Fawzi S. Mohammad

Water conservation through irrigation scheduling under arid climatic conditions

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.

Assessment of smart irrigation controllers under subsurface and drip-irrigation systems for tomato yield in arid regions

Abstract. Here, two types of smart irrigation controllers intended to reduce irrigation water are investigated under Saudi Arabia’s present water crisis scenario. These controllers are specially made for scheduling irrigation and management of landscaping. Consequently, the aim of this study is to adapt the efficient automated controllers to tomato crops, and for extension to other similar agricultural crops. The controllers are based on evapotranspiration and have been shown to be promising tools for scheduling irrigation and quantifying the water required by plants to achieve water savings. In particular, the study aims to evaluate the effectiveness of these technologies (SmartLine SL 1600and Hunter Pro-C) in terms of the amount of irrigation applied and compare them with conventional irrigation scheduling methods. The smart irrigation systems were implemented and tested under drip irrigation and subsurface irrigation for tomato (cv. Nema) in an arid region. The results revealed significant differences between the three irrigation-scheduling methods in both the amount of applied water and yield. For example, each 1 mm water depth applied to the tomato crop via subsurface (or drip) irrigation by SmartLine, Hunter Pro-C, and the control system yielded 129.70 kg (70.33 kg), 161.50 kg (93.47 kg), and 109.78 kg (108.32 kg), respectively. Generally, the data analysis indicates that the Hunter Pro-C system saves water and produces a higher yield with the greatest irrigation water-use efficiency (IWUE) of the irrigation scheduling methods considered. Moreover, the results indicate that the subsurface irrigation system produced a higher yield and IWUE than the drip system.