Several research projects have been conducted to determine water quantities for maximum production, and to evaluate the optimal deficit allowed. It is important to emphasize here that this subject is complicated, as several parameters are involved:

• Timing of stress induced
• Long-term effect of water status in the soil 
• Long-term effect of plant development
• Different varieties and environment and the effect on alternate bearing on tree performance.
• Affect on oil content and quality
  This implies that at least two years are required to evaluate the real effect of water applications on the olive orchard.