• Green Needlegrass Seedling Morphology in Relation to Planting Depth

      Fulbright, T. E.; Wilson, A. M.; Redente, E. F. (Society for Range Management, 1985-05-01)
      Green needlegrass (Stipa viridula Trin.) is commonly used in range seedings and revegetation of disturbed lands in the northern Great Plains. This study was conducted to determine the influence of planting depth, seed source, and temperature on morphology and emergence of green needlegrass seedlings. Seeds from 2 sources were planted at depths of 1.5, 3.0, 4.5, 6.0, and 7.5 cm in pots filled with sandy loam soil. Pots were placed in growth chambers adjusted for either a 20/15 degrees C (15 h light/9 h dark) temperature regime or a 25/20 degrees C regime. Coleoptile length increased with planting depth, while seminal primary root length, adventitious root length, and number of adventitious roots decreased with planting depth. 'SD-93' seedlings had shorter subcoleoptile internodes, longer coleoptiles, and better root development than 'Lodorm' seedlings. Seedlings grown under the warmer temperature regime had better root development than seedlings grown under the cooler regime, but reach of the coleoptile above planting depth was not as great. Results indicated that green needlegrass generally should not be planted at depths greater than 3.0 cm because of lower percent emergence, rate of emergence, and poor root development when seedlings emerged from greater depths.
    • Using Aerial Photography for Detecting Blackbrush (Acacia Rigidula) on South Texas Rangelands

      Everitt, J. H. (Society for Range Management, 1985-05-01)
      Blackbrush (Acacia rigidula) is a native shrub found on a variety of soil types in south Texas and northern Mexico. It often becomes a serious management problem on rangelands, especially where associated species have been removed. During late February to late March it produces small cream to light yellow flowers that encompass the entire plant giving it a conspicuous appearance. Field spectroradiometric plant canopy measurements showed that blackbrush in flower had significantly higher (p=0.05) visible light (0.45- to 75-um waveband [WB) reflectance that did 6 other associated plant species or mixtures of species. The conspicuous light yellow color of blackbrush in flower made it distinguishable from other plant species on both conventional color (0.40- to 0.70-um WB) and color-infrared (CIR) (0.50- to 0.90-um WB) aerial photos. However, conventional color photography was superior to CIR photography because blackbrush had a more distinct image on color photography and it could also be identified on smaller scale photos. Microdensitometric measurements made on conventional color film showed that blackbrush had significantly lower optical counts than those of associated species. These results show that aerial photography may be a useful tool to distinguish blackbrush from other plant species in late winter or early spring to locate its endemic areas, monitor its spread, and delineate areas needing control.
    • Above-Ground Biomass and Nitrogen Quantities in a Big Sacaton (Sporobolus wrightii) Grassland

      Cox, J. R. (Society for Range Management, 1985-05-01)
      Live and standing dead biomass, standing crop, and total nitrogen, within each component, were measured in a big sacaton (Sporobolus wrightii Monro) grassland in southeastern Arizona for 3 years to determine annual fluctuations in above-ground biomass and nitrogen. Mean live biomass varied from 150 kg/ha in February to 2,000 kg/ha in August. Standing dead biomass accumulated after the summer growing season and rapidly disappeared following either fall, winter, or summer moisture, but was the predominant vegetative component for about 49 weeks of each year. Standing crop (live plus standing dead) was greatest in August and averaged 4,450 kg/ha. Total nitrogen varied from 2 to 31 kg/ha in live biomass, from 5 to 15 kg/ha in standing dead biomass, and from 9 to 40 kg/ha in standing crop. The rapid disappearance of standing dead suggests that stocking rates should be based on standing crop just prior to the grazing period rather than peak standing crop after the summer growing season.
    • Cattle Use of Riparian Meadows in the Blue Mountains of Northeastern Oregon

      Gillen, R. L.; Krueger, W. C.; Miller, R. F. (Society for Range Management, 1985-05-01)
      The intensity and pattern of cattle use of small riparian meadows were studied by periodically sampling vegetative standing crop and by continuously monitoring meadows with time-lapse photography. Temperature and relative humidity were also measured in riparian and upland plant communities. Herbage standing crop at the end of the grazing season was similar under continuous grazing and the early and late grazing periods of a two pasture deferred-rotation grazing system. Early grazing tended to decrease the total cattle occupation and the frequency of cattle occupation of riparian meadows when compared to continuous grazing. Late grazing tended to increase the frequency of cattle occupation but did not change the total cattle occupation of riparian meadows when compared to continuous grazing. Cattle were present on a given meadow site on about 60% of all days but for only 3-10% of the total daylight period. Cattle occupation of riparian meadows was greater during the afternoon hours. The seasonal pattern of cattle occupation was influenced by the location where cattle entered a pasture but not by seasonal temperatures. Temperature and the temperature-humidity index did not differ between riparian and upland plant communities between 12:00 noon and 6:00 p.m.
    • Application of Herbicides on Rangelands with a Carpeted Roller: Evaluation of Four Herbicides for Control of Honey Mesquite

      Mayeux, H. S.; Crane, R. A. (Society for Range Management, 1985-05-01)
      A carpeted roller, designed to wipe herbicide solutions onto brush stems and foliage, was evaluated for control of honey mesquite [Prosopis juliflora (Swartz) DC. var. glandulosa (Torr.) Cockerell] at 4 locations. Picloram (4-amino-3,5,6-trichloropicolinic acid) and clopyralid (3,6-dichloropicolinic acid) top-killed honey mesquite at all locations, whether applied in spring or fall. Mortality (root-kill) of plants treated with picloram varied from 38% of plants treated under drought conditions in south Texas to 97% of plants experiencing optimum growing conditions in central Texas. Clopyralid was equal to or slightly more effective than picloram, based on mortality near the end of the second growing season after treatment, whereas glyphosate [N-(phosphonomethyl)glycine] and triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid} were usually less effective. Solutions containing 120 g/L of herbicide active ingredient were more effective than solutions containing 30 g/L, but differences were sometimes slight. Small, widely spaced honey mesquites were more easily controlled with the carpeted roller than larger plants growing in dense stands.
    • Black Sagebrush: Mule Deer Winter Preference and Monoterpenoid Content

      Behan, B.; Welch, B. L. (Society for Range Management, 1985-05-01)
      Wintering mule deer (Odocoileus hemionus hemionus) preference was determined for 7 accessions of black sagebrush (Artemisia nova) grown on a common garden. Preference as expressed as percentage of current annual growth eaten varied from 0.0 to 82.7%. An accession called Pine Valley Ridge was significantly preferred by the deer over the other 6 accessions. We also attempted to relate monoterpenoid content to preference. We found no significant relationship between the two.