Mobile drip irrigation (MDI): Clogging of high flow emitters caused by dragging of driplines on the ground and by solid particles in the irrigation water

Abstract

Mobile drip irrigation (MDI) system is interesting because it combines the efficiency of drip irrigation with the versatility of center-pivot irrigation; however, experimental information about clogging of MDI emitters caused by dragging of driplines on the ground and by solid particles in the irrigation water simultaneously are not presented to date in the literature. The objective of this research was to evaluate the performance of high-flow MDI drippers regarding the clogging resistance of emitters from dragging driplines over different soil types (experiment 1) and regarding clogging resistance from solid particles in the irrigation water (experiment 2). The research was carried out at the Irrigation Material Testing Laboratory at the University of São Paulo (USP), Brazil. In experiment 1, dragging of driplines over ground for 3 soil types, for different dripper models under dynamic and static conditions, were tested. In experiment 2, driplines resistance to clogging by solid particles in the irrigation water was evaluated. Dragging of driplines over ground did not cause significant clogging of emitters (A and B) for the in dynamic conditions, with average relative flow rate of drippers above 97%; however, under static conditions, after 30 days of resting in the field, the average relative flow rate of drippers was close to 55%. In experiment 2, dripper models B and C were analyzed and showed relative flow rate averages > 70% up to 300 h when evaluated in all pre-filter positions tested. Dripper models B and C proved to be resistant to blockage by solid particles smaller than 125 µm in the irrigation water, regardless of dripper pre-filter orientation. With particles up to 212 µm in diameter, dripper model B with pre-filter facing down showed a 25% flow rate reduction. Over the 500 h of evaluation, emitter B with the pre-filter vertical and facing upwards, had the highest average relative flows of 98.2% and 94.6%, respectively, while emitter C gave the best performance with the pre-filter in a diagonal position (84.4% of average relative flow). The results obtained in this paper, showed a better resistance of high-flow MDI drip emitters (3–8 L·h−1) to solid particles in the irrigation water. These results are important because shows an effective clogging alternative by using high-flow emitters on MDI systems, what is the main disadvantage of low-flow emitters on traditional fixed drip irrigation systems in irrigated fields around the world.