Agriculture Reference
In-Depth Information
It is clear from Fig. 4 that highest value of moisture content was observed below
the drippers after 1 h at all operating pressures. Soil moisture moved in the soil 1 day
after irrigation and higher values of soil moisture contents were observed at 15-30 cm
soil depth. The higher values of soil moisture were present at upper soil layer (15-30
cm soil depth) at higher dripper discharges even after 3 days after irrigation. However,
almost similar values of soil moisture were recorded in all the soil layers 7 days after
irrigation.
FIGURE 4 Temporal distribution of soil moisture distribution 1, 3 and 7 days after drip
irrigation at different locations away from the dripper with different dripper discharges at 0.5,
1.0 and 1.5 kg.cm -2 system operating pressures.
Figure 4 shows that wetting front extended up to 15 cm horizontally and 30 cm
vertically with 0.94 l h -1 dripper discharge at 0.5 kg cm -2 system operating pressure
whereas, it extended up to about 20 cm horizontally and about 30 cm vertically at with
1.41 l h -1 dripper discharge at 1.0 kg cm -2 operating pressure after 1 day of irrigation.
However, it reached to about 24 cm vertically and 26 cm horizontally with 1.71 l h -1
dripper discharge at 1.5 kg cm -2 operating pressure after 1 day of irrigation. Similar
trends of wetted fronts were refl ected from the observations taken after 3 days of ir-
rigation.
At higher discharge rates, horizontal distances of water front were relatively larger
as compared to vertical distances which may be attributed to less resistance to water
fl ow in horizontal direction as compared to the vertical and negligible gravity forces
for horizontal fl ow of water. Similar results have been reported in the past [1, 4]. Koon
et al. [1] and Badr and Taalab [4] investigated the effect of drip discharge rate on the
 
Search WWH ::




Custom Search