Using a Line Source Irrigation System to Evaluate Water Requirements of Herbaceous PerennialsRoger Kjelgren and Teresa Cerny-Koenig |
Water shortages throughout the U.S. have increased interest in incorporating water conserving plant species in the landscape. However, there have been limited studies conducted to identify and evaluate drought tolerance of ornamental species, especially herbaceous perennial species. We evaluated the effectiveness of a line source irrigation system for comparing the irrigation requirements of twelve traditional and Intermountain West native, herbaceous perennial species. Water coverage perpendicular to the main irrigation line decreased with increasing distance from the main line. Species were randomly assigned to rows perpendicular to the main line, and parallel to the decreasing irrigation rate. Water application rate and uniformity were measured across the study area. Application rates for positions closest to the sprinkler were unaffected by wind speeds up to 4 m s -1. However, application rates with increasing distance from the main irrigation line were influenced by wind speeds as low as 1 m s -1. Nine of the species had similar shoot biomass under all irrigation treatments. That limited water application did not affect growth under the study conditions suggests that these nine species have potential for use in low water landscapes. Aquilegia chrysantha and Echinacea purpurea exhibited decreasing biomass with lower irrigation rates, suggesting that they are less suited for low water landscapes. A line source irrigation experimental design offers an effective means for assessing the response of a large number of perennial species to drought. However, irrigating when wind speeds are <1 m s -1 and ensuring uniform rooting volumes by the use of border species are strongly suggested to obtain reliable data. Supporting pdf: |
