Trickle Irrigation: Prevention of Clogging

Abstract

ABSTRACT TRICKLE irrigation experiments using Colorado River irrigation water on citrus trees in south-western Arizona were conducted to evaluate clogging of emitters and to investigate methods for controlling clogging. Clogging is related to the water quality in terms of the suspended sediment load, chemical compo-sition, and biological activity. Various combinations of six water treatments, including screen and sand filtra-tion coupled with additions of hypochlorite and acid, were used with eight different trickle emitters to eval-uate long term prevention of clogging. Five of the eight emitter systems under study (No. 1, 5, 6, 7 and 8) required sand and screen filtration (200-mesh) plus chemical treatments to prevent physical clogging of the emitters by suspended materials and to maintain flow rates greater than 70 percent of the design flow. Three emitter systems (No. 2, 3 and 4) continued to operate at greater than 80 percent of the design flow rate with only screen filtration (50-mesh). Our results after 2 yr have indicated that clogging of emitters could be prevented by proper treatment of Colorado River water, which includes in the following order of preference: 1 filtration system for prevention of the rapid physical clogging of emitters caused by suspended materials, 2 chemical treatments for long-term prevention of chemical clogging of emitters caused by precipitation of carbonates, and 3 chemical treatments for long-term prevention of biological clogging of emitters caused by microbial growth and slime development.