Development of a Coupled Model for Simulating Multiple Processes of Subunit Hydraulics, Soil Water/Salt Transport, and Crop Growth in a Drip Irrigation System

Drip irrigation systems are critical for sustainable agriculture, yet their design and management influence complex interactions among drip hydraulics, the transport of soil water (solutes), and plant growth. While these processes have been studied individually, integrated modelling remains underexplored in the current study. This study develops a coupled model combining a hydraulic analysis module, a soil water/solute simulation module, and a crop growth simulation module to simulate drip irrigation systems under various designs (network layouts, irrigation schedules, and soil conditions), which can inform designers and managers of precision drip irrigation systems. Field data from a cotton drip irrigation subunit in Xinjiang, China, were used to calibrate and validate the model, and the results demonstrated the strong accuracy of the model in predicting system performance (emitter pressure/discharge), soil moisture/salinity, and crop growth (LAI, biomass, yield) in the drip subunit ( R 2 > 0.50, d > 0.82). Scenario analyses revealed that hydraulic nonuniformity (CU: 72%–94%) propagates to soil moisture (CU: 93%–99%) and yield (CU: 89%–99%), with increased irrigation depth mitigating heterogeneity and increasing yield. We emphasise the functionality and future applicability of our model in assisting drip network design and irrigation management strategies for drip irrigation systems.