Environmental Engineering Reference
In-Depth Information
8
desired rate of application and make two passes at 90
to each other.
To achieve the proper application overlap, use the effective width as
the width of each pass. For example, if the effective width is 3 m, then
after each pass, move the spreader over 3 m from the centre of the
tyre tracks of the previous pass, to ensure a fairly constant rate of
application over the entire area.
Again, remember that the spreader must be calibrated for each type
of material to be applied. The same settings will not be correct for all
materials.
Determining the Amount of Material to be Applied
Fertilizer, seed and pesticide labels usually list the recommended appli-
cation rate in kilograms per hectare (g/100 m
2
). If a fertilizer label re-
commends 2 kg/100 m
2
, for example, and the area to be fertilized is
6m
2
, the amount of fertilizer needed is 120 g. The calculation is demon-
strated below.
X
represents the quantity to be applied per 6 m
2
.
Calculating from a Proportion
X
g
6m
2
¼
2000 g
100m
2
Cross-multiply (i.e. multiply both sides of the equation first by the de-
nominator on the left-hand side, then by the denominator on the right-
hand side) to obtain
100m
2
6m
2
X
g
2000 g
¼
Then divide both sides by 100 m
2
to obtain
X
120 g
¼
Calculations of Turf Areas
Some turfs have shapes of distinct geometric figures and can be
measured with high accuracy. Some others may be irregular and meas-
urements can be only approximated (Fig. A.3). Superior accuracy is
