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

The experiment was carried out in the private orchards at Tayba Alhasnab area ofsouth Khartoum State, in Sudan during 2012 and 2013 to evaluate the waterproductivity, yield and quality of foster grapefruit irrigated by bubbler and surfaceirrigation system. Irrigation interval was 5 days in bubbler irrigation system andevery 7 to12 days in surface irrigation system depending on the prevailing weatherconditions. The results revealed that higher yield and number of fruits was obtainedon bubbler irrigation system compared to surface irrigation system. Moreover,bubbler irrigation system increased the total yield of foster grapefruit by 28% and25%, respectively as compared to surface irrigation system. Applying irrigatedwater under bubbler irrigation system improved the quality parameters of fostergrapefruit such as fruit diameter recorded significant differences on bubblerirrigation system compared with surface irrigation system in both years, fruitweight and peel thickness recorded significant differences (P≤0.001) betweenbubbler irrigation system and surface irrigation system on finger weight, but ondifferences in peel thickness in both years, total soluble solids of foster grapefruitirrigated 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% andhad highest water productivity (2.9 and 2.7 kg/m3) compared to surface irrigationsystem (0.67 and 0.68 kg/m3). Also highest marginal rate of return was obtainedwith bubbler irrigation system compared to surface irrigation