Formation mechanism for emitter composite-clogging in drip irrigation system

Revealing the mechanism and influential path of emitter clogging in drip irrigation is the basis to control this issue. Eight commonly used flat emitters were tested to analyze the effects of emitter flow path geometric parameters on the hydraulic indexes, clogging performance, and composition of clogging substances, and the influential path was established through the path analysis method. The results indicated that the average cross-sectional velocity ( v ) was significantly correlated to clogging degrees and clogging substance formation. v directly affected the formation of clogging substance components, and was influenced by the width–depth ratio ( W / D ) and the relative radius ( A 1/2 / L ). Among all the components of the clogging substances, solid particle (SP), and CaCO 3 and MgCO 3 precipitates (C–MP) directly affected emitter clogging process, while phospholipid fatty acids (PLFAs) and extracellular polymeric substance (EPS) mainly relied on the indirect impacts. Therefore, emitter with larger v rather than that with larger Q should be a better choice from the perspective of the anti-clogging performance, and larger v could be obtained through the optimized design of emitter structure by controlling the appropriate ranges of W / D and A 1/2 / L .