Date of Award:

5-2015

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Wildland Resources

Committee Chair(s)

Juan Villalba

Committee

Juan Villalba

Committee

Fee Busby

Committee

Eugene W. Schupp

Committee

Kevin B. Jensen

Committee

Kip E. Panter

Abstract

A large portion of the historical steppe and shrub-steppe habitats in eastern Washington have been altered through biotic and abiotic processes resulting in the annual grass medusahead becoming a large component of the altered vegetation. Experiments were conducted to determine: 1) if supplementing cattle with protein would help increase utilization of medusahead, 2) the grass species that could establish in the region, and 3) if mechanical disturbance would aid in such revegetation efforts. Cattle grazing medusahead-infested rangeland increased consumption of medusahead after all forage matured due to a reduction in the quality of forage alternatives. Cattle supplemented with protein increased consumption of medusahead later in the 10-day grazing periods resulting in a reduction of medusahead abundance. Introduced grass species; Vavilov II, Hycrest II crested wheatgrass, and Bozoisky II Russian wildrye, and a native grass mix; Sherman big bluegrass, Secar Snake River wheatgrass, Bannock Thickspike wheatgrass, and Recovery Western wheatgrass were planted at three locations. Sherman big bluegrass was the only native species that established. Hycrest II and Vavilov II also established and Bozoisky II failed to establish. Biomass production of Hycrest II, Vavilov II, and Sherman big bluegrass was similar during the summer harvest. Mechanical disturbance from disking in the fall was successful in establishing Vavilov II and Immigrant forage kochia. In conclusion, cattle can be used to reduce medusahead abundance and Vavilov II, Hycrest II and Sherman big bluegrass are recommended species for revegetation efforts in the scablands of eastern Washington. Mechanical disturbance can be used to help establish Vavilov II and Immigrant forage kochia.

Checksum

61975f5a5f0bfd110584bbc1406fac99

Included in

Agriculture Commons

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