• Factors Influencing Magnesium in High Plains Forage

      Fairbourn, M. L.; Batchelder, A. R. (Society for Range Management, 1980-11-01)
      Greenhouse and field experiments were conducted at the High Plains Grasslands Research Station to determine what might cause tetany-prone forage. The soil was analyzed for ammonium acetate-extractable cations, cation exchange capacity, and alkaline earth carbonates; and the successive harvests of forage plants were analyzed for magnesium (Mg), calcium (Ca), potassium (K), and nitrogen (N). Forages used in the study included legumes: 'Lutana' Cicer milkvetch (Astragalus cicer L.), 'Remont' sainfoin (Onobrychis viciafolia Scop.), 'Dawson', 'Vernal', 'Team', and 'Fremont' alfalfas (Medicago sativa L.); and grasses: 'Latar' orchardgrass (Dactylis glomerata L.), 'Fawn' tall fescue (Festuca arundinacea Schreb), 'Regar' bromegrass Bromus biebersteinii Roem & Schult.), 'Manchar' smooth bromegrass (Bromus inermis Leyss), 'Garrison' creeping foxtail (Alopercurus pratensis L.), 'Luna' pubescent wheatgrass [Agropyron trichophorum (Link) Richt.], and 'Greenar' intermediate wheatgrass [Agropyron intermedium (Host) Beauv.]. Forage Mg level increased when average soil temperature increased from 16.6 to 22.7 degrees C. Fertilization with 1,134 kg of Mg as MgSO4/ha did not increase forage Mg level. Later orchardgrass and Fawn tall fescue consistently produced forage containing more than 0.20% Mg, whereas wheatgrass species produced forage with Mg levels as low as 0.11%. All legumes had Ca levels ranging from 1.0 to 2.5%. One field crop of Later orchardgrass produced forage with a high K accumulation (K/Ca + Mg ratio of 2.7). Predication of blood-serum Mg from forage nutrient content indicated values from 17 to 31 mg/l in lactating cows.
    • Historical Perspectives on Range Burning in the Inland Pacific Northwest

      Shinn, D. A. (Society for Range Management, 1980-11-01)
      Ecological and historical data are combined in assessing the influence of cultural broadcast burning in the inland Pacific Northwest from the distant past into recent history. Twenty-four references to broadcast burning by native peoples were found in the journals of early explorers and settlers. Broadcast burning was apparently an ancient native tradition, derived from the earliest hunting cultures to enter the region. With the influx of European culture, misapprehensions about fire among whites disrupted the original influence of native cultural burning. Early irresponsible burning became associated with the deterioration of natural resources, and efforts to prevent or suppress all fires were incorporated in developing conservation policies. The reduction of burning, combined with markedly intensified grazing by European livestock, distorted the basic character of existing ecosystems and altered native plant communities. Early photographs of rangelands in east-central Oregon were gathered; their dates range from 1880 to the early 1930's. Photo-sites were re-photographed in 1976. Photoset comparisons show expansions of western juniper (Juniperus occidentalis) populations into adjacent rangeland ecosystems.