All of the traditional world oil varieties are high yielding and most of the table varieties have lower oil content. Very good oils have been produced from the dual-purpose Mission variety and from carefully handled Manzanillo and Sevillano varieties. Olive trees must be properly cared for in order to achieve the economic yields. Care includes regular irrigation, pruning, fertilization, and pest management. Olives will survive on very poor sites with shallow soils but will grow very slowly and yield poorly.
Deep soils tend to produce excessively vigorous trees, also with lower yields.
The ideal site for olive oil production is a clay loam soil with good internal and surface drainage. Irrigation is necessary to produce heavy crops and avoid alternate bearing. Regular pruning should be employed to reduce alternate bearing of trees, to encourage production throughout the tree canopy, and to produce sufficient shoot growth for the next year's flowering and fruiting. Olives bear on the previous year's shoot growth, which is shunted while in competition with an excessively heavy fruit load. Harvesting Harvesting is one of the most expensive operations in an olive orchard.