Environmental Engineering Reference
In-Depth Information
Poor growth
Fig. 4.1. Buried debris can restrict turf growth and should be removed before any
attempt to establish turf grass.
Large rocks should also be removed from the root zone. As a general rule,
a few rocks smaller than a golf ball or the size of a small chicken egg
usually do not interfere with turf performance or maintenance and can be
left in place. In some situations, however, especially on recreational or
sport turfs, the presence of even a few small rocks is not acceptable. They
may cause improper operation of, or damage to, specialized turf machin-
ery. In such cases they must be removed before planting.
Rough Grading
In many cases, the terrain chosen for turf establishment is not even.
Especially over large areas, some spots are either lower, higher, flat or
sloped. The objective of grading is to provide a relatively smooth, firm
surface, which assures both pleasant appearance and adequate drainage
of surface water.
For establishment of a residential lawn, rough grading will be needed
occasionally. Most experienced contractors build the house at the highest
point on the property and provide a 1-2% slope away from the house.
Larger turf areas, such as parks or athletic fields, frequently need rough
grading. Golf courses almost always need large-scale rough grading. The
first step in rough grading is usually removal of the topsoil, which is then
stockpiled somewhere nearby for future redistribution over the newly
graded site.
An important rule for shaping a subgrade on which topsoil is to be
placed is that the subgrade should always follow the finished grade
