Abstract

Increasing demand for limited water supplies in populated arid regions over the next decade may require implementation of new water-use practices. Eliminating use of high-quality water for landscape irrigation by using low-quality water delivered through secondary systems is an ideal option for conserving potable water. However, irrigation of woody landscape plants using waters high in inorganic salts may adversely affect soil fertility, structure, plant growth and appearance. Twelve woody ornamentals commonly used in landscapes in Salt Lake County, Utah, were treated with three blends of Utah Lake and Provo River water to assess the quality of plants produced.

Three irrigation treatments, designated high-, medium-, and low-quality water were blended to maintain sodium concentrations of 15, 80 and 120 mg/liter respectively. Soils irrigated with medium-and low-quality water developed significantly higher adjusted sodium absorption ratio (SAR) and salinity than soils irrigated with high quality water and the effect varied with time. Except for four species, medium-and low-quality water did not significantly lower scores for plant appearance. Results of this two-year study support development of secondary water systems and use of lower-quality water for landscape irrigation.