Hydraulic Performance of Drip Emitters under Different Conditions and Water Qualities

Abstract

The aim of this study was to investigate the hydraulic
performance of the drip emitters under different environmental conditions
and irrigation water qualities. Two experiments were carried out under
different conditions in the demonstration farm of the Faculty of
Agriculture, University of Khartoum, during May 2011 to February 2012.
The first experiment was achieved under controlled condition (indoor)
with different emitter types (Black on-line, Blue on-line and Inline) and
levels of water salinity(0.20, 0.35, 3.5, 5.0, and 5.75 ds/m), while the
second experiment was conducted under field (outdoor)condition and
comprised different emitter types (Blue on-line and Inline) and
interspacing (0.5 and 0.3 m). The emitters hydraulic performances were
evaluated with reference to percentage of discharge reduction (R%),
coefficient of discharge variation (CV%), Christiansen’s uniformity
coefficient (CU%), emission uniformity (EU%) and clogging percentage
(Pclog%). Analysis of variation showed that there were significant
differences (P≤ 0.05) among the measured parameters. The results
indicated that the black and blue pressure compensating emitters showed
the highest performance in comparison with the inline emitters at P ≤
0.05, in both experiments. On the other hand, the blue pressure
compensating emitters showed the lowest clogging percentage (Pclog%)
with regard to the five levels of water salinity 0.20, 0.35, 3.5, 5.0, and 5.75

ds/m, respectively. While in the outdoor experiment the 0.5m emitter
inter-spacing showed higher values of discharge (q) uniformity coefficient
(CU)% and lower values of reduction of discharge (R)% as compared
with 0.3m emitter interspace, and both emitter interspaces showed no
significant differences (P ≤ 0.05) in between for values of emission
uniformity (EU)% and Clogging percentage (Pclog). The study concluded
that the emitter type, water quality and emitter interspacing are the crucial
factors affecting the hydraulic performance of drip irrigation systems