OPTIMIZING WATER PRODUCTIVITY, YIELD AND QUALITY OF GRAPEFRUIT IRRIGATED BY BUBBLER AND SURFACE IRRIGATION UNDER KHARTOUM STATE SUDAN CONDITIONS

Abstract

The experiment was carried out in the private orchards at Tayba Alhasnab area of
south Khartoum State, in Sudan during 2012 and 2013 to evaluate the water
productivity, yield and quality of foster grapefruit irrigated by bubbler and surface
irrigation system. Irrigation interval was 5 days in bubbler irrigation system and
every 7 to12 days in surface irrigation system depending on the prevailing weather
conditions. The results revealed that higher yield and number of fruits was obtained
on bubbler irrigation system compared to surface irrigation system. Moreover,
bubbler irrigation system increased the total yield of foster grapefruit by 28% and
25%, respectively as compared to surface irrigation system. Applying irrigated
water under bubbler irrigation system improved the quality parameters of foster
grapefruit such as fruit diameter recorded significant differences on bubbler
irrigation system compared with surface irrigation system in both years, fruit
weight and peel thickness recorded significant differences (P≤0.001) between
bubbler irrigation system and surface irrigation system on finger weight, but on
differences in peel thickness in both years, total soluble solids of foster grapefruit
irrigated by bubbler irrigation system were significantly higher (P≤ 0.001)
compared with surface irrigation system in both years.
However, bubbler irrigation system saved irrigation water by 68% and 71% and
had highest water productivity (2.9 and 2.7 kg/m3) compared to surface irrigation
system (0.67 and 0.68 kg/m3). Also highest marginal rate of return was obtained
with bubbler irrigation system compared to surface irrigation.