn State Cooperative Extension is implied. Issued in furtherance of Cooperative Extension Work, Acts of Congress May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture and the Pennsylvania Legislature. L.F. Hood, Director of Cooperative Extension, The Pennsylvania State University. The Pennsylvania State University is committed to the policy that all persons shall have equal access to programs, facilities, admission, and employment without regard to personal characteristics not related to ability, performance, or qualifications as determined by University policy or by state or federal authorities. The Pennsylvania State University does not discriminate against any person because of age, ancestry, color, disability or handicap, national origin, race, religious creed, sex, sexual orientation, or veteran status. Direct all affirmative action inquiries to the Affirmative Action Office, The Pennsylvania State University, 201 Willard Building, University Park, PA 16802-2801. R5M693
