Evaluating the Influence of Water Quality on Clogging Behavior in Drip Irrigation Emitters: A CT Imaging Study

Applying poor-quality water in drip irrigation has become increasingly common to address agricultural water scarcity. However, emitter clogging remains a critical challenge that limits the widespread adoption of this technology. Currently, the mechanism of emitter clogging under poor-quality water conditions remains insufficiently explored. This study investigates the distribution and accumulation of clogging substances within drip irrigation emitters under three water conditions: saline water, Yellow River water, and a 1:1 mixture of both, at clogging degrees of 5%, 20%, and 50% (i.e., the flow rate reaches 95%, 80%, 50% of the rated flow). The results showed that when clogging reached 20%, Yellow River water led to the highest clogging volume (i.e., the total volume of clogging substance in the flow channel, 1.77 mm3), while at 50%, saline water resulted in the highest clogging volume (5.11 mm3), while the use of blended water improved the clogging situation. Under different water conditions, clogging substances mainly formed on the upstream and downstream faces of the flow channel, accounting for 23.9–31.8% and 9.3–32.4% of the total volume, respectively. With higher clogging levels, the proportion of clogging substances on the downstream face increased significantly, while other areas showed minimal change. The volume of clogging substances was more pronounced at the front of the flow channel than at the back across the entire length, except at the 20% clogging degree for Yellow River water. At 5% clogging, the largest difference in clogging volume was observed with Yellow River water, while at 50%, the largest difference occurred with blended water. This research provides critical insights into the impact of poor-quality water on emitter clogging and suggests that the use of blending water, gradually varying channel structure, and increasing the arc of clogging faces can effectively alleviate clogging and enhance drip irrigation efficiency.