This course provides a comprehensive introduction to four key water-saving irrigation technologies to address water scarcity challenges in arid and semi-arid agricultural regions, supporting efficient water resource utilization and sustainable agricultural development. The four core technologies covered are on-demand irrigation, automated irrigation, fertigation, and tidal irrigation, each offering distinct advantages for different application scenarios. Module 1 introduces on-demand irrigation, including its underlying principles, implementation requirements, and the application of online soil moisture monitoring systems. Module 2 focuses on automated irrigation systems, covering system components, operational requirements, three common system types, measures to improve irrigation uniformity, drip irrigation layout design, control system specifications, and five key functional components. Module 3 examines fertigation technology, explaining its concept, key distinctions from conventional water-saving irrigation practices, five major technical categories, common implementation misconceptions, and important operational considerations. Module 4 presents tidal irrigation technology, including its concept, two main system types, operational methods, and management considerations. This course provides practical guidance for agricultural technicians, farm managers, and irrigation practitioners to select appropriate irrigation technologies, improve water-use efficiency, and support stable and sustainable crop production.