Two field experiments were conducted during (1999/2000) and (2000/2001)
seasons at EI-Serw Agricultural Research Station to investigate the effect of three tile
drainage spacings (15,30 and 60m.) and nitrogen application rate (0,45,60 and 75kg
N/fed) on yield, nitrogen uptake by wheat plant, and nitrogen losses by leaching. The obtained data revealed that decreasing drainage speasing up to 15 m.   Led to an increase in grain , straw yields and nitroGen uptake .Also , N- losses by
leaching increased significantly by decreasing drainage spacing up to 15 m ,so
dividing of N - application rate into 3 doses decreased N- loss by leaching. On the other hand, the restults indicated that incerasing N- fertilizer rate up
to full recommended dose increased significantly grain and straw yields, N- uptake by
wheat plants and nitrogen losses by leaching. From the obtained results, it could be concluded that the maximum wheat
grain and straw yields could be achieved by using drainage spacing of 15 m and
nitrogen application rate of 75 kg 1 fed added in three doses to decrease nitrogen
loss by leaching.