Environmental Engineering Reference
In-Depth Information
particular grass species and determine its ability to withstand low mow-
ing heights. Some creeping grasses with fine leaves, such as cynodon and
zoysia, when properly fertilized and watered, are able to produce ad-
equate leaf surface at very low mowing heights. Species with larger
leaves and elevated stolons and crowns, such as St Augustine grass and
centipede grass, must be cut higher. As a general rule, turf-grasses with
fine leaves can be cut lower than those with larger leaves. Table 6.1
presents preferred mowing heights for turf-grasses commonly found in
the tropics. Variation between cultivars can be substantial, so the values
given should serve only as guidelines.
Turf should not be cut lower than the height recommended for the
particular species or cultivar, but mowing somewhat higher is allowable
if the result does not interfere with the intended use of the turf. If a lower
mowing height should be desired in the future, however, the height must
be lowered gradually. The process must be spread over at least four or
five consecutive mowings. Making the change in one step is likely to
produce 'scalping' (removal of too much leaf area and too many crowns)
and will subject the turf-grass to severe physiological stress.
Mowing height is directly correlated with growth of the root system,
and higher mowing promotes both greater total root mass and greater
rooting depth (Fig. 6.2). Larger numbers of deep roots increase the turf-
grass's ability to draw water from deeper soil zones, and a larger root
system overall promotes absorption of nutrients from the most fertile
zone, the topsoil. Residential lawns and parks can routinely be mowed at
the maximum heights recommended in Table 6.1, or a little above. It is
seldom beneficial to mow lower, but mowing much higher should also be
avoided, even if consistent with the purpose of the turf area. As men-
tioned before, a mower's knife cuts through the stems, which stimulates
their branching and enhances turf density. If turf is mowed too high, too
few stems are cut, so stems branch less and put more energy into vertical
growth. As a result, turf density decreases, and the soil surface may
Table 6.1.
Recommended mowing heights
for tropical turf-grass species.
Species
Mowing height (mm)
Cynodon
5-35
Paspalum
10-50
Zoysia
10-50
Carpet grass
25-75
Centipede grass
25-75
Bahia grass
40-80
St Augustine grass
60-100
