Abstract
A field experiment was carried out on wheat crop at the project sites of Hail Development Company (HADCO), about 500 km north-west of Riyadh, Kingdom of Saudi Arabia. Four centre pivot circles (each 54 ha in area) were used in the study. A model based on the Modified Penman Method (FAO version) was developed and used for irrigation scheduling. The required micro-climatic parameters were continuously monitored by an automatic weather station installed at the site and transmitted to a computer for processing and analyses. The results of the experiment indicated that an appreciable amount of water (25%) was saved as compared to the irrigation practice adopted by HADCO, and the yield is increased significantly by using this technique of scheduling. In addition, the conservation of water results in reducing the working hours of the equipment and labour.