A pot experiment was conducted under greenhouse conditions using pots (perforated at the bottom), with 12 kg soil capacity of each. Pots were seeded with wheat (Triticum aestivum c.v. Sakha 8), to study the effects of traditional soluble-N and slow release-N fertilizers. The soil of each pot was thoroughly mixed with P at a rate of 12 mg P/kg soil. Soil K was in sufficient amount. The experimental pots were contained 288 pots, which arranged in a complete randomized block design with three replicate in four factors of three forms of soil , four N-fertilizers ( two traditional soluble-N and the other two slow release-N fertilizers) , three rates of N-fertilizers as well as two rates of moisture regimes of 70 and 100 WHC . At wheat maturity after 24 weeks-growth, plants in each pot were cut 2-cm above soil surface, carefully washed, dried and weighted. After wheat harvested and in the same pots, in order to study the N-fertilizes residual effect, two successive crops of Sorghum vulgar "c.v. Giza 15" and then barley "Hordium, vulgar c.v. Giza 121" were planted and harvested after 9 and 16 weeks , respectively. The obtained results may be summarized as follows:
The traditional soluble forms of N-fertilizers produced higher dry matter (gm./pot) of wheat crop compared with the slow release forms of N-fertilizers.
Dry weights (gm/pot) of both sorghum and barley were more under fertilization with slow release forms of N-fertilizers, than under fertilization with the traditional soluble forms, with approximately equal to two fold and threefold, respectively.
Slow release forms resulted in less N-uptake by wheat than the traditional soluble forms. While the slow release forms of N-fertilizers affected positively on N-uptake by both of sorghum and barley, with increases approximately equal to twice threefold more than the traditional soluble ones.
·Residues of slow release N- fertilizers have appropriate supply of sorghum and barley, at the two successive with amounts of (N), because their ability to continuous supply (N) for long periods of time.