Which statement best describes water quality effects on irrigation?

• A. Only inorganic solids cause plugging
• B. Only organic solids cause algae growth
• C. Dissolved solids do not affect emitters
• D. Inorganic solids, organic solids, and dissolved solids can cause plugging

Answer: (D)

Water quality affects irrigation performance mainly through solids and dissolved substances that can clog or foul emitters. Inorganic solids such as sand, silt, and mineral precipitates can physically block or abrade the tiny passages in emitters and filters. Organic solids, including algae and biofilm, grow in the system and narrow flow paths, leading to reduced discharge and eventual clogging. Dissolved solids like salts and minerals can precipitate or form scale on emitter outlet surfaces and inside pipes, changing flow characteristics and further increasing the risk of plugging. Because any of these three categories can contribute to clogging, a description that includes inorganic solids, organic solids, and dissolved solids best captures how water quality affects irrigation. In practice, addressing this involves filtration, periodic flushing, disinfection or treatment to manage biofilm, and anti-scaling measures to protect emitters and maintain uniform operation.