CONTRIBUTION OF GROUND WATER TABLE ON MAIZE YIELD AND IRRIGATION REQUIREMENTS IN NORTH NILE DELTA

Due to the increasing demand of food by its ever-increasing population, the pressure on fresh water resources of Egypt is increasing. Optimum utilization of surface and groundwater resources has become extremely important to fill the gap between water demand and supply. Maize (Zea maize L.) of hybrid single cross 10 plant was grown in two field experiments to investigate the effect of irrigation depth and irrigation intervals on contribution of water table and yield of maize crop during 2009and 2010 at Sakha region, Kafr El Sheikh Governorate The site represents the circumstances and conditions of Middle North Nile Delta region and allocated at 31-07' N Latitude, 30-57'E Longitude with an elevation of about 6 metres above mean sea level. Main plots were assigned to depth of irrigation (A) depth 5 cm = 210 m³ /fed. , (B) depth 7 cm = 294 m³ /fed. and (C)Depth 9 cm = 378 m³ /fed. (each irrigation), while subplots were irrigated with irrigation intervals i.e. 10, 15 and 20 days, (1, 2 and 3 respectively) .
            Results showed that SMD was not affected by depth of irrigation applied, but a clear effect was observed from the irrigation intervals. Seasonal SMD values in the first season are 52.0, 67.9 and 83.9 cm for A₁,B₁ and C₁,respectively .In the second season, the corresponding values of the same treatments are 53.0,68.9and 84.9 cm respectively. for treatment A_1, A₂and A₃ which represent the effect of irrigation intervals, values are 52.0, 37.0 and32.0 cm respectively in the first season . While the corresponding values in the second season are 53.0,38.0 and 33.0 cm respectively.
           Fluctuation of water table level, it was observed, that the depth of water table reached the lowest value immediately before irrigation. While the maximum water depth reached at 2 days after irrigation. Contribution of ground water table to ET_c was found to be depended on growth stage and both of depth and intervals of irrigation. Data also showed that with increasing irrigation intervals, the contribution increased also from 8.4 to 20.6 to 40.8 % for A_1, A₂and A₃ treatments, respectively. Under the same irrigation interval of 20 days which accompanied with increase in water depth applied from 5 to 7 to 9 cm i.e. treatments A₃, B₃ and C₃ the contribution of water table  decreased from 40.8 to 14.6 to 10.5 %, respectively.