Abstract: In view of outstanding problems such as the lack of unified communication architecture and logical linkage between head regulation and field execution in high-standard farmland irrigation systems, and the lag in irrigation decisions and execution actions, this paper designs a set of water and fertilizer integrated automatic irrigation control system with PLC as the core controller and LoRa as the field communication network. The system adopts a three-layer overall architecture of "centralized management-head control-field execution", covering the control and management platform, the first water and fertilizer regulation unit, and the field sensing and execution unit. At the control strategy level, a rotation irrigation unit grouping method and a standardized automatic irrigation control process are proposed to realize closed-loop control of irrigation tasks from planning to execution feedback. The system was put into operation in the high-standard farmland demonstration area in Altay Prefecture, Xinjiang. The application results show that the number of irrigation operators has been reduced from 10 in the traditional mode to 1, the rotation irrigation process has been continuous and stable, and the consistency rate between valve opening and closing and task instructions is 100%. The system maintains high stability and reliability under long-term operation conditions. The design and application of this system can provide a complete set of technical reference for the automated upgrading of high-standard farmland irrigation systems in arid and semi-arid areas.