Revegetation of Medusahead-Invaded Rangelands in the Channeled Scablands of Eastern Washington

Abstract

Vegetation on the Channeled Scablands of eastern Washington has been altered to a community dominated by medusahead (Taeniatherum caput-medusae [L.] Nevski). Medusahead is used by livestock but becomes unpalatable as the plant matures and seed heads develop, thus decreasing carrying capacity. The objective of this study was to determine if improved cool-season grasses could establish and persist on medusahead-infested rangelands in the region. A split-plot randomized complete block design consisting of four blocks was established at three different locations. Plots were treated with herbicides to remove all vegetation and seeded in 2010. Seeded species included introduced cool-season grass cultivars: Hycrest II crested wheatgrass (Agropyron cristatum [L.] Gaertn.), Vavilov II Siberian wheatgrass (Agropyron fragile [Roth] P. Candargy), Bozoisky II Russian wildrye (Psathyrostachys juncea [Fisch.] Nevski), and a native cool-season grass mix composed of Sherman big bluegrass (Poa secunda J. Presl), Secar Snake River wheatgrass (Elymus wawawaiensis J. Carlson & Barkworth), Bannock Thickspike wheatgrass (Elymus lanceolatus [Scribn. & J. G. Sm.] Gould), and Recovery Western wheatgrass (Pascopyrum smithii [Rydb.] Á Löve). Sherman big bluegrass was the only native species that established, and frequency was 65% at the end of the study. Hycrest II frequency was 48% at the end of the study. Vavilov II frequency was 50% at the end of the study. Sherman big bluegrass matured early in the season and had greater biomass production than Hycrest II and Vavilov II in May. The later-maturing Hycrest II and Vavilov II were similar in biomass production to Sherman big bluegrass in July. Bozoisky II had poor stand establishment and did not persist. Hycrest II, Vavilov II, and Sherman big bluegrass are forages that can be used for revegetation on the Channeled Scablands of eastern Washington. © Published by Elsevier Inc. on behalf of The Society for Range Management.