Large areas of crops are now grown under water-stressed conditions on non-irrigated and under limited irrigation in semi-arid and arid regions. In the future, this area of water-stressed crops will increase as a result of increasing competition from other water users, declining ground water levels, and the bringing into production of fragile lands that have low water-holding capacity, such as sandy desert soil. Consequently, strategies and practices to increase total yields and efficient water use must be improved.