Four olive cultivars 10-years old with different production purposes (oil, table-and double purposes) which grown in calcareous soils under drip irrigation system at North West region of Egypt were evaluated for their responses to an Integrated and Balanced Fertilization program (IBF) comparing with normal farm fertilization (NFF) during two successive seasons (2006, 2007).Results showed that remarkable and significant differences between cultivars in leaf-macro and micronutrients contents, olive yield and both oil and total acidity percentage as a result of using (IBF). Correlation coefficients cleared that there are high positive relations between leaf nutrients contents and olive yield. They reached to highest values with potassium (r=0.63)and both nitrogen and copper (r=0.58).With respect to oil percent, positive relations were also observed with potassium (r=0.38),copper (r=0.26), calcium (r=0.24) and phosphorus (r=0.18). Otherwise, negative relations were found with total acidity , particularly potassium (r=- 0.72) and
copper (r=- 0.55) and to a less extent, with phosphorus
(r=-0.51),calcium (r=-0.49),magnesium (r=-0.48),nitrogen (r=-0.38) and iron ( r=-0.33).It is clear that potassium and copper had the most effective role on olive yield and its quality. There were also found positive relation between olive yield and its oil content (r=0.20) and in contrast, negative relations between each of them and total acidity (r=-0.48 and-0.14), respectively.
The olive yield of the four cultivars and their oil contents were increased as a result of using (IBF) program where the increasing rates ranged from 23-30% and from 13-26%, respectively. But the total acidity was decreased by rates ranged from 12-33%. In accordance, the highest olive yield was 28.9 kg/tree with 20.7% of oil and 0.7% of total acidity for the double-purpose cultivar (Picual) and the lowest one was 20.6 kg/tree with 7.7% of oil and 0.8% of total acidity for the table-purpose cultivar (Egazy, local cultivar).
It can be concluded that, the addition of macronutrients as soil application through the drip irrigation system and micronutrients as foliar application in an integrated and balanced fertilization (IBF) program to the four studied cultivars, has effective role for improving olive yield and its quality.