Determining clogging threshold of ceramic emitters to promote wolfberry production in Northwest China

Drip irrigation is a worldwide water-saving irrigation technology and benefits crop production. Yet, the emitter clogging is still a crucial problem for application. Recently, ceramic emitter (CE) with porous flow path was proposed as an alternative to the plastic drip emitter for continuous irrigation. However, there is still a gap in the estimation of the CE clogging degree. To address this, we conducted the field experiment in Tongxin, Yinchuan and Qinghai with the aim of the determination of the suitable discharge ratio variation (Dra) threshold of CEs under different climate conditions by using the AquaCrop model and segmented linear regressions. The results showed that there was a determined Dra threshold for soil water content (SWC), wolfberry canopy cover, biomass and yield in three experimental sites by 53.55 % - 54.62 %, 57.11 % - 65.94 %, 55.58 % - 64.30 % and 51.76 % - 61.23 %, respectively. Moreover, the Dra thresholds decreased with the precipitation increased in different climate conditions. Furthermore, we determined the Dra threshold of CEs was 56.1±5.3 % for wolfberry production, which was remarkably lower than the international standard of emitter clogging level by 75 %. Our study provides scientific insight to determine the clogging thresholds of CEs and further generalizes this technique in the irrigation science area.