Full Product Manual

Table Of Contents
Gather Site Data Page 11
Soil absorbs and holds water in much the same way as a sponge. A given type
and volume of soil will hold a given amount of moisture. The ability of soil to
hold moisture, and the amount of moisture it can hold, will greatly affect the
irrigation design and irrigation schedule.
Soil consists of sand, silt and clay particles and the percentage of each is what
determines the soil type. Because the percentage of any one of the three particles
can differ, there is virtually an unlimited number of soil types.
The simplest way to determine the soil type is to place a moistened soil sample in
your hand and squeeze. Take the sample from a representative part of the site and
from approximately the same depth to which you will be watering. In other words,
if you want to water to a depth of six inches, dig down six inches to take your
soil sample. Table 3-2 lists the general characteristics of the three main soil types.
Soil Type
One of the most significant differences between different soil types is the way in
which they absorb and hold water. Capillary action is the primary force in
spreading water horizontally through soil. Vertical movement of water in the soil
is influenced by both gravity and capillary action.
An inline emitter tubing system such as Landscape Dripline relies on the soil to
evenly spread water throughout the planting area. The more homogeneous the
soil in the planting area, the more uniform the water distribution. Therefore,
compacted soil must be tilled to an 8” to 12" (20 - 30 cm) depth and should be
irrigated to field capacity prior to planting. In coarser soils, water is more likely
to be absorbed vertically, but will not spread very far horizontally. The opposite
is true for fine, clay-like soil.
Note: Emitters should be used very carefully in very coarse soils as water will
percolate downward before it can spread very far horizontally. Micro-sprays or
conventional irrigation may be more appropriate.
TABLE 3-2: DETERMINING THE SOIL TYPE
SOIL TYPE CHARACTERISTICS
Coarse Soil particles are loose. Squeezed in the hand when dry, it
falls apart when pressure is released. Squeezed when moist,
it will form a cast, but will crumble easily when touched.
Medium Has a moderate amount of fine grains of sand and very little
clay. When dry, it can be readily broken. Squeezed when
wet, it will form a cast that can be easily handled.
Fine When dry, may form hard lumps or clods. When wet, the soil
is quite plastic and flexible. When squeezed between the
thumb and forefinger the soil will form a ribbon that will
not crack.
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