Two field experiments were carried out during the two successive summer seasons of 2006 and 2007 at Bahteem, Water Requirements Research Station., El Kalyobia Governorate -National Water Research Center. Maize (Zea mays, single cross 10) was grown on the investigated soil under two irrigation systems i.e. surface irrigation (Gl) and drip irrigation (G2). Nitrogen fertilizer was applied in the form of urea (46% N) at four rates Nl (Okg), N2 (90kg), N3 (120kg), and N4 (150 kg N /fed.) Other cultural practices were done as recommended. The experiment was arranged in a split plot design.The irrigation systems were distributed uniformly in the main plots, while, the nitrogen treatments, were distributed randomly in the sub-plots.
Results showed that the effect of rate of the applied nitrogen fertilizer was significant on values of plant height in both the two growing seasons.
Under all rates of the applied N, values of plant height were higher under .the drip irrigation than under the surface irrigation system, however, such an effect of the drip irrigation system on plant height was significant only in the second growth season i.e.2007.
The interaction effect between system of irrigation and rate of the applied nitrogen seemed to be of no significant effect on height of plant in both the growing seasons. The grain yield was highly significantly affected by system of irrigation and rate of the applied nitrogen. The interaction effect among the different studied factors was not significant on grain yield. The concentration of nitrogen in grains of maize was significantly higher in drip irrigation system than the surface irrigation one. Also, rate of the applied nitrogen significantly affected concentration of N in grains of maize plants. However, the highest concentration of nitrogen in maize plants-was attained at a rate of 120 kg N/fed beyond which concentration of nitrogen was significantly decreased as compared with the corresponding one attained owing to application of N at a rate of 120 kg N/fed. The nitrogen concentration in the straw of maize was not significantly affected by system of irrigation or rate of the applied nitrogen within the first growing season. In the second season of growth, both systems of irrigation and rate of the applied nitrogen were of significant effect on N concentration unlike what accrued in the first growth season. Likewise, effect of rate of the applied nitrogen was of significant effect on protein content within the both studied seasons.
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