Environmental Engineering Reference
In-Depth Information
as to build leaf tissue in order to restore photosynthesis as quickly as
possible. All these resources are used at the expense of the roots, causing
a major portion of the young roots to die and interrupting the growth of
others. The greater the percentage of leaf removal, the longer root growth
is disrupted. In addition to physiological stress, the accumulation of
excessive clippings provides favourable conditions for disease develop-
ment, as well as harbouring unwanted insects.
Unlike mowing height, mowing frequency cannot be specified on the
basis of turf-grass variety. Only the growth rate determines mowing
frequency. Because no more than one-third of the leave area should be
removed at any one mowing (Fig. 6.3), mowing frequency generally
increases as mowing height is lowered. For example, if cynodon grows
1 mm per day, a golf green cut to 3 mm should be mowed when its
height reaches slightly above 4 mm, that is, daily. The same cynodon on
the fairway, maintained at a height of 25 mm, should be mowed when its
height reaches 33 mm, that is, weekly. Mowing frequency still cannot be
specified in terms of days per millimetre of mowing height, because turf-
grass growth rate is influenced by weather conditions, moisture condi-
tions, soil fertility and the natural growth rate of the turf-grass involved.
Only the growth of the turf-grass, together with the rule that no more
than about one-third of the leaf area should be removed at each mowing,
can dictate the proper mowing frequency.
Mowing frequency is sometimes influenced by seed-head formation.
Some turf-grasses, such as common cynodon, Bahia grass, carpet grass
and St Augustine grass, may produce seed-heads between regularly
scheduled mowings. Seed-heads detract from the visual quality of turf
and, if unacceptable, must be mowed off. Mowing can also remove
flowering parts of certain weeds, before seeds are formed and spread.
1/3
Cutting blade
2/3
Fig. 6.3. No more than one-third of the leaf area should be removed at any one
mowing. (Drawing by R. Castro.)
