Nut crops are in limited supply within the European Communities (EC) but there is a need to reduce the costs of European nut production if it is to compete with other nut production areas in the world. Irrigation is one of the agricultural practices that has most effect on production but water is a limited resource in European nut producing areas and is costly. Work is being done to reduce production costs by inceasing the efficiency of water utilization by nut trees and particularly to find an appropriate controlled deficit irrigation (CDI) schedule that will give greater yields using reduced amounts of water.