الفهرس 
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Abstract
SUMMARY
Two experiments were designed and carried out at Ismailia Agricultural Research Station, Agricultural Research Center, Ismailia Governorate, in three successive years through 2003-2005 for the field experiment and two successive years (2003-2004) for the pot experiment.
1- The Field Experiment:
The main objective of this experiment’ was to investigate the effect of various levels of N P K combinations on the productivity, quality and• nutrients uptake of some exotic and local alfalfa cultivars, under sandy soil in Ismailia Governorate through three successive years of 2003-2005.
The experiment was laid out in a split-plot design in 4 replications. The NPK treatments were randomly assigned in the main plots. The four applied fertilization treatments under study were formulated as follows: fdur nitrogen fertilization levels of 0, 10, 20 and 30 kg N/fed. applied as ammonium nitrate (33.5% N). In addition, four phosphorus levels of 0, 10, 20 and 30 kg P/fed were applied as super phosphate (6.5 % P) during soil preparation. The Potassium (K) was applied at four levels of 0, 10, 20 and, 40 kg K/fed
as potassium sulfate (43% K). The three nutrients (N, P, K) were combined together and applied in the following combination: control ON — OP — OK, low 10N — 10P- 10K, Medium 20N- 20P-20K and high 30N- 30P- 40K. Amounts of NPK were applied in four application. Each one of the above mentioned combinations applied during establishment and a weak later right after Spring, Summer, Autumn and Winter seasons each year followed by irrigation.
Moreover, micronutrients combinations (Fe, Zn and Mn were applied at a rate of 5 kg/fed. as Fe, Zn and Mn in EDTA formulation having 12% of each of the concerned element. Copper was applied as CuSO4 at a rate of 5 kg/fed
as well as two kg/fed of each of the ammonium molybdate and boric acid were added as a sources for Mo and B. These amounts of micro nutrients were applied in four equal doses in each of the four seasons of each year.
The five alfalfa cultivars include three exotic cultivars (Hallma, Melesia from France and Siriver from Austrelia) and tow local cultivaers (Sewa and Ismailia-1) from Agricultural Research Center, Forage Dept., Egypt.
These cultivars were located in the sub plot of the experimental units
The most important results could be summarized as follows: Fresh and dry forage yield:
Over the applied fertilization treatments each of the three exotic alfalfa cultivars were significantly lower in yearly and total yield than any of the grown local cultivars (Ismalia-1 and Sewa).
Concerning the local cultivars, Ismailia-4 was of the highest yearly and total forage yield followed by Sewa. The high, medium and low fertilizer treatments caused substantial increase in dry alfalfa forage yield compared to the control by 135, 89, and 39 % in the first year, being 89, 51 and 29 % in the second year and 85, 46 and 25 % in the third year. Seasonal total forage yield (fresh and dry) under each fertilization treatment was higher in spring season followed by summer then autumn where the lowest forage yield was produced in winter.
-There was greater response to the highest NPK fertilization level in summer season; then spring; followed by autumn. Whereas, the lowest dry forage yield (fresh and dry) was
produced during winter seasons as compared with their relevant control received the lowest NPK fertilization levels. - Dry leaf/stem ratio during the stand duration indicated the superiority of summer seasons which gave, the highest values of dry leaf/stem ratio, while the lOwest values
resulted during spring seasons of the whole stand duration of 3 years.