SOIL MOISTURE DISTRIBUTION UNDER MICRO IRRIGATION - Management, Performance, and Applications of Micro Irrigation Systems - page 137

10.3 RESULTS AND DISCUSSION
10.3.1 SPATIO-TEMPORAL DISTRIBUTION OF SOIL MOISTURE
Wetting patterns are characterized by the radial distance of the wetting front and the
depth from the emitting source. Spatial distribution of soil moisture was measured by
collecting the soil samples at different depths (15 cm interval, up to 60 cm) below the
dripper and away from the dripper at an interval of 15 cm, up to 30 cm under different
system operating pressures. The soil samples were also collected after 1 h, 1, 3 and 7
days of irrigation for temporal soil moisture distribution. The soil samples from differ-
ent depths were also collected initially for determining the initial soil moisture content.
10.3.2 SPATIAL DISTRIBUTION OF SOIL MOISTURE
The spatial distribution of soil moisture after 1 hr. duration under different system
operating pressures were measured and are presented in Fig. 3. The spatial distribution
of soil moisture was significantly (P<0.05) different at different locations in horizontal
and vertical directions from the dripper 1 hr. after the irrigation. However, it was not
significantly (P<0.05) different at different locations 3 and 7 days after irrigation. The
highest value of soil moisture content was observed below the dripper (a saturated
condition), which decreased as the distance increased from the dripper. Maximum
(25.4%) value of moisture content was observed near the dripper with 1.71 l h -1 drip-
per discharge at operating pressure of 1.5 kg cm -2 while minimum value (20.9%) of
soil moisture content was observed below the dripper with 0.94 l h -1 dripper discharge
at system operating pressure of 0.5 kg cm -2 .
FIGURE 3 Soil moisture distribution 1 h after irrigation at 0.5, 1.0 and 1.5 kg.cm -2 system
operating pressure.
10.3.3 TEMPORAL DISTRIBUTION OF SOIL MOISTURE
The temporal distribution of soil moisture below 15 and 30 cm away from the drip-
per after 1, 3 and 7 days at different locations away from the dripper under different
system operating pressures are presented in Fig. 4.