Environmental Engineering Reference
In-Depth Information
damaged areas on lawns, athletic fields and golf-courses.
L. perenne
is
sometimes used in combination with
Poa pratensis
on lawns and athletic
fields, especially under heavier traffic. In warmer regions, it is used for
winter overseeding of dormant warm-season turf.
L. perenne
is best
adapted as a permanent turf-grass where winters and summers are
moderate and moisture is sufficient.
Lolium multiflorum
Lam., known in many countries as Italian rye-
grass, grows very rapidly. It can be used for lawns, but is usually
reserved for specialized uses such as turf repair, quick temporary turf
cover or overseeding.
Other cool-season genera
Other, less important, cool-season turf-grasses include
Bromus inermis
Leyss. (smooth brome-grass), the genus
Phleum
(timothy grasses),
Dacty-
lis glomerata
L. (orchard grass) and
Puccinellia distans
(L.) Parl. (reflexed
salt-marsh grass). Almost certainly several other cool-season species are
used as turf-grasses in various regions of the world, but most are of
minor importance.
Turf-grass Communities
An individual turf-grass plant lives in a
community
with many
other plants, which may or may not be of the same genus, species or
cultivar. A turf-grass community can be classified as either a
monostand
or a
polystand
. Monostands are composed of turf-grass plants
belonging to only one species and cultivar.
Polystands
are composed of
turf-grass plants of more than one cultivar and/or species. Polystand
turf-grass communities can be further subdivided into
blends,
composed
of two or more cultivars of a single species, and
mixtures,
composed of
two or more different species.
Blends and mixtures are very common in cool-season turf communi-
ties. They increase genetic diversity; community resistance to diseases,
insects, environmental stresses; etc. For example, if one of three varieties
or species within a turf-grass community is damaged or killed by a
disease or insect, the other two may be unaffected and may grow to
take the place of the missing plants, preserving the turf's overall appear-
ance. The most important condition for usage of mixtures and blends is
compatibility of the component varieties or species. Mixed or blended
turf-grasses should have similar leaf texture, growth habit, colour and
shoot density, and fairly equal growth vigour. Unfortunately, warm-
season (tropical) grasses rarely meet
these criteria, so mixtures of
