http://hdl.handle.net/10150/635543 2026-03-08T03:50:17Z http://hdl.handle.net/10150/650529 Journal of Range Management, Volume 44, Number 4 (July 1991) Complete digitized issue. 1991-07-01T00:00:00Z http://hdl.handle.net/10150/644813 Xeric big sagebrush, a new subspecies in the Artemisia tridentata complex Rosentreter, R.; Kelsey, R. G. In 1970 a xeric form of mountain big sagebrush (Artemisia tridentata ssp. vaseyana (Rydb.) Beetle) was reported in west central Idaho. Observations of morphology, habitat, and ecology, and analyses of foliage chemical components, clearly indicate these plants represent a new subspecies (xericensis) in the big sagebrush complex. It grows at lower elevations, 762-1,524 m (2,500-5,000 ft) and drier environments, 305-560 mm (12-22 in) precipitation, than most mountain big sagebrush, and is found on basaitic foothill soils often in association with bluebunch wheatgrass (Agropyron spicatum (Pursh) Scribn. & Smith). In addition to soil type, the radiate growth form and a more branched paniculate inflorescence are 2 morphological characteristics useful in separating ssp. xericensis from ssp. vaseyana. It contains higher concentrations of crude protein (10.4%), phosphorus (0.3%), and total volatiles, and lower concentrations of tannins and total phenols than mountain big sagebrush. Distinct chromatograms were obtained for both subspecies when extracts were analyzed by gas and high performance liquid chromatography. Leaf morphology and fluorescence of leaf water extracts are useful characters for separating ssp. xericensis from ssp. tridentata. The chemical data, in combination with morphology and ecology, suggest this new subspecies was initially derived by hybridization of ssp. tridentata and ssp. vaseyana. 1991-07-01T00:00:00Z http://hdl.handle.net/10150/644808 Vegetational response to short-duration and continuous grazing in southcentral New Mexico White, M. R.; Pieper, R. D.; Donart, G. B.; Trifaro, L. W. Vegetational response of a nine-paddock, short-duration grazing cell was compared to that of a continuous pasture for a 5-year period in southcentral New Mexico. Differences in vegetational response to short-duration and continuous grazing on blue grama rangeland were small. Basal plant cover was slightly hither for the short-duration pastures, but end-of-season standing crop of all species was similar for both systems. Blue grama aboveground productivity and basal cover were higher for the short-duration pastures than for the continuously-grazed pasture. Possible short-term results from short-duration grazing include slightly higher stocking rates and a positive response of blue grama. 1991-07-01T00:00:00Z http://hdl.handle.net/10150/644805 Variability in germination rate among seed lots of Lehmann lovegrass Hardegree, S. P.; Emmerich, W. E. The regeneration success of Lehmann lovegrass (Eragrostis lehmanniana Nees) in southern Arizona may be partially due to rapid germination during sporadic periods of available soil moisture. There is limited information regarding germination rate of Lehmann lovegrass but it is known that total germination response for this species is highly variable. Some of this variability may result from differences in the degree of mechanical scarification during harvest, threshing, and storage. Scarified and nonscarified seed from 7 seed lots were germinated over the water potential range of 0 to -1.16 MPa. Results showed that mechanical scarification increased total germination and germination rate. Mechanical scarification reduced variability among seed lots for germination rate, but increased variability for total germination. The rapid germination hypothesis may be valid for Lehmann lovegrass as long as seed numbers are not limiting. Of the scarified seed that germinated above a water potential of -0.4 MPa, at least 10% did so between days 1 and 2 of the study. 1991-07-01T00:00:00Z