Rainfall simulators have been used more than 50 years to evaluate hydrologic parameters. The generated runoff hydrograph is a continuous integration of all factors that affect runoff flow. The complexity and interaction of site factors on runoff and infiltration processes makes it difficult to identify a single component of the hydrograph that accurately characterizes the entire runoff event. A technique was developed to separate the runoff hydrograph into segments representative of different portions of the flow event. Each segment grouping is analyzed for treatment and/or site factor differences or influences on the runoff. Comparing the treatment or site impacts on each hydrograph component allows a more detailed interpretation of the runoff and infiltration processes. This approach to runoff hydrograph analysis makes it possible to quantitatively assess differences in rainfall simulator runoff results and provide insight into why hydrographs may be similar or different.

Concentration and composition of monoterpenoids in plant tissue affects a variety of environmental and ecological issues such as plant defenses, plant classification and phytotoxicity. Developing the techniques for extracting and estimating the concentration and composition of monoterpenoids must be species-specific because monoterpenoid storage location varies between species. Ashe juniper (Juniperus ashei Buchholz) and redberry juniper (J. pinchotti Sudw) are 2 co-occurring species which differ in palatability and preference. The objective of this study was to determine which of 2 common extraction techniques provided the best estimate of the concentration and composition of monoterpenoids in mature plant tissue. Two extraction techniques were tested by soaking crushed juniper needles in hexane solvent for 6, 12, 18 and 24 hours or by steam distilling samples for 2, 4, 6, or 8 hours. The extracts were analyzed by using 2 different analytical columns in separate gas chromatographs. The hexane solvent soak, regardless of time in the solvent yielded a lower total concentration and a decreased compositional diversity of monoterpenoids compared to the steam distillation technique. An 8-hour steam distillation yielded the greatest concentration and composition of monoterpenoids. Both types of analytical columns resulted in similar estimates of monoterpenoid concentrations and composition.

The winter forage quality of bluebunch wheatgrass (Agropyron spicatum [Pursh] Scribn. &Smith) is generally inadequate for maintenance of wintering Rocky Mountain elk (Cervus elaphus nelsoni Bailey). Previous attempts to improve the winter forage quality of bluebunch wheatgrass by clipping and livestock grazing have achieved mixed results. We report crude protein (CP), (in vitro dry matter digestibility (IVDMD), and dry matter (DM) yield responses of bluebunch wheatgrass to 3 phenological stage/defoliation intensity treatment combinations. The study was conducted in 1993 and 1994 at 2 sites in the Blue Mountains of northeastern Oregon. Bluebunch wheatgrass was hand clipped 1 to a 7.6-cm stubble height in early June under 1 of 3 treatment combinations: 1) mid-boot/whole-plant clipped, 2) mid-boot/one-half of the plant's basal area clipped, and 3) inflorescence emergence/whole-plant clipped. Early November levels of CP and IVDMD were greater under all 3 treatments compared to an unclipped control. Mean forage quality improvement over the control was greatest in the inflorescence emergence treatment with an improvement of 1.3 percentage points for CP and 5.8 percentage points for IVDMD. Dry matter yield of the control exceeded that of all clipping treatments. Increases in forage quality resulting from forage conditioning treatments may be important to the viability of elk populations wintering on rangelands where forage quality, rather than quantity, is limiting.

Squirreltail [Elymus elymoides (Raf.) Swezey] is a native cool-season grass that has been observed to invade rangelands dominated by the weedy annual grasses, cheatgrass (Bromus tectorum L.) and medusahead wildrye [Taeniatherum caput-medusae (L.) (Nevski]. Our objective was to determine if growth characteristics could account for this squirreltail trait. We used growth analysis to examine differences in seedling growth and tissue allocation of 5 squirreltail entries, 2 long-lived perennial grasses ('Goldar' bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) A. Löve] and 'Hycrest' crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult. X A. cristatum (L.) Gaertn.]), cheatgrass, and medusahead wildrye. We monitored the 9 entries in a greenhouse for mean relative growth rate, net assimilation rate, leaf area ratio, specific leaf area, leaf weight ratio, root relative growth rate, specific root length, root-to-shoot dry-mass ratio, and root length-to-leaf area ratio beginning 10 days after sowing at 9 destructive harvests at 3-day intervals. Cheatgrass had high relative growth rate for both shoot and root. Only medusahead wildrye equalled the shoot relative growth rate of cheatgrass, and only Hycrest equalled its root relative growth rate. Cheatgrass seedlings were larger than squirreltail seedlings by 2 to 3 weeks after emergence. Few differences were detected among perennials and medusahead wildrye. Cheatgrass displayed the highest leaf area ratio and specific leaf area of the 9 entries but was similar to medusahead wildrye and Red Deer River squirreltail for specific root length. Growth characteristics cannot account for squirreltail's observed ability to invade annual grass stands. However, the combination of high specific leaf area and specific root length in squirreltail germplasm, as found in cheatgrass, may enhance squirreltail survival under competition with annual grasses, especially medusahead wildrye.

Since settlement, cattle grazing has been a major cause of soil disturbance in cold desert ecosystems. The objective of this study was to determine the impact of cattle grazing in different seasons on cryptogamic soil crusts. This study was conducted adjacent to the Brigham Young University Skaggs Research Ranch, near Malta, Ida. Five areas of a crested wheatgrass pasture each interplanted with shrubs were evaluated. Each of the 5 areas was subdivided into 4 paddocks; a control paddock remained ungrazed, while the other 3 paddocks were grazed in either spring, summer, or winter. Each of the 1.2-ha grazed paddocks was grazed annually in the same season for 2 consecutive years by 10 cows for 4 consecutive days. Percent of the soil surface covered by litter, vascular plant bases, and cryptogams was measured using a 10-pin, point sampling frame. Mosses were the main component of the cryptogamic soil crusts under all grazing treatments. Winter grazing had no effect on the moss component of the crusts while spring and summer grazing reduced mosses. While winter grazing had significantly less impact on the lichen component of crusts relative to spring and summer grazing, there was a 50% reduction relative to the control plots. Total cryptogamic cover in the control paddocks averaged 27.6%; winter grazed paddocks 27.4%; summer grazed paddocks 14.4%; and spring grazed paddocks 10.6%. Controlled winter grazing has minimal impact on the total cryptogamic plant cover that protect soil surfaces on cold desert range ecosystems.

Severe livestock losses caused by tall larkspur (Delphinium spp.) consumption have caused many producers to try various preventative measures, including the use of mineral-salt supplementation. The objective of tbis study was to determine if additions or deletions of a mineral-salt supplement (Binn's #1 Alleviator) would alter the response (i.e., rate of nose pressing) of cattle to tall larkspur exposure. The dose response of 5 Jersey steers was examined by systematically adding 0.25 mg of mineral-salt/kg body weight, and comparing responses in the same steers without salt supplements. Steers were then run under a variable ratio (VR) reinforcement schedule and periodically dosed with tall larkspur at a level causing a significant decrease in responding without provoking overt signs of intoxication. Response rate with and without mineral-salt supplement was the major dependent variable; 3 to 5 "on-off" cycles were conducted for each subject. Steers reduced (P < 0.05) their rate of grain intake by 34% during operant sessions when larkspur was dosed compared to the previous non-dosed 3-day baseline. Rate of nose pressing was reduced (P < 0.01) on tall larkspur dose days by 28% vs. the 3-day non-dosed baseline. This reduction was indicative of the effects of the effects of subclinical larkspur intoxication on steers. On days when larkspur was dosed and animals were intoxicated, the addition of mineral did not alter (P > 0.1) grain intake (1.64 +/- 0.17 kg/session) compared to days when no mineral was given (1.76 +/- 0.13 kg/session). On larkspur dose days (i.e. when animals were intoxicated), the average response rates were 82.9 +/- 3.7 and 85.8 +/- 4.0 responses/min (P > 0.1) when off and on mineral, respectively. We concluded that mineral/salt supplementation had no effect on the response of steers to doses of tall larkspur that produced subclinical intoxication.

Combustion products of burning vegetation can increase seed germination of many species of fire-prone plant communities. We tested the influence of heating sagebrush (Artemisia tridentata Nutt.) subcanopy soil, aqueous extracts of artificially burned soil, and sagebrush smoke on the emergence of several range plant species of the sagebrush-steppe. In addition, test seeds were exposed to sagebrush smoke and aqueous slurries of artificially burned sagebrush subcanopy soil to determine their effect on plant growth. As compared to the control, substrates previously heated from 250 to 750 degrees C significantly (P less than or equal to 0.05) increased the emergence of Thurber's needlegrass [Achnatherum thurberianum (Piper) Barkworth] and needle-and-thread [Hesperostipa comata (Trin. & Rupr.) Barkworth]. Sagebrush smoke and aqueous slurries of artificially burned soil significantly increased the emergence of Sierra Nevada needlegrass [Achnatherum occidentalis (Thurber) Barkworth], Indian ricegrass [Achnatherum hymenoides (Roemer & Schultes) Barkworth], and antelope bitterbrush [Purshia tridentata (Pursh) DC.]. Rates of new leaf production and leaf elongation following treatment of seeds with the smoke of burning sagebrush were significantly greater for cheatgrass (Bromus tectorum L.), basin wildrye [Leymus cinereus (Sribner & Merr.) A. Löve], Idaho fescue (Festuca idahoensis Elmer ), Sierra Nevada needlegrass, and needle-and-thread as compared to the control. After 83 days of growth, smoke-treated seeds of basin wildrye and needle-and-thread produced significantly greater plant mass than their controls. Smoke treatment of certain seeds before sowing is potentially useful for range plant seedings.

Permanent channel cross-sectional transects perpendicular to flow were used to estimate changes in spring and resultant creek channel morphology. Three cattle grazing treatments (none, light, and moderate) were applied to 2-5 ha pastures containing a perennial spring and resultant creek cohort for 5 years. Grazing effects on the total change in channel morphology were not detected, nor did our method detect channel morphology change over the 5 year study period. Ungrazed springs and creeks were observed to change more than grazed springs and creeks although these differences were not statistically significant. Observed, but not significant, change over time appears related to rainfall patterns. Permanent channel cross-sections, one of the currently recommended methods for monitoring livestock grazing impacts on stream channels, may not be adequate for detecting channel changes in low-flow spring/creek systems.

A modified faecal harness for goats was specially designed for grazing conditions in dense mediterranean shrublands and subsequently tested successfully for total faecal collection. The details of design and collection are presented.