Abstract

The ecological life history of budsage (Artemisia spinescens D.C. Eaton) was investigated during 1963 and 1964. The field studies were conducted at the Desert Experimental Range in Millard County, Utah. Laboratory studies were done at Brigham Young University. The different community types in which budsage grows were described and the physical site factors, viz. climate, soil texture, total soluble salts, hydrogen ion concentration of the soil, carbonate content and soil moisture were investigated. Phenology of seedlings, root systems, shoot and flower development, and plant longevity were investigated. Studies were also made on the effects of different seasons and intensities of grazing as they affect flowering, herbage yield, number of plants present and longevity. The various communities studied in which budsage grows were classed into three kinds, viz. budsage-winterfat types, shadscale types including winterfat, and shadscale types without winterfat. The budsage-winterfat types grow in soils which have markedly less gravel between 20 to 30 inches deep than the soils of the other communities studied. The moisture holding capacity of these soils is less than 10 percent in the first two feet. The soils which support shadscale types containing winterfat have less gravel in the upper horizons than the soils which support budsage-winterfat types. The moisture holding capacity of these soils is greater than 10 percent in the upper horizons and are more saline and shallower than the soils which support budsage-winterfat communities. The shadscale types without winterfat are located in the valley bottoms , grow in deep soils which have little gravel and have no salt accumulation in the first 2 feet. Establishment of bud sage seedlings require moist soil for at least one month before drought conditions occur. The seedlings have a taproot, but as the plant matures it becomes a highly branched, shallow root system, which is usually well distributed in the surface layers of the soil. This kind of a root system is probably its principal adaptative characteristic for drought conditions. Budsage ordinarily begins growth in early spring, but in 1963 and 1965 it broke dormancy in response to late summer storms in August. Both these years it was usuable sheep forage throughout the entire grazing season. Budsage completed growth by the first of June, lost its leaves and flower heads in late June and become dormant in early July in both 1963 and 1964. Survival of individual budsage plants was better under mid winter grazing than under late winter grazing. Late winter grazing regardless of intensity allowed very few budsage plants to become established. The season of grazing was more important than intensity of grazing in causing changes in the cover and number of plants. Late winter grazing decreased both the amount and number of budsage. However grazing in this season was most detrimental what it was at a heavy intensity.

Degree

College and Department

Life Sciences; Plant and Wildlife Sciences

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