Deficit irrigation is a strategy which allows your landscape greenery to sustain some extent of water deficiency in order to reduce water consumption, electricity consumption both. In this harsh climate of the Middle East where average temperature goes more than 400C then it is necessary to keep your greenery irrigated.
There are following methods to decide water scheduling 1) Soil Moisture Based, 2) ET based, 3) widely used in residential or even big commercial project- Experience Based (No data analysis required).
Soil Moisture based is cumbersome and gives you locally reading per plot. So only you need an ideal condition to install the sensor probe. ET based is widely being used in industry as it computes lot of data automatically to save your water & electricity cost. ET based can be integrated with the advance irrigation controller. The parameters which you require, is correct crop coefficient (Kc). On average, 85% of ET is solar radiation and 10% is wind. When there is no wind, then solar radiation is 90-95% of ET. If properly installed, correctly data fed then in your commercial project you can reduce water consumption by 30-35%. I’ve seen in many commercial project the proven records of water saving.