A multi-objective approach for optimizing mobile drip irrigation systems: Experimental verifications in northern China

Abstract

Mobile drip irrigation (MDI) systems represent an innovative water-saving irrigation technology that combines the advantages of center pivot irrigation (CPI) systems and drip irrigation systems. While particularly suitable for large-scale agricultural production in northern China, limited research has focused on MDI system design optimization. This study introduces a hydraulic optimization design method for MDI system in northern China. The proposed method integrates HYDRUS-2D numerical simulations with a multi-objective optimization approach to determine the optimal drip-line installation distance based on specific soil textures, crop species, water resource economics, and investment budgets. In addition, an equal-area principle is applied to calculate the precise length of each drip line, ensuring consistent irrigation depth across the entire area. To validate the proposed design method, verification experiments were conducted in Zhuozhou City, Hebei Province. Water application uniformity coefficients of 90.24 %, 94.73 %, and 90.40 % were achieved in three irrigation scenarios with irrigation depths of 26, 23, and 22 mm, respectively. These results demonstrate that the equal-area principle effectively ensures uniform irrigation depth across the controlled area. The numerical simulation combined with the multi-objective optimization approach successfully identified reasonable drip-line installation distances. At each measurement point under the optimal drip-line installation distance, soil moisture content uniformity consistently exceeded 90 % without deep percolation. Furthermore, the average soil moisture content under the MDI system was higher than that under the CPI system, with increases of 15.92 %, 32.24 %, and 11.80 % in the three irrigation scenarios. These findings highlight the superior water use efficiency of the MDI system. The proposed hydraulic optimization design method effectively ensures irrigation performance while minimizing water losses during irrigation. This research underscores the potential of the proposed MDI optimization design method to contribute to the sustainable intensification of agriculture in northern China.