Abstract:
Drip irrigation or trickle irrigation is a type of micro-irrigation system that has the potential
to save water and nutrients by allowing water to drip slowly to the roots of plants, either from
above the soil surface or buried below the surface. Field experiment was conducted at
Haramaya University to evaluate Effect of Drip lateral spacing on Water Productivity and
Onion yield (Allium cepa L.) at rare, Haramaya University, East Hararghe Zone, Ethiopia the
experiment was laid out in completely randomized block plot design. After the installation of
drip irrigation system, the hydraulic characteristics of the drippers that were determined
include emitter flow rate, emitter flow variation, and uniformity coefficient, coefficient of
variation and emission uniformity. Water application uniformity test of irrigation system was
determined for drip lateral spacing in every row and lateral spacing between two rows at the
beginning and end of the experiment. Drip irrigation spacing (100cm, 50cm, 30cm, 25 and
20cm) the lateral spacing were arranged with four blocks. The highest seasonal water
requirement of onion was 426.9 mm at 100% ETc under every drip irrigation spacing. The
analysis of variance revealed that there was significant (p<0.05) difference in yield among
treatments and the highest yield (37.26t/ha) was obtained from drip irrigation of lateral
spacing with 20cm of ETc application and while the lowest (29.61 t/ha) was obtained from
plots treated 100cm treatment. The highest (4.14kg/m3) and the lowest (1.54kg/m3) water
productivity were recorded from the plots treated with drip irrigation at 100cm and drip
irrigation at 20cm treatments, respectively. In terms of water productivity and natural
resource scarcity, irrigating with drip irrigation system with 30cm spacing can be
recommended for production of onion production.
