Submitted to: American Society of Animal Science
Publication Type: Proceedings
Publication Acceptance Date: 3/21/2005
Publication Date: 4/11/2005
Citation: Weston, T.R., Olson, R., Nayigihugu, V., Lake, S.L., Derner, J.D., Schuman, G.E., Hess, B.W. 2005. Characteristics and potential nutritive value of sagebrush-grassland vegetation collected from sites continuously grazed, rested for one year and one year post-disturbance. In: Proceedings of the Western Section, American Society of Animal Science. 56:9-12. Interpretive Summary:
Technical Abstract: Objectives were to assess initial impacts of rangeland management practices on characteristics and nutritive value of native sagebrush-grassland vegetation. Plots were randomly assigned to one of three treatments in a split-block experiment: continually grazed by beef cattle from June through October (Grazed), rested from grazing for one year (Rested), and interseeded with yellow-flowering alfalfa (Medicago sativa ssp. falcata) and rested from grazing for one year (Disturbed-rested). Dominant plant species at peak production included Wyoming big sagebrush (Artemisia tridentata; ARTR), western wheatgrass (Pascopyrum smithii; PASM), prairie junegrass (Koeleria pyramidata; KOPY), Sandberg’s bluegrass (Poa secunda; POSE), rubber rabbitbrush (Chrysothamnus nauseousus; CHNA), and hood’s flox (Phlox hoodii); PHHO). Bare ground tended to be greater (P = 0.07) for the Disturbed-rested treatment. Aerial cover was less (P = 0.03) for Disturbed–rested because mean and relative cover of ARTR decreased (P = 0.02) and mean cover of POSE tended to decrease (P = 0.09) with this treatment. However, relative cover (P < 0.001) and DM yield (P = 0.01) of KOPY were greatest for Disturbed-rested. Although DM yield of PASM also increased (P = 0.01) with the Disturbed-rested treatment, total DM yield did not differ (P = 0.42) among treatments. Nutritive value was not influenced (P = 0.22 to 0.99) by treatment; however, nutritional value of new growth varied (P < 0.01) among the plant species. Relative feed value was greater for CHNA than ARTR, which was greater than the grasses but relative feed value did not differ among grass species. Crude protein was generally greater for shrubs than grasses. Within grasses, CP content was greater for KOPY and POSE than PASM. Disturbing rangelands by interseeding with yellow-flowering alfalfa resulted in greater quantities of grazable forage without major alternations in rangeland productivity.