VALUE AND USE
SPECIES: Lolium perenne | Perennial Ryegrass 



WOOD PRODUCTS VALUE : 
NO-ENTRY


IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
Perennial ryegrass is a palatable and nutritious forage for all classes
of livestock and most wild ruminants [14,54].  In a study to determine
the practicality of using Douglas-fir (Pseudotsuga menziesii)
plantations for sheep range, sheep grazed perennial ryegrass in
proportion to its availability [32].


PALATABILITY : 
Perennial ryegrass is palatable to livestock and big game species.
Older plants can become tough and unpalatable, especially during hot dry
weather [57].

Palatability ratings from selected western states are as follows [9]:

          Wyoming     Montana     North Dakota

cattle    fair        fair        fair
sheep     good        fair        fair
horses    fair        fair        fair


NUTRITIONAL VALUE : 
The crude protein content of perennial ryegrass increases with soil
nitrogen fertility.  Some average values for selected characteristics
are as follows [55]:

                   crude protein (%)     in vitro digestibility (%)
vegetative growth    10.7-18.7 *           88-87
early bloom          10.1-16.9             80-81
heading                   13.2             82
mature                     9.1             71 

* higher values are for higher rates of nitrogen fertilizer

The National Academy of Sciences [41] reported various nutritional
values for perennial ryegrass; typical values for protein content in hay
are as follows:

             digestible protein (% of dry weight)

cattle       5.3
goats        5.6
horses       5.7
rabbits      6.1
sheep        4.9


COVER VALUE : 
Cover values in North Dakota are rated as poor for mule deer,
white-tailed deer, and pronghorn; and fair for upland game birds and
waterfowl [9].


VALUE FOR REHABILITATION OF DISTURBED SITES : 
Perennial ryegrass grows rapidly and is easily established; it is often
used for stabilization of soils [19,20].  Perennial ryegrass is often
seeded in mixtures with slower growing, longer lived species to provide
a quick cover [54].  It is hydroseeded on badly eroded mine spoils in
Virginia and Tennesee as part of a seed mixture containing annual and
perennial grasses, legumes, and native forbs [38].  Streambank
stabilization projects in Utah utilized a grass and forb seed mixture
that included perennial ryegrass [56].

Perennial ryegrass was successfully seeded with orchardgrass (Dactylis
glomerata), white clover (Trifolium repens), annual ryegrass and vetch
(Vicia sativa) for soil stabilization and forage production on severely
burned riparian areas in southwestern Oregon [19].  Fire often alters
the ability of soils to take up water.  In a study on soil wettability
after wildfire in lodgepole pine (Pinus contorta) stands in Oregon,
perennial ryegrass was seeded with tall fescue, white clover, lodgepole
pine and ponderosa pine (Pinus ponderosa).  Use of a wetting agent had
no apparent effect on plant growth, so it is probably not necessary for
successful reseeding after fire [11].  A mixture of grasses and legumes,
including perennial ryegrass, was planted on an area burned by wildfire
in north-central Washington [22].  In Arizona, seedings that included
perennial ryegrass had low initial cover values immediately following a
wildfire.  By the seventh or eighth year, cover values had increased to
nearly 3 times the values on unburned control plots, after which there
was a slight drop in cover values [35].


OTHER USES AND VALUES : 
Perennial ryegrass is a popular turf grass, especially in the south
where it remains green all winter [14].  Perennial ryegrass can be used
as a winter cover or forage crop in warmer climates [14,54,57].  It is
used in mixtures with red clover (Trifolium pratense) in rotation with
strawberries (Fragaria x annassa), nursery stock, or vegetables.
Perennial ryegrass is usually allowed to grow for 3 years, providing
soil improvement and sanitation (in addition to silage and hay crops),
then is plowed under as green manure [20].

Perennial ryegrass is used for brushland conversion to range.  Chamise
(Adenostoma fasciculatum) brushlands in California are cleared by
disking or burning, and then reseeded.  Perennial ryegrass is
recommended (as part of a mixture of species) on better sites above
2,000 feet (610 m) elevation and receiving 28 inches (711 mm) or more of
annual precipitation [4].  Love and Jones [34] recommended it for
coastal areas and at mid- to low elevations (up to 3,000 feet [914 m]).
Hardinggrass (Phalaris tuberosa), tall fescue (Festuca arundinacea) and
legumes are recommended in mixtures with perennial ryegrass for
brushland conversion in certain areas (detailed in [4,42]).  Deer use
increases on sites undergoing this type of treatment.  In general,
seeding after prescribed fire in brushlands increases the amount and
quality of forage available to big game and livestock [42].


MANAGEMENT CONSIDERATIONS : 
Perennial ryegrass was probably the first grass to be cultivated as a
pasture grass in Europe.  Records of its use in Europe date to 1681.
Thomas Jefferson reported perennial ryegrass as a good producer in
Virgina as early as 1782 [14,16].  Annual productivity averaged 2.5
kg/sq m, aboveground dry weight [33].  

Perennial ryegrass is widely planted for range, pasture, hay and turf.
It is one of the more closely studied pasture grasses.  There have been
numerous studies on management, nutritive value, and genetics.  Many
cultivars are available, conferring various characteristics of pest
and/or disease resistance and particular growth properties [14].

Reaction to grazing:  Perennial ryegrass is slower to establish than
common ryegrass, but fully developed stands are equal to common ryegrass
in production and are more persistent [20].  Establishment is, however,
sufficiently rapid to allow grazing at heavy stocking levels as soon as
2 months after seeding [49].  Perennial ryegrass is well suited for use
with subterreanean clover (Trifolium subterraneum) for sheep pasture
grazing in late winter and early spring where soil moisture is adequate
for growth [26].  Such pastures can produce up to 4,465 pounds per acre
(5,000 kg/ha) of forage if properly fertilized and maintained [44].  A
study was conducted in Oregon to determine the practicality of a
rotational short-duration grazing system to maximize pasture growth
during the winter or allow rationing of forage produced during the
previous fall.  There was little or no forage accumulation in January
and February.  The highest cover for perennial ryegrass (measured in
May) occurred on study plots grazed in April (rather than earlier in the
year) [26].

Perennial ryegrass has a higher percentage of standing crop dry weight
with low levels of nitrogen fertilization than with high or no added
nitrogen.  Production is best when clipped every 3 weeks (as opposed to
unclipped, or clipped at 1 or 6 week intervals) [37].  Perennial
ryegrass is considered better for pasture than for hay in Alberta [49].

Tiller number decreases immediately after grazing, then increases so
that by May (after grazing in April or earlier) plants have 1.5 to 3
times as many tillers as ungrazed controls [26].  In a growth chamber
study, the initial reaction of perennial ryegrass to clipping was an
immediate regrowth of the damaged leaves, rather than tiller production
[18,37].

Range management practices are generally based on how they affect
carbohydrate reserves of grasses.  For perennial ryegrass, the peak
carbohydrate reserves occur just after flowering in late spring and
early summer [55].  Maximum levels of carbohydrate reserves do not have
to be maintained for proper management, rather, the reserves must not
fall below a critical level [60].  The critical level differs with
species and cultivars and is probably affected by fertility and season
[58].  In growth chambers, perennial ryegrass was unable to use
carbohydrate reserves when the reserves fell below 6 percent of dry
weight.  At 6 percent, reserves were inadequate for support of the
existing tiller population and some tillers died [60].

Areas of use:  In Utah, perennial ryegrass is used in irrigated
pastures, or for dryland use where there is at least 18 inches (460 mm)
annual precipitation and the winters are mild [25].

Competition:  Where it is planted with long-lived grass and legumes,
perennial ryegrass should not make up more than 25 percent of the
mixture so that sufficient numbers of the longer lived species can
establish.  If it is seeded too heavily in mixtures, it may retard the
growth of the other species [20,42].

Although perennial ryegrass is usually associated with fertile soils,
under low levels of nitrogen it will outyield sheep fescue (Festuca
ovina) and mat nardusgrass (Nardus stricta), which are grasses of
infertile pastures [6].  The highest levels of production are on soils
of medium to high fertility [57].

The practice of seeding grasses on sites managed for conifer
regeneration may result in a decrease in the competitive success of the
conifer seedlings.  In a study on Douglas-fir regeneration, Newton and
Cole [43] found that there were proportional decreases in both root and
shoot growth, regardless of competitor type.  The survival of ponderosa
pine (Pinus ponderosa) seedlings was reduced where they were planted in
grass mixtures that included perennial ryegrass [5].

The ability of perennial ryegrass to effectively suppress woody species
may be an advantage where grasslands are desired management goals.  At
moderate to high densities, perennial ryegrass reduced the dry weight
gain of sugarberry (Celtis laevigata) by up to 84 percent.  It is likely
that perennial ryegrass could help inhibit growth of sugarberry on
grasslands undergoing secondary succession [53].

In a study of the effects of perennial grasses on annual weeds,
perennial ryegrass was least able to suppress annual weeds.  It is
likely, therefore, that perennial ryegrass may not be the best choice
for rehabilitation of degraded pasture and range that is subject to
invasion by weedy annuals [5].

The use of introduced species for soil stabilization and rangeland
conversion is becoming more questionable because the effect of such
species on the community structure of native plants is still poorly
understood.  Management considerations must take into account both the
benefits of erosion control, shrub control and the reduction of shrub
competition with conifers, and the negative aspects of competition for
space and soil moisture with native herbs and shrubs [19].  Perennial
ryegrass has negative effects on natural regeneration of chaparral
because it readily outcompetes native herbs, resulting in a reduction of
wildflowers.  In most cases, natural regeneration after fire may be
sufficient without artificial seedings, and has the added benefit of
costing nothing [29].

Perennial ryegrass was well established in all plots 3 years after the
plots were sprayed with various treatment of silvex, picloram and 2,4-D.
The herbicides in the study gave effective 2-year control of woody
plants [44].

Perennial ryegrass does best in fall seedings where winter months are
mild, but seeding too late in the fall will increase winter-kill to
unacceptable levels.  Some cultivars have more rapid establishment than
others [14].

Seeding rates for perennial ryegrass are as follows [14,54]:

In mixtures:
         5-10 pounds per acre (5.5-11 kg/ha) 
      4.5-5.4 pounds per acre (5-6 kg/ha) with legume
        8 -10 pounds per acre (9-11 kg/ha) with cereal
           29 pounds per acre (33 kg/ha) for erosion control
      219-348 pounds per acre (245-39 kg/ha) for lawns

In pure stands:
        14-25 pounds per acre (16-28 kg/ha)

Perennial ryegrass yields from pure stands grown in western Washington
average from 4.02 to 4.96 tons per acre (9.01-11.12 t/ha) [45].

Diseases and Pests:  Crown rust (Puccinia coronata) may severely reduce
forage value in wet areas.  Other fungal infections include brown rust
(Puccinia dispersa), and red thread (Corticum fuciforme).  Occasional
attacks by Helminthosporum species also occur.  Ergot (Claviceps
purpurea) and blind-seed disease (Phialea temulenta) reduce seed yield
and quality [14].  Leaf blotch (Helminthosporium spiciferum), ergot and
blind seed disease can be substantially controlled by burning perennial
ryegrass fields in the spring [21].

Related categories for Species: Lolium perenne | Perennial Ryegrass