The choice of turfgrass species for landscape
sites has traditionally involved the desired
appearance and usage more than any other concern.
Increasingly, the effect the turf will have
on the environment has become an important
issue. There are many ways turf can modify
the environment and a wide variety of environmental
concerns, which can influence the choice of
turf species.
This guide shows the characterisitcs of the
different cool-season turf species that may
be important in relation to the environmental
concerns of a specific site. The importance
of certain characteristics in species choice
may be self-explanatory but a short explanation
below shows why other characterisitcs are
important. For most characteristics you will
also find variation between varieties of a
species.
1.
Growth Habit
This is often important in soil stabilization
since stoloniferous and rhizomatous
grasses may fill in and repair areas
more easily. This is also related to
recuperative ability after drought or
other stresses.
2.
Establishment Rate
Species that establish rapidly will
stabilize soil more quickly and often
require less water for the establishment
phase.
3.
Nitrogen Requirement
Two primary concerns are utilization
of fossil fuels to produce many nitrogen
fertilizers and the potential of nitrogen
leaching. Nitrogen leaching is dependent
on grass species (and/or cultivar),
amount and form of nitrogen applied,
time of year and amount of water applied.
If sewage wastewater is utilized species
that can use high levels of nitrogen
may be desired. Nitrogen use efficiency
is still being defined for many species.
4.
Mowing Frequency
More frequent mowing requirements can
contribute to increased fuel usage,
added pollutants to the atmosphere,
and added burdens on landfills if clippings
are removed.
5.
Close Mowing Tolerance
Grass that is mown more closely has
reduced water use compared to the same
species at a higher rate of cut. Different
varieties of a species may vary significantly
in their tolerance. However, close mowing
may reduce rooting depth.
6.
Water Use Rates, Drought Tolerance,
Rooting Depth
Interrealated characteristics that are
of varying importance depending on site.
In some situations where irrigation
water is limited a species utilizes
high amounts of water, even if drought
tolerant, may be unacceptable. The rooting
depth helps determine available water
and can relate to short duration drought
tolerance in some species. Other species
are drought tolerant due to low usage.
Another consideration is how well a
species will recover after a period
of drought.
7.
Competiveness
A more competitive species, if properly
managed, can reduce weed encroachment
and thus herbacide use.
8.
Evaporative Cooling Potential
This is primarily related to water use
rate and growth rate. Species that are
growing faster and using more water
will do a better job of cooling the
surrounding area. Lqandscaping can do
a very effective job of reducing cooling
needs and thus total energy expenditures.
9.
Insect Resistance
Reduction of pesticide use is an important
consideration in many sites. In most
species varieties vary in their genetic
resistance but in those species where
vqarieties with the Acremonium endophyte
are available this can provide insect
resistance and other growth benefits.
10.
Salinity Tolerance
This is an important consideration if
sewage wastewater is being used for
irrigation or for marginal well water
in many areas of the country.
